package logic

import (
	"context"
	"math"
	"os"
	"runtime"
	"strings"
	"time"

	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/gcron"

	"easygoadmin/api/v1"
	"easygoadmin/internal/dao"
	"easygoadmin/internal/service"
	"easygoadmin/utility/cache"
)

// ============================== 服务器监控业务实现 ==============================

// sServerMonitor 服务器监控业务实现
// 汇集进程运行时、磁盘、数据库与缓存连通信息
type sServerMonitor struct{}

// procStart 进程启动时间（包加载时刻）
var procStart = time.Now()

func init() {
	service.RegisterServerMonitor(&sServerMonitor{})
}

// Info 查询服务器监控信息
func (s *sServerMonitor) Info(ctx context.Context, req *v1.ServerInfoReq) (res *v1.ServerInfoRes, err error) {
	var m runtime.MemStats
	runtime.ReadMemStats(&m)
	hostname, _ := os.Hostname()

	res = &v1.ServerInfoRes{
		Server: v1.ServerOsInfo{
			Hostname:   hostname,
			GoVersion:  runtime.Version(),
			Arch:       runtime.GOARCH,
			NumCPU:     runtime.NumCPU(),
			Goroutines: runtime.NumGoroutine(),
			Uptime:     time.Since(procStart).Round(time.Second).String(),
		},
		Mem: v1.ServerMemInfo{
			AllocMB:      roundMB(m.Alloc),
			TotalAllocMB: roundMB(m.TotalAlloc),
			SysMB:        roundMB(m.Sys),
			HeapAllocMB:  roundMB(m.HeapAlloc),
			HeapSysMB:    roundMB(m.HeapSys),
			HeapObjects:  m.HeapObjects,
			GCCycles:     m.NumGC,
		},
		Disk: diskUsage(),
	}

	// 数据库连通与版本
	start := time.Now()
	_, err = g.DB().Ctx(ctx).Exec(ctx, "SELECT VERSION()")
	pingMs := time.Since(start).Milliseconds()
	version := ""
	if err == nil {
		if v, verr := g.DB().Ctx(ctx).GetValue(ctx, "SELECT VERSION()"); verr == nil {
			version = v.String()
		}
		res.Db = v1.ServerDbInfo{Version: version, PingMs: pingMs}
	} else {
		res.Db = v1.ServerDbInfo{PingMs: pingMs}
	}

	// 缓存连通
	if cache.UsingMemory() {
		res.Cache = v1.ServerCacheBrief{Mode: "memory", Connected: false}
	} else if _, cerr := g.Redis().Do(ctx, "PING"); cerr == nil {
		res.Cache = v1.ServerCacheBrief{Mode: "redis", Connected: true}
	} else {
		res.Cache = v1.ServerCacheBrief{Mode: "redis", Connected: false}
	}

	// 定时任务调度器状态
	// 挂载数统计 gcron 中 job: 前缀条目（排除上传清理等非任务条目），
	// 应挂载数取任务表 status=1（运行中）的记录数，挂载失败或数据被外部改动会出现差值
	mounted := 0
	for _, e := range gcron.Entries() {
		if strings.HasPrefix(e.Name, "job:") {
			mounted++
		}
	}
	expected, _ := dao.Job.Ctx(ctx).Where("status", 1).Count()
	res.Scheduler = v1.ServerSchedulerInfo{
		Enabled:  !daemonStart.IsZero(),
		Healthy:  !daemonStart.IsZero() && mounted >= int(expected),
		Mounted:  mounted,
		Expected: int(expected),
		StartTime: func() string {
			if daemonStart.IsZero() {
				return ""
			}
			return daemonStart.Format("2006-01-02 15:04:05")
		}(),
	}

	if err != nil {
		// 数据库不通不视为整体失败，仅版本留空；返回详情供页面展示
		err = nil
	}
	return res, nil
}

// roundMB 字节转 MB（保留两位小数）
func roundMB(v uint64) float64 {
	return math.Round(float64(v)/1048576*100) / 100
}