import fs from 'node:fs';
import os from 'node:os';
import path from 'node:path';
import https from 'node:https';
import {fileURLToPath} from 'node:url';
import AdmZip from 'adm-zip';
import * as tar from 'tar';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const VERSION = '3.8.1';
const BASE_URL = 'https://download.kiwix.org/release/kiwix-tools';
const MAX_REDIRECTS = 5;
const BIN_DIR = path.join(__dirname, '..', 'bin');
const PLATFORM_MAP = {
	linux: {name: 'linux', ext: 'tar.gz'},
	darwin: {name: 'macos', ext: 'tar.gz'},
	win32: {name: 'win', ext: 'zip'}
};
const ARCH_MAP = {
	linux: {
		x64: 'x86_64',
		arm64: 'aarch64',
		arm: 'armhf',
		ia32: 'i586'
	},
	darwin: {
		x64: 'x86_64',
		arm64: 'arm64'
	},
	win32: {
		x64: 'x86_64',
		ia32: 'i686'
	}
};


function download(url, dest, redirectsLeft = MAX_REDIRECTS) {
	return new Promise((resolve, reject) => {
		const file = fs.createWriteStream(dest);
		const agent = new https.Agent({maxFreeSockets: 20, maxTotalSockets: 50});

		const cleanupAndReject = err => {
			file.close();
			fs.unlink(dest, () => reject(err));
		};

		const req = https.get(url, {agent}, res => {
			if (res.statusCode >= 300 && res.statusCode < 400 && res.headers.location) {
				res.resume(); // discard body
				file.close();
				if (redirectsLeft <= 0) {
					reject(new Error(`Too many redirects while downloading ${url}`));
					return;
				}
				// Location can be relative, so resolve it against the current URL.
				const nextUrl = new URL(res.headers.location, url).toString();
				resolve(download(nextUrl, dest, redirectsLeft - 1));
				return;
			}
			if (!res.statusCode || res.statusCode >= 400) {
				res.resume();
				cleanupAndReject(new Error(`HTTP ${res.statusCode} - ${res.statusMessage}`));
				return;
			}
			res.pipe(file);
			file.on('finish', () => {
				file.close(resolve);
			});
			file.on('error', cleanupAndReject);
		});

		req.on('error', cleanupAndReject);
	});
}

async function flattenExtractedDir(srcDir, destDir) {
	let entries = await fs.promises.readdir(srcDir, {withFileTypes: true});

	let sourceDir = srcDir;
	if (entries.length === 1 && entries[0].isDirectory()) {
		sourceDir = path.join(srcDir, entries[0].name);
		entries = await fs.promises.readdir(sourceDir, {withFileTypes: true});
	}

	for (const entry of entries) {
		const src = path.join(sourceDir, entry.name);
		const dest = path.join(destDir, entry.name);
		await fs.promises.rename(src, dest);
	}
}

async function extractTarGz(archivePath, destDir) {
	const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'kiwix-extract-'));
	await tar.extract({
		file: archivePath,
		cwd: tmpDir
	});

	await flattenExtractedDir(tmpDir, destDir);
	await fs.promises.rm(tmpDir, {recursive: true, force: true});
}

async function extractZip(archivePath, destDir) {
	const zip = new AdmZip(archivePath);
	const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'kiwix-extract-'));
	await new Promise((resolve, reject) => {
		zip.extractAllToAsync(tmpDir, true, false, err => {
			if (err) reject(err);
			else resolve();
		});
	});

	await flattenExtractedDir(tmpDir, destDir);
	await fs.promises.rm(tmpDir, {recursive: true, force: true});
}

function resolveArchiveName() {
	const platformInfo = PLATFORM_MAP[process.platform];
	if (!platformInfo) {
		throw new Error(`Unsupported platform: ${process.platform}`);
	}

	const archName = ARCH_MAP[process.platform]?.[process.arch];
	if (!archName) {
		const supported = Object.keys(ARCH_MAP[process.platform] || {}).join(', ');
		throw new Error(
			`Unsupported architecture "${process.arch}" for platform "${process.platform}". ` +
			`Supported architectures: ${supported}`
		);
	}

	return {
		archiveName: `kiwix-tools_${platformInfo.name}-${archName}-${VERSION}.${platformInfo.ext}`,
		ext: platformInfo.ext
	};
}

async function install() {
	const {archiveName, ext} = resolveArchiveName();
	const url = `${BASE_URL}/${archiveName}`;
	const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'kiwix-install-'));
	const archivePath = path.join(tmpDir, archiveName);

	console.log(`Platform: ${process.platform}/${process.arch}`);
	console.log(`Downloading kiwix-tools: ${url}`);
	await download(url, archivePath);
	console.log('Download complete!');

	console.log('Extracting...');
	await fs.promises.mkdir(BIN_DIR, {recursive: true});

	if (ext === 'zip') {
		await extractZip(archivePath, BIN_DIR);
	} else {
		await extractTarGz(archivePath, BIN_DIR);
	}

	for (const entry of await fs.promises.readdir(BIN_DIR)) {
		if (entry.startsWith('kiwix-')) {
			const fullPath = path.join(BIN_DIR, entry);
			const stat = await fs.promises.stat(fullPath);
			if (stat.isFile()) {
				await fs.promises.chmod(fullPath, 0o755);
			}
		}
	}

	console.log(`Installed to: ${BIN_DIR}`);
	await fs.promises.rm(tmpDir, {recursive: true, force: true});
}

install().catch(err => {
	console.error('Install failed:', err.message);
	process.exit(1);
});