package main

import (
	"context"
	"crypto/hmac"
	"crypto/sha256"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"log"
	"mime/multipart"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss"
	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss/credentials"
	"github.com/gin-gonic/gin"
	"gorm.io/driver/mysql"
	"gorm.io/gorm"
)

type TemplateConfig struct {
	ID         uint      `gorm:"primaryKey" json:"id"`
	ConfigData string    `gorm:"type:json;column:config_data" json:"config_data"`
	UpdatedAt  time.Time `json:"updated_at"`
}

type UploadConfig struct {
	ID              uint      `gorm:"primaryKey" json:"id"`
	Provider        string    `gorm:"column:provider;size:20" json:"provider"`
	AccessKeyID     string    `gorm:"column:access_key_id;size:255" json:"accessKeyId"`
	AccessKeySecret string    `gorm:"column:access_key_secret;type:text" json:"-"`
	Bucket          string    `gorm:"column:bucket;size:255" json:"bucket"`
	Folder          string    `gorm:"column:folder;size:255" json:"folder"`
	Domain          string    `gorm:"column:domain;size:255" json:"domain"`
	Region          string    `gorm:"column:region;size:100" json:"region"`
	Endpoint        string    `gorm:"column:endpoint;size:255" json:"endpoint"`
	UpdatedAt       time.Time `json:"updated_at"`
}

type Rsvp struct {
	ID         uint      `gorm:"primaryKey" json:"id"`
	Name       string    `gorm:"column:name;size:50" json:"name"`
	GuestCount string    `gorm:"column:guest_count;size:20" json:"guest_count"`
	Wishes     string    `gorm:"column:wishes;type:text" json:"wishes"`
	CreatedAt  time.Time `gorm:"column:created_at" json:"created_at"`
}

var db *gorm.DB

var (
	adminAccount  = getEnv("ADMIN_ACCOUNT", "admin")
	adminPassword = getEnv("ADMIN_PASSWORD", "admin123")
	adminSecret   = getEnv("ADMIN_SECRET", "wedding-admin-secret-2026")
)

func getEnv(k, def string) string {
	if v := os.Getenv(k); v != "" {
		return v
	}
	return def
}

func signToken(account string) string {
	payload := fmt.Sprintf(`{"account":%q,"exp":%d}`, account, time.Now().Add(24*time.Hour).Unix())
	b64 := base64.StdEncoding.EncodeToString([]byte(payload))
	mac := hmac.New(sha256.New, []byte(adminSecret))
	mac.Write([]byte(b64))
	sig := base64.StdEncoding.EncodeToString(mac.Sum(nil))
	return b64 + "." + sig
}

func verifyToken(token string) bool {
	parts := strings.Split(token, ".")
	if len(parts) != 2 {
		return false
	}
	mac := hmac.New(sha256.New, []byte(adminSecret))
	mac.Write([]byte(parts[0]))
	expected := base64.StdEncoding.EncodeToString(mac.Sum(nil))
	if !hmac.Equal([]byte(expected), []byte(parts[1])) {
		return false
	}
	raw, err := base64.StdEncoding.DecodeString(parts[0])
	if err != nil {
		return false
	}
	var claims struct {
		Account string `json:"account"`
		Exp     int64  `json:"exp"`
	}
	if err := json.Unmarshal(raw, &claims); err != nil {
		return false
	}
	return time.Now().Unix() <= claims.Exp
}

func bearerToken(c *gin.Context) string {
	return strings.TrimPrefix(c.GetHeader("Authorization"), "Bearer ")
}

func requireAdmin(c *gin.Context) bool {
	if !verifyToken(bearerToken(c)) {
		c.JSON(401, gin.H{"error": "未授权，请先登录后台"})
		return false
	}
	return true
}

func initDB() {
	dsn := "root:mysql_PKC65h@tcp(127.0.0.1:3306)/nl_wedding?charset=utf8mb4&parseTime=True&loc=Local"
	var err error
	db, err = gorm.Open(mysql.Open(dsn), &gorm.Config{})
	if err != nil {
		log.Fatalf("数据库连接失败: %v", err)
	}

	_ = db.AutoMigrate(&TemplateConfig{}, &UploadConfig{}, &Rsvp{})
	_ = os.MkdirAll("./uploads", os.ModePerm)

	fmt.Println("数据库初始化成功，表结构已同步，上传目录已就绪")
}

func corsMiddleware() gin.HandlerFunc {
	return func(c *gin.Context) {
		c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
		c.Writer.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT")
		c.Writer.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization")
		if c.Request.Method == "OPTIONS" {
			c.AbortWithStatus(204)
			return
		}
		c.Next()
	}
}

func defaultUploadConfig() UploadConfig {
	return UploadConfig{ID: 1, Provider: "local"}
}

func loadUploadConfig() UploadConfig {
	var config UploadConfig
	if err := db.First(&config, 1).Error; err != nil {
		config = defaultUploadConfig()
		_ = db.Create(&config).Error
	}
	if config.Provider == "" {
		config.Provider = "local"
	}
	return config
}

func uploadConfigResponse(config UploadConfig) gin.H {
	return gin.H{
		"provider":    config.Provider,
		"accessKeyId": config.AccessKeyID,
		"hasSecret":   config.AccessKeySecret != "",
		"bucket":      config.Bucket,
		"folder":      config.Folder,
		"domain":      config.Domain,
		"region":      config.Region,
		"endpoint":    config.Endpoint,
		"updated_at":  config.UpdatedAt,
	}
}

func cleanObjectName(name string) string {
	name = filepath.Base(name)
	name = strings.ReplaceAll(name, "\\", "_")
	name = strings.ReplaceAll(name, "/", "_")
	name = strings.TrimSpace(name)
	if name == "" || name == "." {
		return "upload"
	}
	return name
}

func buildObjectKey(folder string, originalName string) string {
	folder = strings.Trim(folder, "/ ")
	name := cleanObjectName(originalName)
	fileName := fmt.Sprintf("%s_%s", time.Now().Format("150405000000000"), name)
	day := time.Now().Format("20060102")
	if folder == "" {
		return day + "/" + fileName
	}
	return folder + "/" + day + "/" + fileName
}

func escapedObjectKey(key string) string {
	parts := strings.Split(key, "/")
	for i, part := range parts {
		parts[i] = url.PathEscape(part)
	}
	return strings.Join(parts, "/")
}

func normalizeEndpoint(endpoint string, region string) string {
	endpoint = strings.TrimSpace(endpoint)
	region = strings.TrimSpace(region)
	if endpoint == "" && region != "" {
		endpoint = "https://oss-" + region + ".aliyuncs.com"
	}
	if endpoint != "" && !strings.HasPrefix(endpoint, "http://") && !strings.HasPrefix(endpoint, "https://") {
		endpoint = "https://" + endpoint
	}
	return endpoint
}

func objectURL(config UploadConfig, objectKey string) string {
	escapedKey := escapedObjectKey(objectKey)
	if strings.TrimSpace(config.Domain) != "" {
		domain := strings.TrimRight(strings.TrimSpace(config.Domain), "/")
		if !strings.HasPrefix(domain, "http://") && !strings.HasPrefix(domain, "https://") {
			domain = "https://" + domain
		}
		return domain + "/" + escapedKey
	}

	endpoint := strings.TrimRight(normalizeEndpoint(config.Endpoint, config.Region), "/")
	u, err := url.Parse(endpoint)
	if err == nil && u.Host != "" {
		return u.Scheme + "://" + config.Bucket + "." + u.Host + "/" + escapedKey
	}
	if endpoint == "" {
		return escapedKey
	}
	return endpoint + "/" + escapedKey
}

func canUseOSS(config UploadConfig) bool {
	return config.Provider == "oss" &&
		strings.TrimSpace(config.AccessKeyID) != "" &&
		strings.TrimSpace(config.AccessKeySecret) != "" &&
		strings.TrimSpace(config.Bucket) != "" &&
		(strings.TrimSpace(config.Endpoint) != "" || strings.TrimSpace(config.Region) != "")
}

func saveLocalUpload(c *gin.Context, file *multipart.FileHeader) {
	filename := fmt.Sprintf("%d_%s", time.Now().Unix(), cleanObjectName(file.Filename))
	savePath := filepath.Join("uploads", filename)

	if err := c.SaveUploadedFile(file, savePath); err != nil {
		c.JSON(500, gin.H{"error": "文件保存至服务器失败"})
		return
	}

	fileURL := fmt.Sprintf("http://localhost:8080/uploads/%s", filename)
	c.JSON(200, gin.H{"code": 200, "url": fileURL, "provider": "local"})
}

func saveOSSUpload(c *gin.Context, fileHeader *multipart.FileHeader, config UploadConfig) bool {
	file, err := fileHeader.Open()
	if err != nil {
		c.JSON(500, gin.H{"error": "文件打开失败"})
		return false
	}
	defer file.Close()

	endpoint := normalizeEndpoint(config.Endpoint, config.Region)
	provider := credentials.NewStaticCredentialsProvider(config.AccessKeyID, config.AccessKeySecret)
	ossConfig := oss.LoadDefaultConfig().
		WithCredentialsProvider(provider).
		WithRegion(config.Region).
		WithEndpoint(endpoint)
	client := oss.NewClient(ossConfig)

	objectKey := buildObjectKey(config.Folder, fileHeader.Filename)
	_, err = client.PutObject(context.Background(), &oss.PutObjectRequest{
		Bucket: oss.Ptr(config.Bucket),
		Key:    oss.Ptr(objectKey),
		Acl:    oss.ObjectACLPublicRead,
		Body:   file,
	})
	if err != nil {
		c.JSON(500, gin.H{"error": "OSS上传失败: " + err.Error()})
		return false
	}

	c.JSON(200, gin.H{"code": 200, "url": objectURL(config, objectKey), "provider": "oss", "key": objectKey})
	return true
}

func collectAlbumImages(configData string) []string {
	var raw map[string]interface{}
	if err := json.Unmarshal([]byte(configData), &raw); err != nil {
		return []string{}
	}

	seen := map[string]bool{}
	images := []string{}
	add := func(value interface{}) {
		src, ok := value.(string)
		if !ok {
			return
		}
		src = strings.TrimSpace(src)
		if src == "" || seen[src] {
			return
		}
		seen[src] = true
		images = append(images, src)
	}

	add(raw["heroImg"])
	add(raw["endImg"])
	if pages, ok := raw["photoPages"].([]interface{}); ok {
		for _, item := range pages {
			page, ok := item.(map[string]interface{})
			if !ok {
				continue
			}
			add(page["img1"])
			add(page["img2"])
			if pageImages, ok := page["images"].([]interface{}); ok {
				for _, src := range pageImages {
					add(src)
				}
			}
		}
	}
	return images
}

func main() {
	initDB()
	r := gin.Default()
	r.Use(corsMiddleware())
	r.Static("/uploads", "./uploads")

	api := r.Group("/api")
	{
		api.POST("/admin/login", func(c *gin.Context) {
			var body struct {
				Account  string `json:"account"`
				Password string `json:"password"`
			}
			if err := c.ShouldBindJSON(&body); err != nil {
				c.JSON(400, gin.H{"error": "参数错误"})
				return
			}
			if body.Account != adminAccount || body.Password != adminPassword {
				c.JSON(401, gin.H{"error": "账号或密码错误"})
				return
			}
			c.JSON(200, gin.H{
				"code":  200,
				"token": signToken(body.Account),
				"user":  gin.H{"account": body.Account},
			})
		})

		api.GET("/config", func(c *gin.Context) {
			var config TemplateConfig
			if err := db.First(&config, 1).Error; err != nil {
				c.JSON(200, gin.H{"code": 200, "data": "{}"})
				return
			}
			c.JSON(200, gin.H{"code": 200, "data": config.ConfigData})
		})

		api.GET("/album", func(c *gin.Context) {
			var config TemplateConfig
			if err := db.First(&config, 1).Error; err != nil {
				c.JSON(200, gin.H{"code": 200, "data": []string{}})
				return
			}
			c.JSON(200, gin.H{"code": 200, "data": collectAlbumImages(config.ConfigData)})
		})

		api.POST("/config", func(c *gin.Context) {
			if !requireAdmin(c) {
				return
			}
			var rawBody interface{}
			if err := c.BindJSON(&rawBody); err != nil {
				c.JSON(400, gin.H{"error": "无效的JSON数据"})
				return
			}
			jsonBytes, _ := json.Marshal(rawBody)

			var config TemplateConfig
			db.FirstOrCreate(&config, 1)
			config.ConfigData = string(jsonBytes)

			if err := db.Save(&config).Error; err != nil {
				c.JSON(500, gin.H{"error": "数据库保存配置失败"})
				return
			}
			c.JSON(200, gin.H{"code": 200, "msg": "配置保存成功"})
		})

		api.GET("/upload/config", func(c *gin.Context) {
			if !requireAdmin(c) {
				return
			}
			c.JSON(200, gin.H{"code": 200, "data": uploadConfigResponse(loadUploadConfig())})
		})

		api.POST("/upload/config", func(c *gin.Context) {
			if !requireAdmin(c) {
				return
			}
			var body struct {
				Provider        string `json:"provider"`
				AccessKeyID     string `json:"accessKeyId"`
				AccessKeySecret string `json:"accessKeySecret"`
				Bucket          string `json:"bucket"`
				Folder          string `json:"folder"`
				Domain          string `json:"domain"`
				Region          string `json:"region"`
				Endpoint        string `json:"endpoint"`
			}
			if err := c.ShouldBindJSON(&body); err != nil {
				c.JSON(400, gin.H{"error": "参数错误"})
				return
			}

			config := loadUploadConfig()
			provider := strings.TrimSpace(body.Provider)
			if provider != "oss" {
				provider = "local"
			}
			config.Provider = provider
			config.AccessKeyID = strings.TrimSpace(body.AccessKeyID)
			if strings.TrimSpace(body.AccessKeySecret) != "" {
				config.AccessKeySecret = strings.TrimSpace(body.AccessKeySecret)
			}
			config.Bucket = strings.TrimSpace(body.Bucket)
			config.Folder = strings.Trim(body.Folder, "/ ")
			config.Domain = strings.TrimSpace(body.Domain)
			config.Region = strings.TrimSpace(body.Region)
			config.Endpoint = strings.TrimSpace(body.Endpoint)

			if err := db.Save(&config).Error; err != nil {
				c.JSON(500, gin.H{"error": "上传配置保存失败"})
				return
			}
			c.JSON(200, gin.H{"code": 200, "data": uploadConfigResponse(config), "msg": "上传配置保存成功"})
		})

		api.POST("/rsvp", func(c *gin.Context) {
			var rsvp Rsvp
			if err := c.ShouldBindJSON(&rsvp); err != nil {
				c.JSON(400, gin.H{"error": "表单数据绑定失败", "details": err.Error()})
				return
			}

			if err := db.Create(&rsvp).Error; err != nil {
				c.JSON(500, gin.H{"error": "出席信息写入数据库失败"})
				return
			}
			c.JSON(200, gin.H{"code": 200, "msg": "回执提交成功"})
		})

		api.POST("/upload", func(c *gin.Context) {
			if !requireAdmin(c) {
				return
			}
			file, err := c.FormFile("file")
			if err != nil {
				c.JSON(400, gin.H{"error": "未获取到上传文件"})
				return
			}

			config := loadUploadConfig()
			if canUseOSS(config) {
				saveOSSUpload(c, file, config)
				return
			}
			saveLocalUpload(c, file)
		})

		api.GET("/rsvp/list", func(c *gin.Context) {
			if !requireAdmin(c) {
				return
			}
			var list []Rsvp
			db.Order("created_at desc").Find(&list)
			c.JSON(200, gin.H{"code": 200, "data": list})
		})
	}

	fmt.Println("婚礼纪后端 API 已在 http://localhost:15201 启动")
	r.Run(":15201")
}