package api

import (
	"errors"
	"net/http"
	"strings"

	"github.com/jackc/pgx/v5"

	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
)

// RadioResponse is the body of GET /api/radio.
type RadioResponse struct {
	Tracks []TrackRef `json:"tracks"`
}

// handleRadio implements GET /api/radio?seed_track=<uuid>.
//
// M6 stub: returns a queue containing only the seed track. The full M4
// implementation (similarity-based candidate pool + scoring) replaces the
// body without changing the request/response shape.
func (h *handlers) handleRadio(w http.ResponseWriter, r *http.Request) {
	raw := strings.TrimSpace(r.URL.Query().Get("seed_track"))
	if raw == "" {
		writeErr(w, http.StatusBadRequest, "bad_request", "seed_track is required")
		return
	}
	id, ok := parseUUID(raw)
	if !ok {
		writeErr(w, http.StatusBadRequest, "bad_request", "invalid seed_track id")
		return
	}
	q := dbq.New(h.pool)
	track, err := q.GetTrackByID(r.Context(), id)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			writeErr(w, http.StatusNotFound, "not_found", "seed_track not found")
			return
		}
		h.logger.Error("api: get radio seed track failed", "err", err)
		writeErr(w, http.StatusInternalServerError, "server_error", "lookup failed")
		return
	}
	album, err := q.GetAlbumByID(r.Context(), track.AlbumID)
	if err != nil {
		h.logger.Error("api: get radio seed album failed", "err", err)
		writeErr(w, http.StatusInternalServerError, "server_error", "lookup failed")
		return
	}
	artist, err := q.GetArtistByID(r.Context(), track.ArtistID)
	if err != nil {
		h.logger.Error("api: get radio seed artist failed", "err", err)
		writeErr(w, http.StatusInternalServerError, "server_error", "lookup failed")
		return
	}
	writeJSON(w, http.StatusOK, RadioResponse{
		Tracks: []TrackRef{trackRefFrom(track, album.Title, artist.Name)},
	})
}