#!/usr/bin/env bun

import * as fs from "node:fs/promises";
import * as path from "node:path";
import { Glob } from "bun";

async function pathExists(candidate: string): Promise<boolean> {
	try {
		await fs.access(candidate);
		return true;
	} catch {
		return false;
	}
}

async function findDocsDir(): Promise<string | undefined> {
	let current = path.resolve(import.meta.dir);
	while (true) {
		const docsDir = path.join(current, "docs");
		if (await pathExists(docsDir)) return docsDir;
		const parent = path.dirname(current);
		if (parent === current) return undefined;
		current = parent;
	}
}

const docsDir = await findDocsDir();
const outputPath = path.resolve(import.meta.dir, "../src/internal-urls/docs-index.generated.ts");

if (docsDir === undefined) {
	const existingIndex = Bun.file(outputPath);
	if (await existingIndex.exists()) {
		process.stderr.write("Docs directory not found; keeping bundled docs index.\n");
		process.exit(0);
	}
	process.stderr.write("Docs directory not found and no bundled docs index exists.\n");
	process.exit(1);
}

const glob = new Glob("**/*.md");
const entries: string[] = [];
for await (const relativePath of glob.scan(docsDir)) {
	entries.push(relativePath.split(path.sep).join("/"));
}
entries.sort();

const docsWithContent = await Promise.all(
	entries.map(async relativePath => ({
		relativePath,
		content: await Bun.file(path.join(docsDir, relativePath)).text(),
	})),
);

const filenamesLiteral = JSON.stringify(entries);

const mapEntries = docsWithContent
	.map(({ relativePath, content }) => `\t${JSON.stringify(relativePath)}: ${JSON.stringify(content)},`)
	.join("\n");
const output = [
	"// Auto-generated by scripts/generate-docs-index.ts - DO NOT EDIT",
	`Reflect.set(globalThis, Symbol.for("gjc.docs-index.generated.loaded"), true);`,
	"",
	`export const EMBEDDED_DOC_FILENAMES: readonly string[] = ${filenamesLiteral};`,
	"",
	`export const EMBEDDED_DOCS: Readonly<Record<string, string>> = {`,
	`${mapEntries}`,
	`};`,
	"",
].join("\n");

await Bun.write(outputPath, output);
process.stderr.write(`Generated ${path.relative(process.cwd(), outputPath)} (${entries.length} docs)\n`);