package api

import (
	"context"
	"net/http"
	"strconv"
	"strings"
	"time"

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

// radarrItemPrefix is what a schedule card's id looks like: "radarr:412". The row has used
// it since the movie schedule shipped, and it is also what the trailer routes recognise —
// see radarrTrailerManifest — so a film with no Emby record can still be asked about
// through the ordinary /v1/items/{id}/trailers path.
const radarrItemPrefix = "radarr:"

// radarrMovieDetail is everything the Radarr-only detail page draws.
//
// It is deliberately not a BaseItem. A film Radarr is tracking but Emby has never imported
// has no Emby record, no user data and nothing to play, and dressing it as one would put a
// Play button, a watched tick and a progress bar on a page where all three are lies. The
// television has a state of its own for this, and the moment Emby does hold the film
// [EmbyItemID] is what sends the viewer to the ordinary page instead.
//
// Every piece of wording here is the gateway's, the arrangement the schedule cards, the
// hero captions and the lifecycle tags already take: a phrasing invented next month reads
// correctly on a television that predates it.
type radarrMovieDetail struct {
	ID             string   `json:"id"`
	Title          string   `json:"title"`
	OriginalTitle  string   `json:"originalTitle,omitempty"`
	Overview       string   `json:"overview,omitempty"`
	Year           int      `json:"year,omitempty"`
	RuntimeMinutes int      `json:"runtimeMinutes,omitempty"`
	Genres         []string `json:"genres"`
	Studio         string   `json:"studio,omitempty"`
	Certificate    string   `json:"certificate,omitempty"`
	Monitored      bool     `json:"monitored"`
	// Radarr's own lifecycle word, as the schedule card wears it: ANNOUNCED, IN CINEMAS,
	// RELEASED. Distinct from [StateLabel], which is about the household's copy.
	Lifecycle     string `json:"lifecycle,omitempty"`
	LifecycleText string `json:"lifecycleText,omitempty"`
	// The subtle status treatment at the top of the page: "Coming Soon", "Awaiting
	// Release", "Not Yet Available", with one line under it saying what that means here.
	StateLabel  string `json:"stateLabel"`
	StateDetail string `json:"stateDetail,omitempty"`
	// The one prominent date. "Expected 14 November 2026" when something has published the
	// day, "Expected November 2026" when the day is inferred rather than published, and
	// "Release date not yet announced" when nothing is known — never a precise-looking
	// date standing in for a guess.
	ExpectedLabel string `json:"expectedLabel"`
	// Cinema, digital and physical dates as Radarr holds them, for the viewer who wants to
	// know which of the three the headline came from. Any of them may be absent.
	ReleaseDates []radarrReleaseDate `json:"releaseDates"`
	// The sentence saying, in as many words, that this cannot be watched here yet.
	AvailabilityNotice string `json:"availabilityNotice"`
	// Whether the Trailer action should be offered at all. Deciding it here rather than on
	// the television is what keeps the button from being one that fails after selection.
	TrailerAvailable bool `json:"trailerAvailable"`
	// Scores from the same store every other page reads, when this title has been looked
	// up before. Empty is the honest answer and the strip simply does not appear.
	Ratings []movieRating `json:"ratings"`
	// Set once Emby holds the film. The television reopens on the ordinary detail page
	// when it sees this, which is how a title stops being a Radarr card without anything
	// having to be invalidated.
	EmbyItemID string `json:"embyItemId,omitempty"`
}

type radarrReleaseDate struct {
	// cinema | digital | physical — a lookup key, not prose.
	Kind  string `json:"kind"`
	Label string `json:"label"`
	Value string `json:"value"`
}

func (s *Server) handleRadarrMovie(w http.ResponseWriter, r *http.Request, sess store.Session) {
	_ = sess
	movieID, ok := radarrMovieID(r.PathValue("id"))
	if !ok {
		writeError(w, http.StatusBadRequest, "a radarr movie id is required")
		return
	}
	if !s.radarrEnabled(r.Context()) {
		writeError(w, http.StatusNotFound, "radarr is not available")
		return
	}
	movie, err := s.radarrMovie(r.Context(), movieID)
	if err != nil {
		s.writeUpstreamError(r.Context(), w, err, "could not read that movie")
		return
	}
	location := s.cfg.RadarrLocation
	if location == nil {
		location = time.Local
	}
	detail := buildRadarrMovieDetail(movie, time.Now().In(location), location)
	detail.EmbyItemID = s.embyMovieItemID(r.Context(), movie.TMDBID)
	detail.Ratings = s.radarrMovieRatings(r.Context(), movie)
	writeJSON(w, http.StatusOK, detail)
}

// radarrMovieID reads the movie out of either form of id: the card's own "radarr:412", and
// the bare number, because a caller holding the number should not have to know the prefix.
func radarrMovieID(raw string) (int, bool) {
	trimmed := strings.TrimPrefix(strings.TrimSpace(raw), radarrItemPrefix)
	id, err := strconv.Atoi(trimmed)
	if err != nil || id <= 0 {
		return 0, false
	}
	return id, true
}

// radarrMovie reads one film, preferring the household's cached catalogue.
//
// That catalogue is one request answering for every title, already shared across the house
// and already refreshed on its own schedule, so a detail page opening normally costs Radarr
// nothing at all. Asking directly is the fallback for a title added since it was read.
func (s *Server) radarrMovie(ctx context.Context, movieID int) (radarr.Movie, error) {
	if movies, err := s.radarrMovieCatalogue(ctx); err == nil {
		for _, movie := range movies {
			if movie.ID == movieID {
				return movie, nil
			}
		}
	}
	return s.radarr.Movie(ctx, movieID)
}

// embyMovieItemID is embyMovieIndex for one title. A failure costs the redirect and never
// the page: the worst case is a Radarr page for a film Emby has quietly imported, which the
// next home refresh corrects.
func (s *Server) embyMovieItemID(ctx context.Context, tmdbID int) string {
	if s.store == nil || tmdbID <= 0 {
		return ""
	}
	found, err := s.store.LibraryProviderItemIDs(ctx, "Tmdb", []int{tmdbID})
	if err != nil {
		s.loggerFor(ctx).Warn("emby movie lookup failed for radarr detail", "error", err)
		return ""
	}
	return found[tmdbID]
}

// radarrMovieRatings reuses the household's ratings store rather than Radarr's own scores.
// Radarr carries a ratings block, but a page showing TMDb's number from Radarr here and
// MDBList's everywhere else would print two different scores for one film under one name.
func (s *Server) radarrMovieRatings(ctx context.Context, movie radarr.Movie) []movieRating {
	settings, enabled := s.mdblistSettings(ctx)
	if !enabled || s.mdblist == nil || s.store == nil {
		return []movieRating{}
	}
	key := store.RatingKey{MediaType: "movie"}
	switch {
	case movie.TMDBID > 0:
		key.Provider, key.ProviderID = "tmdb", strconv.Itoa(movie.TMDBID)
	case strings.TrimSpace(movie.IMDBID) != "":
		key.Provider, key.ProviderID = "imdb", strings.TrimSpace(movie.IMDBID)
	default:
		return []movieRating{}
	}
	ratings, err := s.loadMDBListRatings(ctx, settings.APIKey, key)
	if err != nil {
		s.logMDBListFailure(ctx, "ratings unavailable", radarrItemPrefix+strconv.Itoa(movie.ID), err)
		return []movieRating{}
	}
	return selectedMovieRatings(settings.Sources, ratings)
}

// buildRadarrMovieDetail is the whole of the page's wording, and it is pure so that every
// case a household can actually produce — a film with three dates, one with only a cinema
// date, one Radarr has never been given a date for at all — is answerable without a Radarr.
func buildRadarrMovieDetail(movie radarr.Movie, now time.Time, location *time.Location) radarrMovieDetail {
	release, hasRelease := effectiveRadarrRelease(movie)
	lifecycle := movieLifecycleTag(movie.Status)
	detail := radarrMovieDetail{
		ID:                 radarrItemPrefix + strconv.Itoa(movie.ID),
		Title:              strings.TrimSpace(movie.Title),
		Overview:           strings.TrimSpace(movie.Overview),
		Year:               movie.Year,
		RuntimeMinutes:     movie.Runtime,
		Genres:             nonNilStrings(movie.Genres),
		Studio:             strings.TrimSpace(movie.Studio),
		Certificate:        strings.TrimSpace(movie.Certification),
		Monitored:          movie.Monitored,
		Lifecycle:          lifecycle.Status,
		LifecycleText:      lifecycle.Label,
		ExpectedLabel:      radarrExpectedLabel(release, hasRelease, now, location),
		ReleaseDates:       radarrReleaseDates(movie, location),
		AvailabilityNotice: "Not available to watch in Memby yet",
		TrailerAvailable:   strings.TrimSpace(movie.YouTubeTrailerID) != "",
		Ratings:            []movieRating{},
	}
	// Only when it says something the heading does not, the rule the ordinary Details pane
	// already applies: a film whose original title is its title is the common case, and
	// printing it is a row that reads as a mistake.
	if original := strings.TrimSpace(movie.OriginalTitle); !strings.EqualFold(original, detail.Title) {
		detail.OriginalTitle = original
	}
	detail.StateLabel, detail.StateDetail = radarrMovieState(movie, release, hasRelease, now)
	return detail
}

// radarrMovieState is the status treatment at the top of the page: two or three words for
// what this film is doing, and a line saying what that means to somebody who wanted to
// watch it tonight.
func radarrMovieState(
	movie radarr.Movie, release radarrRelease, hasRelease bool, now time.Time,
) (string, string) {
	switch {
	case movie.HasFile:
		// Downloaded, and yet this page is what opened — so Emby has not scanned it in
		// yet. A matter of minutes rather than of months, and worth saying so.
		return "Almost Ready", "Downloaded — waiting for Memby's library to pick it up"
	case !movie.Monitored:
		return "Not Tracked", "This film is not being monitored, so no copy is being sought"
	case !hasRelease:
		// Deliberately not "Release date not yet announced" — that is what the page has
		// just printed as its headline, and the line under a state exists to add to it.
		return "Awaiting Release", "Nothing to download until a date is announced"
	case release.at.After(now):
		return "Coming Soon", "Not released yet"
	default:
		return "Not Yet Available", "Released — waiting for a copy to arrive"
	}
}

// radarrExpectedLabel is the one date the page leads with, and most of its job is refusing
// to be precise about a date nothing has published.
//
// Radarr's digital date is a published fact and is printed to the day. The cinema-plus-a-
// month estimate the schedule row falls back on is not, so it is printed to the month:
// "Expected November 2026" is true where "Expected 14 November 2026" is a number somebody
// would plan an evening around. Nothing known at all is said plainly rather than guessed.
func radarrExpectedLabel(
	release radarrRelease, hasRelease bool, now time.Time, location *time.Location,
) string {
	if !hasRelease {
		return "Release date not yet announced"
	}
	local := release.at.In(location)
	verb := "Expected "
	if !local.After(now.In(location)) {
		verb = "Released "
	}
	if release.estimated {
		return verb + local.Format("January 2006")
	}
	return verb + local.Format("2 January 2006")
}

// radarrReleaseDates lists what Radarr actually holds, so a viewer can see which of the
// three the headline came from. Only dates that exist appear; an absent one is absent
// rather than dashed.
func radarrReleaseDates(movie radarr.Movie, location *time.Location) []radarrReleaseDate {
	dates := []radarrReleaseDate{}
	add := func(kind, label string, value *time.Time) {
		if value == nil || value.IsZero() {
			return
		}
		dates = append(dates, radarrReleaseDate{
			Kind:  kind,
			Label: label,
			Value: value.In(location).Format("2 January 2006"),
		})
	}
	add("cinema", "In cinemas", movie.InCinemas)
	add("digital", "Digital release", movie.DigitalRelease)
	add("physical", "Physical release", movie.PhysicalRelease)
	return dates
}

// radarrTrailerManifest is the trailer chain for a film with no Emby record.
//
// It is the same manifest shape the ordinary path builds, so the television's existing
// trailer machinery — the availability check, the resolve call, the report, the player's
// candidate exclusion and its retry onto the next provider — works on a Radarr card with no
// second implementation anywhere. The one candidate is Radarr's own YouTube trailer id,
// which comes from TMDb's official trailer field and is ranked as an official source
// rather than as a spare.
func (s *Server) radarrTrailerManifest(ctx context.Context, itemID string, movieID int) (trailerManifest, error) {
	manifest := trailerManifest{SubjectID: itemID, Candidates: []trailerCandidate{}}
	if !s.radarrEnabled(ctx) {
		return manifest, nil
	}
	movie, err := s.radarrMovie(ctx, movieID)
	if err != nil {
		return trailerManifest{}, err
	}
	manifest.Title = strings.TrimSpace(movie.Title)
	trailerID := strings.TrimSpace(movie.YouTubeTrailerID)
	if trailerID == "" {
		return manifest, nil
	}
	source := "https://www.youtube.com/watch?v=" + trailerID
	manifest.Candidates = append(manifest.Candidates, trailerCandidate{
		ID:        trailerCandidateID("youtube", source),
		Provider:  "youtube",
		Name:      "Official Trailer",
		SourceURL: source,
		Priority:  remoteTrailerPriority("youtube", "Official Trailer"),
	})
	return manifest, nil
}