package common

import (
	"fmt"
	"runtime"
)

// InterfaceSliceToStringSlice 将 []interface{} 安全转换为 []string
func InterfaceSliceToStringSlice(slice []interface{}) []string {
	result := make([]string, 0, len(slice))
	for _, v := range slice {
		if str, ok := v.(string); ok && str != "" {
			result = append(result, str)
		}
	}
	return result
}

// FormatBytes 格式化字节大小为人类可读格式
// 例如: 1024 → "1.00 KB", 1048576 → "1.00 MB"
func FormatBytes(bytes uint64) string {
	const unit = 1024
	if bytes < unit {
		return fmt.Sprintf("%d B", bytes)
	}
	div, exp := int64(unit), 0
	for n := bytes / unit; n >= unit; n /= unit {
		div *= unit
		exp++
	}
	return fmt.Sprintf("%.2f %cB", float64(bytes)/float64(div), "KMGTPE"[exp])
}

// Contains 检查切片是否包含元素
func Contains[T comparable](slice []T, item T) bool {
	for _, s := range slice {
		if s == item {
			return true
		}
	}
	return false
}

// Difference 返回在 a 中但不在 b 中的元素
func Difference[T comparable](a, b []T) []T {
	mb := make(map[T]struct{}, len(b))
	for _, x := range b {
		mb[x] = struct{}{}
	}
	var diff []T
	for _, x := range a {
		if _, found := mb[x]; !found {
			diff = append(diff, x)
		}
	}
	return diff
}

// IsWindows 判断是否为Windows系统
func IsWindows() bool {
	return runtime.GOOS == "windows"
}

// IsMac 判断是否为Mac系统
func IsMac() bool {
	return runtime.GOOS == "darwin"
}

// IsLinux 判断是否为Linux系统
func IsLinux() bool {
	return runtime.GOOS == "linux"
}