package services

import (
	"fmt"
	"runtime"

	"github.com/wailsapp/wails/v3/pkg/application"
	"github.com/wailsapp/wails/v3/pkg/services/log"
)

// SystemService 系统监控服务
type SystemService struct {
	logger *log.LogService
}

// MemoryStats 内存统计信息
type MemoryStats struct {
	// 当前堆内存使用量（字节）
	HeapInUse uint64 `json:"heapInUse"`
	// 堆内存分配总量（字节）
	HeapAlloc uint64 `json:"heapAlloc"`
	// 系统内存使用量（字节）
	Sys uint64 `json:"sys"`
	// GC 次数
	NumGC uint32 `json:"numGC"`
	// GC 暂停时间（纳秒）
	PauseTotalNs uint64 `json:"pauseTotalNs"`
	// Goroutine 数量
	NumGoroutine int `json:"numGoroutine"`
}

// SystemInfo 系统信息
type SystemInfo struct {
	OS           string                 `json:"os"`
	Arch         string                 `json:"arch"`
	Debug        bool                   `json:"debug"`
	OSInfo       *OSInfo                `json:"osInfo"`
	PlatformInfo map[string]interface{} `json:"platformInfo"`
}

// OSInfo 操作系统信息
type OSInfo struct {
	ID       string `json:"id"`
	Name     string `json:"name"`
	Version  string `json:"version"`
	Branding string `json:"branding"`
}

// NewSystemService 创建新的系统服务实例
func NewSystemService(logger *log.LogService) *SystemService {
	return &SystemService{
		logger: logger,
	}
}

// GetMemoryStats 获取当前内存统计信息
func (ss *SystemService) GetMemoryStats() MemoryStats {
	var m runtime.MemStats
	runtime.ReadMemStats(&m)

	return MemoryStats{
		HeapInUse:    m.HeapInuse,
		HeapAlloc:    m.HeapAlloc,
		Sys:          m.Sys,
		NumGC:        m.NumGC,
		PauseTotalNs: m.PauseTotalNs,
		NumGoroutine: runtime.NumGoroutine(),
	}
}

// GetSystemInfo 获取系统环境信息
func (ss *SystemService) GetSystemInfo() (*SystemInfo, error) {
	app := application.Get()
	envInfo := app.Env.Info()

	systemInfo := &SystemInfo{
		OS:           envInfo.OS,
		Arch:         envInfo.Arch,
		Debug:        envInfo.Debug,
		PlatformInfo: envInfo.PlatformInfo,
	}

	// 转换OSInfo
	if envInfo.OSInfo != nil {
		systemInfo.OSInfo = &OSInfo{
			ID:       envInfo.OSInfo.ID,
			Name:     envInfo.OSInfo.Name,
			Version:  envInfo.OSInfo.Version,
			Branding: envInfo.OSInfo.Branding,
		}
	}

	return systemInfo, nil
}

// FormatBytes 格式化字节数为人类可读的格式
func (ss *SystemService) FormatBytes(bytes uint64) string {
	const unit = 1024
	if bytes < unit {
		return "< 1 KB"
	}
	div, exp := uint64(unit), 0
	for n := bytes / unit; n >= unit; n /= unit {
		div *= unit
		exp++
	}

	switch exp {
	case 0:
		return "< 1 KB"
	case 1:
		return fmt.Sprintf("%.1f KB", float64(bytes)/float64(div))
	case 2:
		return fmt.Sprintf("%.1f MB", float64(bytes)/float64(div))
	case 3:
		return fmt.Sprintf("%.1f GB", float64(bytes)/float64(div))
	default:
		return fmt.Sprintf("%.1f TB", float64(bytes)/float64(div))
	}
}

// TriggerGC 手动触发垃圾回收
func (ss *SystemService) TriggerGC() {
	runtime.GC()
	ss.logger.Info("Manual GC triggered")
}