package api

import (
	"encoding/base64"
	"errors"
	"net/http"
	"strings"

	"gardomatic.kleiax.de/internal/storage"
)

func (app *application) resolveImage(gardenID int, data string, selectedID *int, userID int, source string) (*int, error) {
	if strings.TrimSpace(data) == "" {
		if selectedID == nil {
			return nil, nil
		}
		if _, err := app.models.Images.Get(gardenID, *selectedID); err != nil {
			return nil, err
		}
		return selectedID, nil
	}
	comma := strings.IndexByte(data, ',')
	if comma < 1 || !strings.HasPrefix(data, "data:image/") || !strings.HasSuffix(data[:comma], ";base64") {
		return nil, errors.New("invalid image data")
	}
	mediaType := strings.TrimSuffix(strings.TrimPrefix(data[:comma], "data:"), ";base64")
	decoded, err := base64.StdEncoding.DecodeString(data[comma+1:])
	if err != nil || len(decoded) == 0 || len(decoded) > storage.MaxImageSize {
		return nil, errors.New("invalid image data")
	}
	image, err := app.models.Images.Insert(storage.Image{GardenID: gardenID, MediaType: mediaType, Data: decoded, Source: source, CreatedBy: userID})
	if err != nil {
		return nil, err
	}
	return &image.ID, nil
}

func (app *application) recordImageAssignment(change storage.ImageAssignment) error {
	if app.models.Images == nil {
		return nil
	}
	return app.models.Images.RecordAssignment(change)
}

func (app *application) listImagesHandler(w http.ResponseWriter, r *http.Request) {
	gardenID, _ := app.readGardenIDParam(r)
	images, err := app.models.Images.GetAllForGarden(gardenID, storage.ImageFilter{Source: r.URL.Query().Get("source"), Query: r.URL.Query().Get("q")})
	if err != nil {
		app.serverErrorResponse(w, r, err)
		return
	}
	if err = app.writeJSON(w, http.StatusOK, envelope{"images": images}, nil); err != nil {
		app.serverErrorResponse(w, r, err)
	}
}

func (app *application) showImageHandler(w http.ResponseWriter, r *http.Request) {
	gardenID, _ := app.readGardenIDParam(r)
	id, err := app.readNamedIDParam(r, "imageID")
	if err != nil {
		app.notFoundResponse(w, r)
		return
	}
	image, err := app.models.Images.Get(gardenID, id)
	if err != nil {
		app.respondToEntityModelError(w, r, err)
		return
	}
	w.Header().Set("Content-Type", image.MediaType)
	w.Header().Set("Cache-Control", "private, max-age=86400")
	_, _ = w.Write(image.Data)
}