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

import { Uri, workspace } from 'vscode';
import { RequestType, CommonLanguageClient } from 'vscode-languageclient';
import { Runtime } from './htmlClient';

export namespace FsContentRequest {
	export const type: RequestType<{ uri: string; encoding?: string; }, string, any, any> = new RequestType('fs/content');
}
export namespace FsStatRequest {
	export const type: RequestType<string, FileStat, any, any> = new RequestType('fs/stat');
}

export namespace FsReadDirRequest {
	export const type: RequestType<string, [string, FileType][], any, any> = new RequestType('fs/readDir');
}

export function serveFileSystemRequests(client: CommonLanguageClient, runtime: Runtime) {
	client.onRequest(FsContentRequest.type, (param: { uri: string; encoding?: string; }) => {
		const uri = Uri.parse(param.uri);
		if (uri.scheme === 'file' && runtime.fs) {
			return runtime.fs.getContent(param.uri);
		}
		return workspace.fs.readFile(uri).then(buffer => {
			return new runtime.TextDecoder(param.encoding).decode(buffer);
		});
	});
	client.onRequest(FsReadDirRequest.type, (uriString: string) => {
		const uri = Uri.parse(uriString);
		if (uri.scheme === 'file' && runtime.fs) {
			return runtime.fs.readDirectory(uriString);
		}
		return workspace.fs.readDirectory(uri);
	});
	client.onRequest(FsStatRequest.type, (uriString: string) => {
		const uri = Uri.parse(uriString);
		if (uri.scheme === 'file' && runtime.fs) {
			return runtime.fs.stat(uriString);
		}
		return workspace.fs.stat(uri);
	});
}

export enum FileType {
	/**
	 * The file type is unknown.
	 */
	Unknown = 0,
	/**
	 * A regular file.
	 */
	File = 1,
	/**
	 * A directory.
	 */
	Directory = 2,
	/**
	 * A symbolic link to a file.
	 */
	SymbolicLink = 64
}
export interface FileStat {
	/**
	 * The type of the file, e.g. is a regular file, a directory, or symbolic link
	 * to a file.
	 */
	type: FileType;
	/**
	 * The creation timestamp in milliseconds elapsed since January 1, 1970 00:00:00 UTC.
	 */
	ctime: number;
	/**
	 * The modification timestamp in milliseconds elapsed since January 1, 1970 00:00:00 UTC.
	 */
	mtime: number;
	/**
	 * The size in bytes.
	 */
	size: number;
}

export interface RequestService {
	getContent(uri: string, encoding?: string): Promise<string>;

	stat(uri: string): Promise<FileStat>;
	readDirectory(uri: string): Promise<[string, FileType][]>;
}

export function getScheme(uri: string) {
	return uri.substr(0, uri.indexOf(':'));
}

export function dirname(uri: string) {
	const lastIndexOfSlash = uri.lastIndexOf('/');
	return lastIndexOfSlash !== -1 ? uri.substr(0, lastIndexOfSlash) : '';
}

export function basename(uri: string) {
	const lastIndexOfSlash = uri.lastIndexOf('/');
	return uri.substr(lastIndexOfSlash + 1);
}

const Slash = '/'.charCodeAt(0);
const Dot = '.'.charCodeAt(0);

export function isAbsolutePath(path: string) {
	return path.charCodeAt(0) === Slash;
}

export function resolvePath(uri: Uri, path: string): Uri {
	if (isAbsolutePath(path)) {
		return uri.with({ path: normalizePath(path.split('/')) });
	}
	return joinPath(uri, path);
}

export function normalizePath(parts: string[]): string {
	const newParts: string[] = [];
	for (const part of parts) {
		if (part.length === 0 || part.length === 1 && part.charCodeAt(0) === Dot) {
			// ignore
		} else if (part.length === 2 && part.charCodeAt(0) === Dot && part.charCodeAt(1) === Dot) {
			newParts.pop();
		} else {
			newParts.push(part);
		}
	}
	if (parts.length > 1 && parts[parts.length - 1].length === 0) {
		newParts.push('');
	}
	let res = newParts.join('/');
	if (parts[0].length === 0) {
		res = '/' + res;
	}
	return res;
}


export function joinPath(uri: Uri, ...paths: string[]): Uri {
	const parts = uri.path.split('/');
	for (let path of paths) {
		parts.push(...path.split('/'));
	}
	return uri.with({ path: normalizePath(parts) });
}
