package media

import (
	"RenewCMS/api/pkg/apperr"
	domainImage "RenewCMS/internal/domain/image"
	"RenewCMS/internal/infrastructure/useCases"
	"errors"
	"net/http"

	"github.com/go-chi/chi/v5"
)

type imageVariantResponse struct {
	Name         string                    `json:"name"`
	Width        *int                      `json:"width"`
	Height       *int                      `json:"height"`
	Fit          domainImage.VariantFit    `json:"fit"`
	Format       domainImage.VariantFormat `json:"format"`
	OutputWidth  int                       `json:"output_width"`
	OutputHeight int                       `json:"output_height"`
	OutputFormat domainImage.VariantFormat `json:"output_format"`
	Generated    bool                      `json:"generated"`
	Size         *int64                    `json:"size"`
	URL          string                    `json:"url"`
}

type imageVariantListResponse struct {
	Unsupported *string                `json:"unsupported"`
	Items       []imageVariantResponse `json:"items"`
}

type variantFailureResponse struct {
	Name  string `json:"name"`
	Cause string `json:"cause"`
}

type generateAllResponse struct {
	Generated int                      `json:"generated"`
	Failed    int                      `json:"failed"`
	Failures  []variantFailureResponse `json:"failures"`
	Items     []imageVariantResponse   `json:"items"`
}

type variantPurgeResponse struct {
	PurgedFiles int   `json:"purged_files"`
	PurgedBytes int64 `json:"purged_bytes"`
}

func toImageVariantResponse(view useCases.ImageVariantView) imageVariantResponse {
	response := imageVariantResponse{
		Name:         view.Variant.Name,
		Width:        view.Variant.Width,
		Height:       view.Variant.Height,
		Fit:          view.Variant.Fit,
		Format:       view.Variant.Format,
		OutputWidth:  view.OutputWidth,
		OutputHeight: view.OutputHeight,
		OutputFormat: view.OutputFormat,
		Generated:    view.Generated,
		URL:          view.URL,
	}
	if view.Generated {
		size := view.Size
		response.Size = &size
	}
	return response
}

func toImageVariantResponses(views []useCases.ImageVariantView) []imageVariantResponse {
	items := make([]imageVariantResponse, 0, len(views))
	for _, view := range views {
		items = append(items, toImageVariantResponse(view))
	}
	return items
}

func writeImageVariantError(w http.ResponseWriter, err error) {
	switch {
	case errors.Is(err, domainImage.ErrVariantNotFound):
		http.Error(w, apperr.VariantNotFoundErrorMessage, http.StatusNotFound)
	case errors.Is(err, domainImage.ErrVariantSourceUnsupported):
		http.Error(w, apperr.VariantSourceUnsupportedErrorMessage, http.StatusUnprocessableEntity)
	case errors.Is(err, domainImage.ErrSourceTooLarge):
		http.Error(w, apperr.VariantSourceTooLargeErrorMessage, http.StatusRequestEntityTooLarge)
	case errors.Is(err, domainImage.ErrVariantSourceUnreadable):
		http.Error(w, apperr.VariantSourceUnreadableErrorMessage, http.StatusUnsupportedMediaType)
	default:
		writeImageError(w, err)
	}
}

func (h *Handler) ListVariants(w http.ResponseWriter, r *http.Request) {
	id, ok := parseImageId(w, r)
	if !ok {
		return
	}

	list, err := h.ListVariantsUseCase.List(id)
	if err != nil {
		writeImageVariantError(w, err)
		return
	}

	response := imageVariantListResponse{Items: toImageVariantResponses(list.Items)}
	if list.Unsupported != "" {
		response.Unsupported = &list.Unsupported
	}
	writeJSON(w, http.StatusOK, response)
}

func (h *Handler) GenerateVariant(w http.ResponseWriter, r *http.Request) {
	id, ok := parseImageId(w, r)
	if !ok {
		return
	}

	view, err := h.GenerateVariantUseCase.Generate(r.Context(), id, chi.URLParam(r, "name"))
	if err != nil {
		writeImageVariantError(w, err)
		return
	}
	writeJSON(w, http.StatusOK, toImageVariantResponse(view))
}

func (h *Handler) GenerateAllVariants(w http.ResponseWriter, r *http.Request) {
	id, ok := parseImageId(w, r)
	if !ok {
		return
	}

	result, err := h.GenerateAllUseCase.Generate(r.Context(), id)
	if err != nil {
		writeImageVariantError(w, err)
		return
	}

	failures := make([]variantFailureResponse, 0, len(result.Failures))
	for _, failure := range result.Failures {
		failures = append(failures, variantFailureResponse{Name: failure.Name, Cause: failure.Cause})
	}
	writeJSON(w, http.StatusOK, generateAllResponse{
		Generated: result.Generated,
		Failed:    result.Failed,
		Failures:  failures,
		Items:     toImageVariantResponses(result.Items),
	})
}

func (h *Handler) PurgeVariant(w http.ResponseWriter, r *http.Request) {
	id, ok := parseImageId(w, r)
	if !ok {
		return
	}

	purged, err := h.PurgeVariantUseCase.Purge(r.Context(), id, chi.URLParam(r, "name"))
	if err != nil {
		writeImageVariantError(w, err)
		return
	}
	writeJSON(w, http.StatusOK, variantPurgeResponse{PurgedFiles: purged.Files, PurgedBytes: purged.Bytes})
}