// 功能描述：独立的报修照片受控存储，内容摘要使同一账户重复上传幂等。
// 版本：1.0.0。
package upload

import (
	"crypto/sha256"
	"fmt"
	"git.apinb.com/bsm-sdk/core/errcode"
	"git.apinb.com/bsm-sdk/core/infra"
	"github.com/gin-gonic/gin"
	"io"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"regexp"
	"strings"
)

var ticketPhotoName = regexp.MustCompile(`^[a-f0-9]{64}\.(jpg|png)$`)

// ServeOwnedTicketPhoto 恢复尚未关联工单的照片，只解析当前账户目录内的摘要文件名。
func ServeOwnedTicketPhoto(ctx *gin.Context, identity, name string) {
	if !ticketPhotoName.MatchString(name) {
		ctx.Status(http.StatusNotFound)
		return
	}
	ServeTicketPhoto(ctx, identity, "/uploads/ticket-photos/"+avatarOwnerDirectory("user_app", identity)+"/"+name)
}

// ticketPhotoPath 只接受当前账户目录中的摘要文件名，不允许用户指定路径。
func ticketPhotoPath(identity, uri string) (string, bool) {
	prefix := "/uploads/ticket-photos/" + avatarOwnerDirectory("user_app", identity) + "/"
	name := strings.TrimPrefix(uri, prefix)
	if !strings.HasPrefix(uri, prefix) || !ticketPhotoName.MatchString(name) {
		return "", false
	}
	return filepath.Join(uploadRoot(), "ticket-photos", filepath.FromSlash(avatarOwnerDirectory("user_app", identity)), name), true
}

// OwnsTicketPhoto 校验工单创建引用的资源归属和完整普通文件。
func OwnsTicketPhoto(identity, uri string) bool {
	path, ok := ticketPhotoPath(identity, uri)
	if !ok {
		return false
	}
	info, err := os.Lstat(path)
	return err == nil && info.Mode().IsRegular() && info.Size() > 0 && info.Size() <= maxAvatarSize
}

// UploadTicketPhoto 由用户Client鉴权入口调用，仅复用图片字节校验，不复用头像存储或权限。
func UploadTicketPhoto(ctx *gin.Context, identity string) {
	ctx.Request.Body = http.MaxBytesReader(ctx.Writer, ctx.Request.Body, maxAvatarSize+(256<<10))
	header, err := ctx.FormFile("file")
	if err != nil || header.Size <= 0 || header.Size > maxAvatarSize {
		infra.Response.Error(ctx, errcode.ErrInvalidArgument)
		return
	}
	file, err := header.Open()
	if err != nil {
		infra.Response.Error(ctx, err)
		return
	}
	defer file.Close()
	content, err := io.ReadAll(io.LimitReader(file, maxAvatarSize+1))
	if err != nil || int64(len(content)) > maxAvatarSize {
		infra.Response.Error(ctx, errcode.ErrInvalidArgument)
		return
	}
	extension, contentType, err := validateAvatar(header.Filename, content)
	if err != nil {
		infra.Response.Error(ctx, errcode.ErrInvalidArgument)
		return
	}
	name := fmt.Sprintf("%x%s", sha256.Sum256(content), extension)
	uri := "/uploads/ticket-photos/" + avatarOwnerDirectory("user_app", identity) + "/" + name
	path, _ := ticketPhotoPath(identity, uri)
	if err := os.MkdirAll(filepath.Dir(path), 0o750); err != nil {
		infra.Response.Error(ctx, err)
		return
	}
	// 先完整写临时文件再原子移动，避免并发重试读到半张图片。
	temp, err := os.CreateTemp(filepath.Dir(path), ".pending-")
	if err != nil {
		infra.Response.Error(ctx, err)
		return
	}
	defer os.Remove(temp.Name())
	_, writeErr := temp.Write(content)
	closeErr := temp.Close()
	if writeErr != nil || closeErr != nil {
		infra.Response.Error(ctx, errcode.ErrInvalidArgument)
		return
	}
	if err := os.Rename(temp.Name(), path); err != nil && !OwnsTicketPhoto(identity, uri) {
		infra.Response.Error(ctx, err)
		return
	}
	infra.Response.Success(ctx, UploadFileReply{URI: uri, ContentType: contentType, Size: int64(len(content))})
	log.Printf("ticket photo upload account=%s digest=%s bytes=%d", identity, name, len(content))
}

// ServeTicketPhoto 在工单归属和证据关联已经校验后读取，禁止公开缓存和MIME嗅探。
func ServeTicketPhoto(ctx *gin.Context, identity, uri string) {
	if !OwnsTicketPhoto(identity, uri) {
		ctx.Status(http.StatusNotFound)
		return
	}
	path, _ := ticketPhotoPath(identity, uri)
	ctx.Header("Cache-Control", "private, no-store")
	ctx.Header("X-Content-Type-Options", "nosniff")
	ctx.File(path)
	log.Printf("ticket photo read account=%s digest=%s", identity, filepath.Base(path))
}