3 files changed, 153 insertions, 0 deletions
diff --git a/src/optimize/index.ts b/src/optimize/index.ts
new file mode 100644
index 000000000..d22854a32
--- /dev/null
+++ b/src/optimize/index.ts
@@ -0,0 +1,85 @@
+import type { Ast, TemplateNode } from '../compiler/interfaces';
+import { NodeVisitor, Optimizer, VisitorFn } from './types';
+import { walk } from 'estree-walker';
+
+import optimizeStyles from './styles.js';
+
+interface VisitorCollection {
+  enter: Map<string, VisitorFn[]>;
+  leave: Map<string, VisitorFn[]>;
+}
+
+function addVisitor(visitor: NodeVisitor, collection: VisitorCollection, nodeName: string, event: 'enter' | 'leave') {
+  if(event in visitor) {
+    if(collection[event].has(nodeName)) {
+      collection[event].get(nodeName)!.push(visitor[event]!);
+    }
+
+    collection.enter.set(nodeName, [visitor[event]!]);
+  }
+}
+
+function collectVisitors(optimizer: Optimizer, htmlVisitors: VisitorCollection, cssVisitors: VisitorCollection, finalizers: Array<() => Promise<void>>) {
+  if(optimizer.visitors) {
+    if(optimizer.visitors.html) {
+      for(const [nodeName, visitor] of Object.entries(optimizer.visitors.html)) {
+        addVisitor(visitor, htmlVisitors, nodeName, 'enter');
+        addVisitor(visitor, htmlVisitors, nodeName, 'leave');
+      }
+    }
+    if(optimizer.visitors.css) {
+      for(const [nodeName, visitor] of Object.entries(optimizer.visitors.css)) {
+        addVisitor(visitor, cssVisitors, nodeName, 'enter');
+        addVisitor(visitor, cssVisitors, nodeName, 'leave');
+      }
+    }
+  }
+  finalizers.push(optimizer.finalize);
+}
+
+function createVisitorCollection() {
+  return {
+    enter: new Map<string, VisitorFn[]>(),
+    leave: new Map<string, VisitorFn[]>(),
+  };
+}
+
+function walkAstWithVisitors(tmpl: TemplateNode, collection: VisitorCollection) {
+  walk(tmpl, {
+    enter(node) {
+      if(collection.enter.has(node.type)) {
+        const fns = collection.enter.get(node.type)!;
+        for(let fn of fns) {
+          fn(node);
+        }
+      }
+    },
+    leave(node) {
+      if(collection.leave.has(node.type)) {
+        const fns = collection.leave.get(node.type)!;
+        for(let fn of fns) {
+          fn(node);
+        }
+      }
+    }
+  });
+}
+
+interface OptimizeOptions { 
+  filename: string,
+  fileID: string
+}
+
+export async function optimize(ast: Ast, opts: OptimizeOptions) {
+  const htmlVisitors = createVisitorCollection();
+  const cssVisitors = createVisitorCollection();
+  const finalizers: Array<() => Promise<void>> = [];
+
+  collectVisitors(optimizeStyles(opts), htmlVisitors, cssVisitors, finalizers);
+
+  walkAstWithVisitors(ast.html, htmlVisitors);
+  walkAstWithVisitors(ast.css, cssVisitors);
+
+  // Run all of the finalizer functions in parallel because why not.
+  await Promise.all(finalizers.map(fn => fn()));
+}
+\ No newline at end of file
diff --git a/src/optimize/styles.ts b/src/optimize/styles.ts
new file mode 100644
index 000000000..b654ca7d1
--- /dev/null
+++ b/src/optimize/styles.ts
@@ -0,0 +1,51 @@
+import type { Ast, TemplateNode } from '../compiler/interfaces';
+import type { Optimizer } from './types'
+import { transformStyle } from '../style.js';
+
+export default function({ filename, fileID }: { filename: string, fileID: string }): Optimizer {
+  const classNames: Set<string> = new Set();
+  let stylesPromises: any[] = [];
+
+  return {
+    visitors: {
+      html: {
+        Element: {
+          enter(node) {
+            for(let attr of node.attributes) {
+              if(attr.name === 'class') {
+                for(let value of attr.value) {
+                  if(value.type === 'Text') {
+                    const classes = value.data.split(' ');
+                    for(const className in classes) {
+                      classNames.add(className);
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      },
+      css: {
+        Style: {
+          enter(node: TemplateNode) {
+            const code = node.content.styles;
+            const typeAttr = node.attributes && node.attributes.find(({ name }: { name: string }) => name === 'type');
+            stylesPromises.push(
+              transformStyle(code, {
+                type: (typeAttr.value[0] && typeAttr.value[0].raw) || undefined,
+                classNames,
+                filename,
+                fileID,
+              })
+            ); // TODO: styles needs to go in <head>
+          }
+        }
+      }
+    },
+    async finalize() {
+      const styles = await Promise.all(stylesPromises); // TODO: clean this up
+      console.log({ styles });
+    }
+  };
+}
+\ No newline at end of file
diff --git a/src/optimize/types.ts b/src/optimize/types.ts
new file mode 100644
index 000000000..e22700cba
--- /dev/null
+++ b/src/optimize/types.ts
@@ -0,0 +1,17 @@
+import type { TemplateNode } from '../compiler/interfaces';
+
+
+export type VisitorFn = (node: TemplateNode) => void;
+
+export interface NodeVisitor {
+  enter?: VisitorFn;
+  leave?: VisitorFn;
+}
+
+export interface Optimizer {
+  visitors?: {
+    html?: Record<string, NodeVisitor>,
+    css?: Record<string, NodeVisitor>
+  },
+  finalize: () => Promise<void>
+}
+\ No newline at end of file