package redis

import (
	"encoding/json"
	"errors"
	"io"
	"net"
	"reflect"
	"strconv"
	"strings"
	"sync"
	"syscall"
	"time"

	"apigo.cc/go/cast"
	"apigo.cc/go/config"
	"apigo.cc/go/log"
	"apigo.cc/go/safe"
	"github.com/gomodule/redigo/redis"
)

type Redis struct {
	name        string
	pool        *redis.Pool
	Config      *Config
	logger      *log.Logger
	Error       error
	subConn     *redis.PubSubConn
	subLock     sync.RWMutex
	subStopChan chan bool
	subs        map[string]*SubCallbacks
	SubRunning  bool
}

type SubCallbacks struct {
	received func([]byte)
	reset    func()
}

var redisInstances = make(map[string]*Redis)
var redisInstancesLock = sync.RWMutex{}

func GetRedis(name string, logger *log.Logger) *Redis {
	if logger == nil {
		logger = log.DefaultLogger
	}

	redisInstancesLock.RLock()
	oldConn := redisInstances[name]
	redisInstancesLock.RUnlock()
	if oldConn != nil {
		return oldConn.CopyByLogger(logger)
	}

	redisConfigsLock.RLock()
	configsLen := len(redisConfigs)
	redisConfigsLock.RUnlock()

	if configsLen == 0 {
		_ = config.Load("redis", &redisConfigs)
	}

	fullName := name

	var conf *Config
	if strings.HasPrefix(name, "redis://") {
		conf = new(Config)
		conf.logger = logger
		conf.ConfigureBy(name)
	} else {
		conf = parseByName(name)
	}

	if pwd, err := confAes.Decrypt([]byte(conf.Password)); err == nil {
		conf.pwd = pwd
	} else {
		conf.pwd = safe.NewSafeBuf([]byte(conf.Password))
	}
	conf.Password = ""

	if conf.Host == "" {
		conf.Host = "127.0.0.1:6379"
	}
	if conf.MaxIdle == 0 {
		conf.MaxIdle = 20
	}
	if conf.MaxActive == 0 {
		conf.MaxActive = 100
	}
	if conf.ConnectTimeout == 0 {
		conf.ConnectTimeout = 10 * time.Second
	}
	if conf.ReadTimeout == 0 {
		conf.ReadTimeout = 10 * time.Second
	}
	if conf.WriteTimeout == 0 {
		conf.WriteTimeout = 10 * time.Second
	}
	if conf.LogSlow == 0 {
		conf.LogSlow = 100 * time.Millisecond
	}

	rd := NewRedis(conf, logger)
	rd.name = fullName
	redisInstancesLock.Lock()
	redisInstances[fullName] = rd
	redisInstancesLock.Unlock()
	return rd.CopyByLogger(logger)
}

func NewRedis(conf *Config, logger *log.Logger) *Redis {
	if logger == nil {
		logger = log.DefaultLogger
	}

	conn := &redis.Pool{
		MaxIdle:     conf.MaxIdle,
		MaxActive:   conf.MaxActive,
		IdleTimeout: conf.IdleTimeout,
		Dial: func() (redis.Conn, error) {
			opts := []redis.DialOption{
				redis.DialConnectTimeout(conf.ConnectTimeout),
				redis.DialReadTimeout(conf.ReadTimeout),
				redis.DialWriteTimeout(conf.WriteTimeout),
				redis.DialDatabase(conf.DB),
			}
			if conf.pwd != nil {
				pwdBuf := conf.pwd.Open()
				defer pwdBuf.Close()
				opts = append(opts, redis.DialPassword(pwdBuf.String()))
			}
			c, err := redis.Dial("tcp", conf.Host, opts...)
			if err != nil {
				logger.Error(err.Error(), "type", "redis", "dsn", conf.Dsn())
				return nil, err
			}
			return c, nil
		},
	}

	rd := new(Redis)
	rd.pool = conn
	rd.Config = conf
	rd.logger = logger

	return rd
}

func (rd *Redis) CopyByLogger(logger *log.Logger) *Redis {
	newRedis := new(Redis)
	newRedis.name = rd.name
	newRedis.pool = rd.pool
	newRedis.subConn = rd.subConn
	newRedis.subs = rd.subs
	newRedis.SubRunning = rd.SubRunning
	newRedis.Config = rd.Config
	if logger == nil {
		newRedis.logger = log.DefaultLogger
	} else {
		newRedis.logger = logger
	}
	return newRedis
}

func (rd *Redis) SetLogger(logger *log.Logger) {
	rd.logger = logger
}

func (rd *Redis) GetLogger() *log.Logger {
	return rd.logger
}

func (rd *Redis) Destroy() error {
	if rd.pool == nil {
		return errors.New("operate on a bad redis pool")
	}
	err := rd.pool.Close()
	if err != nil {
		rd.logger.Error(err.Error(), "type", "redis", "dsn", rd.Config.Dsn())
	}
	redisInstancesLock.Lock()
	delete(redisInstances, rd.name)
	redisInstancesLock.Unlock()
	return err
}

func (rd *Redis) GetPool() *redis.Pool {
	return rd.pool
}

func (rd *Redis) GetNewConnection() (redis.Conn, error) {
	if rd.pool == nil {
		return nil, errors.New("redis pool is not initialized")
	}
	c, err := rd.pool.Dial()
	if err == nil {
		err = c.Err()
	}
	if err != nil {
		if c != nil {
			_ = c.Close()
		}
		return nil, err
	}
	return c, nil
}

func (rd *Redis) GetConnection() (redis.Conn, error) {
	if rd.pool == nil {
		return nil, errors.New("redis pool is not initialized")
	}
	c := rd.pool.Get()
	err := c.Err()
	if err != nil {
		if c != nil {
			_ = c.Close()
		}
		return nil, err
	}
	return c, nil
}

func shouldRetry(err error) bool {
	if err == nil {
		return false
	}

	// 网络错误
	if errors.Is(err, io.EOF) || errors.Is(err, syscall.ECONNRESET) {
		return true
	}

	// 超时错误
	var opErr *net.OpError
	if errors.As(err, &opErr) && opErr.Timeout() {
		return true
	}

	// Redis特定可恢复错误
	var redisErr redis.Error
	if errors.As(err, &redisErr) {
		errMsg := string(redisErr)
		if strings.HasPrefix(errMsg, "LOADING") || strings.HasPrefix(errMsg, "CLUSTERDOWN") {
			return true
		}
	}

	return false
}

func (rd *Redis) Do(cmd string, values ...any) *Result {
	if rd.pool == nil {
		err := errors.New("operate on a bad redis pool")
		rd.logger.Error(err.Error(), "type", "redis", "dsn", rd.Config.Dsn(), "cmd", cmd)
		return &Result{Error: err}
	}
	startTime := time.Now()
	r := rd.do(cmd, values...)
	usedTime := time.Since(startTime)
	if r.Error == nil {
		if rd.Config.LogSlow > 0 && usedTime >= rd.Config.LogSlow {
			rd.logger.Debug("redis slow query", "dsn", rd.Config.Dsn(), "cmd", cmd, "args", values, "used", usedTime.String())
		}
	} else {
		rd.logger.Error(r.Error.Error(), "type", "redis", "dsn", rd.Config.Dsn(), "cmd", cmd, "args", values, "used", usedTime.String())
	}
	return r
}

func (rd *Redis) do(cmd string, values ...any) *Result {
	if strings.Contains(cmd, " ") {
		cmdArr := cast.Split(cmd, " ")
		if len(cmdArr) > 1 {
			cmd = cmdArr[0]
			args := make([]any, 0, len(cmdArr)-1+len(values))
			for i := 1; i < len(cmdArr); i++ {
				args = append(args, cmdArr[i])
			}
			if len(values) > 0 {
				args = append(args, values...)
			}
			values = args
		}
	}

	// 自动序列化
	for i, v := range values {
		if v == nil {
			continue
		}
		rv := reflect.ValueOf(v)
		if rv.Kind() == reflect.Ptr {
			if rv.IsNil() {
				continue
			}
			rv = rv.Elem()
		}
		kind := rv.Kind()
		if kind == reflect.Struct || kind == reflect.Map || (kind == reflect.Slice && rv.Type().Elem().Kind() != reflect.Uint8) {
			// 对于这些类型，优先使用 json.Marshal 以支持自定义 Marshaler (如 time.Time)
			if encoded, err := json.Marshal(v); err == nil {
				values[i] = encoded
			}
		}
	}

	// 从连接池获取
	conn, err := rd.GetConnection()
	var replyData any
	if err == nil {
		replyData, err = conn.Do(cmd, values...)
		_ = conn.Close()
	}

	if err != nil && shouldRetry(err) {
		// 拿全新的连接重试（如果服务器重启可自动恢复）
		conn, err = rd.GetNewConnection()
		if err == nil {
			replyData, err = conn.Do(cmd, values...)
			_ = conn.Close()
		}
	}

	if err != nil {
		return &Result{Error: err}
	}

	r := &Result{}
	switch realValue := replyData.(type) {
	case []byte:
		r.bytesData = realValue
	case string:
		r.bytesData = []byte(realValue)
	case int64:
		r.bytesData = []byte(strconv.FormatInt(realValue, 10))
	case []any:
		if cmd == "HMGET" {
			r.keys = make([]string, len(values)-1)
			for i, v := range values {
				if i > 0 {
					r.keys[i-1] = cast.String(v)
				}
			}
		} else if cmd == "MGET" {
			r.keys = make([]string, len(values))
			for i, v := range values {
				r.keys[i] = cast.String(v)
			}
		}

		if cmd == "HGETALL" {
			r.keys = make([]string, len(realValue)/2)
			r.bytesDatas = make([][]byte, len(realValue)/2)
			i1, i2 := 0, 0
			for i, v := range realValue {
				if v != nil {
					if i%2 == 0 {
						r.keys[i1] = cast.String(v)
						i1++
					} else {
						switch subRealValue := v.(type) {
						case []byte:
							r.bytesDatas[i2] = subRealValue
						case string:
							r.bytesDatas[i2] = []byte(subRealValue)
						default:
							r.bytesDatas[i2] = []byte(cast.String(v))
						}
						i2++
					}
				}
			}
		} else {
			r.bytesDatas = make([][]byte, len(realValue))
			for i, v := range realValue {
				if v != nil {
					switch subRealValue := v.(type) {
					case []byte:
						r.bytesDatas[i] = subRealValue
					case string:
						r.bytesDatas[i] = []byte(subRealValue)
					default:
						r.bytesDatas[i] = []byte(cast.String(v))
					}
				}
			}
		}
	case nil:
		r.bytesData = []byte{}
	default:
		r.bytesData = []byte(cast.String(realValue))
	}
	return r
}