package timer

import (
	"time"
)

// RetryOptions 重试配置
type RetryOptions struct {
	MaxRetries int
	Backoff    time.Duration
	Factor     float64
}

// RetryOption 重试选项函数
type RetryOption func(*RetryOptions)

// WithMaxRetries 设置最大重试次数
func WithMaxRetries(n int) RetryOption {
	return func(o *RetryOptions) {
		o.MaxRetries = n
	}
}

// WithBackoff 设置初始等待时间和增长因子
func WithBackoff(d time.Duration, factor float64) RetryOption {
	return func(o *RetryOptions) {
		o.Backoff = d
		o.Factor = factor
	}
}

// Retry 执行带退避机制的重试
func Retry(fn func() error, opts ...RetryOption) error {
	o := &RetryOptions{
		MaxRetries: 3,
		Backoff:    100 * time.Millisecond,
		Factor:     2.0,
	}
	for _, opt := range opts {
		opt(o)
	}

	var err error
	backoff := o.Backoff
	for i := 0; i <= o.MaxRetries; i++ {
		err = fn()
		if err == nil {
			return nil
		}
		if i < o.MaxRetries {
			time.Sleep(backoff)
			backoff = time.Duration(float64(backoff) * o.Factor)
		}
	}
	return err
}