/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/
import * as os from 'os';
import { virtualMachineHint } from 'vs/base/node/id';
import { IMachineInfo, WorkspaceStats, WorkspaceStatItem } from 'vs/platform/diagnostics/common/diagnosticsService';
import { readdir, stat } from 'fs';
import { join } from 'vs/base/common/path';

export function getMachineInfo(): IMachineInfo {
	const MB = 1024 * 1024;
	const GB = 1024 * MB;

	const machineInfo: IMachineInfo = {
		os: `${os.type()} ${os.arch()} ${os.release()}`,
		memory: `${(os.totalmem() / GB).toFixed(2)}GB (${(os.freemem() / GB).toFixed(2)}GB free)`,
		vmHint: `${Math.round((virtualMachineHint.value() * 100))}%`,
	};

	const cpus = os.cpus();
	if (cpus && cpus.length > 0) {
		machineInfo.cpus = `${cpus[0].model} (${cpus.length} x ${cpus[0].speed})`;
	}

	return machineInfo;
}

export function collectWorkspaceStats(folder: string, filter: string[]): Promise<WorkspaceStats> {
	const configFilePatterns = [
		{ 'tag': 'grunt.js', 'pattern': /^gruntfile\.js$/i },
		{ 'tag': 'gulp.js', 'pattern': /^gulpfile\.js$/i },
		{ 'tag': 'tsconfig.json', 'pattern': /^tsconfig\.json$/i },
		{ 'tag': 'package.json', 'pattern': /^package\.json$/i },
		{ 'tag': 'jsconfig.json', 'pattern': /^jsconfig\.json$/i },
		{ 'tag': 'tslint.json', 'pattern': /^tslint\.json$/i },
		{ 'tag': 'eslint.json', 'pattern': /^eslint\.json$/i },
		{ 'tag': 'tasks.json', 'pattern': /^tasks\.json$/i },
		{ 'tag': 'launch.json', 'pattern': /^launch\.json$/i },
		{ 'tag': 'settings.json', 'pattern': /^settings\.json$/i },
		{ 'tag': 'webpack.config.js', 'pattern': /^webpack\.config\.js$/i },
		{ 'tag': 'project.json', 'pattern': /^project\.json$/i },
		{ 'tag': 'makefile', 'pattern': /^makefile$/i },
		{ 'tag': 'sln', 'pattern': /^.+\.sln$/i },
		{ 'tag': 'csproj', 'pattern': /^.+\.csproj$/i },
		{ 'tag': 'cmake', 'pattern': /^.+\.cmake$/i }
	];

	const fileTypes = new Map<string, number>();
	const configFiles = new Map<string, number>();

	const MAX_FILES = 20000;

	function walk(dir: string, filter: string[], token: { count: number, maxReached: boolean }, done: (allFiles: string[]) => void): void {
		let results: string[] = [];
		readdir(dir, async (err, files) => {
			// Ignore folders that can't be read
			if (err) {
				return done(results);
			}

			let pending = files.length;
			if (pending === 0) {
				return done(results);
			}

			for (const file of files) {
				if (token.maxReached) {
					return done(results);
				}

				stat(join(dir, file), (err, stats) => {
					// Ignore files that can't be read
					if (err) {
						if (--pending === 0) {
							return done(results);
						}
					} else {
						if (stats.isDirectory()) {
							if (filter.indexOf(file) === -1) {
								walk(join(dir, file), filter, token, (res: string[]) => {
									results = results.concat(res);

									if (--pending === 0) {
										return done(results);
									}
								});
							} else {
								if (--pending === 0) {
									done(results);
								}
							}
						} else {
							if (token.count >= MAX_FILES) {
								token.maxReached = true;
							}

							token.count++;
							results.push(file);

							if (--pending === 0) {
								done(results);
							}
						}
					}
				});
			}
		});
	}

	const addFileType = (fileType: string) => {
		if (fileTypes.has(fileType)) {
			fileTypes.set(fileType, fileTypes.get(fileType)! + 1);
		}
		else {
			fileTypes.set(fileType, 1);
		}
	};

	const addConfigFiles = (fileName: string) => {
		for (const each of configFilePatterns) {
			if (each.pattern.test(fileName)) {
				if (configFiles.has(each.tag)) {
					configFiles.set(each.tag, configFiles.get(each.tag)! + 1);
				} else {
					configFiles.set(each.tag, 1);
				}
			}
		}
	};

	const acceptFile = (name: string) => {
		if (name.lastIndexOf('.') >= 0) {
			const suffix: string | undefined = name.split('.').pop();
			if (suffix) {
				addFileType(suffix);
			}
		}
		addConfigFiles(name);
	};

	const token: { count: number, maxReached: boolean } = { count: 0, maxReached: false };

	return new Promise((resolve, reject) => {
		walk(folder, filter, token, async (files) => {
			files.forEach(acceptFile);

			// TODO@rachel commented out due to severe performance issues
			// see https://github.com/Microsoft/vscode/issues/70563
			// const launchConfigs = await collectLaunchConfigs(folder);

			resolve({
				configFiles: asSortedItems(configFiles),
				fileTypes: asSortedItems(fileTypes),
				fileCount: token.count,
				maxFilesReached: token.maxReached,
				// launchConfigFiles: launchConfigs
			});
		});
	});
}

function asSortedItems(map: Map<string, number>): WorkspaceStatItem[] {
	const a: WorkspaceStatItem[] = [];
	map.forEach((value, index) => a.push({ name: index, count: value }));
	return a.sort((a, b) => b.count - a.count);
}