import twas from 'twas';
import cache from 'webext-storage-cache';
import React from 'dom-chef';
import {RepoIcon} from '@primer/octicons-react';
import elementReady from 'element-ready';
import * as pageDetect from 'github-url-detection';

import features from '.';
import * as api from '../github-helpers/api';
import {getRepo} from '../github-helpers';

interface CommitTarget {
	oid: string;
	committedDate: string;
	resourcePath: string;
	history: {
		totalCount: number;
	};
}

const fresh = [
	'Freshly baked',
	'Freshly brewed',
	'Newly minted',
	'Hot off the presses',
	'Straight out of the oven',
	'Still hot',
	'Smells fresh',
	'Just a baby',
	'It’s my birthday',
	'So it begins, the great battle of our time',
];

const dateFormatter = new Intl.DateTimeFormat('en-US', {
	year: 'numeric',
	month: 'long',
	day: 'numeric',
});

const getRepoAge = async (commitSha: string, commitsCount: number): Promise<[committedDate: string, resourcePath: string]> => {
	const {repository} = await api.v4(`
		repository() {
			defaultBranchRef {
				target {
					... on Commit {
						history(first: 5, after: "${commitSha} ${commitsCount - Math.min(6, commitsCount)}") {
							nodes {
								committedDate
								resourcePath
							}
						}
					}
				}
			}
		}
	`);

	const {committedDate, resourcePath} = repository.defaultBranchRef.target.history.nodes
		.reverse()
		// Filter out any invalid commit dates #3185
		.find((commit: CommitTarget) => new Date(commit.committedDate).getFullYear() > 1970);

	return [committedDate, resourcePath];
};

const getFirstCommit = cache.function(async (): Promise<[committedDate: string, resourcePath: string]> => {
	const {repository} = await api.v4(`
		repository() {
			defaultBranchRef {
				target {
					... on Commit {
						oid
						committedDate
						resourcePath
						history {
							totalCount
						}
					}
				}
			}
		}
	`);

	const {oid: commitSha, history, committedDate, resourcePath} = repository.defaultBranchRef.target as CommitTarget;
	const commitsCount = history.totalCount;
	if (commitsCount === 1) {
		return [committedDate, resourcePath];
	}

	return getRepoAge(commitSha, commitsCount);
}, {
	cacheKey: () => __filebasename + ':' + getRepo()!.nameWithOwner,
});

async function init(): Promise<void> {
	const [firstCommitDate, firstCommitHref] = await getFirstCommit()!;
	const birthday = new Date(firstCommitDate);

	// `twas` could also return `an hour ago` or `just now`
	const [value, unit] = twas(birthday.getTime())
		.replace('just now', '1 second')
		.replace(/^an?/, '1')
		.split(' ');

	// About a day old or less ?
	const age = Date.now() - birthday.getTime() < 10e7
		? fresh[Math.floor(Math.random() * fresh.length)]
		: `${value} ${unit} old`;

	const sidebarAboutSection = await elementReady('.repository-content .BorderGrid-cell');
	sidebarAboutSection!.append(
		<h3 className="sr-only">Repository age</h3>,
		<div className="mt-3">
			<a href={firstCommitHref} className="muted-link Link--muted" title={`First commit dated ${dateFormatter.format(birthday)}`}>
				<RepoIcon className="mr-2"/>{age}
			</a>
		</div>,
	);
}

void features.add(__filebasename, {
	include: [
		pageDetect.isRepoRoot,
	],
	exclude: [
		pageDetect.isEmptyRepoRoot,
	],
	awaitDomReady: false,
	init,
});
