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

'use strict';

import cp = require('child_process');
import path = require('path');
import vscode = require('vscode');
import { getAllPackages } from './goPackages';
import { envPath } from './goPath';
import { getBinPath, getCurrentGoPath, getImportPath } from './util';

export function browsePackages() {
	let workDir = '';
	let selectedText = '';
	const editor = vscode.window.activeTextEditor;
	if (editor) {
		const currentUri = editor.document.uri;
		workDir = path.dirname(currentUri.fsPath);
		const selection = editor.selection;
		if (!selection.isEmpty) {
			// get selected text
			selectedText = editor.document.getText(selection);
		} else {
			// if selection is empty, then get the whole line the cursor is currently on.
			selectedText = editor.document.lineAt(selection.active.line).text;
		}
		selectedText = getImportPath(selectedText) || selectedText.trim();
	} else if (vscode.workspace.workspaceFolders && vscode.workspace.workspaceFolders.length === 1) {
		const currentUri = vscode.workspace.workspaceFolders[0].uri;
		workDir = currentUri.fsPath;
	}

	showPackageFiles(selectedText, true, workDir);
}

function showPackageFiles(pkg: string, showAllPkgsIfPkgNotFound: boolean, workDir: string) {
	const goRuntimePath = getBinPath('go');
	if (!goRuntimePath) {
		return vscode.window.showErrorMessage(
			`Failed to run "go list" to fetch packages as the "go" binary cannot be found in either GOROOT(${process.env['GOROOT']}) or PATH(${envPath})`
		);
	}

	if (!pkg && showAllPkgsIfPkgNotFound) {
		return showPackageList(workDir);
	}

	const options: { [key: string]: any } = {
		env: Object.assign({}, process.env, { GOPATH: getCurrentGoPath() })
	};

	if (workDir) {
		options['cwd'] = workDir;
	}

	cp.execFile(
		goRuntimePath,
		['list', '-f', '{{.Dir}}:{{.GoFiles}}:{{.TestGoFiles}}:{{.XTestGoFiles}}', pkg],
		options,
		(err, stdout, stderr) => {
			if (!stdout || stdout.indexOf(':') === -1) {
				if (showAllPkgsIfPkgNotFound) {
					return showPackageList(workDir);
				}

				return;
			}

			const matches = stdout && stdout.match(/(.*):\[(.*)\]:\[(.*)\]:\[(.*)\]/);
			if (matches) {
				const dir = matches[1];
				let files = matches[2] ? matches[2].split(' ') : [];
				const testfiles = matches[3] ? matches[3].split(' ') : [];
				const xtestfiles = matches[4] ? matches[4].split(' ') : [];
				files = files.concat(testfiles);
				files = files.concat(xtestfiles);
				vscode.window.showQuickPick(files, { placeHolder: `Below are Go files from ${pkg}` }).then((file) => {
					// if user abandoned list, file will be null and path.join will error out.
					// therefore return.
					if (!file) {
						return;
					}

					vscode.workspace.openTextDocument(path.join(dir, file)).then((document) => {
						vscode.window.showTextDocument(document);
					});
				});
			}
		}
	);
}

function showPackageList(workDir: string) {
	return getAllPackages(workDir).then((pkgMap) => {
		const pkgs: string[] = Array.from(pkgMap.keys());
		if (pkgs.length === 0) {
			return vscode.window.showErrorMessage(
				'Could not find packages. Ensure `gopkgs -format {{.Name}};{{.ImportPath}}` runs successfully.'
			);
		}

		vscode.window
			.showQuickPick(pkgs.sort(), { placeHolder: 'Select a package to browse' })
			.then((pkgFromDropdown) => {
				if (!pkgFromDropdown) {
					return;
				}
				showPackageFiles(pkgFromDropdown, false, workDir);
			});
	});
}