package handler

import (
	"errors"
	"net/http"
	"strconv"
	"strings"

	"github.com/gin-gonic/gin"

	"gitea.kmux.cn/zhilv/scriptforge/internal/auth"
	"gitea.kmux.cn/zhilv/scriptforge/internal/model"
	"gitea.kmux.cn/zhilv/scriptforge/internal/service"
)

func getUserID(c *gin.Context) uint {
	val, exists := c.Get("user_id")
	if !exists {
		return 0
	}
	switch v := val.(type) {
	case uint:
		return v
	case float64:
		return uint(v)
	default:
		return 0
	}
}

// --- Auth handlers ---

type registerRequest struct {
	Username string `json:"username" binding:"required,min=3,max=32"`
	Password string `json:"password" binding:"required,min=6"`
}

func Register(authSvc *auth.AuthService) gin.HandlerFunc {
	return func(c *gin.Context) {
		var req registerRequest
		if err := c.ShouldBindJSON(&req); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		user, err := authSvc.Register(req.Username, req.Password)
		if errors.Is(err, auth.ErrUserExists) {
			c.JSON(http.StatusConflict, gin.H{"error": "username already exists"})
			return
		}
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}
		token, _ := authSvc.GenerateToken(user.ID, user.Username, user.Role)
		c.JSON(http.StatusCreated, gin.H{
			"id":       user.ID,
			"username": user.Username,
			"role":     user.Role,
			"token":    token,
		})
	}
}

func Login(authSvc *auth.AuthService) gin.HandlerFunc {
	return func(c *gin.Context) {
		var req registerRequest
		if err := c.ShouldBindJSON(&req); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		user, token, err := authSvc.Login(req.Username, req.Password)
		if errors.Is(err, auth.ErrInvalidCredentials) {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "invalid credentials"})
			return
		}
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}
		c.JSON(http.StatusOK, gin.H{
			"id":       user.ID,
			"username": user.Username,
			"role":     user.Role,
			"token":    token,
		})
	}
}

func GetMe(authSvc *auth.AuthService) gin.HandlerFunc {
	return func(c *gin.Context) {
		userID := getUserID(c)
		if userID == 0 {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "not authenticated"})
			return
		}
		user, err := authSvc.GetUserByID(userID)
		if err != nil {
			c.JSON(http.StatusNotFound, gin.H{"error": "user not found"})
			return
		}
		c.JSON(http.StatusOK, gin.H{
			"id":       user.ID,
			"username": user.Username,
			"role":     user.Role,
		})
	}
}

// --- Script handlers ---

type createRequest struct {
	Title       string `json:"title" binding:"required,max=128"`
	Description string `json:"description" binding:"max=512"`
	Content     string `json:"content" binding:"required,max=16384"`
	CategoryID  uint   `json:"category_id" binding:"required"`
	ExpiresIn   string `json:"expires_in" binding:"required,oneof=1h 24h 7d 30d"`
	Publish     bool   `json:"publish"`
}

func CreateScript(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		var req createRequest
		if err := c.ShouldBindJSON(&req); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}

		scheme := "https"
		if strings.HasPrefix(c.Request.Host, "localhost") || strings.HasPrefix(c.Request.Host, "127.0.0.1") {
			scheme = "http"
		}

		userID := getUserID(c)

		result, err := svc.Create(service.CreateInput{
			Title:       req.Title,
			Description: req.Description,
			Content:     req.Content,
			CategoryID:  req.CategoryID,
			ExpiresIn:   req.ExpiresIn,
			Publish:     req.Publish,
			UserID:      userID,
		}, scheme, c.Request.Host)

		if errors.Is(err, service.ErrInvalidCategory) {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid category"})
			return
		}
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}

		c.JSON(http.StatusCreated, gin.H{
			"id":          result.Script.ID,
			"title":       result.Script.Title,
			"description": result.Script.Description,
			"category_id": result.Script.CategoryID,
			"admin_token": result.AdminToken,
			"url":         result.RawURL,
			"status":      result.Script.Status,
			"expires_at":  result.Script.ExpiresAt,
		})
	}
}

func GetScript(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		id := c.Param("id")

		script, err := svc.GetByID(id)
		if errors.Is(err, service.ErrNotFound) {
			c.JSON(http.StatusNotFound, gin.H{"error": "script not found or expired"})
			return
		}
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}

		cat, _ := svc.GetCategoryByID(script.CategoryID)
		variants, _ := svc.GetVariants(script.CategoryID)

		scheme := "https"
		if strings.HasPrefix(c.Request.Host, "localhost") || strings.HasPrefix(c.Request.Host, "127.0.0.1") {
			scheme = "http"
		}
		fullURL := scheme + "://" + c.Request.Host + "/raw/" + script.ID

		var commands []gin.H
		for _, v := range variants {
			cmd := strings.ReplaceAll(v.CommandTemplate, "{url}", fullURL)
			entry := gin.H{
				"variant": v.Name,
				"label":   v.Label,
				"command": cmd,
			}
			if v.SourceTemplate != "" {
				entry["source_command"] = strings.ReplaceAll(v.SourceTemplate, "{url}", fullURL)
			}
			commands = append(commands, entry)
		}

		categoryName := ""
		categoryLabel := ""
		categoryIcon := ""
		if cat != nil {
			categoryName = cat.Name
			categoryLabel = cat.Label
			categoryIcon = cat.Icon
		}

		c.JSON(http.StatusOK, gin.H{
			"id":             script.ID,
			"title":          script.Title,
			"description":    script.Description,
			"category_id":    script.CategoryID,
			"category_name":  categoryName,
			"category_label": categoryLabel,
			"category_icon":  categoryIcon,
			"content":        script.Content,
			"content_length": len(script.Content),
			"status":         script.Status,
			"commands":       commands,
			"expires_at":     script.ExpiresAt,
			"published_at":   script.PublishedAt,
			"expired":        false,
		})
	}
}

func PublishScript(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		id := c.Param("id")
		token := c.Query("token")
		if token == "" {
			c.JSON(http.StatusBadRequest, gin.H{"error": "token required"})
			return
		}

		script, err := svc.Publish(id, token)
		if errors.Is(err, service.ErrNotFound) {
			c.JSON(http.StatusNotFound, gin.H{"error": "not found or invalid token"})
			return
		}
		if errors.Is(err, service.ErrAlreadyPublished) {
			c.JSON(http.StatusBadRequest, gin.H{"error": "already published"})
			return
		}
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}

		c.JSON(http.StatusOK, gin.H{"id": script.ID, "status": script.Status, "published_at": script.PublishedAt})
	}
}

func DeleteScript(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		id := c.Param("id")
		token := c.Query("token")
		if token == "" {
			c.JSON(http.StatusBadRequest, gin.H{"error": "token required"})
			return
		}

		if err := svc.Delete(id, token); errors.Is(err, service.ErrNotFound) {
			c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
			return
		} else if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}
		c.Status(http.StatusNoContent)
	}
}

func ListMarket(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
		perPage, _ := strconv.Atoi(c.DefaultQuery("per_page", "20"))
		catID, _ := strconv.Atoi(c.DefaultQuery("category_id", "0"))
		search := c.Query("search")

		result, err := svc.ListMarket(service.MarketQuery{
			Page:       page,
			PerPage:    perPage,
			CategoryID: uint(catID),
			Search:     search,
		})
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}

		items := make([]gin.H, len(result.Items))
		for i, s := range result.Items {
			cat, _ := svc.GetCategoryByID(s.CategoryID)
			items[i] = gin.H{
				"id":            s.ID,
				"title":         s.Title,
				"description":   s.Description,
				"category_id":   s.CategoryID,
				"category_name": cat.Name,
				"category_label": cat.Label,
				"category_icon":  cat.Icon,
				"published_at":  s.PublishedAt,
			}
		}

		c.JSON(http.StatusOK, gin.H{
			"items":    items,
			"total":    result.Total,
			"page":     result.Page,
			"per_page": result.PerPage,
		})
	}
}

// --- Admin: Runtime management ---

func ListCategories(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		cats, err := svc.ListCategories()
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}
		c.JSON(http.StatusOK, gin.H{"categories": cats})
	}
}

func CreateCategory(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		var cat model.RuntimeCategory
		if err := c.ShouldBindJSON(&cat); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		if err := svc.CreateCategory(&cat); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}
		c.JSON(http.StatusCreated, gin.H{"category": cat})
	}
}

func UpdateCategory(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		id, _ := strconv.Atoi(c.Param("id"))
		var cat model.RuntimeCategory
		cat.ID = uint(id)
		if err := c.ShouldBindJSON(&cat); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		if err := svc.UpdateCategory(&cat); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}
		c.JSON(http.StatusOK, gin.H{"category": cat})
	}
}

func DeleteCategory(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		id, _ := strconv.Atoi(c.Param("id"))
		if err := svc.DeleteCategory(uint(id)); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}
		c.Status(http.StatusNoContent)
	}
}

func CreateVariant(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		var v model.RuntimeVariant
		if err := c.ShouldBindJSON(&v); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		if err := svc.CreateVariant(&v); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}
		c.JSON(http.StatusCreated, gin.H{"variant": v})
	}
}

func UpdateVariant(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		id, _ := strconv.Atoi(c.Param("id"))
		var v model.RuntimeVariant
		v.ID = uint(id)
		if err := c.ShouldBindJSON(&v); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		if err := svc.UpdateVariant(&v); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}
		c.JSON(http.StatusOK, gin.H{"variant": v})
	}
}

func DeleteVariant(svc *service.ScriptService) gin.HandlerFunc {
	return func(c *gin.Context) {
		id, _ := strconv.Atoi(c.Param("id"))
		if err := svc.DeleteVariant(uint(id)); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": "internal error"})
			return
		}
		c.Status(http.StatusNoContent)
	}
}