package api

import (
	"encoding/json"
	"net/http"

	"github.com/ponzischeme89/memby/server/internal/cache"
	"github.com/ponzischeme89/memby/server/internal/store"
)

type flagRequest struct {
	Value bool `json:"value"`
}

// handleItem serves full metadata for one item. The TV asks for this only after D-pad
// focus settles, so it is worth caching for longer than a home row.
func (s *Server) handleItem(w http.ResponseWriter, r *http.Request, sess store.Session) {
	ctx := r.Context()
	itemID := r.PathValue("id")
	if itemID == "" {
		writeError(w, http.StatusBadRequest, "item id is required")
		return
	}
	key := cache.UserKey(sess.EmbyUserID, "item:"+itemID)

	if raw, err := s.cache.Get(ctx, key); err == nil {
		w.Header().Set("X-Memby-Cache", "hit")
		writeRaw(w, http.StatusOK, raw)
		return
	}

	item, err := s.emby.Item(ctx, credentials(sess), itemID, fieldsDetail)
	if err != nil {
		s.writeUpstreamError(w, err, "could not load the item")
		return
	}
	if err := s.cache.Set(ctx, key, item, s.cfg.ItemTTL); err != nil {
		s.log.Warn("item cache write failed", "error", err)
	}
	w.Header().Set("X-Memby-Cache", "miss")
	writeRaw(w, http.StatusOK, item)
}

// handleTrailer answers with the item's first local trailer, or 404 when it has none.
// The screensaver's Play action uses this before asking for a playback URL.
func (s *Server) handleTrailer(w http.ResponseWriter, r *http.Request, sess store.Session) {
	itemID := r.PathValue("id")
	if itemID == "" {
		writeError(w, http.StatusBadRequest, "item id is required")
		return
	}
	result, err := s.emby.LocalTrailers(r.Context(), credentials(sess), itemID)
	if err != nil {
		s.writeUpstreamError(w, err, "could not load trailers")
		return
	}
	if len(result.Items) == 0 {
		writeError(w, http.StatusNotFound, "no trailer available")
		return
	}
	writeRaw(w, http.StatusOK, result.Items[0])
}

func (s *Server) handleFavorite(w http.ResponseWriter, r *http.Request, sess store.Session) {
	s.setFlag(w, r, sess, func(itemID string, value bool) (json.RawMessage, error) {
		return s.emby.SetFavorite(r.Context(), credentials(sess), itemID, value)
	})
}

func (s *Server) handlePlayed(w http.ResponseWriter, r *http.Request, sess store.Session) {
	s.setFlag(w, r, sess, func(itemID string, value bool) (json.RawMessage, error) {
		return s.emby.SetPlayed(r.Context(), credentials(sess), itemID, value)
	})
}

// setFlag applies a user-data mutation and drops this user's cached views, so the next
// home request reflects it rather than serving the row it just contradicted.
func (s *Server) setFlag(
	w http.ResponseWriter,
	r *http.Request,
	sess store.Session,
	apply func(itemID string, value bool) (json.RawMessage, error),
) {
	itemID := r.PathValue("id")
	if itemID == "" {
		writeError(w, http.StatusBadRequest, "item id is required")
		return
	}
	var req flagRequest
	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 4<<10)).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "malformed request body")
		return
	}

	userData, err := apply(itemID, req.Value)
	if err != nil {
		s.writeUpstreamError(w, err, "could not update the item")
		return
	}
	if err := s.cache.InvalidateUser(r.Context(), sess.EmbyUserID); err != nil {
		s.log.Warn("cache invalidation failed", "error", err)
	}
	writeRaw(w, http.StatusOK, userData)
}