const std = @import("std");
const expect = std.testing.expect;
const Environment = @import("./env.zig");
const string = @import("string_types.zig").string;
const stringZ = @import("string_types.zig").stringZ;
const CodePoint = @import("string_types.zig").CodePoint;
const assert = std.debug.assert;
pub inline fn containsChar(self: string, char: u8) bool {
    return indexOfChar(self, char) != null;
}

pub inline fn contains(self: string, str: string) bool {
    return std.mem.indexOf(u8, self, str) != null;
}
pub const includes = contains;

pub inline fn containsAny(in: anytype, target: string) bool {
    for (in) |str| if (contains(str, target)) return true;
    return false;
}

pub inline fn indexAny(in: anytype, target: string) ?usize {
    for (in) |str, i| if (indexOf(str, target) != null) return i;
    return null;
}

pub inline fn indexAnyComptime(target: string, comptime chars: string) ?usize {
    for (target) |parent, i| {
        inline for (chars) |char| {
            if (char == parent) return i;
        }
    }
    return null;
}

pub inline fn indexOfChar(self: string, char: u8) ?usize {
    return std.mem.indexOfScalar(@TypeOf(char), self, char);
}

pub fn indexOfCharNeg(self: string, char: u8) i32 {
    var i: u32 = 0;
    while (i < self.len) : (i += 1) {
        if (self[i] == char) return @intCast(i32, i);
    }
    return -1;
}

pub fn indexOfSigned(self: string, str: string) i32 {
    const i = std.mem.indexOf(u8, self, str) orelse return -1;
    return @intCast(i32, i);
}

pub inline fn lastIndexOfChar(self: string, char: u8) ?usize {
    return std.mem.lastIndexOfScalar(u8, self, char);
}

pub inline fn lastIndexOf(self: string, str: string) ?usize {
    return std.mem.lastIndexOf(u8, self, str);
}

pub inline fn indexOf(self: string, str: string) ?usize {
    return std.mem.indexOf(u8, self, str);
}

pub fn cat(allocator: std.mem.Allocator, first: string, second: string) !string {
    var out = try allocator.alloc(u8, first.len + second.len);
    std.mem.copy(u8, out, first);
    std.mem.copy(u8, out[first.len..], second);
    return out;
}

// 30 character string or a slice
pub const StringOrTinyString = struct {
    pub const Max = 30;
    const Buffer = [Max]u8;

    remainder_buf: Buffer = undefined,
    remainder_len: u7 = 0,
    is_tiny_string: u1 = 0,
    pub inline fn slice(this: *const StringOrTinyString) []const u8 {
        // This is a switch expression instead of a statement to make sure it uses the faster assembly
        return switch (this.is_tiny_string) {
            1 => this.remainder_buf[0..this.remainder_len],
            0 => @intToPtr([*]const u8, std.mem.readIntNative(usize, this.remainder_buf[0..@sizeOf(usize)]))[0..std.mem.readIntNative(usize, this.remainder_buf[@sizeOf(usize) .. @sizeOf(usize) * 2])],
        };
    }

    pub fn deinit(this: *StringOrTinyString, _: std.mem.Allocator) void {
        if (this.is_tiny_string == 1) return;

        // var slice_ = this.slice();
        // allocator.free(slice_);
    }

    pub fn initAppendIfNeeded(stringy: string, comptime Appender: type, appendy: Appender) !StringOrTinyString {
        if (stringy.len <= StringOrTinyString.Max) {
            return StringOrTinyString.init(stringy);
        }

        return StringOrTinyString.init(try appendy.append(string, stringy));
    }

    pub fn init(stringy: string) StringOrTinyString {
        switch (stringy.len) {
            0 => {
                return StringOrTinyString{ .is_tiny_string = 1, .remainder_len = 0 };
            },
            1...(@sizeOf(Buffer)) => {
                @setRuntimeSafety(false);
                var tiny = StringOrTinyString{
                    .is_tiny_string = 1,
                    .remainder_len = @truncate(u7, stringy.len),
                };
                @memcpy(&tiny.remainder_buf, stringy.ptr, tiny.remainder_len);
                return tiny;
            },
            else => {
                var tiny = StringOrTinyString{
                    .is_tiny_string = 0,
                    .remainder_len = 0,
                };
                std.mem.writeIntNative(usize, tiny.remainder_buf[0..@sizeOf(usize)], @ptrToInt(stringy.ptr));
                std.mem.writeIntNative(usize, tiny.remainder_buf[@sizeOf(usize) .. @sizeOf(usize) * 2], stringy.len);
                return tiny;
            },
        }
    }

    pub fn initLowerCase(stringy: string) StringOrTinyString {
        switch (stringy.len) {
            0 => {
                return StringOrTinyString{ .is_tiny_string = 1, .remainder_len = 0 };
            },
            1...(@sizeOf(Buffer)) => {
                @setRuntimeSafety(false);
                var tiny = StringOrTinyString{
                    .is_tiny_string = 1,
                    .remainder_len = @truncate(u7, stringy.len),
                };
                _ = copyLowercase(stringy, &tiny.remainder_buf);
                return tiny;
            },
            else => {
                var tiny = StringOrTinyString{
                    .is_tiny_string = 0,
                    .remainder_len = 0,
                };
                std.mem.writeIntNative(usize, tiny.remainder_buf[0..@sizeOf(usize)], @ptrToInt(stringy.ptr));
                std.mem.writeIntNative(usize, tiny.remainder_buf[@sizeOf(usize) .. @sizeOf(usize) * 2], stringy.len);
                return tiny;
            },
        }
    }
};

pub fn copyLowercase(in: string, out: []u8) string {
    @setRuntimeSafety(false);
    var in_slice: string = in;
    var out_slice: []u8 = out[0..in.len];

    begin: while (out_slice.len > 0) {
        @setRuntimeSafety(false);
        for (in_slice) |c, i| {
            @setRuntimeSafety(false);
            switch (c) {
                'A'...'Z' => {
                    @setRuntimeSafety(false);
                    @memcpy(out_slice.ptr, in_slice.ptr, i);
                    out_slice[i] = std.ascii.toLower(c);
                    const end = i + 1;
                    if (end >= out_slice.len) break :begin;
                    in_slice = in_slice[end..];
                    out_slice = out_slice[end..];
                    continue :begin;
                },
                else => {},
            }
        }

        @memcpy(out_slice.ptr, in_slice.ptr, in_slice.len);
        break :begin;
    }

    return out[0..in.len];
}

test "eqlComptimeCheckLen" {
    try std.testing.expectEqual(eqlComptime("bun-darwin-aarch64.zip", "bun-darwin-aarch64.zip"), true);
    const sizes = [_]u8{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 23, 22, 24 };
    inline for (sizes) |size| {
        var buf: [size]u8 = undefined;
        std.mem.set(u8, &buf, 'a');
        var buf_copy: [size]u8 = undefined;
        std.mem.set(u8, &buf_copy, 'a');

        var bad: [size]u8 = undefined;
        std.mem.set(u8, &bad, 'b');
        try std.testing.expectEqual(std.mem.eql(u8, &buf, &buf_copy), eqlComptime(&buf, comptime brk: {
            var buf_copy_: [size]u8 = undefined;
            std.mem.set(u8, &buf_copy_, 'a');
            break :brk buf_copy_;
        }));

        try std.testing.expectEqual(std.mem.eql(u8, &buf, &bad), eqlComptime(&bad, comptime brk: {
            var buf_copy_: [size]u8 = undefined;
            std.mem.set(u8, &buf_copy_, 'a');
            break :brk buf_copy_;
        }));
    }
}

test "eqlComptimeUTF16" {
    try std.testing.expectEqual(eqlComptimeUTF16(std.unicode.utf8ToUtf16LeStringLiteral("bun-darwin-aarch64.zip"), "bun-darwin-aarch64.zip"), true);
    const sizes = [_]u16{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 23, 22, 24 };
    inline for (sizes) |size| {
        var buf: [size]u16 = undefined;
        std.mem.set(u16, &buf, @as(u8, 'a'));
        var buf_copy: [size]u16 = undefined;
        std.mem.set(u16, &buf_copy, @as(u8, 'a'));

        var bad: [size]u16 = undefined;
        std.mem.set(u16, &bad, @as(u16, 'b'));
        try std.testing.expectEqual(std.mem.eql(u16, &buf, &buf_copy), eqlComptimeUTF16(&buf, comptime &brk: {
            var buf_copy_: [size]u8 = undefined;
            std.mem.set(u8, &buf_copy_, @as(u8, 'a'));
            break :brk buf_copy_;
        }));

        try std.testing.expectEqual(std.mem.eql(u16, &buf, &bad), eqlComptimeUTF16(&bad, comptime &brk: {
            var buf_copy_: [size]u8 = undefined;
            std.mem.set(u8, &buf_copy_, @as(u8, 'a'));
            break :brk buf_copy_;
        }));
    }
}

test "copyLowercase" {
    {
        var in = "Hello, World!";
        var out = std.mem.zeroes([in.len]u8);
        var out_ = copyLowercase(in, &out);
        try std.testing.expectEqualStrings(out_, "hello, world!");
    }

    {
        var in = "_ListCache";
        var out = std.mem.zeroes([in.len]u8);
        var out_ = copyLowercase(in, &out);
        try std.testing.expectEqualStrings(out_, "_listcache");
    }
}

test "StringOrTinyString" {
    const correct: string = "helloooooooo";
    const big = "wawaweewaverylargeihaveachairwawaweewaverylargeihaveachairwawaweewaverylargeihaveachairwawaweewaverylargeihaveachair";
    var str = StringOrTinyString.init(correct);
    try std.testing.expectEqualStrings(correct, str.slice());

    str = StringOrTinyString.init(big);
    try std.testing.expectEqualStrings(big, str.slice());
    try std.testing.expect(@sizeOf(StringOrTinyString) == 32);
}

test "StringOrTinyString Lowercase" {
    const correct: string = "HELLO!!!!!";
    var str = StringOrTinyString.initLowerCase(correct);
    try std.testing.expectEqualStrings("hello!!!!!", str.slice());
}

/// startsWith except it checks for non-empty strings
pub fn hasPrefix(self: string, str: string) bool {
    return str.len > 0 and startsWith(self, str);
}

pub fn startsWith(self: string, str: string) bool {
    if (str.len > self.len) {
        return false;
    }

    var i: usize = 0;
    while (i < str.len) {
        if (str[i] != self[i]) {
            return false;
        }
        i += 1;
    }

    return true;
}

pub inline fn endsWith(self: string, str: string) bool {
    return str.len == 0 or @call(.{ .modifier = .always_inline }, std.mem.endsWith, .{ u8, self, str });
}

pub inline fn endsWithComptime(self: string, comptime str: anytype) bool {
    return self.len >= str.len and eqlComptimeIgnoreLen(self[self.len - str.len .. self.len], comptime str);
}

pub inline fn startsWithChar(self: string, char: u8) bool {
    return self.len > 0 and self[0] == char;
}

pub inline fn endsWithChar(self: string, char: u8) bool {
    return self.len == 0 or self[self.len - 1] == char;
}

pub fn withoutTrailingSlash(this: string) []const u8 {
    var href = this;
    while (href.len > 1 and href[href.len - 1] == '/') {
        href = href[0 .. href.len - 1];
    }

    return href;
}

pub fn withoutLeadingSlash(this: string) []const u8 {
    return std.mem.trimLeft(u8, this, "/");
}

pub fn endsWithAny(self: string, str: string) bool {
    const end = self[self.len - 1];
    for (str) |char| {
        if (char == end) {
            return true;
        }
    }

    return false;
}

pub fn quotedAlloc(allocator: std.mem.Allocator, self: string) !string {
    var count: usize = 0;
    for (self) |char| {
        count += @boolToInt(char == '"');
    }

    if (count == 0) {
        return allocator.dupe(u8, self);
    }

    var i: usize = 0;
    var out = try allocator.alloc(u8, self.len + count);
    for (self) |char| {
        if (char == '"') {
            out[i] = '\\';
            i += 1;
        }
        out[i] = char;
        i += 1;
    }

    return out;
}

pub fn eqlAnyComptime(self: string, comptime list: []const string) bool {
    inline for (list) |item| {
        if (eqlComptimeCheckLenWithType(u8, self, item, true)) return true;
    }

    return false;
}

pub fn endsWithAnyComptime(self: string, comptime str: string) bool {
    if (comptime str.len < 10) {
        const last = self[self.len - 1];
        inline for (str) |char| {
            if (char == last) {
                return true;
            }
        }

        return false;
    } else {
        return endsWithAny(self, str);
    }
}

pub fn eql(self: string, other: anytype) bool {
    if (self.len != other.len) return false;
    if (comptime @TypeOf(other) == *string) {
        return eql(self, other.*);
    }

    for (self) |c, i| {
        if (other[i] != c) return false;
    }
    return true;
}

pub inline fn eqlInsensitive(self: string, other: anytype) bool {
    return std.ascii.eqlIgnoreCase(self, other);
}

pub fn eqlComptime(self: string, comptime alt: anytype) bool {
    return eqlComptimeCheckLenWithType(u8, self, alt, true);
}

pub fn eqlComptimeUTF16(self: []const u16, comptime alt: []const u8) bool {
    return eqlComptimeCheckLenWithType(u16, self, comptime std.unicode.utf8ToUtf16LeStringLiteral(alt), true);
}

pub fn eqlComptimeIgnoreLen(self: string, comptime alt: anytype) bool {
    return eqlComptimeCheckLenWithType(u8, self, alt, false);
}

inline fn eqlComptimeCheckLenWithType(comptime Type: type, a: []const Type, comptime b: anytype, comptime check_len: bool) bool {
    @setEvalBranchQuota(9999);
    if (comptime check_len) {
        if (comptime b.len == 0) {
            return a.len == 0;
        }

        switch (a.len) {
            b.len => {},
            else => return false,
        }
    }

    const len = comptime b.len;
    comptime var dword_length = b.len >> 3;
    const slice = comptime if (@typeInfo(@TypeOf(b)) != .Pointer) b else std.mem.span(b);
    const divisor = comptime @sizeOf(Type);

    comptime var b_ptr: usize = 0;

    inline while (dword_length > 0) : (dword_length -= 1) {
        if (@bitCast(usize, a[b_ptr..][0 .. @sizeOf(usize) / divisor].*) != comptime @bitCast(usize, (slice[b_ptr..])[0 .. @sizeOf(usize) / divisor].*))
            return false;
        comptime b_ptr += @sizeOf(usize);
        if (comptime b_ptr == b.len) return true;
    }

    if (comptime @sizeOf(usize) == 8) {
        if (comptime (len & 4) != 0) {
            if (@bitCast(u32, a[b_ptr..][0 .. @sizeOf(u32) / divisor].*) != comptime @bitCast(u32, (slice[b_ptr..])[0 .. @sizeOf(u32) / divisor].*))
                return false;

            comptime b_ptr += @sizeOf(u32);

            if (comptime b_ptr == b.len) return true;
        }
    }

    if (comptime (len & 2) != 0) {
        if (@bitCast(u16, a[b_ptr..][0 .. @sizeOf(u16) / divisor].*) != comptime @bitCast(u16, slice[b_ptr .. b_ptr + (@sizeOf(u16) / divisor)].*))
            return false;

        comptime b_ptr += @sizeOf(u16);

        if (comptime b_ptr == b.len) return true;
    }

    if ((comptime (len & 1) != 0) and a[b_ptr] != comptime b[b_ptr]) return false;

    return true;
}

pub fn eqlCaseInsensitiveASCII(a: string, comptime b: anytype, comptime check_len: bool) bool {
    if (comptime check_len) {
        if (comptime b.len == 0) {
            return a.len == 0;
        }

        switch (a.len) {
            b.len => void{},
            else => return false,
        }
    }

    // pray to the auto vectorization gods
    inline for (b) |c, i| {
        const char = comptime std.ascii.toLower(c);
        if (char != std.ascii.toLower(a[i])) return false;
    }

    return true;
}

pub fn eqlLong(a_: string, b: string, comptime check_len: bool) bool {
    if (comptime check_len) {
        if (a_.len == 0) {
            return b.len == 0;
        }

        if (a_.len != b.len) {
            return false;
        }
    }

    const len = b.len;
    var dword_length = b.len >> 3;
    var b_ptr: usize = 0;
    const a = a_.ptr;

    while (dword_length > 0) : (dword_length -= 1) {
        const slice = b.ptr;
        if (@bitCast(usize, a[b_ptr..len][0..@sizeOf(usize)].*) != @bitCast(usize, (slice[b_ptr..b.len])[0..@sizeOf(usize)].*))
            return false;
        b_ptr += @sizeOf(usize);
        if (b_ptr == b.len) return true;
    }

    if (comptime @sizeOf(usize) == 8) {
        if ((len & 4) != 0) {
            const slice = b.ptr;
            if (@bitCast(u32, a[b_ptr..len][0..@sizeOf(u32)].*) != @bitCast(u32, (slice[b_ptr..b.len])[0..@sizeOf(u32)].*))
                return false;

            b_ptr += @sizeOf(u32);

            if (b_ptr == b.len) return true;
        }
    }

    if ((len & 2) != 0) {
        if (@bitCast(u16, a[b_ptr..len][0..@sizeOf(u16)].*) != @bitCast(u16, b.ptr[b_ptr..len][0..@sizeOf(u16)].*))
            return false;

        b_ptr += @sizeOf(u16);

        if (b_ptr == b.len) return true;
    }

    if (((len & 1) != 0) and a[b_ptr] != b[b_ptr]) return false;

    return true;
}

pub inline fn append(allocator: std.mem.Allocator, self: string, other: string) !string {
    return std.fmt.allocPrint(allocator, "{s}{s}", .{ self, other });
}

pub inline fn joinBuf(out: []u8, parts: anytype, comptime parts_len: usize) []u8 {
    var remain = out;
    var count: usize = 0;
    comptime var i: usize = 0;
    inline while (i < parts_len) : (i += 1) {
        const part = parts[i];
        std.mem.copy(u8, remain, part);
        remain = remain[part.len..];
        count += part.len;
    }

    return out[0..count];
}

pub fn index(self: string, str: string) i32 {
    if (std.mem.indexOf(u8, self, str)) |i| {
        return @intCast(i32, i);
    } else {
        return -1;
    }
}

pub fn eqlUtf16(comptime self: string, other: []const u16) bool {
    return std.mem.eql(u16, std.unicode.utf8ToUtf16LeStringLiteral(self), other);
}

pub fn toUTF8Alloc(allocator: std.mem.Allocator, js: []const u16) !string {
    return try toUTF8AllocWithType(allocator, []const u16, js);
}

pub inline fn appendUTF8MachineWordToUTF16MachineWord(output: *[4]u16, input: *const [4]u8) void {
    output[0] = input[0];
    output[1] = input[1];
    output[2] = input[2];
    output[3] = input[3];
}

pub inline fn copyU8IntoU16(output_: []u16, input_: []const u8) void {
    var output = output_;
    var input = input_;
    if (comptime Environment.allow_assert) {
        std.debug.assert(input.len <= output.len);
    }
    while (input.len >= 4) {
        appendUTF8MachineWordToUTF16MachineWord(output[0..4], input[0..4]);
        output = output[4..];
        input = input[4..];
    }

    for (input) |c, i| {
        output[i] = c;
    }
}

pub inline fn copyU16IntoU8(output_: []u8, comptime InputType: type, input_: InputType) void {
    var output = output_;
    var input = input_;
    if (comptime Environment.allow_assert) {
        std.debug.assert(input.len <= output.len);
    }

    while (input.len >= 4) {
        output[0] = @intCast(u8, input[0]);
        output[1] = @intCast(u8, input[1]);
        output[2] = @intCast(u8, input[2]);
        output[3] = @intCast(u8, input[3]);

        output = output[4..];
        input = input[4..];
    }

    for (input) |c, i| {
        output[i] = @intCast(u8, c);
    }
}

const strings = @This();

pub fn toUTF16Alloc(allocator: std.mem.Allocator, bytes: []const u8, comptime fail_if_invalid: bool) !?[]u16 {
    if (strings.firstNonASCII(bytes)) |i| {
        const ascii = bytes[0..i];
        const chunk = bytes[i..];
        var output = try std.ArrayList(u16).initCapacity(allocator, ascii.len + 2);
        errdefer output.deinit();
        output.items.len = ascii.len;
        strings.copyU8IntoU16(output.items, ascii);

        var remaining = chunk;

        {
            var sequence: [4]u8 = undefined;

            if (remaining.len >= 4) {
                sequence = remaining[0..4].*;
            } else {
                sequence[0] = remaining[0];
                sequence[1] = if (remaining.len > 1) remaining[1] else 0;
                sequence[2] = if (remaining.len > 2) remaining[2] else 0;
                sequence[3] = 0;
            }

            const replacement = strings.convertUTF8BytesIntoUTF16(&sequence);
            remaining = remaining[@maximum(replacement.len, 1)..];
            const new_len = strings.u16Len(replacement.code_point);
            try output.ensureUnusedCapacity(new_len);
            output.items.len += @as(usize, new_len);

            if (comptime fail_if_invalid) {
                if (replacement.code_point == unicode_replacement)
                    return error.InvalidByteSequence;
            }

            switch (replacement.code_point) {
                0...0xffff => {
                    output.items[output.items.len - 1] = @intCast(u16, replacement.code_point);
                },
                else => |c| {
                    output.items[output.items.len - 2 .. output.items.len][0..2].* = [2]u16{ strings.u16Lead(c), strings.u16Trail(c) };
                },
            }
        }

        while (strings.firstNonASCII(remaining)) |j| {
            const last = remaining[0..j];
            remaining = remaining[j..];

            var sequence: [4]u8 = undefined;

            if (remaining.len >= 4) {
                sequence = remaining[0..4].*;
            } else {
                sequence[0] = remaining[0];
                sequence[1] = if (remaining.len > 1) remaining[1] else 0;
                sequence[2] = if (remaining.len > 2) remaining[2] else 0;
                sequence[3] = 0;
            }

            const replacement = strings.convertUTF8BytesIntoUTF16(&sequence);
            remaining = remaining[@maximum(replacement.len, 1)..];
            const new_len = j + @as(usize, strings.u16Len(replacement.code_point));
            try output.ensureUnusedCapacity(new_len);
            output.items.len += new_len;
            strings.copyU8IntoU16(output.items[output.items.len - new_len ..][0..j], last);

            if (comptime fail_if_invalid) {
                if (replacement.code_point == unicode_replacement)
                    return error.InvalidByteSequence;
            }

            switch (replacement.code_point) {
                0...0xffff => {
                    output.items[output.items.len - 1] = @intCast(u16, replacement.code_point);
                },
                else => |c| {
                    output.items[output.items.len - 2 .. output.items.len][0..2].* = [2]u16{ strings.u16Lead(c), strings.u16Trail(c) };
                },
            }
        }

        if (remaining.len > 0) {
            try output.ensureUnusedCapacity(remaining.len);
            output.items.len += remaining.len;
            strings.copyU8IntoU16(output.items[output.items.len - remaining.len ..], remaining);
        }

        return output.toOwnedSlice();
    }

    return null;
}

pub fn utf16Codepoint(comptime Type: type, input: Type) UTF16Replacement {
    const c0 = @as(u21, input[0]);

    if (c0 & ~@as(u21, 0x03ff) == 0xd800) {
        // surrogate pair
        if (input.len == 1)
            return .{
                .len = 1,
            };
        //error.DanglingSurrogateHalf;
        const c1 = @as(u21, input[1]);
        if (c1 & ~@as(u21, 0x03ff) != 0xdc00)
            if (input.len == 1)
                return .{
                    .len = 1,
                };
        // return error.ExpectedSecondSurrogateHalf;

        return .{ .len = 2, .code_point = 0x10000 + (((c0 & 0x03ff) << 10) | (c1 & 0x03ff)) };
    } else if (c0 & ~@as(u21, 0x03ff) == 0xdc00) {
        // return error.UnexpectedSecondSurrogateHalf;
        return .{ .len = 1 };
    } else {
        return .{ .code_point = c0, .len = 1 };
    }
}

pub fn toUTF8AllocWithType(allocator: std.mem.Allocator, comptime Type: type, utf16: Type) ![]u8 {
    var list = std.ArrayList(u8).initCapacity(allocator, utf16.len) catch unreachable;
    var utf16_remaining = utf16;

    while (firstNonASCII16(Type, utf16_remaining)) |i| {
        const to_copy = utf16_remaining[0..i];
        utf16_remaining = utf16_remaining[i..];

        const replacement = utf16Codepoint(Type, utf16_remaining);
        utf16_remaining = utf16_remaining[replacement.len..];

        const count: usize = switch (replacement.code_point) {
            0...0x7F => 1,
            (0x7F + 1)...0x7FF => 2,
            (0x7FF + 1)...0xFFFF => 3,
            else => 4,
        };
        try list.ensureUnusedCapacity(i + count);
        list.items.len += i;

        copyU16IntoU8(
            list.items[list.items.len - i ..],
            Type,
            to_copy,
        );

        list.items.len += count;

        _ = encodeWTF8RuneT(
            list.items.ptr[list.items.len - count .. list.items.len - count + 4][0..4],
            u32,
            @as(u32, replacement.code_point),
        );
    }

    try list.ensureUnusedCapacity(utf16_remaining.len);
    const old_len = list.items.len;
    list.items.len += utf16_remaining.len;
    copyU16IntoU8(list.items[old_len..], Type, utf16_remaining);

    return list.toOwnedSlice();
}

pub const EncodeIntoResult = struct {
    read: u32 = 0,
    written: u32 = 0,
};
pub fn allocateLatin1IntoUTF8(allocator: std.mem.Allocator, comptime Type: type, latin1_: Type) ![]u8 {
    var list = try std.ArrayList(u8).initCapacity(allocator, latin1_.len);
    var latin1 = latin1_;
    while (latin1.len > 0) {
        var read: usize = 0;
        var break_outer = false;

        outer: while (latin1.len >= 128) {
            try list.ensureUnusedCapacity(128);
            var base = list.items.ptr[list.items.len..list.items.len].ptr;

            comptime var count: usize = 0;
            inline while (count < 8) : (count += 1) {
                const vec: AsciiVector = latin1[(comptime count * ascii_vector_size)..][0..ascii_vector_size].*;
                const cmp = vec > max_16_ascii;
                const bitmask = @ptrCast(*const u16, &cmp).*;
                const first = @ctz(u16, bitmask);
                if (first < 16) {
                    latin1 = latin1[(comptime count * ascii_vector_size)..];
                    list.items.len += (comptime count * ascii_vector_size);
                    try list.appendSlice(latin1[0..first]);
                    latin1 = latin1[first..];
                    break_outer = true;
                    break :outer;
                }
                base[(comptime count * ascii_vector_size)..(comptime count * ascii_vector_size + ascii_vector_size)][0..ascii_vector_size].* = @bitCast([ascii_vector_size]u8, vec);
            }

            latin1 = latin1[(comptime count * ascii_vector_size)..];
            list.items.len += (comptime count * ascii_vector_size);
        }

        if (!break_outer) {
            while (latin1.len >= ascii_vector_size) {
                const vec: AsciiVector = latin1[0..ascii_vector_size].*;
                const cmp = vec > max_16_ascii;
                const bitmask = @ptrCast(*const u16, &cmp).*;
                const first = @ctz(u16, bitmask);
                if (first < 16) {
                    try list.appendSlice(latin1[0..first]);
                    latin1 = latin1[first..];
                    break;
                }

                try list.ensureUnusedCapacity(ascii_vector_size);
                list.items.len += ascii_vector_size;
                list.items[list.items.len - ascii_vector_size ..][0..ascii_vector_size].* = @bitCast([ascii_vector_size]u8, vec);
                latin1 = latin1[ascii_vector_size..];
            }
        }

        while (read < latin1.len and latin1[read] < 0x80) : (read += 1) {}
        try list.appendSlice(latin1[0..read]);
        latin1 = latin1[read..];

        if (latin1.len > 0) {
            try list.ensureUnusedCapacity(2);
            var buf = list.items.ptr[list.items.len .. list.items.len + 2][0..2];
            list.items.len += 2;
            buf[0..2].* = latin1ToCodepointBytesAssumeNotASCII(latin1[0]);
            latin1 = latin1[1..];
        }
    }

    return list.toOwnedSlice();
}

pub const UTF16Replacement = struct {
    code_point: u32 = unicode_replacement,
    len: u3 = 0,
};

// This variation matches WebKit behavior.
pub fn convertUTF8BytesIntoUTF16(sequence: *const [4]u8) UTF16Replacement {
    if (Environment.allow_assert)
        assert(sequence[0] > 127);
    const len = wtf8ByteSequenceLengthWithInvalid(sequence[0]);
    switch (len) {
        2 => {
            if (Environment.allow_assert)
                assert(sequence[0] >= 0xC2);
            if (Environment.allow_assert)
                assert(sequence[0] <= 0xDF);
            if (sequence[1] < 0x80 or sequence[1] > 0xBF) {
                return .{ .len = 1 };
            }
            return .{ .len = len, .code_point = ((@as(u32, sequence[0]) << 6) + @as(u32, sequence[1])) - 0x00003080 };
        },
        3 => {
            if (Environment.allow_assert)
                assert(sequence[0] >= 0xE0);
            if (Environment.allow_assert)
                assert(sequence[0] <= 0xEF);
            switch (sequence[0]) {
                0xE0 => {
                    if (sequence[1] < 0xA0 or sequence[1] > 0xBF) {
                        return .{ .len = 1 };
                    }
                },
                0xED => {
                    if (sequence[1] < 0x80 or sequence[1] > 0x9F) {
                        return .{ .len = 1 };
                    }
                },
                else => {
                    if (sequence[1] < 0x80 or sequence[1] > 0xBF) {
                        return .{ .len = 1 };
                    }
                },
            }
            if (sequence[2] < 0x80 or sequence[2] > 0xBF) {
                return .{ .len = 2 };
            }
            return .{
                .len = len,
                .code_point = ((@as(u32, sequence[0]) << 12) + (@as(u32, sequence[1]) << 6) + @as(u32, sequence[2])) - 0x000E2080,
            };
        },
        4 => {
            if (Environment.allow_assert)
                assert(sequence[0] >= 0xF0);
            if (Environment.allow_assert)
                assert(sequence[0] <= 0xF4);
            switch (sequence[0]) {
                0xF0 => {
                    if (sequence[1] < 0x90 or sequence[1] > 0xBF) {
                        return .{ .len = 1 };
                    }
                },
                0xF4 => {
                    if (sequence[1] < 0x80 or sequence[1] > 0x8F) {
                        return .{ .len = 1 };
                    }
                },
                else => {
                    if (sequence[1] < 0x80 or sequence[1] > 0xBF) {
                        return .{ .len = 1 };
                    }
                },
            }

            if (sequence[2] < 0x80 or sequence[2] > 0xBF) {
                return .{ .len = 2 };
            }
            if (sequence[3] < 0x80 or sequence[3] > 0xBF) {
                return .{ .len = 3 };
            }
            return .{
                .len = 4,
                .code_point = ((@as(u32, sequence[0]) << 18) +
                    (@as(u32, sequence[1]) << 12) +
                    (@as(u32, sequence[2]) << 6) + @as(u32, sequence[3])) - 0x03C82080,
            };
        },
        else => unreachable,
    }
}

pub fn copyLatin1IntoUTF8(buf_: []u8, comptime Type: type, latin1_: Type) EncodeIntoResult {
    var buf = buf_;
    var latin1 = latin1_;
    while (buf.len > 0 and latin1.len > 0) {
        var read: usize = 0;
        var break_outer = false;

        outer: while (latin1.len >= 128 and buf.len >= 128) {
            comptime var count: usize = 0;
            inline while (count < 8) : (count += 1) {
                const vec: AsciiVector = latin1[(comptime count * ascii_vector_size)..][0..ascii_vector_size].*;
                const cmp = vec > max_16_ascii;
                const bitmask = @ptrCast(*const u16, &cmp).*;
                const first = @ctz(u16, bitmask);
                if (first < 16) {
                    latin1 = latin1[(comptime count * ascii_vector_size)..];
                    buf = buf[(comptime count * ascii_vector_size)..];
                    break_outer = true;
                    break :outer;
                }
                buf[(comptime count * ascii_vector_size)..][0..8].* = @bitCast([ascii_vector_size]u8, vec)[0..8].*;
                buf[(comptime count * ascii_vector_size)..][8..ascii_vector_size].* = @bitCast([ascii_vector_size]u8, vec)[8..ascii_vector_size].*;
            }

            latin1 = latin1[(comptime count * ascii_vector_size)..];
            buf = buf[(comptime count * ascii_vector_size)..];
        }

        while (latin1.len > ascii_vector_size and !break_outer) {
            const vec: AsciiVector = latin1[0..ascii_vector_size].*;
            const cmp = vec > max_16_ascii;
            const bitmask = @ptrCast(*const u16, &cmp).*;
            const first = @ctz(u16, bitmask);
            if (first < 16) {
                break;
            }
            buf[0..8].* = @bitCast([ascii_vector_size]u8, vec)[0..8].*;
            buf[8..ascii_vector_size].* = @bitCast([ascii_vector_size]u8, vec)[8..ascii_vector_size].*;
            latin1 = latin1[ascii_vector_size..];
            buf = buf[ascii_vector_size..];
        }

        while (read < latin1.len and latin1[read] < 0x80) : (read += 1) {}

        const written = @minimum(read, buf.len);
        if (written == 0) break;
        @memcpy(buf.ptr, latin1.ptr, written);
        latin1 = latin1[written..];
        buf = buf[written..];
        if (latin1.len > 0 and buf.len >= 2) {
            buf[0..2].* = latin1ToCodepointBytesAssumeNotASCII(latin1[0]);
            latin1 = latin1[1..];
            buf = buf[2..];
        }
    }

    return .{
        .read = @truncate(u32, buf_.len - buf.len),
        .written = @truncate(u32, latin1_.len - latin1.len),
    };
}

test "copyLatin1IntoUTF8" {
    var input: string = "hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!";
    var output = std.mem.zeroes([500]u8);
    const result = copyLatin1IntoUTF8(&output, string, input);
    try std.testing.expectEqual(input.len, result.read);
    try std.testing.expectEqual(input.len, result.written);

    try std.testing.expectEqualSlices(u8, input, output[0..result.written]);
}

pub fn latin1ToCodepointAssumeNotASCII(char: u8, comptime CodePointType: type) CodePointType {
    return @intCast(
        CodePointType,
        @bitCast(
            u16,
            latin1ToCodepointBytesAssumeNotASCII(char),
        ),
    );
}

pub fn latin1ToCodepointBytesAssumeNotASCII(char: u32) [2]u8 {
    return [2]u8{
        @truncate(u8, 0xc0 | char >> 6),
        @truncate(u8, 0x80 | (char & 0x3f)),
    };
}

pub fn copyUTF16IntoUTF8(buf: []u8, comptime Type: type, utf16: Type) EncodeIntoResult {
    var remaining = buf;
    var utf16_remaining = utf16;
    var ended_on_non_ascii = false;

    while (firstNonASCII16(Type, utf16_remaining)) |i| {
        const end = @minimum(i, remaining.len);
        const to_copy = utf16_remaining[0..end];
        copyU16IntoU8(remaining, Type, to_copy);
        remaining = remaining[end..];
        utf16_remaining = utf16_remaining[end..];

        if (@minimum(utf16_remaining.len, remaining.len) == 0)
            break;

        const replacement = utf16Codepoint(Type, utf16_remaining);

        const width: usize = switch (replacement.code_point) {
            0...0x7F => 1,
            (0x7F + 1)...0x7FF => 2,
            (0x7FF + 1)...0xFFFF => 3,
            else => 4,
        };

        if (width > remaining.len) {
            ended_on_non_ascii = width > 1;
            break;
        }

        utf16_remaining = utf16_remaining[replacement.len..];
        _ = encodeWTF8RuneT(remaining.ptr[0..4], u32, @as(u32, replacement.code_point));
        remaining = remaining[width..];
    }

    if (remaining.len > 0 and !ended_on_non_ascii and utf16_remaining.len > 0) {
        const len = @minimum(remaining.len, utf16_remaining.len);
        copyU16IntoU8(remaining[0..len], Type, utf16_remaining[0..len]);
        utf16_remaining = utf16_remaining[len..];
        remaining = remaining[len..];
    }

    return .{
        .read = @truncate(u32, utf16.len - utf16_remaining.len),
        .written = @truncate(u32, buf.len - remaining.len),
    };
}

// Check utf16 string equals utf8 string without allocating extra memory
pub fn utf16EqlString(text: []const u16, str: string) bool {
    if (text.len > str.len) {
        // Strings can't be equal if UTF-16 encoding is longer than UTF-8 encoding
        return false;
    }

    var temp = [4]u8{ 0, 0, 0, 0 };
    const n = text.len;
    var j: usize = 0;
    var i: usize = 0;
    // TODO: is it safe to just make this u32 or u21?
    var r1: i32 = undefined;
    var k: u4 = 0;
    while (i < n) : (i += 1) {
        r1 = text[i];
        if (r1 >= 0xD800 and r1 <= 0xDBFF and i + 1 < n) {
            const r2: i32 = text[i + 1];
            if (r2 >= 0xDC00 and r2 <= 0xDFFF) {
                r1 = (r1 - 0xD800) << 10 | (r2 - 0xDC00) + 0x10000;
                i += 1;
            }
        }

        const width = encodeWTF8Rune(&temp, r1);
        if (j + width > str.len) {
            return false;
        }
        k = 0;
        while (k < width) : (k += 1) {
            if (temp[k] != str[j]) {
                return false;
            }
            j += 1;
        }
    }

    return j == str.len;
}

// This is a clone of golang's "utf8.EncodeRune" that has been modified to encode using
// WTF-8 instead. See https://simonsapin.github.io/wtf-8/ for more info.
pub fn encodeWTF8Rune(p: *[4]u8, r: i32) u3 {
    return @call(
        .{
            .modifier = .always_inline,
        },
        encodeWTF8RuneT,
        .{
            p,
            u32,
            @intCast(u32, r),
        },
    );
}

pub fn encodeWTF8RuneT(p: *[4]u8, comptime R: type, r: R) u3 {
    switch (r) {
        0...0x7F => {
            p[0] = @intCast(u8, r);
            return 1;
        },
        (0x7F + 1)...0x7FF => {
            p[0] = @truncate(u8, 0xC0 | ((r >> 6)));
            p[1] = @truncate(u8, 0x80 | (r & 0x3F));
            return 2;
        },
        (0x7FF + 1)...0xFFFF => {
            p[0] = @truncate(u8, 0xE0 | ((r >> 12)));
            p[1] = @truncate(u8, 0x80 | ((r >> 6) & 0x3F));
            p[2] = @truncate(u8, 0x80 | (r & 0x3F));
            return 3;
        },
        else => {
            p[0] = @truncate(u8, 0xF0 | ((r >> 18)));
            p[1] = @truncate(u8, 0x80 | ((r >> 12) & 0x3F));
            p[2] = @truncate(u8, 0x80 | ((r >> 6) & 0x3F));
            p[3] = @truncate(u8, 0x80 | (r & 0x3F));
            return 4;
        },
    }
}

pub inline fn wtf8ByteSequenceLength(first_byte: u8) u3 {
    return switch (first_byte) {
        0 => 0,
        1...0x80 - 1 => 1,
        else => if ((first_byte & 0xE0) == 0xC0)
            @as(u3, 2)
        else if ((first_byte & 0xF0) == 0xE0)
            @as(u3, 3)
        else if ((first_byte & 0xF8) == 0xF0)
            @as(u3, 4)
        else
            @as(u3, 1),
    };
}

/// 0 == invalid
pub inline fn wtf8ByteSequenceLengthWithInvalid(first_byte: u8) u3 {
    return switch (first_byte) {
        0...0x80 - 1 => 1,
        else => if ((first_byte & 0xE0) == 0xC0)
            @as(u3, 2)
        else if ((first_byte & 0xF0) == 0xE0)
            @as(u3, 3)
        else if ((first_byte & 0xF8) == 0xF0)
            @as(u3, 4)
        else
            @as(u3, 0),
    };
}

/// Convert potentially ill-formed UTF-8 or UTF-16 bytes to a Unicode Codepoint.
/// Invalid codepoints are replaced with `zero` parameter
/// This is a clone of esbuild's decodeWTF8Rune
/// which was a clone of golang's "utf8.DecodeRune" that was modified to decode using WTF-8 instead.
/// Asserts a multi-byte codepoint
pub inline fn decodeWTF8RuneTMultibyte(p: *const [4]u8, len: u3, comptime T: type, comptime zero: T) T {
    std.debug.assert(len > 1);

    const s1 = p[1];
    if ((s1 & 0xC0) != 0x80) return zero;

    if (len == 2) {
        const cp = @as(T, p[0] & 0x1F) << 6 | @as(T, s1 & 0x3F);
        if (cp < 0x80) return zero;
        return cp;
    }

    const s2 = p[2];

    if ((s2 & 0xC0) != 0x80) return zero;

    if (len == 3) {
        const cp = (@as(T, p[0] & 0x0F) << 12) | (@as(T, s1 & 0x3F) << 6) | (@as(T, s2 & 0x3F));
        if (cp < 0x800) return zero;
        return cp;
    }

    const s3 = p[3];
    {
        const cp = (@as(T, p[0] & 0x07) << 18) | (@as(T, s1 & 0x3F) << 12) | (@as(T, s2 & 0x3F) << 6) | (@as(T, s3 & 0x3F));
        if (cp < 0x10000 or cp > 0x10FFFF) return zero;
        return cp;
    }

    unreachable;
}

const ascii_vector_size = 16;
const ascii_u16_vector_size = 8;
const max_16_ascii = @splat(ascii_vector_size, @as(u8, 127));
const max_u16_ascii = @splat(ascii_u16_vector_size, @as(u16, 127));
const AsciiVector = std.meta.Vector(ascii_vector_size, u8);
const AsciiU16Vector = std.meta.Vector(ascii_u16_vector_size, u16);
const max_4_ascii = @splat(4, @as(u8, 127));
pub fn isAllASCII(slice: []const u8) bool {
    var remaining = slice;

    // The NEON SIMD unit is 128-bit wide and includes 16 128-bit registers that can be used as 32 64-bit registers
    if (comptime Environment.isAarch64 or Environment.isX64) {
        while (remaining.len >= 128) {
            comptime var count: usize = 0;
            inline while (count < 8) : (count += 1) {
                const vec: AsciiVector = remaining[(comptime count * ascii_vector_size)..][0..ascii_vector_size].*;

                if ((@reduce(.Or, vec > max_16_ascii))) {
                    return false;
                }
            }
            remaining = remaining[comptime ascii_vector_size * count..];
        }

        while (remaining.len >= ascii_vector_size) {
            const vec: AsciiVector = remaining[0..ascii_vector_size].*;

            if ((@reduce(.Or, vec > max_16_ascii))) {
                return false;
            }

            remaining = remaining[ascii_vector_size..];
        }

        while (remaining.len >= 4) {
            const vec: std.meta.Vector(4, u8) = remaining[0..4].*;

            remaining = remaining[4..];
            if (@reduce(.Or, vec > max_4_ascii)) {
                return false;
            }
        }
    }

    for (remaining) |char| {
        if (char > 127) {
            return false;
        }
    }

    return true;
}

//#define U16_LEAD(supplementary) (UChar)(((supplementary)>>10)+0xd7c0)
pub inline fn u16Lead(supplementary: anytype) u16 {
    return @intCast(u16, (supplementary >> 10) + 0xd7c0);
}

//#define U16_TRAIL(supplementary) (UChar)(((supplementary)&0x3ff)|0xdc00)
pub inline fn u16Trail(supplementary: anytype) u16 {
    return @intCast(u16, (supplementary & 0x3ff) | 0xdc00);
}

//#define U16_LENGTH(c) ((uint32_t)(c)<=0xffff ? 1 : 2)
pub inline fn u16Len(supplementary: anytype) u2 {
    return switch (@intCast(u32, supplementary)) {
        0...0xffff => 1,
        else => 2,
    };
}

pub fn firstNonASCII(slice: []const u8) ?u32 {
    var remaining = slice;

    if (comptime Environment.isAarch64 or Environment.isX64) {
        while (remaining.len >= 128) {
            comptime var count: usize = 0;
            inline while (count < 8) : (count += 1) {
                const vec: AsciiVector = remaining[(comptime count * ascii_vector_size)..][0..ascii_vector_size].*;
                const cmp = vec > max_16_ascii;
                const bitmask = @ptrCast(*const u16, &cmp).*;
                const first = @ctz(u16, bitmask);
                if (first < 16) {
                    return @intCast(u32, (comptime count * ascii_vector_size) + @as(u32, first) + @intCast(u32, slice.len - remaining.len));
                }
            }
            remaining = remaining[comptime ascii_vector_size * count..];
        }

        while (remaining.len >= ascii_vector_size) {
            const vec: AsciiVector = remaining[0..ascii_vector_size].*;
            const cmp = vec > max_16_ascii;
            const bitmask = @ptrCast(*const u16, &cmp).*;
            const first = @ctz(u16, bitmask);
            if (first < 16) {
                return @as(u32, first) + @intCast(u32, slice.len - remaining.len);
            }

            remaining = remaining[ascii_vector_size..];
        }
    }

    for (remaining) |char, i| {
        if (char > 127) {
            return @truncate(u32, i + (slice.len - remaining.len));
        }
    }

    return null;
}

pub fn firstNonASCII16(comptime Slice: type, slice: Slice) ?u32 {
    var remaining = slice;

    if (comptime Environment.isAarch64 or Environment.isX64) {
        while (remaining.len >= 64) {
            comptime var count: usize = 0;
            inline while (count < 8) : (count += 1) {
                const vec: AsciiU16Vector = remaining[(comptime count * ascii_u16_vector_size)..][0..ascii_u16_vector_size].*;
                const cmp = vec > max_u16_ascii;
                const bitmask = @ptrCast(*const u16, &cmp).*;
                const first = @ctz(u16, bitmask);
                if (first < ascii_u16_vector_size) {
                    return @intCast(u32, (comptime count * ascii_u16_vector_size) +
                        @as(u32, first) +
                        @intCast(u32, slice.len - remaining.len));
                }
            }
            remaining = remaining[comptime ascii_u16_vector_size * count..];
        }

        while (remaining.len >= ascii_u16_vector_size) {
            const vec: AsciiU16Vector = remaining[0..ascii_u16_vector_size].*;
            const cmp = vec > max_u16_ascii;
            const bitmask = @ptrCast(*const u16, &cmp).*;
            const first = @ctz(u16, bitmask);
            if (first < ascii_u16_vector_size) {
                return @intCast(u32, @as(u32, first) +
                    @intCast(u32, slice.len - remaining.len));
            }
            remaining = remaining[ascii_u16_vector_size..];
        }
    }

    for (remaining) |char, i| {
        if (char > 127) {
            return @truncate(u32, i + (slice.len - remaining.len));
        }
    }

    return null;
}

test "isAllASCII" {
    const yes = "aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123";
    try std.testing.expectEqual(true, isAllASCII(yes));

    const no = "aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdoka🙂sdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123";
    try std.testing.expectEqual(false, isAllASCII(no));
}

test "firstNonASCII" {
    const yes = "aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123";
    try std.testing.expectEqual(true, firstNonASCII(yes) == null);

    {
        const no = "aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdoka🙂sdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123";
        try std.testing.expectEqual(@as(u32, 50), firstNonASCII(no).?);
    }

    {
        const no = "aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd12312🙂3";
        try std.testing.expectEqual(@as(u32, 366), firstNonASCII(no).?);
    }
}

test "firstNonASCII16" {
    @setEvalBranchQuota(99999);
    const yes = std.mem.span(std.unicode.utf8ToUtf16LeStringLiteral("aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123"));
    try std.testing.expectEqual(true, firstNonASCII16(@TypeOf(yes), yes) == null);

    {
        @setEvalBranchQuota(99999);
        const no = std.mem.span(std.unicode.utf8ToUtf16LeStringLiteral("aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdoka🙂sdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123"));
        try std.testing.expectEqual(@as(u32, 50), firstNonASCII16(@TypeOf(no), no).?);
    }
    {
        @setEvalBranchQuota(99999);
        const no = std.mem.span(std.unicode.utf8ToUtf16LeStringLiteral("🙂sdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123"));
        try std.testing.expectEqual(@as(u32, 0), firstNonASCII16(@TypeOf(no), no).?);
    }
    {
        @setEvalBranchQuota(99999);
        const no = std.mem.span(std.unicode.utf8ToUtf16LeStringLiteral("a🙂sdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123"));
        try std.testing.expectEqual(@as(u32, 1), firstNonASCII16(@TypeOf(no), no).?);
    }
    {
        @setEvalBranchQuota(99999);
        const no = std.mem.span(std.unicode.utf8ToUtf16LeStringLiteral("aspdokasdpokasdpokasd aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd123123aspdokasdpokasdpokasdaspdokasdpokasdpokasdaspdokasdpokasdpokasd12312🙂3"));
        try std.testing.expectEqual(@as(u32, 366), firstNonASCII16(@TypeOf(no), no).?);
    }
}

pub fn formatUTF16(slice_: []align(1) const u16, writer: anytype) !void {
    var slice = slice_;
    var chunk: [512 + 4]u8 = undefined;
    var chunk_i: u16 = 0;

    while (slice.len > 0) {
        if (chunk_i >= chunk.len - 5) {
            try writer.writeAll(chunk[0..chunk_i]);
            chunk_i = 0;
        }

        var cp: u32 = slice[0];
        slice = slice[1..];
        if (cp & ~@as(u32, 0x03ff) == 0xd800 and slice.len > 0) {
            cp = 0x10000 + (((cp & 0x03ff) << 10) | (slice[0] & 0x03ff));
            slice = slice[1..];
        }

        chunk_i += @as(
            u8,
            @call(
                .{ .modifier = .always_inline },
                encodeWTF8RuneT,
                .{ chunk[chunk_i..][0..4], u32, cp },
            ),
        );
    }

    try writer.writeAll(chunk[0..chunk_i]);
}

test "print UTF16" {
    var err = std.io.getStdErr();
    const utf16 = comptime std.unicode.utf8ToUtf16LeStringLiteral("❌ ✅ opkay ");
    try formatUTF16(utf16, err.writer());
    // std.unicode.fmtUtf16le(utf16le: []const u16)
}

/// Convert potentially ill-formed UTF-8 or UTF-16 bytes to a Unicode Codepoint.
/// - Invalid codepoints are replaced with `zero` parameter
/// - Null bytes return 0
pub fn decodeWTF8RuneT(p: *const [4]u8, len: u3, comptime T: type, comptime zero: T) T {
    if (len == 0) return zero;
    if (len == 1) return p[0];

    return decodeWTF8RuneTMultibyte(p, len, T, zero);
}

pub fn codepointSize(comptime R: type, r: R) u3 {
    return switch (r) {
        0b0000_0000...0b0111_1111 => 1,
        0b1100_0000...0b1101_1111 => 2,
        0b1110_0000...0b1110_1111 => 3,
        0b1111_0000...0b1111_0111 => 4,
        else => 0,
    };
}

// /// Encode Type into UTF-8 bytes.
// /// - Invalid unicode data becomes U+FFFD REPLACEMENT CHARACTER.
// /// -
// pub fn encodeUTF8RuneT(out: *[4]u8, comptime R: type, c: R) u3 {
//     switch (c) {
//         0b0000_0000...0b0111_1111 => {
//             out[0] = @intCast(u8, c);
//             return 1;
//         },
//         0b1100_0000...0b1101_1111 => {
//             out[0] = @truncate(u8, 0b11000000 | (c >> 6));
//             out[1] = @truncate(u8, 0b10000000 | c & 0b111111);
//             return 2;
//         },

//         0b1110_0000...0b1110_1111 => {
//             if (0xd800 <= c and c <= 0xdfff) {
//                 // Replacement character
//                 out[0..3].* = [_]u8{ 0xEF, 0xBF, 0xBD };

//                 return 3;
//             }

//             out[0] = @truncate(u8, 0b11100000 | (c >> 12));
//             out[1] = @truncate(u8, 0b10000000 | (c >> 6) & 0b111111);
//             out[2] = @truncate(u8, 0b10000000 | c & 0b111111);
//             return 3;
//         },
//         0b1111_0000...0b1111_0111 => {
//             out[0] = @truncate(u8, 0b11110000 | (c >> 18));
//             out[1] = @truncate(u8, 0b10000000 | (c >> 12) & 0b111111);
//             out[2] = @truncate(u8, 0b10000000 | (c >> 6) & 0b111111);
//             out[3] = @truncate(u8, 0b10000000 | c & 0b111111);
//             return 4;
//         },
//         else => {
//             // Replacement character
//             out[0..3].* = [_]u8{ 0xEF, 0xBF, 0xBD };

//             return 3;
//         },
//     }
// }

pub fn containsNonBmpCodePoint(text: string) bool {
    var iter = CodepointIterator.init(text);
    var curs = CodepointIterator.Cursor{};

    while (iter.next(&curs)) {
        if (curs.c > 0xFFFF) {
            return true;
        }
    }

    return false;
}

// this is std.mem.trim except it doesn't forcibly change the slice to be const
pub fn trim(slice: anytype, values_to_strip: []const u8) @TypeOf(slice) {
    var begin: usize = 0;
    var end: usize = slice.len;
    while (begin < end and std.mem.indexOfScalar(u8, values_to_strip, slice[begin]) != null) : (begin += 1) {}
    while (end > begin and std.mem.indexOfScalar(u8, values_to_strip, slice[end - 1]) != null) : (end -= 1) {}
    return slice[begin..end];
}

pub fn containsNonBmpCodePointUTF16(_text: []const u16) bool {
    const n = _text.len;
    if (n > 0) {
        var i: usize = 0;
        var text = _text[0 .. n - 1];
        while (i < n - 1) : (i += 1) {
            switch (text[i]) {
                // Check for a high surrogate
                0xD800...0xDBFF => {
                    // Check for a low surrogate
                    switch (text[i + 1]) {
                        0xDC00...0xDFFF => {
                            return true;
                        },
                        else => {},
                    }
                },
                else => {},
            }
        }
    }

    return false;
}

pub fn join(slices: []const string, delimiter: string, allocator: std.mem.Allocator) !string {
    return try std.mem.join(allocator, delimiter, slices);
}

pub fn cmpStringsAsc(_: void, a: string, b: string) bool {
    return std.mem.order(u8, a, b) == .lt;
}

pub fn cmpStringsDesc(_: void, a: string, b: string) bool {
    return std.mem.order(u8, a, b) == .gt;
}

const sort_asc = std.sort.asc(u8);
const sort_desc = std.sort.desc(u8);

pub fn sortAsc(in: []string) void {
    std.sort.sort([]const u8, in, {}, cmpStringsAsc);
}

pub fn sortDesc(in: []string) void {
    std.sort.sort([]const u8, in, {}, cmpStringsDesc);
}

pub fn isASCIIHexDigit(c: u8) bool {
    return std.ascii.isDigit(c) or std.ascii.isXDigit(c);
}

pub fn toASCIIHexValue(character: u8) u8 {
    std.debug.assert(isASCIIHexDigit(character));
    return switch (character) {
        0...('A' - 1) => character - '0',
        else => (character - 'A' + 10) & 0xF,
    };
}

pub inline fn utf8ByteSequenceLength(first_byte: u8) u3 {
    return switch (first_byte) {
        0b0000_0000...0b0111_1111 => 1,
        0b1100_0000...0b1101_1111 => 2,
        0b1110_0000...0b1110_1111 => 3,
        0b1111_0000...0b1111_0111 => 4,
        else => 0,
    };
}

pub fn NewCodePointIterator(comptime CodePointType: type, comptime zeroValue: comptime_int) type {
    return struct {
        const Iterator = @This();
        bytes: []const u8,
        i: usize,
        next_width: usize = 0,
        width: u3 = 0,
        c: CodePointType = zeroValue,

        pub const Cursor = struct {
            i: u32 = 0,
            c: CodePointType = zeroValue,
            width: u3 = 0,
        };

        pub fn init(str: string) Iterator {
            return Iterator{ .bytes = str, .i = 0, .c = zeroValue };
        }

        pub fn initOffset(str: string, i: usize) Iterator {
            return Iterator{ .bytes = str, .i = i, .c = zeroValue };
        }

        pub inline fn next(it: *const Iterator, cursor: *Cursor) bool {
            const pos: u32 = @as(u32, cursor.width) + cursor.i;
            if (pos >= it.bytes.len) {
                return false;
            }

            const cp_len = wtf8ByteSequenceLength(it.bytes[pos]);
            const error_char = comptime std.math.minInt(CodePointType);

            const codepoint = @as(
                CodePointType,
                switch (cp_len) {
                    0 => return false,
                    1 => it.bytes[pos],
                    else => decodeWTF8RuneTMultibyte(it.bytes[pos..].ptr[0..4], cp_len, CodePointType, error_char),
                },
            );

            cursor.* = Cursor{
                .i = pos,
                .c = if (error_char != codepoint)
                    codepoint
                else
                    unicode_replacement,
                .width = if (codepoint != error_char) cp_len else 1,
            };

            return true;
        }

        inline fn nextCodepointSlice(it: *Iterator) []const u8 {
            const bytes = it.bytes;
            const prev = it.i;
            const next_ = prev + it.next_width;
            if (bytes.len <= next_) return "";

            const cp_len = utf8ByteSequenceLength(bytes[next_]);
            it.next_width = cp_len;
            it.i = @minimum(next_, bytes.len);

            const slice = bytes[prev..][0..cp_len];
            it.width = @intCast(u3, slice.len);
            return slice;
        }

        pub fn needsUTF8Decoding(slice: string) bool {
            var it = Iterator{ .bytes = slice, .i = 0 };

            while (true) {
                const part = it.nextCodepointSlice();
                @setRuntimeSafety(false);
                switch (part.len) {
                    0 => return false,
                    1 => continue,
                    else => return true,
                }
            }
        }

        pub fn scanUntilQuotedValueOrEOF(iter: *Iterator, comptime quote: CodePointType) usize {
            while (iter.c > -1) {
                if (!switch (iter.nextCodepoint()) {
                    quote => false,
                    '\\' => brk: {
                        if (iter.nextCodepoint() == quote) {
                            continue;
                        }
                        break :brk true;
                    },
                    else => true,
                }) {
                    return iter.i + 1;
                }
            }

            return iter.i;
        }

        pub fn nextCodepoint(it: *Iterator) CodePointType {
            const slice = it.nextCodepointSlice();

            it.c = switch (slice.len) {
                0 => zeroValue,
                1 => @intCast(CodePointType, slice[0]),
                2 => @intCast(CodePointType, std.unicode.utf8Decode2(slice) catch unreachable),
                3 => @intCast(CodePointType, std.unicode.utf8Decode3(slice) catch unreachable),
                4 => @intCast(CodePointType, std.unicode.utf8Decode4(slice) catch unreachable),
                else => unreachable,
            };

            return it.c;
        }

        /// Look ahead at the next n codepoints without advancing the iterator.
        /// If fewer than n codepoints are available, then return the remainder of the string.
        pub fn peek(it: *Iterator, n: usize) []const u8 {
            const original_i = it.i;
            defer it.i = original_i;

            var end_ix = original_i;
            var found: usize = 0;
            while (found < n) : (found += 1) {
                const next_codepoint = it.nextCodepointSlice() orelse return it.bytes[original_i..];
                end_ix += next_codepoint.len;
            }

            return it.bytes[original_i..end_ix];
        }
    };
}

pub const CodepointIterator = NewCodePointIterator(CodePoint, -1);
pub const UnsignedCodepointIterator = NewCodePointIterator(u32, 0);

pub fn NewLengthSorter(comptime Type: type, comptime field: string) type {
    return struct {
        const LengthSorter = @This();
        pub fn lessThan(_: LengthSorter, lhs: Type, rhs: Type) bool {
            return @field(lhs, field).len < @field(rhs, field).len;
        }
    };
}

test "join" {
    var string_list = &[_]string{ "abc", "def", "123", "hello" };
    const list = try join(string_list, "-", std.heap.page_allocator);
    try std.testing.expectEqualStrings("abc-def-123-hello", list);
}

test "sortAsc" {
    var string_list = [_]string{ "abc", "def", "123", "hello" };
    var sorted_string_list = [_]string{ "123", "abc", "def", "hello" };
    var sorted_join = try join(&sorted_string_list, "-", std.heap.page_allocator);
    sortAsc(&string_list);
    var string_join = try join(&string_list, "-", std.heap.page_allocator);

    try std.testing.expectEqualStrings(sorted_join, string_join);
}

test "sortDesc" {
    var string_list = [_]string{ "abc", "def", "123", "hello" };
    var sorted_string_list = [_]string{ "hello", "def", "abc", "123" };
    var sorted_join = try join(&sorted_string_list, "-", std.heap.page_allocator);
    sortDesc(&string_list);
    var string_join = try join(&string_list, "-", std.heap.page_allocator);

    try std.testing.expectEqualStrings(sorted_join, string_join);
}

pub usingnamespace @import("exact_size_matcher.zig");

pub const unicode_replacement = 0xFFFD;
pub const unicode_replacement_str = brk: {
    var out: [std.unicode.utf8CodepointSequenceLength(unicode_replacement) catch unreachable]u8 = undefined;
    _ = std.unicode.utf8Encode(unicode_replacement, &out) catch unreachable;
    break :brk out;
};

test "eqlCaseInsensitiveASCII" {
    try std.testing.expect(eqlCaseInsensitiveASCII("abc", "ABC", true));
    try std.testing.expect(eqlCaseInsensitiveASCII("abc", "abc", true));
    try std.testing.expect(eqlCaseInsensitiveASCII("aBcD", "aBcD", true));
    try std.testing.expect(!eqlCaseInsensitiveASCII("aBcD", "NOOO", true));
    try std.testing.expect(!eqlCaseInsensitiveASCII("aBcD", "LENGTH CHECK", true));
}