package handler

import (
	"crypto/rand"
	"encoding/hex"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"

	"github.com/gin-gonic/gin"

	"github.com/yuxingu/digital-psychology/apps/api/internal/avatar"
	"github.com/yuxingu/digital-psychology/apps/api/pkg/response"
)

// MediaHandler serves uploaded media files.
type MediaHandler struct {
	AvatarDir string
}

// Register mounts public media routes.
func (h *MediaHandler) Register(api *gin.RouterGroup) {
	api.GET("/media/avatars/:file", h.ServeAvatar)
	api.GET("/media/uploads/:file", h.ServeUpload)
	api.POST("/upload", h.Upload)
}

// ServeAvatar streams a stored avatar image.
func (h *MediaHandler) ServeAvatar(c *gin.Context) {
	dir := h.AvatarDir
	if dir == "" {
		dir = "data/avatars"
	}
	full, err := avatar.ResolveAbs(dir, c.Param("file"))
	if err != nil {
		c.Status(http.StatusNotFound)
		return
	}
	c.Header("Cache-Control", "public, max-age=86400")
	c.File(full)
	_ = filepath.Ext(full)
}

func (h *MediaHandler) uploadDir() string {
	return "data/uploads"
}

func (h *MediaHandler) ServeUpload(c *gin.Context) {
	name := filepath.Base(c.Param("file"))
	full := filepath.Join(h.uploadDir(), name)
	if _, err := os.Stat(full); err != nil {
		c.Status(http.StatusNotFound)
		return
	}
	c.File(full)
}

func (h *MediaHandler) Upload(c *gin.Context) {
	fh, err := c.FormFile("file")
	if err != nil {
		response.Fail(c, http.StatusBadRequest, 10000, "请选择文件")
		return
	}
	src, err := fh.Open()
	if err != nil {
		response.Fail(c, http.StatusBadRequest, 10000, "读取失败")
		return
	}
	defer src.Close()
	ext := strings.ToLower(filepath.Ext(fh.Filename))
	if ext == "" {
		ext = ".jpg"
	}
	var b [8]byte
	_, _ = rand.Read(b[:])
	name := hex.EncodeToString(b[:]) + ext
	if err := os.MkdirAll(h.uploadDir(), 0o755); err != nil {
		response.Fail(c, http.StatusInternalServerError, 50001, "保存失败")
		return
	}
	dstPath := filepath.Join(h.uploadDir(), name)
	dst, err := os.Create(dstPath)
	if err != nil {
		response.Fail(c, http.StatusInternalServerError, 50001, "保存失败")
		return
	}
	defer dst.Close()
	if _, err := io.Copy(dst, src); err != nil {
		response.Fail(c, http.StatusInternalServerError, 50001, "保存失败")
		return
	}
	response.OK(c, "/api/v1/media/uploads/"+name)
}