/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

// Regenerate vendored codex app-server protocol types.
//
// Resolution order for the codex binary:
//   1. $CODEX_BIN
//   2. node_modules/@openai/codex-<platform>-<arch>/vendor/.../bin/codex
//   3. `which codex`
//
// The locally installed binary's --version must match build/codex/codex-version.txt
// unless --no-version-check is passed.
//
// Generated files land in src/vs/platform/agentHost/node/codex/protocol/generated/

import { spawnSync } from 'node:child_process';
import { mkdtempSync, readdirSync, readFileSync, writeFileSync, statSync, rmSync, mkdirSync } from 'node:fs';
import { tmpdir } from 'node:os';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const REPO_ROOT = path.resolve(__dirname, '..', '..');
const VERSION_FILE = path.join(REPO_ROOT, 'build', 'codex', 'codex-version.txt');
const OUT_DIR = path.join(REPO_ROOT, 'src', 'vs', 'platform', 'agentHost', 'node', 'codex', 'protocol', 'generated');
const FORMATTER = path.join(REPO_ROOT, 'build', 'lib', 'formatter.ts');

const args = process.argv.slice(2);
const noVersionCheck = args.includes('--no-version-check');

function resolveCodexBinary() {
	if (process.env.CODEX_BIN) {
		return process.env.CODEX_BIN;
	}
	const platformMap = {
		'linux-x64': '@openai/codex-linux-x64/vendor/x86_64-unknown-linux-musl/bin/codex',
		'linux-arm64': '@openai/codex-linux-arm64/vendor/aarch64-unknown-linux-musl/bin/codex',
		'darwin-x64': '@openai/codex-darwin-x64/vendor/x86_64-apple-darwin/bin/codex',
		'darwin-arm64': '@openai/codex-darwin-arm64/vendor/aarch64-apple-darwin/bin/codex',
		'win32-x64': '@openai/codex-win32-x64/vendor/x86_64-pc-windows-msvc/bin/codex.exe',
		'win32-arm64': '@openai/codex-win32-arm64/vendor/aarch64-pc-windows-msvc/bin/codex.exe',
	};
	const key = `${process.platform}-${process.arch}`;
	const rel = platformMap[key];
	if (rel) {
		const candidate = path.join(REPO_ROOT, 'node_modules', rel);
		try {
			statSync(candidate);
			return candidate;
		} catch { /* fall through */ }
	}
	const which = spawnSync(process.platform === 'win32' ? 'where' : 'which', ['codex'], { encoding: 'utf8' });
	if (which.status === 0) {
		return which.stdout.trim().split(/\r?\n/)[0];
	}
	throw new Error('Cannot locate codex binary. Install via `npm install` (vendors @openai/codex) or set $CODEX_BIN.');
}

function readBinaryVersion(bin) {
	const r = spawnSync(bin, ['--version'], { encoding: 'utf8' });
	if (r.status !== 0) {
		throw new Error(`codex --version failed:\n${r.stderr}`);
	}
	// Output looks like: "codex-cli 0.134.0"
	const m = r.stdout.match(/(\d+\.\d+\.\d+(?:-[A-Za-z0-9.]+)?)/);
	if (!m) {
		throw new Error(`Could not parse codex version from: ${r.stdout}`);
	}
	return m[1];
}

function readPinnedVersion() {
	return readFileSync(VERSION_FILE, 'utf8').trim();
}

function formatGeneratedTypes(files) {
	for (let i = 0; i < files.length; i += 100) {
		const batch = files.slice(i, i + 100);
		const r = spawnSync(process.execPath, ['--experimental-strip-types', FORMATTER, '--replace', ...batch], { cwd: REPO_ROOT, encoding: 'utf8' });
		if (r.status !== 0) {
			throw new Error(`formatting generated protocol files failed:\n${r.stderr || r.stdout}`);
		}
		for (const file of batch) {
			const formatted = readFileSync(file, 'utf8').replace(/\r\n/g, '\n');
			writeFileSync(file, formatted);
		}
	}
}

function generate(bin, outDir, codexVersion) {
	const tmp = mkdtempSync(path.join(tmpdir(), 'codex-gen-'));
	const r = spawnSync(bin, ['app-server', 'generate-ts', '--out', tmp, '--experimental'], { encoding: 'utf8' });
	if (r.status !== 0) {
		throw new Error(`codex app-server generate-ts failed:\n${r.stderr}`);
	}
	// Wipe out existing generated content (excluding README.md).
	for (const entry of readdirSync(outDir, { withFileTypes: true })) {
		if (entry.name === 'README.md') { continue; }
		rmSync(path.join(outDir, entry.name), { recursive: true, force: true });
	}
	const generatedFiles = [];
	const HEADER = sourcePath =>
		`// AUTOGENERATED - do not edit.\n` +
		`// Source: \`codex app-server generate-ts --experimental\`\n` +
		`// Generated from @openai/codex ${codexVersion}, licensed Apache-2.0.\n` +
		`// Modified by VS Code to rewrite imports and apply repository formatting.\n` +
		`// See README.md in this directory for provenance and licensing notes.\n` +
		`// Regenerate: npm run codex:gen-protocol\n` +
		`// Source file: ${sourcePath}\n\n`;

	function copyRecursive(srcDir, dstDir, rel = '') {
		for (const entry of readdirSync(srcDir, { withFileTypes: true })) {
			const src = path.join(srcDir, entry.name);
			const dst = path.join(dstDir, entry.name);
			const relPath = path.posix.join(rel, entry.name);
			if (entry.isDirectory()) {
				mkdirSync(dst, { recursive: true });
				copyRecursive(src, dst, relPath);
			} else if (entry.isFile() && entry.name.endsWith('.ts')) {
				const body = readFileSync(src, 'utf8')
					// Strip ts-rs's own header so we don't double up
					.replace(/^\/\/ GENERATED CODE!.*$\n/m, '')
					.replace(/^\/\/ This file was generated by.*$\n/m, '')
					.replace(/^\s*\n/, '')
					// Rewrite relative imports to use .js extension (VS Code uses node16 module resolution).
					// Directory specifiers (no trailing file part) become `<dir>/index.js`.
					.replace(/(from\s+["'])(\.\.?\/[^"']+?)(["'])/g, (_m, p, spec, q) => {
						// If the spec resolves to a directory in our generated tree, point at its index.
						const abs = path.resolve(path.dirname(src), spec);
						let suffix = '.js';
						try {
							if (statSync(abs).isDirectory()) {
								suffix = '/index.js';
							}
						} catch { /* not a directory; assume .ts file */ }
						return `${p}${spec}${suffix}${q}`;
					});
				writeFileSync(dst, HEADER(relPath) + body);
				generatedFiles.push(dst);
			}
		}
	}

	mkdirSync(outDir, { recursive: true });
	copyRecursive(tmp, outDir);
	formatGeneratedTypes(generatedFiles);
	rmSync(tmp, { recursive: true, force: true });
}

function main() {
	const bin = resolveCodexBinary();
	const binVersion = readBinaryVersion(bin);
	const pinnedVersion = readPinnedVersion();

	console.log(`codex binary: ${bin}`);
	console.log(`codex --version: ${binVersion}`);
	console.log(`pinned version: ${pinnedVersion}`);

	if (!noVersionCheck && binVersion !== pinnedVersion) {
		console.error(`\nVersion mismatch: binary is ${binVersion}, pinned is ${pinnedVersion}.`);
		console.error(`Either update ${path.relative(REPO_ROOT, VERSION_FILE)} or install the matching codex version.`);
		console.error(`Use --no-version-check to override.`);
		process.exit(1);
	}

	mkdirSync(OUT_DIR, { recursive: true });
	generate(bin, OUT_DIR, binVersion);

	const count = readdirSync(OUT_DIR, { recursive: true }).filter(f => typeof f === 'string' && f.endsWith('.ts')).length;
	console.log(`\nWrote ${count} files to ${path.relative(REPO_ROOT, OUT_DIR)}`);
}

main();