const { GET_BODYSHOP_BY_ID } = require("../graphql-client/queries");
const devDebugLogger = require("./devDebugLogger");
const client = require("../graphql-client/graphql-client").client;

const BODYSHOP_CACHE_TTL = 3600; // 1 hour

/**
 * Generate a cache key for a bodyshop
 * @param bodyshopId
 * @returns {`bodyshop-cache:${string}`}
 */
const getBodyshopCacheKey = (bodyshopId) => `bodyshop-cache:${bodyshopId}`;

/**
 * Generate a cache key for a user socket mapping
 * @param email
 * @returns {`user:${string}:${string}:socketMapping`}
 */
const getUserSocketMappingKey = (email) =>
  `user:${process.env?.NODE_ENV === "production" ? "prod" : "dev"}:${email}:socketMapping`;

/**
 * Fetch bodyshop data from the database
 * @param bodyshopId
 * @param logger
 * @returns {Promise<*>}
 */
const fetchBodyshopFromDB = async (bodyshopId, logger) => {
  try {
    const response = await client.request(GET_BODYSHOP_BY_ID, { id: bodyshopId });
    const bodyshop = response.bodyshops_by_pk;
    if (!bodyshop) {
      throw new Error(`Bodyshop with ID ${bodyshopId} not found`);
    }
    return bodyshop; // Return the full object as-is
  } catch (error) {
    logger.log("fetch-bodyshop-from-db", "ERROR", "redis", null, {
      bodyshopId,
      error: error?.message,
      stack: error?.stack
    });
    throw error;
  }
};

/**
 * Apply Redis helper functions
 * @param pubClient
 * @param app
 * @param logger
 */
const applyRedisHelpers = ({ pubClient, app, logger }) => {
  // Store session data in Redis
  const setSessionData = async (socketId, key, value) => {
    try {
      await pubClient.hset(`socket:${socketId}`, key, JSON.stringify(value)); // Use Redis pubClient
    } catch (error) {
      logger.log(`Error Setting Session Data for socket ${socketId}: ${error}`, "ERROR", "redis");
    }
  };

  // Retrieve session data from Redis
  const getSessionData = async (socketId, key) => {
    try {
      const data = await pubClient.hget(`socket:${socketId}`, key);
      return data ? JSON.parse(data) : null;
    } catch (error) {
      logger.log(`Error Getting Session Data for socket ${socketId}: ${error}`, "ERROR", "redis");
    }
  };

  // Clear session data from Redis
  const clearSessionData = async (socketId) => {
    try {
      await pubClient.del(`socket:${socketId}`);
    } catch (error) {
      logger.log(`Error Clearing Session Data for socket ${socketId}: ${error}`, "ERROR", "redis");
    }
  };

  /**
   * Add a socket mapping for a user
   * @param email
   * @param socketId
   * @param bodyshopId
   * @returns {Promise<void>}
   */
  const addUserSocketMapping = async (email, socketId, bodyshopId) => {
    const socketMappingKey = getUserSocketMappingKey(email);
    try {
      devDebugLogger(`Adding socket ${socketId} to user ${email} for bodyshop ${bodyshopId}`);
      // Save the mapping: socketId -> bodyshopId
      await pubClient.hset(socketMappingKey, socketId, bodyshopId);
      // Set TTL (24 hours) for the mapping hash
      await pubClient.expire(socketMappingKey, 86400);
    } catch (error) {
      logger.log(`Error adding socket mapping for ${email} (bodyshop ${bodyshopId}): ${error}`, "ERROR", "redis");
    }
  };

  /**
   * Refresh the TTL for a user's socket mapping
   * @param email
   * @returns {Promise<void>}
   */
  const refreshUserSocketTTL = async (email) => {
    const socketMappingKey = getUserSocketMappingKey(email);

    try {
      const exists = await pubClient.exists(socketMappingKey);
      if (exists) {
        await pubClient.expire(socketMappingKey, 86400);
        devDebugLogger(`Refreshed TTL for ${email} socket mapping`);
      }
    } catch (error) {
      logger.log(`Error refreshing TTL for ${email}: ${error}`, "ERROR", "redis");
    }
  };

  /**
   * Remove a socket mapping for a user
   * @param email
   * @param socketId
   * @returns {Promise<void>}
   */
  const removeUserSocketMapping = async (email, socketId) => {
    const socketMappingKey = getUserSocketMappingKey(email);

    try {
      devDebugLogger(`Removing socket ${socketId} mapping for user ${email}`);
      // Look up the bodyshopId associated with this socket
      const bodyshopId = await pubClient.hget(socketMappingKey, socketId);
      if (!bodyshopId) {
        devDebugLogger(`Socket ${socketId} not found for user ${email}`);
        return;
      }
      // Remove the socket mapping
      await pubClient.hdel(socketMappingKey, socketId);
      devDebugLogger(`Removed socket ${socketId} (associated with bodyshop ${bodyshopId}) for user ${email}`);

      // Refresh TTL if any socket mappings remain
      const remainingSockets = await pubClient.hlen(socketMappingKey);
      if (remainingSockets > 0) {
        await pubClient.expire(socketMappingKey, 86400);
      }
    } catch (error) {
      logger.log(`Error removing socket mapping for ${email}: ${error}`, "ERROR", "redis");
    }
  };

  /**
   * Get all socket mappings for a user
   * @param email
   * @returns {Promise<{}>}
   */
  const getUserSocketMapping = async (email) => {
    const socketMappingKey = getUserSocketMappingKey(email);

    try {
      // Retrieve all socket mappings for the user
      const mapping = await pubClient.hgetall(socketMappingKey);
      const ttl = await pubClient.ttl(socketMappingKey);
      // Group socket IDs by bodyshopId
      const result = {};
      for (const [socketId, bodyshopId] of Object.entries(mapping)) {
        if (!result[bodyshopId]) {
          result[bodyshopId] = { socketIds: [], ttl };
        }
        result[bodyshopId].socketIds.push(socketId);
      }
      return result;
    } catch (error) {
      console.error(`Error retrieving socket mappings for ${email}:`, error);
      throw error;
    }
  };

  /**
   * Get socket IDs for a user by bodyshopId
   * @param email
   * @param bodyshopId
   * @returns {Promise<{socketIds: [string, string], ttl: *}>}
   */
  const getUserSocketMappingByBodyshop = async (email, bodyshopId) => {
    const socketMappingKey = getUserSocketMappingKey(email);

    try {
      // Retrieve all socket mappings for the user
      const mapping = await pubClient.hgetall(socketMappingKey);
      const ttl = await pubClient.ttl(socketMappingKey);
      // Filter socket IDs for the provided bodyshopId
      const socketIds = Object.entries(mapping).reduce((acc, [socketId, bId]) => {
        if (bId === bodyshopId) {
          acc.push(socketId);
        }
        return acc;
      }, []);
      return { socketIds, ttl };
    } catch (error) {
      logger.log(`Error retrieving socket mappings for ${email} by bodyshop ${bodyshopId}: ${error}`, "ERROR", "redis");
      throw error;
    }
  };

  /**
   * Get bodyshop data from Redis
   * @param bodyshopId
   * @returns {Promise<*>}
   */
  const getBodyshopFromRedis = async (bodyshopId) => {
    const key = getBodyshopCacheKey(bodyshopId);
    try {
      // Check if data exists in Redis
      const cachedData = await pubClient.get(key);
      if (cachedData) {
        return JSON.parse(cachedData); // Parse and return the full object
      }

      // Cache miss: fetch from DB
      const bodyshopData = await fetchBodyshopFromDB(bodyshopId, logger);

      // Store in Redis as a single JSON string
      const jsonData = JSON.stringify(bodyshopData);
      await pubClient.set(key, jsonData);
      await pubClient.expire(key, BODYSHOP_CACHE_TTL);

      devDebugLogger("bodyshop-cache-miss", {
        bodyshopId,
        action: "Fetched from DB and cached"
      });

      return bodyshopData; // Return the full object
    } catch (error) {
      logger.log("get-bodyshop-from-redis", "ERROR", "redis", null, {
        bodyshopId,
        error: error.message
      });
      throw error;
    }
  };

  /**
   * Update or invalidate bodyshop data in Redis
   * @param bodyshopId
   * @param values
   * @returns {Promise<void>}
   */
  const updateOrInvalidateBodyshopFromRedis = async (bodyshopId, values = null) => {
    const key = getBodyshopCacheKey(bodyshopId);
    try {
      if (!values) {
        // Invalidate cache by deleting the key
        await pubClient.del(key);
        devDebugLogger("bodyshop-cache-invalidate", {
          bodyshopId,
          action: "Cache invalidated"
        });
      } else {
        // Update cache with the full provided values
        const jsonData = JSON.stringify(values);
        await pubClient.set(key, jsonData);
        await pubClient.expire(key, BODYSHOP_CACHE_TTL);
        devDebugLogger("bodyshop-cache-update", {
          bodyshopId,
          action: "Cache updated",
          values
        });
      }
    } catch (error) {
      logger.log("update-or-invalidate-bodyshop-from-redis", "ERROR", "api", "redis", {
        bodyshopId,
        values,
        error: error.message
      });
      throw error;
    }
  };

  // NOTE: The following code was written for an abandoned branch and things have changes since the,
  // Leaving it here for demonstration purposes, commenting it out so it does not get used

  // Store multiple session data in Redis
  // const setMultipleSessionData = async (socketId, keyValues) => {
  //   try {
  //     // keyValues is expected to be an object { key1: value1, key2: value2, ... }
  //     const entries = Object.entries(keyValues).map(([key, value]) => [key, JSON.stringify(value)]);
  //     await pubClient.hset(`socket:${socketId}`, ...entries.flat());
  //   } catch (error) {
  //     logger.log(`Error Setting Multiple Session Data for socket ${socketId}: ${error}`, "ERROR", "redis");
  //   }
  // };

  // Retrieve multiple session data from Redis
  // const getMultipleSessionData = async (socketId, keys) => {
  //   try {
  //     const data = await pubClient.hmget(`socket:${socketId}`, keys);
  //     // Redis returns an object with null values for missing keys, so we parse the non-null ones
  //     return Object.fromEntries(keys.map((key, index) => [key, data[index] ? JSON.parse(data[index]) : null]));
  //   } catch (error) {
  //     logger.log(`Error Getting Multiple Session Data for socket ${socketId}: ${error}`, "ERROR", "redis");
  //   }
  // };

  // const setMultipleFromArraySessionData = async (socketId, keyValueArray) => {
  //   try {
  //     // Use Redis multi/pipeline to batch the commands
  //     const multi = pubClient.multi();
  //     keyValueArray.forEach(([key, value]) => {
  //       multi.hset(`socket:${socketId}`, key, JSON.stringify(value));
  //     });
  //     await multi.exec(); // Execute all queued commands
  //   } catch (error) {
  //     logger.log(`Error Setting Multiple Session Data for socket ${socketId}: ${error}`, "ERROR", "redis");
  //   }
  // };

  // Helper function to add an item to the end of the Redis list
  // const addItemToEndOfList = async (socketId, key, newItem) => {
  //   try {
  //     await pubClient.rpush(`socket:${socketId}:${key}`, JSON.stringify(newItem));
  //   } catch (error) {
  //     let userEmail = "unknown";
  //     let socketMappings = {};
  //     try {
  //       const userData = await getSessionData(socketId, "user");
  //       if (userData && userData.email) {
  //         userEmail = userData.email;
  //         socketMappings = await getUserSocketMapping(userEmail);
  //       }
  //     } catch (sessionError) {
  //       logger.log(`Failed to fetch session data for socket ${socketId}: ${sessionError}`, "ERROR", "redis");
  //     }
  //     const mappingString = JSON.stringify(socketMappings, null, 2);
  //     const errorMessage = `Error adding item to the end of the list for socket ${socketId}: ${error}. User: ${userEmail}, Socket Mappings: ${mappingString}`;
  //     logger.log(errorMessage, "ERROR", "redis");
  //   }
  // };

  // Helper function to add an item to the beginning of the Redis list
  // const addItemToBeginningOfList = async (socketId, key, newItem) => {
  //   try {
  //     await pubClient.lpush(`socket:${socketId}:${key}`, JSON.stringify(newItem));
  //   } catch (error) {
  //     logger.log(`Error adding item to the beginning of the list for socket ${socketId}: ${error}`, "ERROR", "redis");
  //   }
  // };

  // Helper function to clear a list in Redis
  // const clearList = async (socketId, key) => {
  //   try {
  //     await pubClient.del(`socket:${socketId}:${key}`);
  //   } catch (error) {
  //     logger.log(`Error clearing list for socket ${socketId}: ${error}`, "ERROR", "redis");
  //   }
  // };

  // Add methods to manage room users
  // const addUserToRoom = async (room, user) => {
  //   try {
  //     await pubClient.sadd(room, JSON.stringify(user));
  //   } catch (error) {
  //     logger.log(`Error adding user to room ${room}: ${error}`, "ERROR", "redis");
  //   }
  // };

  // Remove users from room
  // const removeUserFromRoom = async (room, user) => {
  //   try {
  //     await pubClient.srem(room, JSON.stringify(user));
  //   } catch (error) {
  //     logger.log(`Error removing user to room ${room}: ${error}`, "ERROR", "redis");
  //   }
  // };

  // Get Users in room
  // const getUsersInRoom = async (room) => {
  //   try {
  //     const users = await pubClient.smembers(room);
  //     return users.map((user) => JSON.parse(user));
  //   } catch (error) {
  //     logger.log(`Error getting users in room ${room}: ${error}`, "ERROR", "redis");
  //   }
  // };

  const api = {
    getUserSocketMappingKey,
    getBodyshopCacheKey,
    setSessionData,
    getSessionData,
    clearSessionData,
    addUserSocketMapping,
    removeUserSocketMapping,
    getUserSocketMappingByBodyshop,
    getUserSocketMapping,
    refreshUserSocketTTL,
    getBodyshopFromRedis,
    updateOrInvalidateBodyshopFromRedis
    // setMultipleSessionData,
    // getMultipleSessionData,
    // setMultipleFromArraySessionData,
    // addItemToEndOfList,
    // addItemToBeginningOfList,
    // clearList,
    // addUserToRoom,
    // removeUserFromRoom,
    // getUsersInRoom,
  };

  Object.assign(module.exports, api);

  app.use((req, res, next) => {
    req.sessionUtils = api;
    next();
  });

  return api;
};

module.exports = { applyRedisHelpers };
