package handler

import (
	"crypto/sha256"
	"encoding/hex"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"affiliate_dash/internal/pkg/response"
	"affiliate_dash/internal/service"

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

// DeliveryHandler 提供用户侧公开发货页面使用的接口。
type DeliveryHandler struct {
	deliverySvc *service.DeliveryService
}

func NewDeliveryHandler(deliverySvc *service.DeliveryService) *DeliveryHandler {
	return &DeliveryHandler{deliverySvc: deliverySvc}
}

func (h *DeliveryHandler) GetOrder(c *gin.Context) {
	order, err := h.deliverySvc.GetOrder(c.Param("order_no"), parseDeliveryAuth(c))
	if err != nil {
		writeDeliveryError(c, err)
		return
	}
	response.OK(c, order)
}

type deliveryBindReq struct {
	GameAccount string `json:"game_account" binding:"required"`
}

func (h *DeliveryHandler) Bind(c *gin.Context) {
	var req deliveryBindReq
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "请输入玩家编号")
		return
	}
	result, err := h.deliverySvc.Bind(c.Param("order_no"), req.GameAccount, parseDeliveryAuth(c))
	if err != nil {
		writeDeliveryError(c, err)
		return
	}
	response.OK(c, result)
}

func (h *DeliveryHandler) GetBindResult(c *gin.Context) {
	bindUUID := strings.TrimSpace(c.Query("bind_uuid"))
	if bindUUID == "" {
		response.BadRequest(c, "bind_uuid 不能为空")
		return
	}
	result, err := h.deliverySvc.GetBindResultLinked(c.Param("order_no"), bindUUID, parseDeliveryAuth(c))
	if err != nil {
		writeDeliveryError(c, err)
		return
	}
	response.OK(c, result)
}

type deliverySubmitReq struct {
	GameAccount string `json:"game_account" binding:"required"`
	BindUUID    string `json:"bind_uuid" binding:"required"`
}

func (h *DeliveryHandler) Submit(c *gin.Context) {
	var req deliverySubmitReq
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "玩家编号和绑定凭证不能为空")
		return
	}
	result, err := h.deliverySvc.Submit(c.Param("order_no"), req.GameAccount, req.BindUUID, parseDeliveryAuth(c))
	if err != nil {
		writeDeliveryError(c, err)
		return
	}
	response.OK(c, result)
}

// ImageProxy 代理外链图片并落盘缓存（仅无本地 SKU 图时的兜底）。
// 正式商品图请使用 frontend/public/images/products/{sku}.webp（go run ./cmd/sync_product_images）。
func (h *DeliveryHandler) ImageProxy(c *gin.Context) {
	rawURL := strings.TrimSpace(c.Query("url"))
	if rawURL == "" || (!strings.HasPrefix(rawURL, "http://") && !strings.HasPrefix(rawURL, "https://")) {
		response.BadRequest(c, "无效的图片地址")
		return
	}

	sku := strings.TrimSpace(c.Query("sku"))
	publicDirs := []string{
		"../frontend/public/images/products",
		"frontend/public/images/products",
		"public/images/products",
	}
	uploadDirs := []string{"data/uploads/products", "../data/uploads/products", "uploads/products"}

	tryLocal := func(dirs []string, name string) bool {
		if name == "" {
			return false
		}
		for _, base := range dirs {
			localPath := filepath.Join(base, name+".webp")
			if info, err := os.Stat(localPath); err == nil && info.Size() > 0 {
				c.Header("Cache-Control", "public, max-age=2592000, immutable")
				c.File(localPath)
				return true
			}
		}
		return false
	}

	// 1. 优先 SKU 命名的静态缓存
	if tryLocal(publicDirs, sku) {
		return
	}

	// 2. 历史：URL 中的乐玩 UUID → 先查 public，再查 uploads
	var uuidName string
	if strings.Contains(rawURL, "/products/") {
		parts := strings.Split(rawURL, "/products/")
		if len(parts) > 1 {
			sub := strings.Split(parts[1], "/")
			if len(sub) > 0 && sub[0] != "" {
				uuidName = sub[0]
			}
		}
	}
	if tryLocal(publicDirs, uuidName) || tryLocal(uploadDirs, uuidName) {
		return
	}

	// 3. URL hash 缓存（uploads 运行时兜底）
	hash := sha256.Sum256([]byte(rawURL))
	hashName := hex.EncodeToString(hash[:])
	if tryLocal(uploadDirs, hashName) {
		return
	}

	// 4. 本地无缓存时请求远端
	req, err := http.NewRequestWithContext(c.Request.Context(), http.MethodGet, rawURL, nil)
	if err != nil {
		response.BadRequest(c, "构建请求失败")
		return
	}
	client := &http.Client{Timeout: 15 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		response.Fail(c, http.StatusBadGateway, http.StatusBadGateway, "图片下载失败")
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		response.Fail(c, resp.StatusCode, resp.StatusCode, "远端图片响应异常")
		return
	}

	data, err := io.ReadAll(resp.Body)
	if err != nil {
		response.Fail(c, http.StatusBadGateway, http.StatusBadGateway, "读取图片内容失败")
		return
	}

	// 5. 仅将未知外链写入 uploads 哈希缓存（不再按 UUID 污染正式目录）
	cacheDir := "data/uploads/products"
	_ = os.MkdirAll(cacheDir, 0755)
	_ = os.WriteFile(filepath.Join(cacheDir, hashName+".webp"), data, 0644)

	contentType := resp.Header.Get("Content-Type")
	if contentType == "" {
		contentType = "image/webp"
	}
	c.Header("Cache-Control", "public, max-age=2592000, immutable")
	c.Data(http.StatusOK, contentType, data)
}

func parseDeliveryAuth(c *gin.Context) service.DeliveryLinkAuth {
	exp := int64(0)
	if value := strings.TrimSpace(c.Query("exp")); value != "" {
		if parsed, err := strconv.ParseInt(value, 10, 64); err == nil {
			exp = parsed
		}
	}
	return service.DeliveryLinkAuth{
		Exp:  exp,
		Sign: strings.TrimSpace(c.Query("sign")),
	}
}

func writeDeliveryError(c *gin.Context, err error) {
	type statusCoder interface {
		HTTPStatus() int
	}
	if sc, ok := err.(statusCoder); ok {
		status := sc.HTTPStatus()
		response.Fail(c, status, status, strings.TrimSpace(err.Error()))
		return
	}
	msg := strings.TrimSpace(err.Error())
	if msg == "订单不存在" {
		response.NotFound(c, msg)
		return
	}
	if msg == "链接参数缺失" || msg == "发货链接未生成" || msg == "发货链接已失效" || msg == "发货链接已过期" || msg == "发货链接签名无效" {
		response.Forbidden(c, msg)
		return
	}
	response.BadRequest(c, msg)
}