/**
 * Copyright (c) 2026 Niolla
 * All rights reserved.
 *
 * This source code is proprietary and confidential.
 * Unauthorized copying, modification, distribution, or use
 * of this file, via any medium, is strictly prohibited.
 */

// app/utils/cache.util.js

const redis = require("../config/redisClient");
const { log } = require("./consoleLog.utill");
const db = require("../models");
const User = db.User;


///////////////////////////////
//      User Cache          //
/////////////////////////////

const CACHE_TTL = 20 * 60; // 20 minutes (in seconds)

const getCacheKey = (email) => `user:${email}`;

async function getCachedUser(email) {
  const key = getCacheKey(email);

  try {
    // 1. Check Redis first
    if (process.env.CACHE === "true") {
      const cached = await redis.get(key);

      if (cached) {
        log("⚡ Cache HIT - returning user from Redis");
        return JSON.parse(cached);
      }
    }

    log("Cache MISS - fetching user from DB");
    // 2. Fetch from DB
    const user = await User.findOne({ where: { email } });
    if (!user) return null;

    const plainUser = user.get({ plain: true });

    // 3. Store in Redis
    if (process.env.CACHE === "true") {
      await redis.set(
        key,
        JSON.stringify(plainUser),
        "EX",
        CACHE_TTL
      );
    }

    return plainUser;

  } catch (err) {
    log("Error fetching user:", err);
    throw new Error("Failed to fetch user");
  }
}

// Invalidate cache
async function clearUserCache(email) {
  const key = getCacheKey(email);

  try {
    await redis.del(key);
    log(`Cache cleared for user: ${email}`);
  } catch (err) {
    log("Error clearing cache:", err);
  }
}



///////////////////////////////
//      Permission Cache    //
/////////////////////////////

const PERM_TTL = 10 * 60;

const getPermKey = (userId) => `perm:user:${userId}`;

async function getCachedPermissions(userId) {
  if (process.env.CACHE !== "true") return null;

  try {
    const cached = await redis.get(getPermKey(userId));
    return cached ? JSON.parse(cached) : null;
  } catch (err) {
    console.log("Cache read error:", err);
    return null;
  }
}

async function setCachedPermissions(userId, permissions) {
  if (process.env.CACHE !== "true") return;

  try {
    await redis.set(
      getPermKey(userId),
      JSON.stringify(permissions),
      "EX",
      PERM_TTL
    );
  } catch (err) {
    console.log("Cache write error:", err);
  }
}

async function clearPermissionCache(userId) {
  try {
    await redis.del(getPermKey(userId));
  } catch (err) {
    console.log("Cache delete error:", err);
  }
}


module.exports = {
  getCachedUser,
  clearUserCache,
  getCachedPermissions,
  setCachedPermissions,
  clearPermissionCache
};