package services

import (
	"testing"
)

// TestAudioPayloadIsEmpty pins the write-after-success guard on
// updateAudioBookItem (2026-10-21 incident: multi-file audiobooks
// surfaced as 1 second long because a failed re-extraction overwrote a
// populated audio_metadata). An empty payload — nil, or no tracks, no
// chapters, no duration — is the signature of a failed extraction and
// must never replace existing audio data.
func TestAudioPayloadIsEmpty(t *testing.T) {
	require := func(cond bool, msg string) {
		if !cond {
			t.Fatal(msg)
		}
	}

	require(audioPayloadIsEmpty(nil), "nil payload must read as empty")
	require(audioPayloadIsEmpty(&AudioMetadataPayload{}), "zero-value payload must read as empty")
	require(audioPayloadIsEmpty(&AudioMetadataPayload{DurationSeconds: 0}), "zero-duration payload must read as empty")

	// A real book always carries at least one of the audio facts.
	require(!audioPayloadIsEmpty(&AudioMetadataPayload{DurationSeconds: 302.6}),
		"duration-only payload (single-track book) is not empty")
	require(!audioPayloadIsEmpty(&AudioMetadataPayload{
		Tracks: []AudioTrack{{Index: 0, Path: "01.mp3"}},
	}), "track manifest is not empty")
	require(!audioPayloadIsEmpty(&AudioMetadataPayload{
		Chapters: []AudioChapter{{Index: 0, Title: "Chapter 1"}},
	}), "chapters are not empty")
}