import fs from 'fs';
import path from 'path';
import { TextDocument } from 'vscode';
import { Language } from 'web-tree-sitter';

import { LanguageIdentifier } from 'base/common/languages/languages';
import { ILanguageServiceProvider } from 'base/common/languages/languageService';

import { ROOT_DIR } from './TestUtil';

// In the test, we need to import Parser from "web-tree-sitter" as a const.
const Parser = require('web-tree-sitter');

/**
 * TestOnly: Language service for tree-sitter languages, used in test code.
 */
export class TestLanguageServiceProvider implements ILanguageServiceProvider {
	_parser: any;

	constructor(parser: any) {
		this._parser = parser;
	}

	async parse(identifier: LanguageIdentifier, input: string) {
		return undefined;
	}

	async parseTextDocument(document: TextDocument) {
		return undefined;
	}

	async getLanguage(langId: string): Promise<Language | undefined> {
		const nodeModulesPath = path.join(ROOT_DIR, 'node_modules');
		const wasmPath = path.join(
			nodeModulesPath,
			'@unit-mesh',
			'treesitter-artifacts',
			'wasm',
			`tree-sitter-${langId}.wasm`,
		);

		const bits = fs.readFileSync(wasmPath);
		await Parser.init();
		return await Parser.Language.load(bits);
	}

	getParser(): any {
		return this._parser;
	}

	isSupportLanguage(identifier: LanguageIdentifier): boolean {
		return true;
	}

	ready(): Promise<void> {
		return Promise.resolve();
	}

	dispose(): void {
		// pass
	}
}