package staticimages

import (
	"RenewCMS/internal/domain/image"
	"RenewCMS/internal/infrastructure/useCases"
	"errors"
	"io"
	"net/http"
	"path"
	"strconv"
	"strings"
	"time"

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

const cacheControl = "public, no-cache"
const svgContentSecurityPolicy = "default-src 'none'; style-src 'unsafe-inline'; sandbox"
const fallbackContentType = "application/octet-stream"

var contentTypeExtensions = map[string]string{
	".png":  "image/png",
	".jpeg": "image/jpeg",
	".webp": "image/webp",
	".svg":  "image/svg+xml",
}

type Handler struct {
	openMedia *useCases.OpenMediaUseCase
	modTime   time.Time
}

func NewHandler(openMedia *useCases.OpenMediaUseCase) *Handler {
	return &Handler{
		openMedia: openMedia,
		modTime:   time.Now(),
	}
}

func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("X-Content-Type-Options", "nosniff")

	cleaned := cleanPath(requestedPath(r))
	blob, err := h.openMedia.Open(cleaned)
	if errors.Is(err, image.ErrBlobNotFound) {
		http.NotFound(w, r)
		return
	}
	if err != nil {
		http.Error(w, "Unable to read the file", http.StatusInternalServerError)
		return
	}
	defer blob.Content.Close()

	contentType := contentTypeFor(cleaned)
	w.Header().Set("Content-Type", contentType)
	w.Header().Set("Cache-Control", cacheControl)
	if contentType == "image/svg+xml" {
		w.Header().Set("Content-Security-Policy", svgContentSecurityPolicy)
	}

	if content, ok := blob.Content.(io.ReadSeeker); ok {
		http.ServeContent(w, r, cleaned, blob.ModTime, content)
		return
	}
	w.Header().Set("Content-Length", strconv.FormatInt(blob.Size, 10))
	if !blob.ModTime.IsZero() {
		w.Header().Set("Last-Modified", blob.ModTime.UTC().Format(http.TimeFormat))
	}
	w.WriteHeader(http.StatusOK)
	if r.Method != http.MethodHead {
		_, _ = io.Copy(w, blob.Content)
	}
}

func requestedPath(r *http.Request) string {
	if rctx := chi.RouteContext(r.Context()); rctx != nil && rctx.RoutePath != "" {
		return rctx.RoutePath
	}
	return r.URL.Path
}

func cleanPath(p string) string {
	return strings.TrimPrefix(path.Clean("/"+p), "/")
}

func contentTypeFor(p string) string {
	ext := path.Ext(p)
	if contentType, ok := contentTypeExtensions[ext]; ok {
		return contentType
	}
	return fallbackContentType
}