package workbench

import (
	"errors"
	"io"
	"mime/multipart"
	"net/http"
	"strings"

	"aigateway.local/core/internal/identity"
	"aigateway.local/core/internal/platform/apiresponse"
)

// FilesPortalHTTPHandler serves each portal user's personal file store. Unlike
// the admin handler every object is scoped to the authenticated account, so a
// user can only ever see and open their own files.
type FilesPortalHTTPHandler struct {
	files    *FileService
	identity *identity.Service
	mux      *http.ServeMux
}

func NewFilesPortalHTTPHandler(files *FileService, identityService *identity.Service) *FilesPortalHTTPHandler {
	h := &FilesPortalHTTPHandler{files: files, identity: identityService, mux: http.NewServeMux()}
	h.mux.HandleFunc("POST /api/v1/portal/files", h.upload)
	h.mux.HandleFunc("GET /api/v1/portal/files", h.list)
	h.mux.HandleFunc("GET /api/v1/portal/files/{id}/download", h.download)
	h.mux.HandleFunc("DELETE /api/v1/portal/files/{id}", h.delete)
	return h
}

func (h *FilesPortalHTTPHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { h.mux.ServeHTTP(w, r) }

func (h *FilesPortalHTTPHandler) account(w http.ResponseWriter, r *http.Request) (identity.Account, bool) {
	account, err := h.identity.Authenticate(r.Context(), identity.KindPortal, r.Header.Get("Authorization"))
	if err != nil {
		apiresponse.Error(w, http.StatusUnauthorized, "登录状态无效或已过期")
		return identity.Account{}, false
	}
	return account, true
}

func (h *FilesPortalHTTPHandler) upload(w http.ResponseWriter, r *http.Request) {
	a, ok := h.account(w, r)
	if !ok {
		return
	}
	var (
		body          io.Reader
		originalName  = strings.TrimSpace(r.URL.Query().Get("filename"))
		contentType   = r.Header.Get("Content-Type")
	)
	if strings.HasPrefix(contentType, "multipart/form-data") {
		part, err := h.firstFilePart(r)
		if err != nil {
			apiresponse.Error(w, http.StatusBadRequest, "缺少上传文件")
			return
		}
		defer part.Close()
		body = part
		originalName = part.FileName()
		if ct := part.Header.Get("Content-Type"); ct != "" {
			contentType = ct
		}
	}
	if originalName == "" {
		apiresponse.Error(w, http.StatusBadRequest, "缺少文件名")
		return
	}
	obj, err := h.files.Upload(r.Context(), "personal", &a.ID, a.ID, originalName, contentType, body)
	if err != nil {
		fileError(w, err)
		return
	}
	apiresponse.OK(w, obj)
}

func (h *FilesPortalHTTPHandler) firstFilePart(r *http.Request) (*multipart.Part, error) {
	reader, err := r.MultipartReader()
	if err != nil {
		return nil, err
	}
	for {
		part, err := reader.NextPart()
		if err == io.EOF {
			return nil, errors.New("no file part")
		}
		if err != nil {
			return nil, err
		}
		if part.FormName() == "file" {
			return part, nil
		}
	}
}

func (h *FilesPortalHTTPHandler) list(w http.ResponseWriter, r *http.Request) {
	a, ok := h.account(w, r)
	if !ok {
		return
	}
	items, err := h.files.ListPersonal(r.Context(), a.ID)
	if err != nil {
		fileError(w, err)
		return
	}
	apiresponse.OK(w, items)
}

func (h *FilesPortalHTTPHandler) download(w http.ResponseWriter, r *http.Request) {
	a, ok := h.account(w, r)
	if !ok {
		return
	}
	obj, err := h.files.GetPersonal(r.Context(), a.ID, r.PathValue("id"))
	if err != nil {
		fileError(w, err)
		return
	}
	serveFileContent(w, r, h.files, obj)
}

func (h *FilesPortalHTTPHandler) delete(w http.ResponseWriter, r *http.Request) {
	a, ok := h.account(w, r)
	if !ok {
		return
	}
	if err := h.files.DeletePersonal(r.Context(), a.ID, r.PathValue("id")); err != nil {
		fileError(w, err)
		return
	}
	apiresponse.OK(w, map[string]bool{"deleted": true})
}
