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

import * as path from 'path';
import * as cp from 'child_process';
import { Uri, window, Disposable } from 'vscode';
import { QuickPickItem } from 'vscode';
import { workspace } from 'vscode';

/**
 * A file opener using window.createQuickPick().
 * 
 * It shows how the list of items can be dynamically updated based on
 * the user's input in the filter field.
 */
export async function quickOpen() {
	const uri = await pickFile();
	if (uri) {
		const document = await workspace.openTextDocument(uri);
		await window.showTextDocument(document);
	}
}

class FileItem implements QuickPickItem {

	label: string;
	description: string;
	
	constructor(public base: Uri, public uri: Uri) {
		this.label = path.basename(uri.fsPath);
		this.description = path.dirname(path.relative(base.fsPath, uri.fsPath));
	}
}

async function pickFile() {
	const disposables: Disposable[] = [];
	try {
		return await new Promise<Uri | undefined>((resolve, reject) => {
			const input = window.createQuickPick<FileItem>();
			input.placeholder = 'Type to search for files';
			let rgs: cp.ChildProcess[] = [];
			disposables.push(
				input.onDidChangeValue(value => {
					rgs.forEach(rg => rg.kill());
					if (!value) {
						input.items = [];
						return;
					}
					input.busy = true;
					const cwds = workspace.workspaceFolders ? workspace.workspaceFolders.map(f => f.uri.fsPath) : [process.cwd()];
					rgs = cwds.map(cwd => {
						const rg = cp.exec(`rg --files -g '*${value}*'`, { cwd }, (err, stdout) => {
							const i = rgs.indexOf(rg);
							if (i !== -1) {
								if (rgs.length === cwds.length) {
									input.items = [];
								}
								if (!err) {
									input.items = input.items.concat(
										stdout
											.split('\n').slice(0, 50)
											.map(relative => new FileItem(Uri.file(cwd), Uri.file(path.join(cwd, relative))))
									);
								}
								rgs.splice(i, 1);
								if (!rgs.length) {
									input.busy = false;
								}
							}
						});
						return rg;
					});
				}),
				input.onDidChangeSelection(items => {
					resolve(items[0].uri);
					input.hide();
				}),
				input.onDidHide(() => {
					rgs.forEach(rg => rg.kill());
					resolve(undefined);
					input.dispose();
				})
			);
			input.show();
		});
	} finally {
		disposables.forEach(d => d.dispose());
	}
}