"""Tests for domain/audio_buffer.py — fit_audio_to_duration, ffmpeg_time_stretch."""

import numpy as np
import pytest

from abogen.domain.audio_buffer import fit_audio_to_duration, ffmpeg_time_stretch, SAMPLE_RATE


class TestFitAudioToDuration:
    def test_exact_length(self):
        audio = np.ones(24000, dtype="float32")
        result = fit_audio_to_duration(audio, 1.0, SAMPLE_RATE)
        assert len(result) == 24000

    def test_shorter_pads_with_zeros(self):
        audio = np.ones(12000, dtype="float32")
        result = fit_audio_to_duration(audio, 1.0, SAMPLE_RATE)
        assert len(result) == 24000
        assert result[0] == 1.0
        assert result[12000] == 0.0

    def test_longer_trims(self):
        audio = np.ones(48000, dtype="float32")
        result = fit_audio_to_duration(audio, 1.0, SAMPLE_RATE)
        assert len(result) == 24000
        assert result[-1] == 1.0

    def test_empty_input(self):
        result = fit_audio_to_duration(np.array([], dtype="float32"), 0.5, SAMPLE_RATE)
        assert len(result) == 12000
        assert np.all(result == 0.0)

    def test_output_dtype(self):
        audio = np.ones(100, dtype="float32")
        result = fit_audio_to_duration(audio, 0.5, SAMPLE_RATE)
        assert result.dtype == np.float32


class TestFfmpegTimeStretch:
    def test_no_stretch_below_threshold(self):
        audio = np.ones(24000, dtype="float32")
        result = ffmpeg_time_stretch(audio, 0.8, SAMPLE_RATE)
        np.testing.assert_array_equal(result, audio)

    def test_no_stretch_at_exactly_one(self):
        audio = np.ones(24000, dtype="float32")
        result = ffmpeg_time_stretch(audio, 1.0, SAMPLE_RATE)
        np.testing.assert_array_equal(result, audio)

    def test_empty_audio(self):
        result = ffmpeg_time_stretch(np.array([], dtype="float32"), 2.0, SAMPLE_RATE)
        assert len(result) == 0

    def test_stretch_reduces_duration(self):
        audio = np.random.randn(48000).astype("float32")
        result = ffmpeg_time_stretch(audio, 2.0, SAMPLE_RATE)
        assert len(result) < len(audio)
        assert len(result) > 0
        assert result.dtype == np.float32