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

'use strict';

import { spawnSync } from 'child_process';
import { constants, statSync } from 'fs';
import { tmpdir } from 'os';
import path = require('path');
import { additionalDeps, bundledDeps, referenceGeneratedDepsByArch } from './dep-lists';
import { ArchString } from './types';

// A flag that can easily be toggled.
// Make sure to compile the build directory after toggling the value.
// If false, we warn about new dependencies if they show up
// while running the Debian prepare package task for a release.
// If true, we fail the build if there are new dependencies found during that task.
// The reference dependencies, which one has to update when the new dependencies
// are valid, are in dep-lists.ts
const FAIL_BUILD_FOR_NEW_DEPENDENCIES: boolean = true;

export function getDependencies(buildDir: string, applicationName: string, arch: ArchString, sysroot: string): string[] {
	// Get the files for which we want to find dependencies.
	const nativeModulesPath = path.join(buildDir, 'resources', 'app', 'node_modules.asar.unpacked');
	const findResult = spawnSync('find', [nativeModulesPath, '-name', '*.node']);
	if (findResult.status) {
		console.error('Error finding files:');
		console.error(findResult.stderr.toString());
		return [];
	}

	const files = findResult.stdout.toString().trimEnd().split('\n');

	const appPath = path.join(buildDir, applicationName);
	files.push(appPath);

	// Add chrome sandbox and crashpad handler.
	files.push(path.join(buildDir, 'chrome-sandbox'));
	files.push(path.join(buildDir, 'chrome_crashpad_handler'));

	// Generate the dependencies.
	const dependencies: Set<string>[] = files.map((file) => calculatePackageDeps(file, arch, sysroot));
	// Add additional dependencies.
	const additionalDepsSet = new Set(additionalDeps);
	dependencies.push(additionalDepsSet);

	// Merge all the dependencies.
	const mergedDependencies = mergePackageDeps(dependencies);
	let sortedDependencies: string[] = [];
	for (const dependency of mergedDependencies) {
		sortedDependencies.push(dependency);
	}
	sortedDependencies.sort();

	// Exclude bundled dependencies
	sortedDependencies = sortedDependencies.filter(dependency => {
		return !bundledDeps.some(bundledDep => dependency.startsWith(bundledDep));
	});

	const referenceGeneratedDeps = referenceGeneratedDepsByArch[arch];
	if (JSON.stringify(sortedDependencies) !== JSON.stringify(referenceGeneratedDeps)) {
		const failMessage = 'The dependencies list has changed.'
			+ '\nOld:\n' + referenceGeneratedDeps.join('\n')
			+ '\nNew:\n' + sortedDependencies.join('\n');
		if (FAIL_BUILD_FOR_NEW_DEPENDENCIES) {
			throw new Error(failMessage);
		} else {
			console.warn(failMessage);
		}
	}

	return sortedDependencies;
}

// Based on https://source.chromium.org/chromium/chromium/src/+/main:chrome/installer/linux/debian/calculate_package_deps.py.
function calculatePackageDeps(binaryPath: string, arch: ArchString, sysroot: string): Set<string> {
	try {
		if (!(statSync(binaryPath).mode & constants.S_IXUSR)) {
			throw new Error(`Binary ${binaryPath} needs to have an executable bit set.`);
		}
	} catch (e) {
		// The package might not exist. Don't re-throw the error here.
		console.error('Tried to stat ' + binaryPath + ' but failed.');
	}

	// Get the Chromium dpkg-shlibdeps file.
	const dpkgShlibdepsUrl = 'https://raw.githubusercontent.com/chromium/chromium/100.0.4896.160/third_party/dpkg-shlibdeps/dpkg-shlibdeps.pl';
	const dpkgShlibdepsScriptLocation = `${tmpdir()}/dpkg-shlibdeps.pl`;
	const result = spawnSync('curl', [dpkgShlibdepsUrl, '-o', dpkgShlibdepsScriptLocation]);
	if (result.status !== 0) {
		throw new Error('Cannot retrieve dpkg-shlibdeps. Stderr:\n' + result.stderr);
	}
	const cmd = [dpkgShlibdepsScriptLocation, '--ignore-weak-undefined'];
	switch (arch) {
		case 'amd64':
			cmd.push(`-l${sysroot}/usr/lib/x86_64-linux-gnu`,
				`-l${sysroot}/lib/x86_64-linux-gnu`);
			break;
		case 'armhf':
			cmd.push(`-l${sysroot}/usr/lib/arm-linux-gnueabihf`,
				`-l${sysroot}/lib/arm-linux-gnueabihf`);
			break;
		case 'arm64':
			cmd.push(`-l${sysroot}/usr/lib/aarch64-linux-gnu`,
				`-l${sysroot}/lib/aarch64-linux-gnu`);
			break;
		default:
			throw new Error('Unsupported architecture ' + arch);
	}
	cmd.push(`-l${sysroot}/usr/lib`);
	cmd.push('-O', '-e', path.resolve(binaryPath));

	const dpkgShlibdepsResult = spawnSync('perl', cmd, { cwd: sysroot });
	if (dpkgShlibdepsResult.status !== 0) {
		throw new Error(`dpkg-shlibdeps failed with exit code ${dpkgShlibdepsResult.status}. stderr:\n${dpkgShlibdepsResult.stderr} `);
	}

	const shlibsDependsPrefix = 'shlibs:Depends=';
	const requiresList = dpkgShlibdepsResult.stdout.toString('utf-8').trimEnd().split('\n');
	let depsStr = '';
	for (const line of requiresList) {
		if (line.startsWith(shlibsDependsPrefix)) {
			depsStr = line.substring(shlibsDependsPrefix.length);
		}
	}
	const requires = new Set(depsStr.split(', ').sort());
	return requires;
}

// Based on https://source.chromium.org/chromium/chromium/src/+/main:chrome/installer/linux/rpm/merge_package_deps.py.
function mergePackageDeps(inputDeps: Set<string>[]): Set<string> {
	// For now, see if directly appending the dependencies helps.
	const requires = new Set<string>();
	for (const depSet of inputDeps) {
		for (const dep of depSet) {
			const trimmedDependency = dep.trim();
			if (trimmedDependency.length && !trimmedDependency.startsWith('#')) {
				requires.add(trimmedDependency);
			}
		}
	}
	return requires;
}