package jellyfin

import (
	"errors"
	"net/http"
	"os"
	"path"
	"path/filepath"
	"strings"

	"github.com/mithral/vellum/internal/auth"
	"github.com/mithral/vellum/internal/catalog"
	"github.com/mithral/vellum/internal/httpx"
	"github.com/mithral/vellum/internal/stream"
)

// handlePlaybackInfo answers GET /Items/{itemId}/PlaybackInfo.
//
// The response always describes the one thing Vellum can do — direct play — and
// reports SupportsTranscoding=false. If the client has disabled both direct
// play and direct stream it is asking for a transcode; that is refused with
// ErrorCode "NoCompatibleStream" and a warning, rather than by handing back a
// TranscodingUrl that would not exist.
func (h *Handlers) handlePlaybackInfo(w http.ResponseWriter, r *http.Request, u auth.User) {
	id, isLib, ok := decodeID(r.PathValue("itemId"))
	if !ok || isLib {
		httpx.WriteError(w, http.StatusNotFound, "item not found")
		return
	}
	it, ok := h.authorizedItem(w, r, u, id)
	if !ok {
		return
	}
	f, err := h.firstFile(r.Context(), id)
	if err != nil {
		h.fail(w, "load file facts", err)
		return
	}

	q := r.URL.Query()
	directPlay := queryBoolDefault(q.Get("EnableDirectPlay"), true)
	directStream := queryBoolDefault(q.Get("EnableDirectStream"), true)

	src := buildMediaSource(it, f, tokenFromRequest(r))
	resp := PlaybackInfoResponse{MediaSources: []MediaSourceInfo{src}}
	if !directPlay && !directStream {
		resp.ErrorCode = "NoCompatibleStream"
		h.log.Warn("jellyfin client requires transcoding; refusing",
			"item", it.ID, "kind", it.Kind)
	}
	httpx.WriteJSON(w, http.StatusOK, resp)
}

// handleVideoStream serves a video item's file.
func (h *Handlers) handleVideoStream(w http.ResponseWriter, r *http.Request, u auth.User) {
	h.serveStream(w, r, u)
}

// handleAudioStream serves an audio (or other non-video) item's file. Jellyfin
// clients fetch audiobook and music tracks here.
func (h *Handlers) handleAudioStream(w http.ResponseWriter, r *http.Request, u auth.User) {
	h.serveStream(w, r, u)
}

// serveStream streams the item's first file through internal/stream, so Range
// requests (seeking) work exactly as they do for the web app. Auth already came
// from tokenFromRequest, which includes the ?api_key= form that <video>/<audio>
// elements require.
func (h *Handlers) serveStream(w http.ResponseWriter, r *http.Request, u auth.User) {
	// Accept /stream and /stream.<ext> (stream.mp4, stream.mkv, ...). The
	// subtree pattern also catches other suffixes; refuse those.
	last := path.Base(strings.TrimSuffix(r.URL.Path, "/"))
	if last != "stream" && !strings.HasPrefix(last, "stream.") {
		httpx.WriteError(w, http.StatusNotFound, "not found")
		return
	}

	id, isLib, ok := decodeID(r.PathValue("itemId"))
	if !ok || isLib {
		httpx.WriteError(w, http.StatusNotFound, "item not found")
		return
	}
	it, ok := h.authorizedItem(w, r, u, id)
	if !ok {
		return
	}

	f, err := catalog.FirstFile(r.Context(), h.db, id)
	if errors.Is(err, catalog.ErrNotFound) {
		httpx.WriteError(w, http.StatusNotFound, "item has no file")
		return
	}
	if err != nil {
		h.fail(w, "load file", err)
		return
	}

	w.Header().Set("Content-Disposition", "inline")
	abs := filepath.Join(it.RootPath, filepath.FromSlash(f.Path))
	if err := stream.ServeFile(w, r, abs); err != nil {
		if errors.Is(err, os.ErrNotExist) {
			httpx.WriteError(w, http.StatusNotFound, "file is not available")
			return
		}
		if errors.Is(err, stream.ErrNotAFile) {
			httpx.WriteError(w, http.StatusBadRequest, "item is not a file")
			return
		}
		h.fail(w, "serve file", err)
		return
	}
}

// queryBoolDefault parses a Jellyfin boolean query parameter, returning def
// when it is absent or unparseable.
func queryBoolDefault(v string, def bool) bool {
	switch strings.ToLower(strings.TrimSpace(v)) {
	case "":
		return def
	case "1", "true", "yes":
		return true
	case "0", "false", "no":
		return false
	}
	return def
}