package utils

import (
	"fmt"
	"time"
)

// FormatTime 格式化时间为字符串
func FormatTime(t time.Time, layout string) string {
	if layout == "" {
		layout = "2006-01-02 15:04:05"
	}
	return t.Format(layout)
}

// ParseTime 解析时间字符串
func ParseTime(timeStr, layout string) (time.Time, error) {
	if layout == "" {
		layout = "2006-01-02 15:04:05"
	}
	return time.Parse(layout, timeStr)
}

// GetTimeAgo 获取相对时间描述
func GetTimeAgo(t time.Time) string {
	now := time.Now()
	diff := now.Sub(t)
	
	if diff < time.Minute {
		return "刚刚"
	}
	
	if diff < time.Hour {
		minutes := int(diff.Minutes())
		return fmt.Sprintf("%d分钟前", minutes)
	}
	
	if diff < 24*time.Hour {
		hours := int(diff.Hours())
		return fmt.Sprintf("%d小时前", hours)
	}
	
	if diff < 30*24*time.Hour {
		days := int(diff.Hours() / 24)
		return fmt.Sprintf("%d天前", days)
	}
	
	if diff < 365*24*time.Hour {
		months := int(diff.Hours() / (24 * 30))
		return fmt.Sprintf("%d个月前", months)
	}
	
	years := int(diff.Hours() / (24 * 365))
	return fmt.Sprintf("%d年前", years)
}

// IsToday 检查时间是否为今天
func IsToday(t time.Time) bool {
	now := time.Now()
	return t.Year() == now.Year() && t.YearDay() == now.YearDay()
}

// IsThisWeek 检查时间是否为本周
func IsThisWeek(t time.Time) bool {
	now := time.Now()
	year, week := now.ISOWeek()
	tYear, tWeek := t.ISOWeek()
	return year == tYear && week == tWeek
}

// IsThisMonth 检查时间是否为本月
func IsThisMonth(t time.Time) bool {
	now := time.Now()
	return t.Year() == now.Year() && t.Month() == now.Month()
}

// IsThisYear 检查时间是否为今年
func IsThisYear(t time.Time) bool {
	now := time.Now()
	return t.Year() == now.Year()
}

// GetWeekRange 获取本周的开始和结束时间
func GetWeekRange(t time.Time) (start, end time.Time) {
	// 获取周一作为周开始
	weekday := int(t.Weekday())
	if weekday == 0 {
		weekday = 7 // 周日为7
	}
	
	start = t.AddDate(0, 0, -(weekday-1))
	start = time.Date(start.Year(), start.Month(), start.Day(), 0, 0, 0, 0, start.Location())
	
	end = start.AddDate(0, 0, 6)
	end = time.Date(end.Year(), end.Month(), end.Day(), 23, 59, 59, 999999999, end.Location())
	
	return start, end
}

// GetMonthRange 获取本月的开始和结束时间
func GetMonthRange(t time.Time) (start, end time.Time) {
	start = time.Date(t.Year(), t.Month(), 1, 0, 0, 0, 0, t.Location())
	end = start.AddDate(0, 1, -1)
	end = time.Date(end.Year(), end.Month(), end.Day(), 23, 59, 59, 999999999, end.Location())
	
	return start, end
}

// GetYearRange 获取本年的开始和结束时间
func GetYearRange(t time.Time) (start, end time.Time) {
	start = time.Date(t.Year(), 1, 1, 0, 0, 0, 0, t.Location())
	end = time.Date(t.Year(), 12, 31, 23, 59, 59, 999999999, t.Location())
	
	return start, end
}

// Timestamp 获取当前时间戳（秒）
func Timestamp() int64 {
	return time.Now().Unix()
}

// TimestampMilli 获取当前时间戳（毫秒）
func TimestampMilli() int64 {
	return time.Now().UnixNano() / 1e6
}

// FromTimestamp 从时间戳创建时间对象
func FromTimestamp(timestamp int64) time.Time {
	return time.Unix(timestamp, 0)
}

// FromTimestampMilli 从毫秒时间戳创建时间对象
func FromTimestampMilli(timestamp int64) time.Time {
	return time.Unix(0, timestamp*1e6)
}

// FormatDuration 格式化持续时间
func FormatDuration(d time.Duration) string {
	if d < time.Minute {
		return fmt.Sprintf("%.0f秒", d.Seconds())
	}
	
	if d < time.Hour {
		return fmt.Sprintf("%.0f分钟", d.Minutes())
	}
	
	if d < 24*time.Hour {
		return fmt.Sprintf("%.1f小时", d.Hours())
	}
	
	days := d.Hours() / 24
	return fmt.Sprintf("%.1f天", days)
}