'use strict';

// Eagle's item API has no arbitrary custom fields. Keep plugin metadata in
// userData, keyed by library + item ID, without editing Eagle metadata.json.
const fs = require('fs');
const path = require('path');
const crypto = require('crypto');

function identity(sourcePath, itemId) {
	const directory = path.dirname(path.resolve(sourcePath));
	const match = path.basename(directory).match(/^(.+)\.info$/i);
	return match
		? path.dirname(directory) + ':' + (itemId || match[1])
		: path.resolve(sourcePath);
}

function createStore(userDataPath, sourcePath, itemId) {
	const key = crypto.createHash('sha256').update(identity(sourcePath, itemId)).digest('hex');
	const directory = path.join(userDataPath, 'SpineViewer', 'preview-settings');
	const file = path.join(directory, key + '.json');
	return {
		file,
		read() {
			try {
				const data = JSON.parse(fs.readFileSync(file, 'utf8'));
				return typeof data.premultipliedAlpha === 'boolean' ? data.premultipliedAlpha : undefined;
			} catch (e) {
				if (e.code === 'ENOENT') return undefined;
				throw e;
			}
		},
		// This method is called only by the user's checkbox change event.
		write(premultipliedAlpha) {
			if (typeof premultipliedAlpha !== 'boolean') throw new TypeError('预乘设置必须为布尔值');
			fs.mkdirSync(directory, { recursive: true });
			const temp = file + '.' + crypto.randomBytes(8).toString('hex') + '.tmp';
			try {
				fs.writeFileSync(temp, JSON.stringify({ premultipliedAlpha }, null, 2) + '\n', { flag: 'wx' });
				fs.renameSync(temp, file);
			} finally {
				try { fs.unlinkSync(temp); } catch (e) { if (e.code !== 'ENOENT') throw e; }
			}
		}
	};
}

async function resolveDataPath(app) {
	try {
		const value = app && (app.userDataPath || (typeof app.getPath === 'function' && await app.getPath('userData')));
		if (typeof value === 'string' && value) return value;
	} catch (e) { /* Some Eagle format-view windows reject app.getPath IPC. */ }
	const home = require('os').homedir();
	if (process.platform === 'darwin') return path.join(home, 'Library', 'Application Support', 'Eagle');
	if (process.platform === 'win32') return path.join(process.env.APPDATA || path.join(home, 'AppData', 'Roaming'), 'Eagle');
	return path.join(process.env.XDG_CONFIG_HOME || path.join(home, '.config'), 'Eagle');
}

// 尾缀表是全局偏好（不是每个素材一份）：同一台机器上所有素材、所有库共用。
// 查看器在加载资源前读取它，用户的增删都会立即落盘。
function createSuffixStore(userDataPath) {
	const directory = path.join(userDataPath, 'SpineViewer');
	const file = path.join(directory, 'suffix-settings.json');
	return {
		file,
		read() {
			try {
				const data = JSON.parse(fs.readFileSync(file, 'utf8'));
				return Array.isArray(data.suffixes) ? data.suffixes : [];
			} catch (e) {
				if (e.code === 'ENOENT') return [];
				throw e;
			}
		},
		// 仅在用户通过下拉列表增删尾缀时调用。
		write(suffixes) {
			if (!Array.isArray(suffixes)) throw new TypeError('尾缀设置必须为数组');
			fs.mkdirSync(directory, { recursive: true });
			const temp = file + '.' + crypto.randomBytes(8).toString('hex') + '.tmp';
			try {
				fs.writeFileSync(temp, JSON.stringify({ suffixes }, null, 2) + '\n', { flag: 'wx' });
				fs.renameSync(temp, file);
			} finally {
				try { fs.unlinkSync(temp); } catch (e) { if (e.code !== 'ENOENT') throw e; }
			}
		}
	};
}

module.exports = { createStore, createSuffixStore, resolveDataPath };