#include "RedisHelper.h"
#include <chrono>
#include <cstdlib>
#include <thread>
#include <algorithm>
#include <cstring>

namespace services {

RedisHelper &RedisHelper::instance() {
    static RedisHelper inst;
    return inst;
}

RedisHelper::RedisHelper() : _initialized(false) {
    LOG_INFO << "RedisHelper created (connection will be established on first use)";
}

RedisHelper::~RedisHelper() = default;

void RedisHelper::ensureConnected() {
    if (_initialized) return;
    
    std::lock_guard<std::mutex> lock(_initMutex);
    if (_initialized) return;  // Double-check
    
    try {
        sw::redis::ConnectionOptions opts;
        opts.host = getRedisHost();
        opts.port = getRedisPort();
        
        const char* envPass = std::getenv("REDIS_PASS");
        if (envPass && strlen(envPass) > 0) {
            opts.password = envPass;
        }
        
        opts.socket_timeout = std::chrono::milliseconds(1000);
        opts.connect_timeout = std::chrono::milliseconds(1000);

        LOG_INFO << "Connecting to Redis at " << opts.host << ":" << opts.port;

        _redis = std::make_unique<sw::redis::Redis>(opts);
        _redis->ping();
        
        _initialized = true;
        LOG_INFO << "Redis connection established successfully";
    } catch (const sw::redis::Error& e) {
        LOG_ERROR << "Failed to connect to Redis: " << e.what();
        throw;
    }
}

std::string RedisHelper::getRedisHost() const {
    const char* envHost = std::getenv("REDIS_HOST");
    if (envHost) return std::string(envHost);
    
    try {
        const auto& config = drogon::app().getCustomConfig();
        if (config.isMember("redis") && config["redis"].isMember("host")) {
            return config["redis"]["host"].asString();
        }
    } catch (...) {}
    
    return "redis";
}

int RedisHelper::getRedisPort() const {
    const char* envPort = std::getenv("REDIS_PORT");
    if (envPort) {
        try {
            return std::stoi(envPort);
        } catch (...) {}
    }
    
    try {
        const auto& config = drogon::app().getCustomConfig();
        if (config.isMember("redis") && config["redis"].isMember("port")) {
            return config["redis"]["port"].asInt();
        }
    } catch (...) {}
    
    return 6379;
}

void RedisHelper::executeInThreadPool(std::function<void()> task) {
    auto loop = drogon::app().getLoop();
    if (!loop) {
        LOG_ERROR << "Event loop not available, executing task synchronously";
        try {
            task();
        } catch (const std::exception& e) {
            LOG_ERROR << "Error executing task: " << e.what();
        }
        return;
    }
    
    loop->queueInLoop([task = std::move(task)]() {
        std::thread([task]() {
            try {
                task();
            } catch (const std::exception& e) {
                LOG_ERROR << "Error in thread pool task: " << e.what();
            }
        }).detach();
    });
}

// Define a macro to generate async methods
#define REDIS_ASYNC_IMPL(method, return_type, operation) \
void RedisHelper::method##Async(const std::string &key, \
                                std::function<void(return_type)> callback) { \
    executeAsync<return_type>( \
        [this, key]() { \
            return _redis->operation; \
        }, \
        std::move(callback) \
    ); \
}

// Specialized async methods using the template

void RedisHelper::setexAsync(const std::string &key,
                              const std::string &value,
                              long ttlSeconds,
                              std::function<void(bool)> callback) {
    executeAsync<bool>(
        [this, key, value, ttlSeconds]() {
            _redis->setex(key, ttlSeconds, value);
            return true;
        },
        std::move(callback)
    );
}

void RedisHelper::getAsync(const std::string &key,
                            std::function<void(sw::redis::OptionalString)> callback) {
    executeAsync<sw::redis::OptionalString>(
        [this, key]() {
            return _redis->get(key);
        },
        std::move(callback)
    );
}

void RedisHelper::delAsync(const std::string &key,
                           std::function<void(bool)> callback) {
    executeAsync<bool>(
        [this, key]() {
            return _redis->del(key) > 0;
        },
        std::move(callback)
    );
}

void RedisHelper::saddAsync(const std::string &setName,
                            const std::string &value,
                            std::function<void(bool)> callback) {
    executeAsync<bool>(
        [this, setName, value]() {
            return _redis->sadd(setName, value) > 0;
        },
        std::move(callback)
    );
}

void RedisHelper::sremAsync(const std::string &setName,
                            const std::string &value,
                            std::function<void(bool)> callback) {
    executeAsync<bool>(
        [this, setName, value]() {
            return _redis->srem(setName, value) > 0;
        },
        std::move(callback)
    );
}

void RedisHelper::smembersAsync(const std::string &setName,
                                std::function<void(std::vector<std::string>)> callback) {
    executeAsync<std::vector<std::string>>(
        [this, setName]() {
            std::vector<std::string> members;
            _redis->smembers(setName, std::back_inserter(members));
            return members;
        },
        std::move(callback)
    );
}

void RedisHelper::keysAsync(const std::string &pattern,
                            std::function<void(std::vector<std::string>)> callback) {
    executeAsync<std::vector<std::string>>(
        [this, pattern]() {
            std::vector<std::string> keys;
            _redis->keys(pattern, std::back_inserter(keys));
            return keys;
        },
        std::move(callback)
    );
}

void RedisHelper::expireAsync(const std::string &key,
                              long ttlSeconds,
                              std::function<void(bool)> callback) {
    executeAsync<bool>(
        [this, key, ttlSeconds]() {
            return _redis->expire(key, ttlSeconds);
        },
        std::move(callback)
    );
}

// Sync versions for compatibility
std::unique_ptr<sw::redis::Redis> RedisHelper::getConnection() {
    ensureConnected();
    
    sw::redis::ConnectionOptions opts;
    opts.host = getRedisHost();
    opts.port = getRedisPort();
    
    const char* envPass = std::getenv("REDIS_PASS");
    if (envPass && strlen(envPass) > 0) {
        opts.password = envPass;
    }
    
    opts.socket_timeout = std::chrono::milliseconds(200);
    opts.connect_timeout = std::chrono::milliseconds(200);
    
    return std::make_unique<sw::redis::Redis>(opts);
}

bool RedisHelper::storeKey(const std::string &key, const std::string &value, int ttl) {
    try {
        ensureConnected();
        if (ttl > 0) {
            _redis->setex(key, ttl, value);
        } else {
            _redis->set(key, value);
        }
        return true;
    } catch (const sw::redis::Error &e) {
        LOG_ERROR << "Redis SET error: " << e.what();
        return false;
    }
}

std::string RedisHelper::getKey(const std::string &key) {
    try {
        ensureConnected();
        auto val = _redis->get(key);
        return val.has_value() ? val.value() : "";
    } catch (const sw::redis::Error &e) {
        LOG_ERROR << "Redis GET error: " << e.what();
        return "";
    }
}

bool RedisHelper::deleteKey(const std::string &key) {
    try {
        ensureConnected();
        return _redis->del(key) > 0;
    } catch (const sw::redis::Error &e) {
        LOG_ERROR << "Redis DEL error: " << e.what();
        return false;
    }
}

bool RedisHelper::addToSet(const std::string &setName, const std::string &value) {
    try {
        ensureConnected();
        return _redis->sadd(setName, value) > 0;
    } catch (const sw::redis::Error &e) {
        LOG_ERROR << "Redis SADD error: " << e.what();
        return false;
    }
}

bool RedisHelper::removeFromSet(const std::string &setName, const std::string &value) {
    try {
        ensureConnected();
        return _redis->srem(setName, value) > 0;
    } catch (const sw::redis::Error &e) {
        LOG_ERROR << "Redis SREM error: " << e.what();
        return false;
    }
}

// Deprecated command executor - simplified
void RedisHelper::executeAsync(const std::string &command,
                               std::function<void(bool, const std::string&)> callback) {
    // For the single use case in the code (EXPIRE), handle it directly
    std::istringstream iss(command);
    std::string op, key;
    long ttl;
    iss >> op >> key >> ttl;
    
    if (op == "EXPIRE" || op == "expire") {
        expireAsync(key, ttl, [callback](bool success) {
            callback(success, success ? "1" : "0");
        });
    } else {
        if (auto loop = drogon::app().getLoop()) {
            loop->queueInLoop([callback]() {
                callback(false, "Unsupported command in executeAsync. Use specific async methods.");
            });
        } else {
            callback(false, "Unsupported command in executeAsync. Use specific async methods.");
        }
    }
}

} // namespace services