package binanceservice

import (
	"context"
	"fmt"
	"sync"
	"time"

	"github.com/go-admin-team/go-admin-core/logger"
	"github.com/go-redis/redis/v8"
)

// LockManagerConfig 锁管理器专用配置
type LockManagerConfig struct {
	Type       LockType      `json:"type"`
	Scope      LockScope     `json:"scope"`
	Key        string        `json:"key"`
	Expiration time.Duration `json:"expiration"`
	Timeout    time.Duration `json:"timeout"`
	RetryDelay time.Duration `json:"retry_delay"`
}

// LockType 锁类型
type LockType string

const (
	LockTypeLocal       LockType = "local"
	LockTypeDistributed LockType = "distributed"
)

// LockScope 锁范围
type LockScope string

const (
	ScopeOrder    LockScope = "order"
	ScopePosition LockScope = "position"
	ScopeUser     LockScope = "user"
	ScopeSymbol   LockScope = "symbol"
	ScopeGlobal   LockScope = "global"
)

// Lock 锁接口
type Lock interface {
	Lock(ctx context.Context) error
	Unlock(ctx context.Context) error
	TryLock(ctx context.Context) (bool, error)
	IsLocked() bool
	GetKey() string
	GetExpiration() time.Duration
}

// LocalLock 本地锁
type LocalLock struct {
	key        string
	mu         *sync.RWMutex
	locked     bool
	expiration time.Duration
	acquiredAt time.Time
}

// DistributedLock 分布式锁
type DistributedLock struct {
	key        string
	value      string
	expiration time.Duration
	redisClient *redis.Client
	locked     bool
	acquiredAt time.Time
	refreshTicker *time.Ticker
	stopRefresh   chan struct{}
}

// LockManager 锁管理器
type LockManager struct {
	config       *OptimizedConfig
	redisClient  *redis.Client
	localLocks   map[string]*LocalLock
	localMutex   sync.RWMutex
	metrics      *MetricsCollector
}

// LockConfig 已在 config_optimized.go 中定义

// NewLockManager 创建锁管理器
func NewLockManager(config *OptimizedConfig, redisClient *redis.Client, metrics *MetricsCollector) *LockManager {
	return &LockManager{
		config:      config,
		redisClient: redisClient,
		localLocks:  make(map[string]*LocalLock),
		metrics:     metrics,
	}
}

// CreateLock 创建锁
func (lm *LockManager) CreateLock(config LockManagerConfig) Lock {
	switch config.Type {
	case LockTypeDistributed:
		return lm.createDistributedLock(config)
	case LockTypeLocal:
		return lm.createLocalLock(config)
	default:
		// 默认使用分布式锁
		return lm.createDistributedLock(config)
	}
}

// createLocalLock 创建本地锁
func (lm *LockManager) createLocalLock(config LockManagerConfig) *LocalLock {
	lm.localMutex.Lock()
	defer lm.localMutex.Unlock()

	key := lm.buildLockKey(config.Scope, config.Key)
	if lock, exists := lm.localLocks[key]; exists {
		return lock
	}

	lock := &LocalLock{
		key:        key,
		mu:         &sync.RWMutex{},
		expiration: config.Expiration,
	}

	lm.localLocks[key] = lock
	return lock
}

// createDistributedLock 创建分布式锁
func (lm *LockManager) createDistributedLock(config LockManagerConfig) *DistributedLock {
	key := lm.buildLockKey(config.Scope, config.Key)
	value := fmt.Sprintf("%d_%s", time.Now().UnixNano(), generateRandomString(8))

	return &DistributedLock{
		key:         key,
		value:       value,
		expiration:  config.Expiration,
		redisClient: lm.redisClient,
		stopRefresh: make(chan struct{}),
	}
}

// buildLockKey 构建锁键名
func (lm *LockManager) buildLockKey(scope LockScope, key string) string {
	return fmt.Sprintf("lock:%s:%s", scope, key)
}

// AcquireLock 获取锁（带超时和重试）
func (lm *LockManager) AcquireLock(ctx context.Context, config LockManagerConfig) (Lock, error) {
	lock := lm.CreateLock(config)
	startTime := time.Now()

	// 设置超时上下文
	lockCtx := ctx
	if config.Timeout > 0 {
		var cancel context.CancelFunc
		lockCtx, cancel = context.WithTimeout(ctx, config.Timeout)
		defer cancel()
	}

	// 重试获取锁
	for {
		select {
		case <-lockCtx.Done():
			waitTime := time.Since(startTime)
			if lm.metrics != nil {
				lm.metrics.RecordLockOperation(false, waitTime)
			}
			return nil, fmt.Errorf("获取锁超时: %s", config.Key)

		default:
			err := lock.Lock(lockCtx)
			if err == nil {
				waitTime := time.Since(startTime)
				if lm.metrics != nil {
					lm.metrics.RecordLockOperation(true, waitTime)
				}
				return lock, nil
			}

			// 等待重试
			select {
			case <-lockCtx.Done():
				return nil, lockCtx.Err()
			case <-time.After(config.RetryDelay):
				continue
			}
		}
	}
}

// ReleaseLock 释放锁
func (lm *LockManager) ReleaseLock(ctx context.Context, lock Lock) error {
	if lock == nil {
		return nil
	}
	return lock.Unlock(ctx)
}

// WithLock 使用锁执行操作
func (lm *LockManager) WithLock(ctx context.Context, config LockManagerConfig, operation func() error) error {
	lock, err := lm.AcquireLock(ctx, config)
	if err != nil {
		return fmt.Errorf("获取锁失败: %w", err)
	}

	defer func() {
		if unlockErr := lm.ReleaseLock(ctx, lock); unlockErr != nil {
			logger.Errorf("释放锁失败 [%s]: %v", config.Key, unlockErr)
		}
	}()

	return operation()
}

// CleanupExpiredLocks 清理过期的本地锁
func (lm *LockManager) CleanupExpiredLocks() {
	lm.localMutex.Lock()
	defer lm.localMutex.Unlock()

	now := time.Now()
	for key, lock := range lm.localLocks {
		if lock.locked && lock.expiration > 0 && now.Sub(lock.acquiredAt) > lock.expiration {
			lock.locked = false
			logger.Warnf("本地锁已过期并被清理: %s", key)
		}
	}
}

// GetLockStatus 获取锁状态
func (lm *LockManager) GetLockStatus() map[string]interface{} {
	lm.localMutex.RLock()
	defer lm.localMutex.RUnlock()

	status := make(map[string]interface{})
	localLocks := make(map[string]interface{})

	for key, lock := range lm.localLocks {
		localLocks[key] = map[string]interface{}{
			"locked":      lock.locked,
			"acquired_at": lock.acquiredAt,
			"expiration":  lock.expiration,
		}
	}

	status["local_locks"] = localLocks
	status["total_local_locks"] = len(lm.localLocks)

	return status
}

// LocalLock 实现

// Lock 获取本地锁
func (ll *LocalLock) Lock(ctx context.Context) error {
	ll.mu.Lock()
	defer ll.mu.Unlock()

	if ll.locked {
		return fmt.Errorf("锁已被占用: %s", ll.key)
	}

	ll.locked = true
	ll.acquiredAt = time.Now()
	return nil
}

// Unlock 释放本地锁
func (ll *LocalLock) Unlock(ctx context.Context) error {
	ll.mu.Lock()
	defer ll.mu.Unlock()

	if !ll.locked {
		return fmt.Errorf("锁未被占用: %s", ll.key)
	}

	ll.locked = false
	return nil
}

// TryLock 尝试获取本地锁
func (ll *LocalLock) TryLock(ctx context.Context) (bool, error) {
	ll.mu.Lock()
	defer ll.mu.Unlock()

	if ll.locked {
		return false, nil
	}

	ll.locked = true
	ll.acquiredAt = time.Now()
	return true, nil
}

// IsLocked 检查本地锁是否被占用
func (ll *LocalLock) IsLocked() bool {
	ll.mu.RLock()
	defer ll.mu.RUnlock()
	return ll.locked
}

// GetKey 获取锁键名
func (ll *LocalLock) GetKey() string {
	return ll.key
}

// GetExpiration 获取过期时间
func (ll *LocalLock) GetExpiration() time.Duration {
	return ll.expiration
}

// DistributedLock 实现

// Lock 获取分布式锁
func (dl *DistributedLock) Lock(ctx context.Context) error {
	// 使用 SET key value EX seconds NX 命令
	result := dl.redisClient.SetNX(ctx, dl.key, dl.value, dl.expiration)
	if result.Err() != nil {
		return fmt.Errorf("获取分布式锁失败: %w", result.Err())
	}

	if !result.Val() {
		return fmt.Errorf("分布式锁已被占用: %s", dl.key)
	}

	dl.locked = true
	dl.acquiredAt = time.Now()

	// 启动锁续期
	dl.startRefresh()

	return nil
}

// Unlock 释放分布式锁
func (dl *DistributedLock) Unlock(ctx context.Context) error {
	if !dl.locked {
		return fmt.Errorf("分布式锁未被占用: %s", dl.key)
	}

	// 停止续期
	dl.stopRefreshProcess()

	// 使用 Lua 脚本确保只删除自己的锁
	luaScript := `
		if redis.call("get", KEYS[1]) == ARGV[1] then
			return redis.call("del", KEYS[1])
		else
			return 0
		end
	`

	result := dl.redisClient.Eval(ctx, luaScript, []string{dl.key}, dl.value)
	if result.Err() != nil {
		return fmt.Errorf("释放分布式锁失败: %w", result.Err())
	}

	dl.locked = false
	return nil
}

// TryLock 尝试获取分布式锁
func (dl *DistributedLock) TryLock(ctx context.Context) (bool, error) {
	result := dl.redisClient.SetNX(ctx, dl.key, dl.value, dl.expiration)
	if result.Err() != nil {
		return false, fmt.Errorf("尝试获取分布式锁失败: %w", result.Err())
	}

	if result.Val() {
		dl.locked = true
		dl.acquiredAt = time.Now()
		dl.startRefresh()
		return true, nil
	}

	return false, nil
}

// IsLocked 检查分布式锁是否被占用
func (dl *DistributedLock) IsLocked() bool {
	return dl.locked
}

// GetKey 获取锁键名
func (dl *DistributedLock) GetKey() string {
	return dl.key
}

// GetExpiration 获取过期时间
func (dl *DistributedLock) GetExpiration() time.Duration {
	return dl.expiration
}

// startRefresh 启动锁续期
func (dl *DistributedLock) startRefresh() {
	if dl.expiration <= 0 {
		return
	}

	// 每隔过期时间的1/3进行续期
	refreshInterval := dl.expiration / 3
	dl.refreshTicker = time.NewTicker(refreshInterval)

	go func() {
		defer dl.refreshTicker.Stop()

		for {
			select {
			case <-dl.stopRefresh:
				return
			case <-dl.refreshTicker.C:
				if !dl.locked {
					return
				}

				// 使用 Lua 脚本续期
				luaScript := `
					if redis.call("get", KEYS[1]) == ARGV[1] then
						return redis.call("expire", KEYS[1], ARGV[2])
					else
						return 0
					end
				`

				ctx := context.Background()
				result := dl.redisClient.Eval(ctx, luaScript, []string{dl.key}, dl.value, int(dl.expiration.Seconds()))
				if result.Err() != nil {
					logger.Errorf("分布式锁续期失败 [%s]: %v", dl.key, result.Err())
					return
				}

				if result.Val().(int64) == 0 {
					logger.Warnf("分布式锁已被其他进程占用，停止续期 [%s]", dl.key)
					dl.locked = false
					return
				}
			}
		}
	}()
}

// stopRefreshProcess 停止续期进程
func (dl *DistributedLock) stopRefreshProcess() {
	if dl.refreshTicker != nil {
		close(dl.stopRefresh)
		dl.refreshTicker.Stop()
		dl.refreshTicker = nil
		dl.stopRefresh = make(chan struct{})
	}
}

// 辅助函数

// generateRandomString 生成随机字符串
func generateRandomString(length int) string {
	const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	b := make([]byte, length)
	for i := range b {
		b[i] = charset[time.Now().UnixNano()%int64(len(charset))]
	}
	return string(b)
}

// 预定义的锁配置

// GetOrderLockConfig 获取订单锁配置
func GetOrderLockConfig(orderID string) LockManagerConfig {
	return LockManagerConfig{
		Type:       LockTypeDistributed,
		Scope:      ScopeOrder,
		Key:        orderID,
		Expiration: 30 * time.Second,
		Timeout:    5 * time.Second,
		RetryDelay: 100 * time.Millisecond,
	}
}

// GetPositionLockConfig 获取持仓锁配置
func GetPositionLockConfig(userID, symbol string) LockManagerConfig {
	return LockManagerConfig{
		Type:       LockTypeDistributed,
		Scope:      ScopePosition,
		Key:        fmt.Sprintf("%s_%s", userID, symbol),
		Expiration: 60 * time.Second,
		Timeout:    10 * time.Second,
		RetryDelay: 200 * time.Millisecond,
	}
}

// GetUserLockConfig 获取用户锁配置
func GetUserLockConfig(userID string) LockManagerConfig {
	return LockManagerConfig{
		Type:       LockTypeLocal,
		Scope:      ScopeUser,
		Key:        userID,
		Expiration: 30 * time.Second,
		Timeout:    3 * time.Second,
		RetryDelay: 50 * time.Millisecond,
	}
}

// GetSymbolLockConfig 获取交易对锁配置
func GetSymbolLockConfig(symbol string) LockManagerConfig {
	return LockManagerConfig{
		Type:       LockTypeLocal,
		Scope:      ScopeSymbol,
		Key:        symbol,
		Expiration: 15 * time.Second,
		Timeout:    2 * time.Second,
		RetryDelay: 25 * time.Millisecond,
	}
}

// GetGlobalLockConfig 获取全局锁配置
func GetGlobalLockConfig(operation string) LockManagerConfig {
	return LockManagerConfig{
		Type:       LockTypeDistributed,
		Scope:      ScopeGlobal,
		Key:        operation,
		Expiration: 120 * time.Second,
		Timeout:    30 * time.Second,
		RetryDelay: 500 * time.Millisecond,
	}
}

// 全局锁管理器实例
var GlobalLockManager *LockManager

// InitLockManager 初始化锁管理器
func InitLockManager(config *OptimizedConfig, redisClient *redis.Client, metrics *MetricsCollector) {
	GlobalLockManager = NewLockManager(config, redisClient, metrics)

	// 启动清理过期锁的定时任务
	go func() {
		ticker := time.NewTicker(time.Minute)
		defer ticker.Stop()

		for range ticker.C {
			GlobalLockManager.CleanupExpiredLocks()
		}
	}()
}

// GetLockManager 获取全局锁管理器
func GetLockManager() *LockManager {
	return GlobalLockManager
}

// WithOrderLock 使用订单锁执行操作
func WithOrderLock(ctx context.Context, orderID string, operation func() error) error {
	if GlobalLockManager == nil {
		return operation()
	}

	config := GetOrderLockConfig(orderID)
	return GlobalLockManager.WithLock(ctx, config, operation)
}

// WithPositionLock 使用持仓锁执行操作
func WithPositionLock(ctx context.Context, userID, symbol string, operation func() error) error {
	if GlobalLockManager == nil {
		return operation()
	}

	config := GetPositionLockConfig(userID, symbol)
	return GlobalLockManager.WithLock(ctx, config, operation)
}

// WithUserLock 使用用户锁执行操作
func WithUserLock(ctx context.Context, userID string, operation func() error) error {
	if GlobalLockManager == nil {
		return operation()
	}

	config := GetUserLockConfig(userID)
	return GlobalLockManager.WithLock(ctx, config, operation)
}