package api

import (
	"errors"
	"net/http"
	"strings"

	"git.golem15.com/golem15/sm-journal-plugin/classes"
	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/wire"
	"gocloud.dev/blob"
)

// UploadMedia is POST /_journal/api/v1/media/upload (JOURNAL-006). The
// route authenticates, checks permissions, the folder and the form, then
// stores the file with classes.StoreMedia, which the Blog Editor's image
// upload shares.
func UploadMedia(app *backpack.App) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		r, pr, ok := requireBackendPrincipal(app, w, r)
		if !ok {
			return
		}
		if !requireAccessPosts(w, pr) {
			return
		}
		folder := strings.TrimSpace(r.FormValue("folder"))
		if len(folder) > 100 || !classes.MediaFolderPattern.MatchString(folder) || strings.Contains(folder, "..") {
			writeValidation(w, map[string][]string{"folder": {"The folder format is invalid."}})
			return
		}
		file, header, err := r.FormFile("file")
		if err != nil {
			writeValidation(w, map[string][]string{"file": {"The file field is required."}})
			return
		}
		defer file.Close()
		bucket, _ := app.Lookup[*blob.Bucket]()
		stored, err := classes.StoreMedia(r.Context(), bucket, folder, header.Filename, file)
		if err != nil {
			writeMediaStoreError(w, err)
			return
		}
		wire.WriteJSON(w, http.StatusCreated, map[string]any{
			"data": map[string]any{
				"url":  stored.URL,
				"path": stored.Path,
			},
		})
	}
}

// writeMediaStoreError answers a StoreMedia failure as the route always
// has: a classes.MediaError is a 422 on its field with its message, any
// other error the opaque 500.
func writeMediaStoreError(w http.ResponseWriter, err error) {
	var refused *classes.MediaError
	if errors.As(err, &refused) && refused != nil {
		writeValidation(w, map[string][]string{refused.Field: {refused.Message}})
		return
	}
	writeAPIError(w, http.StatusInternalServerError, "Internal server error")
}