import * as path from 'path';

import * as fs from 'fs';

import * as child_process from 'child_process';

const isWindows = process.platform === 'win32';

const is64bit = process.arch === 'x64';

export function subsystemForLinuxPresent(): boolean {

if (!isWindows) {

return false;

}

const bashPath32bitApp = path.join(process.env['SystemRoot'], 'Sysnative', 'bash.exe');

const bashPath64bitApp = path.join(process.env['SystemRoot'], 'System32', 'bash.exe');

const bashPathHost = is64bit ? bashPath64bitApp : bashPath32bitApp;

return fs.existsSync(bashPathHost);

}

function windowsPathToWSLPath(windowsPath: string): string {

if (!isWindows || !windowsPath) {

return undefined;

} else if (path.isAbsolute(windowsPath)) {

return `/mnt/${windowsPath.substr(0, 1).toLowerCase()}/${windowsPath.substr(3).replace(/\\/g, '/')}`;

} else {

return windowsPath.replace(/\\/g, '/');

}

}

export interface ILaunchArgs {

cwd: string;

executable: string;

args: string[];

combined: string[];

localRoot?: string;

remoteRoot?: string;

}

export function createLaunchArg(useSubsytemLinux: boolean | undefined, useExternalConsole: boolean, cwd: string | undefined, executable: string, args?: string[], program?: string): ILaunchArgs {

if (useSubsytemLinux && subsystemForLinuxPresent()) {

const bashPath32bitApp = path.join(process.env['SystemRoot'], 'Sysnative', 'bash.exe');

const bashPath64bitApp = path.join(process.env['SystemRoot'], 'System32', 'bash.exe');

const bashPathHost = is64bit ? bashPath64bitApp : bashPath32bitApp;

const subsystemLinuxPath = useExternalConsole ? bashPath64bitApp : bashPathHost;

const bashCommand = [executable].concat(args || []).map(element => {

if (element === program) { // workaround for issue #35249

element = element.replace(/\\/g, '/');

}

return element.indexOf(' ') > 0 ? `'${element}'` : element;

}).join(' ');

return <ILaunchArgs>{

cwd,

executable: subsystemLinuxPath,

args: ['-ic', bashCommand],

combined: [subsystemLinuxPath].concat(['-ic', bashCommand]),

localRoot: cwd,

remoteRoot: windowsPathToWSLPath(cwd)

};

} else {

return <ILaunchArgs>{

cwd: cwd,

executable: executable,

args: args || [],

combined: [executable].concat(args || [])

};

}

}

export function spawn(useWSL: boolean, executable: string, args?: string[], options?: child_process.SpawnOptions) {

const launchArgs = createLaunchArg(useWSL, false, undefined, executable, args);

return child_process.spawn(launchArgs.executable, launchArgs.args, options);

}

export function spawnSync(useWSL: boolean, executable: string, args?: string[], options?: child_process.SpawnSyncOptions) {

const launchArgs = createLaunchArg(useWSL, false, undefined, executable, args);

return child_process.spawnSync(launchArgs.executable, launchArgs.args, options);

}