package handler

import (
	"bytes"
	"encoding/json"
	"io"
	"net/http"
	"regexp"
	"strconv"
	"strings"

	"silk-server-go/internal/middleware"
	"silk-server-go/internal/model"
	"silk-server-go/internal/service"

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

var uuidPattern = regexp.MustCompile(`^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$`)

// isUUID 判断字符串是否为标准 UUID 格式（roomId 等外键校验用）
func isUUID(s string) bool {
	return uuidPattern.MatchString(s)
}

// RegisterInspectionRoutes 注册 AI 巡检路由
func RegisterInspectionRoutes(rg *gin.RouterGroup, db *gorm.DB, s3 *service.S3Service, ai *service.AIClient, imageBucket string) {
	rg.POST("/inspections", middleware.RequirePermission(db, "inspection:create"), createInspection(db, s3, ai, imageBucket))
	rg.GET("/inspections", middleware.RequirePermission(db, "inspection:read"), listInspections(db))
}

// currentUserID 从 JWT 上下文取用户 ID
func currentUserID(c *gin.Context) *string {
	if user, ok := c.Get("user"); ok {
		if m, ok := user.(map[string]interface{}); ok {
			if s, ok := m["sub"].(string); ok && s != "" {
				return &s
			}
		}
	}
	return nil
}

// createInspection 拍照巡检：图片存 S3 → 调 AI /detect → 写记录。
// 幂等：客户端传 Idempotency-Key 头时，重复请求返回已有记录。
func createInspection(db *gorm.DB, s3 *service.S3Service, ai *service.AIClient, bucket string) gin.HandlerFunc {
	return func(c *gin.Context) {
		idemKey := strings.TrimSpace(c.GetHeader("Idempotency-Key"))
		roomID := strings.TrimSpace(c.PostForm("roomId"))

		if idemKey != "" {
			var exist model.InspectionRecord
			if db.Where("idempotency_key = ?", idemKey).First(&exist).Error == nil {
				c.JSON(http.StatusOK, exist)
				return
			}
		}

		file, header, err := c.Request.FormFile("file")
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "请选择图片文件（字段名 file）"})
			return
		}
		defer file.Close()

		if err := validateImageFile(header.Filename, header.Size); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		imageBytes, err := io.ReadAll(file)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "读取图片失败"})
			return
		}

		key, ext, err := buildObjectKey("inspections", header.Filename)
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		contentType, _ := imageContentType(ext)
		if err := s3.EnsureBucket(bucket); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "图片存储不可用: " + err.Error()})
			return
		}
		if err := s3.UploadImage(bucket, key, bytes.NewReader(imageBytes), contentType); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "图片上传失败: " + err.Error()})
			return
		}
		imageURL := s3.Endpoint() + "/" + bucket + "/" + key

		rec := model.InspectionRecord{
			UserID:   currentUserID(c),
			ImageURL: &imageURL,
			AIStatus: "done",
		}
		if roomID != "" {
			if !isUUID(roomID) {
				c.JSON(http.StatusBadRequest, gin.H{"error": "roomId 不是合法的 UUID"})
				return
			}
			rec.RoomID = &roomID
		}
		if idemKey != "" {
			rec.IdempotencyKey = &idemKey
		}

		detRes, aiErr := ai.Detect(c.Request.Context(), imageBytes, header.Filename)
		if aiErr != nil {
			rec.AIStatus = "failed"
		} else {
			raw, _ := json.Marshal(detRes.Detections)
			rec.Detections = raw
		}

		if err := db.Create(&rec).Error; err != nil {
			// 并发幂等：唯一索引冲突时返回已有记录
			if idemKey != "" {
				var exist model.InspectionRecord
				if db.Where("idempotency_key = ?", idemKey).First(&exist).Error == nil {
					c.JSON(http.StatusOK, exist)
					return
				}
			}
			c.JSON(http.StatusInternalServerError, gin.H{"error": "创建巡检记录失败"})
			return
		}
		c.JSON(http.StatusCreated, rec)
	}
}

// listInspections 巡检记录列表（roomId/limit 过滤）
func listInspections(db *gorm.DB) gin.HandlerFunc {
	return func(c *gin.Context) {
		q := db.Model(&model.InspectionRecord{})
		if room := c.Query("roomId"); room != "" {
			q = q.Where("room_id = ?", room)
		}
		limit := 50
		if l, err := strconv.Atoi(c.Query("limit")); err == nil && l > 0 && l <= 200 {
			limit = l
		}
		var list []model.InspectionRecord
		q.Order("created_at DESC").Limit(limit).Find(&list)
		c.JSON(http.StatusOK, list)
	}
}