package binanceservice

import (
	"context"
	"errors"
	"fmt"
	"net"
	"strings"
	"time"

	"github.com/go-admin-team/go-admin-core/logger"
	"gorm.io/gorm"
)

// ErrorType 错误类型
type ErrorType string

const (
	ErrorTypeNetwork    ErrorType = "network"
	ErrorTypeDatabase   ErrorType = "database"
	ErrorTypeBusiness   ErrorType = "business"
	ErrorTypeSystem     ErrorType = "system"
	ErrorTypeValidation ErrorType = "validation"
	ErrorTypeTimeout    ErrorType = "timeout"
	ErrorTypeRateLimit  ErrorType = "rate_limit"
	ErrorTypeAuth       ErrorType = "auth"
)

// ErrorSeverity 错误严重程度
type ErrorSeverity string

const (
	SeverityLow      ErrorSeverity = "low"
	SeverityMedium   ErrorSeverity = "medium"
	SeverityHigh     ErrorSeverity = "high"
	SeverityCritical ErrorSeverity = "critical"
)

// ErrorAction 错误处理动作
type ErrorAction string

const (
	ActionRetry     ErrorAction = "retry"
	ActionFallback  ErrorAction = "fallback"
	ActionAlert     ErrorAction = "alert"
	ActionIgnore    ErrorAction = "ignore"
	ActionCircuit   ErrorAction = "circuit"
	ActionDegrade   ErrorAction = "degrade"
)

// ErrorInfo 错误信息
type ErrorInfo struct {
	Type        ErrorType     `json:"type"`
	Severity    ErrorSeverity `json:"severity"`
	Message     string        `json:"message"`
	OriginalErr error         `json:"-"`
	Context     string        `json:"context"`
	Timestamp   time.Time     `json:"timestamp"`
	Retryable   bool          `json:"retryable"`
	Action      ErrorAction   `json:"action"`
}

// RetryConfig 和 CircuitBreakerConfig 已在 config_optimized.go 中定义

// ErrorHandler 错误处理器
type ErrorHandler struct {
	config           *OptimizedConfig
	metricsCollector *MetricsCollector
	circuitBreakers  map[string]*CircuitBreaker
}

// CircuitBreaker 熔断器
type CircuitBreaker struct {
	name         string
	config       CircuitBreakerConfig
	state        CircuitState
	failureCount int
	successCount int
	lastFailTime time.Time
	nextRetry    time.Time
	halfOpenCalls int
}

// CircuitState 熔断器状态
type CircuitState string

const (
	StateClosed   CircuitState = "closed"
	StateOpen     CircuitState = "open"
	StateHalfOpen CircuitState = "half_open"
)

// NewErrorHandler 创建错误处理器
func NewErrorHandler(config *OptimizedConfig, metricsCollector *MetricsCollector) *ErrorHandler {
	return &ErrorHandler{
		config:           config,
		metricsCollector: metricsCollector,
		circuitBreakers:  make(map[string]*CircuitBreaker),
	}
}

// ClassifyError 分类错误
func (eh *ErrorHandler) ClassifyError(err error, context string) *ErrorInfo {
	if err == nil {
		return nil
	}

	errorInfo := &ErrorInfo{
		OriginalErr: err,
		Message:     err.Error(),
		Context:     context,
		Timestamp:   time.Now(),
	}

	// 根据错误类型分类
	switch {
	case isNetworkError(err):
		errorInfo.Type = ErrorTypeNetwork
		errorInfo.Severity = SeverityMedium
		errorInfo.Retryable = true
		errorInfo.Action = ActionRetry

	case isDatabaseError(err):
		errorInfo.Type = ErrorTypeDatabase
		errorInfo.Severity = SeverityHigh
		errorInfo.Retryable = isRetryableDatabaseError(err)
		errorInfo.Action = ActionRetry

	case isTimeoutError(err):
		errorInfo.Type = ErrorTypeTimeout
		errorInfo.Severity = SeverityMedium
		errorInfo.Retryable = true
		errorInfo.Action = ActionRetry

	case isRateLimitError(err):
		errorInfo.Type = ErrorTypeRateLimit
		errorInfo.Severity = SeverityMedium
		errorInfo.Retryable = true
		errorInfo.Action = ActionRetry

	case isAuthError(err):
		errorInfo.Type = ErrorTypeAuth
		errorInfo.Severity = SeverityHigh
		errorInfo.Retryable = false
		errorInfo.Action = ActionAlert

	case isValidationError(err):
		errorInfo.Type = ErrorTypeValidation
		errorInfo.Severity = SeverityLow
		errorInfo.Retryable = false
		errorInfo.Action = ActionIgnore

	case isBusinessError(err):
		errorInfo.Type = ErrorTypeBusiness
		errorInfo.Severity = SeverityMedium
		errorInfo.Retryable = false
		errorInfo.Action = ActionFallback

	default:
		errorInfo.Type = ErrorTypeSystem
		errorInfo.Severity = SeverityHigh
		errorInfo.Retryable = true
		errorInfo.Action = ActionRetry
	}

	return errorInfo
}

// HandleError 处理错误
func (eh *ErrorHandler) HandleError(err error, context string) *ErrorInfo {
	errorInfo := eh.ClassifyError(err, context)
	if errorInfo == nil {
		return nil
	}

	// 记录错误指标
	if eh.metricsCollector != nil {
		eh.metricsCollector.RecordError(string(errorInfo.Type), errorInfo.Message, context)
	}

	// 根据错误动作处理
	switch errorInfo.Action {
	case ActionAlert:
		eh.sendAlert(errorInfo)
	case ActionCircuit:
		eh.triggerCircuitBreaker(context)
	case ActionDegrade:
		eh.enableDegradedMode(context)
	}

	// 记录日志
	eh.logError(errorInfo)

	return errorInfo
}

// RetryWithBackoff 带退避的重试
func (eh *ErrorHandler) RetryWithBackoff(ctx context.Context, operation func() error, config RetryConfig, context string) error {
	var lastErr error
	delay := config.RetryDelay

	for attempt := 1; attempt <= config.MaxRetries; attempt++ {
		// 检查上下文是否已取消
		select {
		case <-ctx.Done():
			return ctx.Err()
		default:
		}

		// 检查熔断器状态
		if !eh.canExecute(context) {
			return fmt.Errorf("circuit breaker is open for %s", context)
		}

		// 执行操作
		// 注意：config中没有TimeoutPerTry字段，这里暂时注释掉
		// if config.TimeoutPerTry > 0 {
		//	var cancel context.CancelFunc
		//	operationCtx, cancel = context.WithTimeout(ctx, config.TimeoutPerTry)
		//	defer cancel()
		// }

		err := operation()
		if err == nil {
			// 成功，记录成功指标
			if eh.metricsCollector != nil {
				eh.metricsCollector.RecordRetry(true)
			}
			eh.recordSuccess(context)
			return nil
		}

		lastErr = err
		errorInfo := eh.ClassifyError(err, context)

		// 记录失败
		eh.recordFailure(context)

		// 如果不可重试，直接返回
		if errorInfo != nil && !errorInfo.Retryable {
			logger.Warnf("不可重试的错误 [%s]: %v", context, err)
			return err
		}

		// 最后一次尝试，不再等待
		if attempt == config.MaxRetries {
			break
		}

		// 计算下次重试延迟
		nextDelay := eh.calculateDelay(delay, config)
		logger.Infof("重试 %d/%d [%s] 在 %v 后，错误: %v", attempt, config.MaxRetries, context, nextDelay, err)

		// 等待重试
		select {
		case <-ctx.Done():
			return ctx.Err()
		case <-time.After(nextDelay):
			delay = nextDelay
		}
	}

	// 记录重试失败指标
	if eh.metricsCollector != nil {
		eh.metricsCollector.RecordRetry(false)
	}

	return fmt.Errorf("重试 %d 次后仍然失败 [%s]: %w", config.MaxRetries, context, lastErr)
}

// calculateDelay 计算重试延迟
func (eh *ErrorHandler) calculateDelay(currentDelay time.Duration, config RetryConfig) time.Duration {
	nextDelay := time.Duration(float64(currentDelay) * config.BackoffFactor)

	// 限制最大延迟
	if nextDelay > config.MaxRetryDelay {
		nextDelay = config.MaxRetryDelay
	}

	// 添加10%抖动（简化版本，不依赖JitterEnabled字段）
	jitter := time.Duration(float64(nextDelay) * 0.1)
	if jitter > 0 {
		nextDelay += time.Duration(time.Now().UnixNano() % int64(jitter))
	}

	return nextDelay
}

// canExecute 检查是否可以执行操作（熔断器检查）
func (eh *ErrorHandler) canExecute(context string) bool {
	cb := eh.getCircuitBreaker(context)
	if cb == nil || !cb.config.Enabled {
		return true
	}

	now := time.Now()

	switch cb.state {
	case StateClosed:
		return true

	case StateOpen:
		if now.After(cb.nextRetry) {
			cb.state = StateHalfOpen
			cb.halfOpenCalls = 0
			return true
		}
		return false

	case StateHalfOpen:
		return cb.halfOpenCalls < cb.config.HalfOpenMaxCalls

	default:
		return true
	}
}

// recordSuccess 记录成功
func (eh *ErrorHandler) recordSuccess(context string) {
	cb := eh.getCircuitBreaker(context)
	if cb == nil || !cb.config.Enabled {
		return
	}

	switch cb.state {
	case StateHalfOpen:
		cb.successCount++
		if cb.successCount >= cb.config.SuccessThreshold {
			cb.state = StateClosed
			cb.failureCount = 0
			cb.successCount = 0
		}

	case StateClosed:
		cb.failureCount = 0
	}
}

// recordFailure 记录失败
func (eh *ErrorHandler) recordFailure(context string) {
	cb := eh.getCircuitBreaker(context)
	if cb == nil || !cb.config.Enabled {
		return
	}

	cb.failureCount++
	cb.lastFailTime = time.Now()

	switch cb.state {
	case StateClosed:
		if cb.failureCount >= cb.config.FailureThreshold {
			cb.state = StateOpen
			cb.nextRetry = time.Now().Add(cb.config.Timeout)
			logger.Warnf("熔断器开启 [%s]: 失败次数 %d", context, cb.failureCount)
		}

	case StateHalfOpen:
		cb.state = StateOpen
		cb.nextRetry = time.Now().Add(cb.config.Timeout)
		cb.successCount = 0
		logger.Warnf("熔断器重新开启 [%s]", context)
	}
}

// getCircuitBreaker 获取熔断器
func (eh *ErrorHandler) getCircuitBreaker(context string) *CircuitBreaker {
	cb, exists := eh.circuitBreakers[context]
	if !exists {
		cb = &CircuitBreaker{
			name:   context,
			config: eh.config.CircuitBreakerConfig,
			state:  StateClosed,
		}
		eh.circuitBreakers[context] = cb
	}
	return cb
}

// triggerCircuitBreaker 触发熔断器
func (eh *ErrorHandler) triggerCircuitBreaker(context string) {
	cb := eh.getCircuitBreaker(context)
	if cb != nil && cb.config.Enabled {
		cb.state = StateOpen
		cb.nextRetry = time.Now().Add(cb.config.Timeout)
		logger.Warnf("手动触发熔断器 [%s]", context)
	}
}

// sendAlert 发送告警
func (eh *ErrorHandler) sendAlert(errorInfo *ErrorInfo) {
	// 这里可以集成告警系统，如钉钉、邮件等
	logger.Errorf("告警: [%s] %s - %s", errorInfo.Type, errorInfo.Context, errorInfo.Message)
}

// enableDegradedMode 启用降级模式
func (eh *ErrorHandler) enableDegradedMode(context string) {
	logger.Warnf("启用降级模式 [%s]", context)
	// 这里可以实现具体的降级逻辑
}

// logError 记录错误日志
func (eh *ErrorHandler) logError(errorInfo *ErrorInfo) {
	switch errorInfo.Severity {
	case SeverityLow:
		logger.Infof("[%s] %s: %s", errorInfo.Type, errorInfo.Context, errorInfo.Message)
	case SeverityMedium:
		logger.Warnf("[%s] %s: %s", errorInfo.Type, errorInfo.Context, errorInfo.Message)
	case SeverityHigh, SeverityCritical:
		logger.Errorf("[%s] %s: %s", errorInfo.Type, errorInfo.Context, errorInfo.Message)
	}
}

// GetCircuitBreakerStatus 获取熔断器状态
func (eh *ErrorHandler) GetCircuitBreakerStatus() map[string]interface{} {
	status := make(map[string]interface{})
	for name, cb := range eh.circuitBreakers {
		status[name] = map[string]interface{}{
			"state":         cb.state,
			"failure_count": cb.failureCount,
			"success_count": cb.successCount,
			"last_fail_time": cb.lastFailTime,
			"next_retry":     cb.nextRetry,
		}
	}
	return status
}

// 错误分类辅助函数

// isNetworkError 判断是否为网络错误
func isNetworkError(err error) bool {
	if err == nil {
		return false
	}

	// 检查网络相关错误
	var netErr net.Error
	if errors.As(err, &netErr) {
		return true
	}

	// 检查常见网络错误消息
	errorMsg := strings.ToLower(err.Error())
	networkKeywords := []string{
		"connection refused",
		"connection reset",
		"connection timeout",
		"network unreachable",
		"no route to host",
		"dns",
		"socket",
	}

	for _, keyword := range networkKeywords {
		if strings.Contains(errorMsg, keyword) {
			return true
		}
	}

	return false
}

// isDatabaseError 判断是否为数据库错误
func isDatabaseError(err error) bool {
	if err == nil {
		return false
	}

	// 检查GORM错误
	if errors.Is(err, gorm.ErrRecordNotFound) ||
		errors.Is(err, gorm.ErrInvalidTransaction) ||
		errors.Is(err, gorm.ErrNotImplemented) {
		return true
	}

	// 检查数据库相关错误消息
	errorMsg := strings.ToLower(err.Error())
	dbKeywords := []string{
		"database",
		"sql",
		"mysql",
		"postgres",
		"connection pool",
		"deadlock",
		"constraint",
		"duplicate key",
	}

	for _, keyword := range dbKeywords {
		if strings.Contains(errorMsg, keyword) {
			return true
		}
	}

	return false
}

// isRetryableDatabaseError 判断是否为可重试的数据库错误
func isRetryableDatabaseError(err error) bool {
	if err == nil {
		return false
	}

	// 不可重试的错误
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return false
	}

	errorMsg := strings.ToLower(err.Error())
	nonRetryableKeywords := []string{
		"constraint",
		"duplicate key",
		"foreign key",
		"syntax error",
	}

	for _, keyword := range nonRetryableKeywords {
		if strings.Contains(errorMsg, keyword) {
			return false
		}
	}

	return true
}

// isTimeoutError 判断是否为超时错误
func isTimeoutError(err error) bool {
	if err == nil {
		return false
	}

	// 检查超时错误
	var netErr net.Error
	if errors.As(err, &netErr) && netErr.Timeout() {
		return true
	}

	if errors.Is(err, context.DeadlineExceeded) {
		return true
	}

	errorMsg := strings.ToLower(err.Error())
	return strings.Contains(errorMsg, "timeout") ||
		strings.Contains(errorMsg, "deadline exceeded")
}

// isRateLimitError 判断是否为限流错误
func isRateLimitError(err error) bool {
	if err == nil {
		return false
	}

	errorMsg := strings.ToLower(err.Error())
	rateLimitKeywords := []string{
		"rate limit",
		"too many requests",
		"429",
		"quota exceeded",
		"throttle",
	}

	for _, keyword := range rateLimitKeywords {
		if strings.Contains(errorMsg, keyword) {
			return true
		}
	}

	return false
}

// isAuthError 判断是否为认证错误
func isAuthError(err error) bool {
	if err == nil {
		return false
	}

	errorMsg := strings.ToLower(err.Error())
	authKeywords := []string{
		"unauthorized",
		"authentication",
		"invalid signature",
		"api key",
		"401",
		"403",
		"forbidden",
	}

	for _, keyword := range authKeywords {
		if strings.Contains(errorMsg, keyword) {
			return true
		}
	}

	return false
}

// isValidationError 判断是否为验证错误
func isValidationError(err error) bool {
	if err == nil {
		return false
	}

	errorMsg := strings.ToLower(err.Error())
	validationKeywords := []string{
		"validation",
		"invalid parameter",
		"bad request",
		"400",
		"missing required",
		"invalid format",
	}

	for _, keyword := range validationKeywords {
		if strings.Contains(errorMsg, keyword) {
			return true
		}
	}

	return false
}

// isBusinessError 判断是否为业务错误
func isBusinessError(err error) bool {
	if err == nil {
		return false
	}

	errorMsg := strings.ToLower(err.Error())
	businessKeywords := []string{
		"insufficient balance",
		"order not found",
		"position not found",
		"invalid order status",
		"market closed",
		"symbol not found",
	}

	for _, keyword := range businessKeywords {
		if strings.Contains(errorMsg, keyword) {
			return true
		}
	}

	return false
}

// 全局错误处理器实例
var GlobalErrorHandler *ErrorHandler

// InitErrorHandler 初始化错误处理器
func InitErrorHandler(config *OptimizedConfig, metricsCollector *MetricsCollector) {
	GlobalErrorHandler = NewErrorHandler(config, metricsCollector)
}

// GetErrorHandler 获取全局错误处理器
func GetErrorHandler() *ErrorHandler {
	return GlobalErrorHandler
}

// HandleErrorWithRetry 处理错误并重试的便捷函数
func HandleErrorWithRetry(ctx context.Context, operation func() error, context string) error {
	if GlobalErrorHandler == nil {
		return operation()
	}

	config := RetryConfig{
		MaxRetries:     3,
		RetryDelay:     100 * time.Millisecond,
		MaxRetryDelay:  5 * time.Second,
		BackoffFactor:  2.0,
		ApiRetryCount:  3,
		DbRetryCount:   3,
	}

	return GlobalErrorHandler.RetryWithBackoff(ctx, operation, config, context)
}