import fs from 'fs';
import path from 'path';
import { fileURLToPath } from 'url';

const __dirname = path.dirname(fileURLToPath(import.meta.url));

/**
 * 아바타 이미지 저장 디렉터리
 * @returns {string}
 */
export function getAvatarsDir() {
    const dir = process.env.AVATARS_PATH || path.join(__dirname, '..', '..', 'data', 'avatars');
    if (!fs.existsSync(dir)) {
        fs.mkdirSync(dir, { recursive: true });
    }
    return dir;
}

/**
 * @param {number|string} userId
 * @returns {string}
 */
export function getAvatarFilePath(userId) {
    const filePath = path.join(getAvatarsDir(), `${userId}.png`);
    return fs.existsSync(filePath) ? filePath : null;
}

/**
 * @param {number|string} userId
 * @returns {string|null}
 */
export function getAvatarUrl(userId) {
    return getAvatarFilePath(userId) ? `/api/v1/auth/avatar/${userId}` : null;
}

/**
 * base64 data URL을 PNG로 저장
 * @param {number|string} userId
 * @param {string} dataUrl
 * @returns {string|null}
 */
export function saveAvatarImage(userId, dataUrl) {
    if (!dataUrl || !dataUrl.startsWith('data:image')) {
        return null;
    }
    const base64 = dataUrl.replace(/^data:image\/\w+;base64,/, '');
    if (!base64) {
        return null;
    }
    const fileName = `${userId}.png`;
    const filePath = path.join(getAvatarsDir(), fileName);
    fs.writeFileSync(filePath, Buffer.from(base64, 'base64'));
    return fs.existsSync(filePath) ? fileName : null;
}

/**
 * 아바타 이미지 삭제
 * @param {number|string} userId
 * @returns {boolean}
 */
export function deleteAvatarImage(userId) {
    const filePath = path.join(getAvatarsDir(), `${userId}.png`);
    if (!fs.existsSync(filePath)) return false;
    try {
        fs.unlinkSync(filePath);
        return true;
    } catch (err) {
        console.warn(`[avatar] 삭제 실패: ${filePath}`, err);
        return false;
    }
}