package reconnect

import "time"

// StrategyType 定义重连策略类型
type StrategyType string

const (
	// StrategyExponentialBackoff 指数退避策略
	StrategyExponentialBackoff StrategyType = "exponential"
	// StrategyFixedInterval 固定间隔策略
	StrategyFixedInterval StrategyType = "fixed"
	// StrategyLinearBackoff 线性退避策略
	StrategyLinearBackoff StrategyType = "linear"
)

// ConnectionState 连接状态
type ConnectionState int

const (
	// StateDisconnected 断开连接
	StateDisconnected ConnectionState = iota
	// StateConnecting 正在连接
	StateConnecting
	// StateConnected 已连接
	StateConnected
	// StateReconnecting 正在重连
	StateReconnecting
)

func (s ConnectionState) String() string {
	switch s {
	case StateDisconnected:
		return "disconnected"
	case StateConnecting:
		return "connecting"
	case StateConnected:
		return "connected"
	case StateReconnecting:
		return "reconnecting"
	default:
		return "unknown"
	}
}

// Config 重连配置
type Config struct {
	// Strategy 重连策略类型
	Strategy StrategyType

	// MaxRetries 最大重试次数，-1 表示无限重试
	MaxRetries int

	// InitialDelay 初始延迟时间
	InitialDelay time.Duration

	// MaxDelay 最大延迟时间
	MaxDelay time.Duration

	// Multiplier 指数退避乘数（仅用于指数退避策略）
	Multiplier float64

	// LinearIncrement 线性增量（仅用于线性退避策略）
	LinearIncrement time.Duration

	// HealthCheckInterval 健康检查间隔
	HealthCheckInterval time.Duration

	// HealthCheckTimeout 健康检查超时时间
	HealthCheckTimeout time.Duration

	// OnStateChange 状态变化回调函数
	OnStateChange func(oldState, newState ConnectionState)

	// OnReconnect 重连回调函数（重连成功时调用）
	OnReconnect func(attempt int)

	// OnError 错误回调函数
	OnError func(err error)
}

// DefaultConfig 返回默认配置
func DefaultConfig() Config {
	return Config{
		Strategy:            StrategyExponentialBackoff,
		MaxRetries:          -1, // 无限重试
		InitialDelay:        1 * time.Second,
		MaxDelay:            30 * time.Second,
		Multiplier:          2.0,
		LinearIncrement:     1 * time.Second,
		HealthCheckInterval: 10 * time.Second,
		HealthCheckTimeout:  5 * time.Second,
	}
}

// Validate 验证配置
func (c *Config) Validate() {
	if c.InitialDelay <= 0 {
		c.InitialDelay = 1 * time.Second
	}
	if c.MaxDelay <= 0 {
		c.MaxDelay = 30 * time.Second
	}
	if c.Multiplier <= 0 {
		c.Multiplier = 2.0
	}
	if c.LinearIncrement <= 0 {
		c.LinearIncrement = 1 * time.Second
	}
	if c.HealthCheckInterval <= 0 {
		c.HealthCheckInterval = 10 * time.Second
	}
	if c.HealthCheckTimeout <= 0 {
		c.HealthCheckTimeout = 5 * time.Second
	}
}