/*
 * This file is part of p2pool-salvium-redis
 * Redis storage backend for p2pool-salvium observer mode
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3.
 */

#ifdef WITH_REDIS

#include "common.h"
#include "redis_storage.h"
#include <hiredis/hiredis.h>
#include <cstring>

LOG_CATEGORY(RedisStorage)

namespace p2pool {

// Global instance
static RedisStorage* g_redis_storage = nullptr;

RedisStorage& get_redis_storage() {
    if (!g_redis_storage) {
        g_redis_storage = new RedisStorage();
    }
    return *g_redis_storage;
}

RedisStorage::RedisStorage()
    : m_ctx(nullptr)
    , m_port(6379)
    , m_db(0)
    , m_prefix("p2pool:")
    , m_connected(false)
{
}

RedisStorage::~RedisStorage() {
    disconnect();
}

bool RedisStorage::connect(const std::string& host, int port, int db) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (m_connected && m_ctx) {
        return true;
    }

    m_host = host;
    m_port = port;
    m_db = db;

    struct timeval timeout = { 5, 0 }; // 5 seconds
    m_ctx = redisConnectWithTimeout(host.c_str(), port, timeout);

    if (!m_ctx) {
        LOGERR(1, "Failed to allocate Redis context");
        return false;
    }

    if (m_ctx->err) {
        LOGERR(1, "Redis connection error: " << static_cast<const char*>(m_ctx->errstr));
        redisFree(m_ctx);
        m_ctx = nullptr;
        return false;
    }

    // Select database
    if (db != 0) {
        redisReply* reply = static_cast<redisReply*>(redisCommand(m_ctx, "SELECT %d", db));
        if (!reply || reply->type == REDIS_REPLY_ERROR) {
            LOGERR(1, "Failed to select Redis database " << db);
            if (reply) freeReplyObject(reply);
            redisFree(m_ctx);
            m_ctx = nullptr;
            return false;
        }
        freeReplyObject(reply);
    }

    m_connected = true;
    LOGINFO(1, "Connected to Redis at " << host << ":" << port << " db=" << db);
    return true;
}

void RedisStorage::disconnect() {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (m_ctx) {
        redisFree(m_ctx);
        m_ctx = nullptr;
    }
    m_connected = false;
}

bool RedisStorage::reconnect_if_needed() {
    if (m_connected && m_ctx && m_ctx->err == 0) {
        return true;
    }

    LOGWARN(3, "Redis connection lost, reconnecting...");

    if (m_ctx) {
        redisFree(m_ctx);
        m_ctx = nullptr;
    }
    m_connected = false;

    // Try to reconnect (without lock - caller holds it)
    struct timeval timeout = { 5, 0 };
    m_ctx = redisConnectWithTimeout(m_host.c_str(), m_port, timeout);

    if (!m_ctx || m_ctx->err) {
        LOGERR(1, "Redis reconnection failed");
        if (m_ctx) {
            redisFree(m_ctx);
            m_ctx = nullptr;
        }
        return false;
    }

    // Select database
    if (m_db != 0) {
        redisReply* reply = static_cast<redisReply*>(redisCommand(m_ctx, "SELECT %d", m_db));
        if (!reply || reply->type == REDIS_REPLY_ERROR) {
            if (reply) freeReplyObject(reply);
            redisFree(m_ctx);
            m_ctx = nullptr;
            return false;
        }
        freeReplyObject(reply);
    }

    m_connected = true;
    LOGINFO(1, "Redis reconnected successfully");
    return true;
}

std::string RedisStorage::prefixed_key(const std::string& key) const {
    return m_prefix + key;
}

bool RedisStorage::ping() {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    redisReply* reply = static_cast<redisReply*>(redisCommand(m_ctx, "PING"));
    if (!reply) return false;

    bool ok = (reply->type == REDIS_REPLY_STATUS && strcmp(reply->str, "PONG") == 0);
    freeReplyObject(reply);
    return ok;
}

bool RedisStorage::set(const std::string& key, const std::string& value) {
    return set(key, reinterpret_cast<const uint8_t*>(value.data()), value.size());
}

bool RedisStorage::set(const std::string& key, const uint8_t* data, size_t size) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "SET %s %b", pkey.c_str(), data, size)
    );

    if (!reply) {
        LOGERR(3, "Redis SET failed for key: " << key);
        return false;
    }

    bool ok = (reply->type == REDIS_REPLY_STATUS && strcmp(reply->str, "OK") == 0);
    freeReplyObject(reply);
    return ok;
}

bool RedisStorage::get(const std::string& key, std::string& value) {
    std::vector<uint8_t> data;
    if (!get(key, data)) return false;
    value.assign(data.begin(), data.end());
    return true;
}

bool RedisStorage::get(const std::string& key, std::vector<uint8_t>& data) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "GET %s", pkey.c_str())
    );

    if (!reply) {
        return false;
    }

    if (reply->type == REDIS_REPLY_NIL) {
        freeReplyObject(reply);
        return false;
    }

    if (reply->type != REDIS_REPLY_STRING) {
        freeReplyObject(reply);
        return false;
    }

    data.assign(
        reinterpret_cast<uint8_t*>(reply->str),
        reinterpret_cast<uint8_t*>(reply->str) + reply->len
    );
    freeReplyObject(reply);
    return true;
}

bool RedisStorage::del(const std::string& key) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "DEL %s", pkey.c_str())
    );

    if (!reply) return false;

    freeReplyObject(reply);
    return true;
}

bool RedisStorage::exists(const std::string& key) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "EXISTS %s", pkey.c_str())
    );

    if (!reply) return false;

    bool exists = (reply->type == REDIS_REPLY_INTEGER && reply->integer > 0);
    freeReplyObject(reply);
    return exists;
}

bool RedisStorage::hset(const std::string& key, const std::string& field, const uint8_t* data, size_t size) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "HSET %s %s %b", pkey.c_str(), field.c_str(), data, size)
    );

    if (!reply) {
        LOGERR(3, "Redis HSET failed for key: " << key << " field: " << field);
        return false;
    }

    freeReplyObject(reply);
    return true;
}

bool RedisStorage::hget(const std::string& key, const std::string& field, std::vector<uint8_t>& data) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "HGET %s %s", pkey.c_str(), field.c_str())
    );

    if (!reply || reply->type == REDIS_REPLY_NIL) {
        if (reply) freeReplyObject(reply);
        return false;
    }

    if (reply->type != REDIS_REPLY_STRING) {
        freeReplyObject(reply);
        return false;
    }

    data.assign(
        reinterpret_cast<uint8_t*>(reply->str),
        reinterpret_cast<uint8_t*>(reply->str) + reply->len
    );
    freeReplyObject(reply);
    return true;
}

bool RedisStorage::hdel(const std::string& key, const std::string& field) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "HDEL %s %s", pkey.c_str(), field.c_str())
    );

    if (!reply) return false;

    freeReplyObject(reply);
    return true;
}

bool RedisStorage::hgetall(const std::string& key, std::vector<std::pair<std::string, std::vector<uint8_t>>>& result) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "HGETALL %s", pkey.c_str())
    );

    if (!reply || reply->type != REDIS_REPLY_ARRAY) {
        if (reply) freeReplyObject(reply);
        return false;
    }

    result.clear();
    for (size_t i = 0; i + 1 < reply->elements; i += 2) {
        redisReply* field = reply->element[i];
        redisReply* value = reply->element[i + 1];

        if (field->type == REDIS_REPLY_STRING && value->type == REDIS_REPLY_STRING) {
            std::string fieldStr(field->str, field->len);
            std::vector<uint8_t> valueData(
                reinterpret_cast<uint8_t*>(value->str),
                reinterpret_cast<uint8_t*>(value->str) + value->len
            );
            result.emplace_back(std::move(fieldStr), std::move(valueData));
        }
    }

    freeReplyObject(reply);
    return true;
}

int64_t RedisStorage::hlen(const std::string& key) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return -1;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "HLEN %s", pkey.c_str())
    );

    if (!reply || reply->type != REDIS_REPLY_INTEGER) {
        if (reply) freeReplyObject(reply);
        return -1;
    }

    int64_t len = reply->integer;
    freeReplyObject(reply);
    return len;
}

bool RedisStorage::lpush(const std::string& key, const std::string& value) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "LPUSH %s %s", pkey.c_str(), value.c_str())
    );

    if (!reply) return false;

    freeReplyObject(reply);
    return true;
}

bool RedisStorage::rpush(const std::string& key, const std::string& value) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "RPUSH %s %s", pkey.c_str(), value.c_str())
    );

    if (!reply) return false;

    freeReplyObject(reply);
    return true;
}

bool RedisStorage::lrange(const std::string& key, int64_t start, int64_t stop, std::vector<std::string>& result) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "LRANGE %s %lld %lld", pkey.c_str(), start, stop)
    );

    if (!reply || reply->type != REDIS_REPLY_ARRAY) {
        if (reply) freeReplyObject(reply);
        return false;
    }

    result.clear();
    for (size_t i = 0; i < reply->elements; ++i) {
        if (reply->element[i]->type == REDIS_REPLY_STRING) {
            result.emplace_back(reply->element[i]->str, reply->element[i]->len);
        }
    }

    freeReplyObject(reply);
    return true;
}

int64_t RedisStorage::llen(const std::string& key) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return -1;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "LLEN %s", pkey.c_str())
    );

    if (!reply || reply->type != REDIS_REPLY_INTEGER) {
        if (reply) freeReplyObject(reply);
        return -1;
    }

    int64_t len = reply->integer;
    freeReplyObject(reply);
    return len;
}

bool RedisStorage::sadd(const std::string& key, const std::string& member) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "SADD %s %s", pkey.c_str(), member.c_str())
    );

    if (!reply) return false;

    freeReplyObject(reply);
    return true;
}

bool RedisStorage::srem(const std::string& key, const std::string& member) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "SREM %s %s", pkey.c_str(), member.c_str())
    );

    if (!reply) return false;

    freeReplyObject(reply);
    return true;
}

bool RedisStorage::smembers(const std::string& key, std::vector<std::string>& result) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "SMEMBERS %s", pkey.c_str())
    );

    if (!reply || reply->type != REDIS_REPLY_ARRAY) {
        if (reply) freeReplyObject(reply);
        return false;
    }

    result.clear();
    for (size_t i = 0; i < reply->elements; ++i) {
        if (reply->element[i]->type == REDIS_REPLY_STRING) {
            result.emplace_back(reply->element[i]->str, reply->element[i]->len);
        }
    }

    freeReplyObject(reply);
    return true;
}

bool RedisStorage::sismember(const std::string& key, const std::string& member) {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    std::string pkey = prefixed_key(key);
    redisReply* reply = static_cast<redisReply*>(
        redisCommand(m_ctx, "SISMEMBER %s %s", pkey.c_str(), member.c_str())
    );

    if (!reply || reply->type != REDIS_REPLY_INTEGER) {
        if (reply) freeReplyObject(reply);
        return false;
    }

    bool is_member = (reply->integer > 0);
    freeReplyObject(reply);
    return is_member;
}

bool RedisStorage::flushdb() {
    std::lock_guard<std::mutex> lock(m_mutex);

    if (!reconnect_if_needed()) return false;

    redisReply* reply = static_cast<redisReply*>(redisCommand(m_ctx, "FLUSHDB"));
    if (!reply) return false;

    freeReplyObject(reply);
    LOGWARN(1, "Redis database flushed!");
    return true;
}

} // namespace p2pool

#endif // WITH_REDIS