package handler

import (
	"encoding/json"
	"errors"
	"io"
	"log"
	"net/http"
	"net/url"
	"strconv"
	"strings"

	"github.com/gin-gonic/gin"

	qiniuservice "wx_service/internal/common/qiniu/service"
	"wx_service/internal/middleware"
	"wx_service/internal/model"
)

type UploadHandler struct {
	qiniuService *qiniuservice.QiniuService
}

func NewUploadHandler(qiniuService *qiniuservice.QiniuService) *UploadHandler {
	return &UploadHandler{qiniuService: qiniuService}
}

type qiniuTokenRequest struct {
	// filename 用于保留文件后缀（可选），例如："a.png"、"video.mp4"
	Filename string `json:"filename"`
}

type qiniuCallbackPayload struct {
	Key      string `json:"key"`
	Hash     string `json:"hash"`
	Fsize    int64  `json:"fsize"`
	MimeType string `json:"mimeType"`
}

// QiniuToken 返回七牛直传所需的 token/key/upload_url 等信息。
// 建议放在鉴权后：用当前登录用户生成 key，避免前端写入任意路径。
func (h *UploadHandler) QiniuToken(c *gin.Context) {
	user := middleware.MustCurrentUser(c)

	var req qiniuTokenRequest
	_ = c.ShouldBindJSON(&req) // filename 可选，解析失败也不影响生成 token

	token, err := h.qiniuService.CreateUploadToken(user.MiniProgramID, user.ID, req.Filename)
	if err != nil {
		if errors.Is(err, qiniuservice.ErrQiniuNotConfigured) {
			c.JSON(http.StatusServiceUnavailable, model.Error(http.StatusServiceUnavailable, "未配置七牛上传服务，请联系管理员"))
			return
		}
		c.JSON(http.StatusInternalServerError, model.Error(http.StatusInternalServerError, "获取上传凭证失败，请稍后重试"))
		return
	}

	c.JSON(http.StatusOK, model.Success(token))
}

// QiniuCallback 处理七牛上传回调（无需登录），通过签名验签确保来源可信。
// 说明：
// - 验签失败返回 401（非可信请求，直接拒绝）
// - 业务处理临时失败返回 503（触发七牛重试）
func (h *UploadHandler) QiniuCallback(c *gin.Context) {
	rawBody, err := io.ReadAll(c.Request.Body)
	if err != nil {
		c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "读取回调内容失败"))
		return
	}

	if err := h.qiniuService.VerifyCallbackSignature(c.Request, rawBody); err != nil {
		switch {
		case errors.Is(err, qiniuservice.ErrQiniuNotConfigured):
			c.JSON(http.StatusServiceUnavailable, model.Error(http.StatusServiceUnavailable, "七牛服务未配置"))
		default:
			c.JSON(http.StatusUnauthorized, model.Error(http.StatusUnauthorized, "回调验签失败"))
		}
		return
	}

	payload, err := parseQiniuCallbackPayload(c.ContentType(), rawBody)
	if err != nil {
		c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "回调内容格式错误"))
		return
	}
	if strings.TrimSpace(payload.Key) == "" {
		c.JSON(http.StatusBadRequest, model.Error(http.StatusBadRequest, "回调内容缺少 key"))
		return
	}

	// 当前阶段先记录日志。后续如接入 DB/任务系统，处理失败可保持 503 以触发七牛重试。
	log.Printf("[qiniu_callback] key=%s hash=%s fsize=%d mimeType=%s", payload.Key, payload.Hash, payload.Fsize, payload.MimeType)
	c.JSON(http.StatusOK, model.Success(gin.H{"ok": true}))
}

func parseQiniuCallbackPayload(contentType string, raw []byte) (qiniuCallbackPayload, error) {
	var payload qiniuCallbackPayload
	trimmed := strings.TrimSpace(strings.ToLower(contentType))
	if strings.Contains(trimmed, "application/json") {
		if err := json.Unmarshal(raw, &payload); err != nil {
			return qiniuCallbackPayload{}, err
		}
		return payload, nil
	}

	values, err := url.ParseQuery(string(raw))
	if err != nil {
		return qiniuCallbackPayload{}, err
	}
	payload.Key = strings.TrimSpace(values.Get("key"))
	payload.Hash = strings.TrimSpace(values.Get("hash"))
	payload.MimeType = strings.TrimSpace(values.Get("mimeType"))
	if rawFsize := strings.TrimSpace(values.Get("fsize")); rawFsize != "" {
		fsize, parseErr := strconv.ParseInt(rawFsize, 10, 64)
		if parseErr != nil {
			return qiniuCallbackPayload{}, parseErr
		}
		payload.Fsize = fsize
	}
	return payload, nil
}