package api

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

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

type personFilmographyResponse struct {
	Items []json.RawMessage `json:"items"`
}

// handlePerson returns Emby's person item. PremiereDate and EndDate are the person's
// birth and death dates; Overview is their biography.
//
// It is cached for the household rather than per viewer, and outside the namespace a
// playback stop invalidates. Nothing about who Cillian Murphy is depends on who is
// asking or on what they finished watching ten minutes ago, and filing it under the
// viewer meant a cast page paid Emby again after every episode anybody in the house
// completed.
func (s *Server) handlePerson(w http.ResponseWriter, r *http.Request, sess store.Session) {
	ctx := r.Context()
	personID := r.PathValue("id")
	if personID == "" {
		writeError(w, http.StatusBadRequest, "person id is required")
		return
	}
	person, hit, err := s.cachedRead(ctx, cache.MetadataKey("person:v2:"+personID), s.cfg.ItemTTL,
		func(ctx context.Context) (json.RawMessage, error) {
			return s.emby.Item(ctx, credentials(sess), personID,
				"Overview,Genres,PrimaryImageAspectRatio")
		})
	if err != nil {
		s.writeUpstreamError(ctx, w, err, "could not load the person")
		return
	}
	writeCached(w, hit, person)
}

// Filmography is kept separate from the biography so life dates can decorate the cast
// row without also loading every cast member's credits.
//
// Unlike the biography this one is genuinely per viewer — it asks Emby for user data, so
// the grid can mark what has been watched — and therefore stays where invalidation can
// reach it. What it gains instead is coalescing: this is the most expensive query the
// gateway makes of Emby, a recursive scan of the whole library filtered by person, and
// three televisions opening the same cast card used to mean three of them.
func (s *Server) handlePersonFilmography(w http.ResponseWriter, r *http.Request, sess store.Session) {
	ctx := r.Context()
	personID := r.PathValue("id")
	if personID == "" {
		writeError(w, http.StatusBadRequest, "person id is required")
		return
	}
	key := cache.UserKey(sess.EmbyUserID, "person-filmography:v1:"+personID)
	body, hit, err := s.cachedRead(ctx, key, s.cfg.ItemTTL,
		func(ctx context.Context) (json.RawMessage, error) {
			result, err := s.emby.Items(ctx, credentials(sess), url.Values{
				"PersonIds":        {personID},
				"IncludeItemTypes": {"Movie,Series"},
				"Recursive":        {"true"},
				"SortBy":           {"ProductionYear,SortName"},
				"SortOrder":        {"Descending"},
				"Limit":            {"60"},
				"Fields":           {"Overview,ProductionYear,PrimaryImageAspectRatio"},
				"EnableImages":     {"true"},
				"EnableImageTypes": {"Primary"},
				"ImageTypeLimit":   {"1"},
				"EnableUserData":   {"true"},
			})
			if err != nil {
				return nil, err
			}
			items := result.Items
			if items == nil {
				items = []json.RawMessage{}
			}
			return json.Marshal(personFilmographyResponse{Items: items})
		})
	if err != nil {
		s.writeUpstreamError(ctx, w, err, "could not load the person's filmography")
		return
	}
	writeCached(w, hit, body)
}