package handlers

import (
	"net/http"
	"runtime"
	"time"

	"visiona-local/server/internal/deps"

	"github.com/gin-gonic/gin"
)

type SystemHandler struct {
	startTime  time.Time
	version    string
	buildTime  string
	pythonBin  string // 由 main.go 傳入，InstallDriver 會用到
	shutdownFn func()
	depsCache  []deps.Dependency
}

func NewSystemHandler(version, buildTime, pythonBin string, shutdownFn func()) *SystemHandler {
	return &SystemHandler{
		startTime:  time.Now(),
		version:    version,
		buildTime:  buildTime,
		pythonBin:  pythonBin,
		shutdownFn: shutdownFn,
		depsCache:  deps.CheckAll(),
	}
}

func (h *SystemHandler) HealthCheck(c *gin.Context) {
	c.JSON(200, gin.H{"status": "ok"})
}

func (h *SystemHandler) Info(c *gin.Context) {
	c.JSON(200, gin.H{
		"success": true,
		"data": gin.H{
			"version":   h.version,
			"platform":  runtime.GOOS + "/" + runtime.GOARCH,
			"uptime":    time.Since(h.startTime).Seconds(),
			"goVersion": runtime.Version(),
		},
	})
}

func (h *SystemHandler) Metrics(c *gin.Context) {
	var ms runtime.MemStats
	runtime.ReadMemStats(&ms)

	c.JSON(200, gin.H{
		"success": true,
		"data": gin.H{
			"version":        h.version,
			"buildTime":      h.buildTime,
			"platform":       runtime.GOOS + "/" + runtime.GOARCH,
			"goVersion":      runtime.Version(),
			"uptimeSeconds":  time.Since(h.startTime).Seconds(),
			"goroutines":     runtime.NumGoroutine(),
			"memHeapAllocMB": float64(ms.HeapAlloc) / 1024 / 1024,
			"memSysMB":       float64(ms.Sys) / 1024 / 1024,
			"memHeapObjects": ms.HeapObjects,
			"gcCycles":       ms.NumGC,
			"nextGcMB":       float64(ms.NextGC) / 1024 / 1024,
		},
	})
}

func (h *SystemHandler) Deps(c *gin.Context) {
	c.JSON(200, gin.H{
		"success": true,
		"data":    gin.H{"deps": h.depsCache},
	})
}

// InstallDriver 安裝 Kneron WinUSB driver（僅 Windows 有意義）。
// 呼叫 platform-specific 實作（見 system_driver_windows.go / system_driver_other.go）。
func (h *SystemHandler) InstallDriver(c *gin.Context) {
	if runtime.GOOS != "windows" {
		c.JSON(400, gin.H{
			"success": false,
			"error": gin.H{
				"code":    "DRIVER_NOT_NEEDED",
				"message": runtime.GOOS + " 不需要安裝 WinUSB driver",
			},
		})
		return
	}
	pyBin := h.pythonBin
	if pyBin == "" {
		c.JSON(500, gin.H{
			"success": false,
			"error": gin.H{
				"code":    "PYTHON_NOT_AVAILABLE",
				"message": "Python interpreter 未就緒，請確認 bundled Python runtime 初始化完成",
			},
		})
		return
	}
	if err := installKneronWinUSBDriverHandler(pyBin); err != nil {
		c.JSON(500, gin.H{
			"success": false,
			"error": gin.H{
				"code":    "DRIVER_INSTALL_FAILED",
				"message": err.Error(),
			},
		})
		return
	}
	c.JSON(200, gin.H{
		"success": true,
		"data":    gin.H{"message": "WinUSB driver 安裝完成，請重新插拔裝置或直接點擊連線。"},
	})
}

func (h *SystemHandler) Restart(c *gin.Context) {
	c.JSON(200, gin.H{"success": true, "data": gin.H{"message": "restarting"}})
	if f, ok := c.Writer.(http.Flusher); ok {
		f.Flush()
	}

	go func() {
		time.Sleep(200 * time.Millisecond)
		// shutdownFn signals the main goroutine to perform exec after server shutdown
		if h.shutdownFn != nil {
			h.shutdownFn()
		}
	}()
}