package api

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

	"git.fabledsword.com/bvandeusen/minstrel/internal/apierror"
)

const (
	castTokenMinExpSeconds = 60
	castTokenMaxExpSeconds = 86400 // 24h
	castTokenDefaultExp    = 21600 // 6h
)

type castTokenRequest struct {
	TrackID    string `json:"trackId"`
	ExpSeconds int    `json:"expSeconds,omitempty"`
}

type castTokenResponse struct {
	Token string `json:"token"`
	Exp   int64  `json:"exp"`
	URL   string `json:"url"`
}

// handleCastStreamToken issues a short-lived HMAC stream token for the
// given trackId. Authenticated via the standard session cookie / bearer.
//
// The returned URL is a fully-formed stream URL (token + exp embedded
// as query params) that the client passes verbatim to a UPnP / Sonos
// device's AVTransport.SetAVTransportURI call — those devices cannot
// carry the user's session, so the signed query string is the only way
// they can fetch the bytes.
//
// expSeconds is clamped to [60, 86400]; default 21600 (6h) — long enough
// to play through any typical track without re-minting mid-playback.
//
// Part of the output-picker UPnP slice. See
// docs/superpowers/specs/2026-06-03-android-output-picker-upnp-design.md.
func (h *handlers) handleCastStreamToken(w http.ResponseWriter, r *http.Request) {
	if _, ok := requireUser(w, r); !ok {
		return
	}
	var req castTokenRequest
	if !decodeBody(w, r, &req) {
		return
	}
	trackUUID, ok := parseUUID(req.TrackID)
	if !ok || !trackUUID.Valid {
		writeErr(w, apierror.BadRequest("invalid_track_id", "trackId must be a UUID"))
		return
	}
	expSec := clampExpSeconds(req.ExpSeconds)
	exp := time.Now().Add(time.Duration(expSec) * time.Second).Unix()
	token := SignStreamToken(h.streamSecret, req.TrackID, exp)

	scheme := "http"
	if r.TLS != nil {
		scheme = "https"
	}
	url := scheme + "://" + r.Host + "/api/tracks/" + req.TrackID +
		"/stream?token=" + token + "&exp=" + strconv.FormatInt(exp, 10)

	writeJSON(w, http.StatusOK, castTokenResponse{Token: token, Exp: exp, URL: url})
}

// clampExpSeconds applies the [60, 86400] window with a 6h default for
// non-positive inputs. Extracted so it doesn't bloat the handler's
// detekt-equivalent line count and so the test can exercise edges directly.
func clampExpSeconds(v int) int {
	if v <= 0 {
		return castTokenDefaultExp
	}
	if v < castTokenMinExpSeconds {
		return castTokenMinExpSeconds
	}
	if v > castTokenMaxExpSeconds {
		return castTokenMaxExpSeconds
	}
	return v
}