package cache

import (
	"sync"
	"time"

	"github.com/go-redis/redis/v7"
)

// RedisConfig config
type RedisConfig struct {
	Addr         string
	Password     string
	DB           int
	DialTimeout  time.Duration
	ReadTimeout  time.Duration
	WriteTimeout time.Duration
	PoolTimeout  time.Duration
	PoolSize     int
}

// RedisClusterConfig redis cluster configure
type RedisClusterConfig struct {
	// A seed list of host:port addresses of cluster nodes.
	Addrs []string

	Password string
	DB       int

	// The maximum number of retries before giving up. Command is retried
	// on network errors and MOVED/ASK redirects.
	// Default is 16.
	MaxRedirects int

	// Enables read-only commands on slave nodes.
	ReadOnly bool
	// Allows routing read-only commands to the closest master or slave node.
	RouteByLatency bool

	//OnConnect func(*Conn) error

	MaxRetries      int
	MinRetryBackoff time.Duration
	MaxRetryBackoff time.Duration

	DialTimeout  time.Duration
	ReadTimeout  time.Duration
	WriteTimeout time.Duration

	// PoolSize applies per cluster node and not for the whole cluster.
	PoolSize           int
	PoolTimeout        time.Duration
	IdleTimeout        time.Duration
	IdleCheckFrequency time.Duration
}

var (
	redisConfig        RedisConfig
	redisClusterConfig RedisClusterConfig
	once               sync.Once
	cache              *RedisCache
	isCluster          bool
)

// RedisCache define
type RedisCache struct {
	c  *redis.Client
	cc *redis.ClusterClient
}

// SetRedisConfig set
func SetRedisConfig(cfg RedisConfig) {
	redisConfig = cfg
}

// SetRedisClusterConfig set
func SetRedisClusterConfig(cfg RedisClusterConfig) {
	redisClusterConfig = cfg
}

// NewRedisCache new RedisCache object
func NewRedisCache() *RedisCache {
	client := redis.NewClient(&redis.Options{
		Addr:         redisConfig.Addr,
		Password:     redisConfig.Password,
		DialTimeout:  redisConfig.DialTimeout,
		ReadTimeout:  redisConfig.ReadTimeout,
		WriteTimeout: redisConfig.WriteTimeout,
		PoolSize:     redisConfig.PoolSize,
		PoolTimeout:  redisConfig.PoolTimeout,
	})

	client.Ping().Result()
	return &RedisCache{c: client}
}

// NewRedisClusterCache new RedisCluster object
func NewRedisClusterCache() *RedisCache {
	var config redis.ClusterOptions

	config.Addrs = redisClusterConfig.Addrs
	config.Password = redisClusterConfig.Password

	config.DialTimeout = redisClusterConfig.DialTimeout
	config.ReadTimeout = redisClusterConfig.ReadTimeout
	config.WriteTimeout = redisClusterConfig.WriteTimeout

	config.PoolSize = redisClusterConfig.PoolSize
	config.PoolTimeout = redisClusterConfig.PoolTimeout
	config.IdleTimeout = redisClusterConfig.IdleTimeout
	config.IdleCheckFrequency = redisClusterConfig.IdleCheckFrequency

	client := redis.NewClusterClient(&config)

	client.Ping()
	return &RedisCache{cc: client}
}

// Get get value from cache
func (c RedisCache) Get(key string) (string, error) {
	if c.cc != nil {
		return c.cc.Get(key).Result()
	}
	return c.c.Get(key).Result()
}

// Set set key-value to cache
func (c RedisCache) Set(key, value string, expiration time.Duration) error {
	if c.cc != nil {
		return c.cc.Set(key, value, expiration).Err()
	}
	return c.c.Set(key, value, expiration).Err()
}

// Del Del value from cache
func (c RedisCache) Del(key string) (int64, error) {
	if c.cc != nil {
		return c.cc.Del(key).Result()
	}
	return c.c.Del(key).Result()
}

// Info info
func (c RedisCache) Info() (string, error) {
	if c.cc != nil {
		return c.cc.ClusterInfo().Result()
	}
	return c.c.Info().Result()
}

// Subscribe subscribe message
func (c RedisCache) Subscribe(channels string, cb func(channel string, message string, err error)) error {
	pubsub := &redis.PubSub{}
	if c.cc != nil {
		pubsub = c.cc.Subscribe(channels)
	} else {
		pubsub = c.c.Subscribe(channels)
	}
	defer pubsub.Close()

	var (
		msg *redis.Message
		err error
	)
	msg, err = pubsub.ReceiveMessage()
	for err == nil {
		cb(msg.Channel, msg.Payload, nil)
		msg, err = pubsub.ReceiveMessage()
	}

	cb("", "", err)
	return err
}

// Publish publish message
func (c RedisCache) Publish(channel, message string) error {
	if c.cc != nil {
		return c.cc.Publish(channel, message).Err()
	}
	return c.c.Publish(channel, message).Err()
}

func connect() (*RedisCache, error) {
	if cache != nil {
		return cache, nil
	}
	//*
	var err error
	once.Do(func() {
		isCluster = false
		if len(redisConfig.Addr) > 0 {
			cache = NewRedisCache()
		}

		if len(redisClusterConfig.Addrs) > 0 {
			cache = NewRedisClusterCache()
			isCluster = true
		}
	})
	//*/
	return cache, err
}

// Get key from cache
func Get(key string) (string, error) {
	c, err := connect()
	if err != nil {
		return "", err
	}
	return c.Get(key)
}

// Set key-value to cache
func Set(key, value string, expiration time.Duration) error {
	c, err := connect()
	if err != nil {
		return err
	}
	return c.Set(key, value, expiration)
}

// Del delete key from cache
func Del(key string) (int64, error) {
	c, err := connect()
	if err != nil {
		return 0, err
	}
	return c.Del(key)
}

func Info() (string, error) {
	c, err := connect()
	if err != nil {
		return "", err
	}

	return c.Info()
}

// Publish publish message
func Publish(channel, message string) error {
	c, err := connect()
	if err != nil {
		return err
	}

	return c.Publish(channel, message)
}

func Subscribe(channels string, cb func(channel string, message string, err error)) error {
	c, err := connect()
	if err != nil {
		return err
	}

	return c.Subscribe(channels, cb)
}