package controller

import (
	"bytes"
	"errors"
	"image"
	"image/jpeg"
	"image/png"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"metazone.cc/metalab/internal/common"
	"metazone.cc/metalab/internal/model"

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

// CommentController 评论控制器
type CommentController struct {
	commentService commentUseCase
}

// NewCommentController 构造函数
func NewCommentController(cs commentUseCase) *CommentController {
	return &CommentController{commentService: cs}
}

// ListRootComments 获取文章顶级评论 GET /api/posts/:id/comments
func (ctrl *CommentController) ListRootComments(c *gin.Context) {
	postID, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		common.Error(c, http.StatusBadRequest, "无效的文章ID")
		return
	}

	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))

	comments, total, err := ctrl.commentService.ListRootComments(uint(postID), page, pageSize)
	if err != nil {
		common.Error(c, http.StatusInternalServerError, "获取评论失败")
		return
	}

	common.Ok(c, gin.H{
		"items":       comments,
		"total":       total,
		"page":        page,
		"total_pages": common.PageCount(total, pageSize),
	})
}

// ListReplies 获取顶级评论的全部回复 GET /api/posts/:id/comments/:root_id/replies
func (ctrl *CommentController) ListReplies(c *gin.Context) {
	rootID, err := strconv.ParseUint(c.Param("root_id"), 10, 64)
	if err != nil {
		common.Error(c, http.StatusBadRequest, "无效的评论ID")
		return
	}

	replies, err := ctrl.commentService.ListReplies(uint(rootID))
	if err != nil {
		common.Error(c, http.StatusInternalServerError, "获取回复失败")
		return
	}

	common.Ok(c, gin.H{"replies": replies})
}

// CreateRoot POST /api/posts/:id/comments
func (ctrl *CommentController) CreateRoot(c *gin.Context) {
	uid, _, ok := common.GetGinUser(c)
	if !ok {
		common.Error(c, http.StatusUnauthorized, "请先登录")
		return
	}

	postID, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		common.Error(c, http.StatusBadRequest, "无效的文章ID")
		return
	}

	var req struct {
		Body string `json:"body" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		common.Error(c, http.StatusBadRequest, "请输入评论内容")
		return
	}

	comment, err := ctrl.commentService.CreateRoot(uid, uint(postID), req.Body)
	if err != nil {
		common.Error(c, http.StatusBadRequest, err.Error())
		return
	}

	common.Ok(c, comment)
}

// CreateReply POST /api/comments/:id/reply
func (ctrl *CommentController) CreateReply(c *gin.Context) {
	uid, _, ok := common.GetGinUser(c)
	if !ok {
		common.Error(c, http.StatusUnauthorized, "请先登录")
		return
	}

	parentID, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		common.Error(c, http.StatusBadRequest, "无效的评论ID")
		return
	}

	var req struct {
		Body string `json:"body" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		common.Error(c, http.StatusBadRequest, "请输入回复内容")
		return
	}

	reply, err := ctrl.commentService.CreateReply(uid, uint(parentID), req.Body)
	if err != nil {
		common.Error(c, http.StatusBadRequest, err.Error())
		return
	}

	common.Ok(c, reply)
}

// Delete DELETE /api/comments/:id
func (ctrl *CommentController) Delete(c *gin.Context) {
	uid, role, ok := common.GetGinUser(c)
	if !ok {
		common.Error(c, http.StatusUnauthorized, "请先登录")
		return
	}

	commentID, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		common.Error(c, http.StatusBadRequest, "无效的评论ID")
		return
	}

	// 权限检查由 service 层统一处理
	isAdmin := model.HasMinRole(role, model.RoleAdmin)
	if err := ctrl.commentService.Delete(uint(commentID), uid, isAdmin); err != nil {
		if errors.Is(err, common.ErrPermissionDenied) {
			common.Error(c, http.StatusForbidden, err.Error())
			return
		}
		common.Error(c, http.StatusBadRequest, err.Error())
		return
	}

	common.OkMessage(c, "删除成功")
}

// SearchUsers GET /api/users/search?q=keyword
func (ctrl *CommentController) SearchUsers(c *gin.Context) {
	_, _, ok := common.GetGinUser(c)
	if !ok {
		common.Error(c, http.StatusUnauthorized, "请先登录")
		return
	}

	q := c.Query("q")
	if q == "" {
		common.Ok(c, []model.UserSearchResult{})
		return
	}

	users, err := ctrl.commentService.SearchUsers(q)
	if err != nil {
		common.Error(c, http.StatusInternalServerError, "搜索用户失败")
		return
	}

	common.Ok(c, users)
}

// UploadImage 上传评论图片 POST /api/comments/upload-image
// 需要 LV4+（Exp ≥ 1500），复用帖子图片上传的 WebP 转码逻辑
func (ctrl *CommentController) UploadImage(c *gin.Context) {
	uid, _, ok := common.GetGinUser(c)
	if !ok {
		common.Error(c, http.StatusUnauthorized, "请先登录")
		return
	}

	// LV4+ 检查（Exp ≥ 1500）
	expVal, exists := c.Get("exp")
	if !exists {
		common.Error(c, http.StatusForbidden, "无法获取经验值")
		return
	}
	exp := expVal.(int)
	if exp < 1500 {
		common.Error(c, http.StatusForbidden, "需 Lv4 以上才能上传评论图片")
		return
	}

	file, header, err := c.Request.FormFile("file")
	if err != nil {
		common.Error(c, http.StatusBadRequest, "请选择文件")
		return
	}
	defer file.Close()

	// 检查扩展名
	ext := strings.ToLower(filepath.Ext(header.Filename))
	allowedExt := map[string]bool{".jpg": true, ".jpeg": true, ".png": true, ".gif": true, ".webp": true}
	if !allowedExt[ext] {
		common.Error(c, http.StatusBadRequest, "仅支持 jpg/jpeg/png/gif/webp 格式")
		return
	}

	// 限制 5MB
	if header.Size > 5<<20 {
		common.Error(c, http.StatusBadRequest, "图片大小不能超过 5MB")
		return
	}

	data, err := io.ReadAll(file)
	if err != nil {
		common.Error(c, http.StatusInternalServerError, "读取文件失败")
		return
	}

	storageDir := "storage/uploads/posts"
	if err := os.MkdirAll(storageDir, 0755); err != nil {
		common.Error(c, http.StatusInternalServerError, "存储初始化失败")
		return
	}

	ts := time.Now().UnixMilli()
	isJPEGPNG := ext == ".jpg" || ext == ".jpeg" || ext == ".png"

	var savePath, url string

	// JPEG/PNG 转 WebP
	if isJPEGPNG {
		img, _, err := image.Decode(bytes.NewReader(data))
		if err != nil {
			common.Error(c, http.StatusBadRequest, "图片格式无效")
			return
		}
		webpData := encodeWebPBinary(img, len(data))
		if webpData != nil && len(webpData) < len(data) {
			filename := strconv.FormatUint(uint64(uid), 10) + "_" + strconv.FormatInt(ts, 10) + ".webp"
			savePath = filepath.Join(storageDir, filename)
			os.WriteFile(savePath, webpData, 0644)
			url = "/uploads/posts/" + filename
		}
	}

	// 回退存储
	if savePath == "" {
		dataOut := data
		if isJPEGPNG {
			decImg, _, decErr := image.Decode(bytes.NewReader(data))
			if decErr == nil {
				var buf bytes.Buffer
				if ext == ".png" {
					png.Encode(&buf, decImg)
				} else {
					jpeg.Encode(&buf, decImg, &jpeg.Options{Quality: 92})
				}
				dataOut = buf.Bytes()
			}
		}
		filename := strconv.FormatUint(uint64(uid), 10) + "_" + strconv.FormatInt(ts, 10) + ext
		savePath = filepath.Join(storageDir, filename)
		os.WriteFile(savePath, dataOut, 0644)
		url = "/uploads/posts/" + filename
	}

	// 返回标准 JSON（前端将 URL 插入评论文本）
	common.Ok(c, gin.H{"url": url})
}
