/*
 * SPDX-FileCopyrightText: syuilo and misskey-project
 * SPDX-License-Identifier: AGPL-3.0-only
 */

import * as fs from 'fs/promises';
import * as path from 'node:path';
import MagicString from 'magic-string';
import { collectModifications } from './locale-inliner/collect-modifications.js';
import { applyWithLocale } from './locale-inliner/apply-with-locale.js';
import { blankLogger } from './logger.js';
import type { Logger } from './logger.js';
import type { Locale } from '../../locales/index.js';
import type { Manifest as ViteManifest } from 'vite';

export class LocaleInliner {
	outputDir: string;
	scriptsDir: string;
	i18nFile: string;
	i18nFileName: string;
	logger: Logger;
	chunks: ScriptChunk[];

	static async create(options: {
		outputDir: string,
		scriptsDir: string,
		i18nFile: string,
		logger: Logger,
	}): Promise<LocaleInliner> {
		const manifest: ViteManifest = JSON.parse(await fs.readFile(`${options.outputDir}/manifest.json`, 'utf-8'));
		return new LocaleInliner({ ...options, manifest });
	}

	constructor(options: {
		outputDir: string,
		scriptsDir: string,
		i18nFile: string,
		manifest: ViteManifest,
		logger: Logger,
	}) {
		this.outputDir = options.outputDir;
		this.scriptsDir = options.scriptsDir;
		this.i18nFile = options.i18nFile;
		this.i18nFileName = this.stripScriptDir(options.manifest[this.i18nFile].file);
		this.logger = options.logger;
		this.chunks = Object.values(options.manifest).filter(chunk => this.isScriptFile(chunk.file)).map(chunk => ({
			fileName: this.stripScriptDir(chunk.file),
			chunkName: chunk.name,
		}));
	}

	async loadFiles() {
		await Promise.all(this.chunks.map(async chunk => {
			const filePath = path.join(this.outputDir, this.scriptsDir, chunk.fileName);
			chunk.sourceCode = await fs.readFile(filePath, 'utf-8');
		}));
	}

	collectsModifications() {
		for (const chunk of this.chunks) {
			if (!chunk.sourceCode) {
				throw new Error(`Source code for ${chunk.fileName} is not loaded.`);
			}
			const fileLogger = this.logger.prefixed(`${chunk.fileName} (${chunk.chunkName}): `);
			chunk.modifications = collectModifications(chunk.sourceCode, chunk.fileName, fileLogger, this);
		}
	}

	async saveAllLocales(locales: Record<string, Locale>) {
		const localeNames = Object.keys(locales);
		for (const localeName of localeNames) {
			await this.saveLocale(localeName, locales[localeName]);
		}
	}

	async saveLocale(localeName: string, localeJson: Locale) {
		// create directory
		await fs.mkdir(path.join(this.outputDir, localeName), { recursive: true });
		const localeLogger = localeName === 'ja-JP' ? this.logger : blankLogger; // we want to log for single locale only
		for (const chunk of this.chunks) {
			if (!chunk.sourceCode || !chunk.modifications) {
				throw new Error(`Source code or modifications for ${chunk.fileName} is not available.`);
			}
			const fileLogger = localeLogger.prefixed(`${chunk.fileName} (${chunk.chunkName}): `);
			const magicString = new MagicString(chunk.sourceCode);
			applyWithLocale(magicString, chunk.modifications, localeName, localeJson, fileLogger);

			await fs.writeFile(path.join(this.outputDir, localeName, chunk.fileName), magicString.toString());
		}
	}

	isScriptFile(fileName: string) {
		return fileName.startsWith(this.scriptsDir + '/') && fileName.endsWith('.js');
	}

	stripScriptDir(fileName: string) {
		if (!fileName.startsWith(this.scriptsDir + '/')) {
			throw new Error(`${fileName} does not start with ${this.scriptsDir}/`);
		}
		return fileName.slice(this.scriptsDir.length + 1);
	}
}

interface ScriptChunk {
	fileName: string;
	chunkName?: string;
	sourceCode?: string;
	modifications?: TextModification[];
}

export type TextModification = {
	type: 'delete';
	begin: number;
	end: number;
	localizedOnly: boolean;
} | {
	// can be used later to insert '../scripts' for common files
	type: 'insert';
	begin: number;
	text: string;
	localizedOnly: boolean;
} | {
	type: 'replace';
	begin: number;
	end: number;
	text: string;
	localizedOnly: boolean;
} | {
	type: 'localized';
	begin: number;
	end: number;
	localizationKey: string[];
	localizedOnly: true;
} | {
	type: 'parameterized-function';
	begin: number;
	end: number;
	localizationKey: string[];
	localizedOnly: true;
} | {
	type: 'locale-name';
	begin: number;
	end: number;
	literal: boolean;
	localizedOnly: true;
} | {
	type: 'locale-json';
	begin: number;
	end: number;
	localizedOnly: true;
};