package handler

import (
	"fmt"
	"math/rand"
	"net/http"
	"sync"
	"time"

	"silk-server-go/internal/middleware"

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

// notificationItem 通知项
type notificationItem struct {
	ID        string `json:"id"`
	Channel   string `json:"channel"`
	Target    string `json:"target"`
	Title     string `json:"title"`
	Body      string `json:"body"`
	CreatedAt string `json:"createdAt"`
}

// 通知内存存储（后续可替换为 Redis）
var (
	notificationStore []notificationItem
	notificationMu    sync.Mutex
)

// RegisterNotificationRoutes 注册通知路由
func RegisterNotificationRoutes(rg *gin.RouterGroup, db *gorm.DB) {
	readPerm := middleware.RequirePermission(db, "alarm:read")
	rg.GET("/notifications", readPerm, listNotifications())
	rg.POST("/notifications", readPerm, createNotification())
}

// listNotifications 通知列表（上限200）
func listNotifications() gin.HandlerFunc {
	return func(c *gin.Context) {
		notificationMu.Lock()
		defer notificationMu.Unlock()

		limit := 200
		if len(notificationStore) < limit {
			limit = len(notificationStore)
		}
		// 返回最新的 limit 条（存储已按新到旧排序）
		result := make([]notificationItem, limit)
		copy(result, notificationStore[:limit])

		c.JSON(http.StatusOK, result)
	}
}

// createNotification 手动发通知
func createNotification() gin.HandlerFunc {
	return func(c *gin.Context) {
		var body struct {
			Channel string `json:"channel"`
			Target  string `json:"target"`
			Title   string `json:"title"`
			Body    string `json:"body"`
		}
		if err := c.ShouldBindJSON(&body); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}

		ntf := notificationItem{
			ID:        fmt.Sprintf("%d%d", time.Now().UnixNano(), rand.Intn(1000000)),
			Channel:   body.Channel,
			Target:    body.Target,
			Title:     body.Title,
			Body:      body.Body,
			CreatedAt: time.Now().Format(time.RFC3339),
		}

		notificationMu.Lock()
		// 插入到头部（最新在前）
		notificationStore = append([]notificationItem{ntf}, notificationStore...)
		// 保留最近 500 条
		if len(notificationStore) > 500 {
			notificationStore = notificationStore[:500]
		}
		notificationMu.Unlock()

		c.JSON(http.StatusCreated, ntf)
	}
}