/**************************************************************************/
/*  test_audio_stream_wav.cpp                                             */
/**************************************************************************/
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
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#include "tests/test_macros.h"

TEST_FORCE_LINK(test_audio_stream_wav)

#include "core/io/file_access.h"
#include "core/io/marshalls.h"
#include "core/math/math_defs.h"
#include "core/math/math_funcs.h"
#include "scene/resources/audio_stream_wav.h"
#include "tests/test_utils.h"

namespace TestAudioStreamWAV {

// Default wav rate for test cases.
constexpr float WAV_RATE = 44100;
/* Default wav count for test cases. 1 second of audio is used so that the file can be listened
to manually if needed. */
constexpr int WAV_COUNT = WAV_RATE;

float gen_wav(float frequency, float wav_rate, int wav_number) {
	// formula for generating a sin wave with given frequency.
	return Math::sin((Math::TAU * frequency / wav_rate) * wav_number);
}

/* Generates a 440Hz sin wave in channel 0 (mono channel or left stereo channel)
 * and a 261.63Hz wave in channel 1 (right stereo channel).
 * These waves correspond to the music notes A4 and C4 respectively.
 */
Vector<uint8_t> gen_pcm8_test(float wav_rate, int wav_count, bool stereo) {
	Vector<uint8_t> buffer;
	buffer.resize(stereo ? wav_count * 2 : wav_count);

	uint8_t *write_ptr = buffer.ptrw();
	for (int i = 0; i < buffer.size(); i++) {
		float wav;
		if (stereo) {
			if (i % 2 == 0) {
				wav = gen_wav(440, wav_rate, i / 2);
			} else {
				wav = gen_wav(261.63, wav_rate, i / 2);
			}
		} else {
			wav = gen_wav(440, wav_rate, i);
		}

		// Map sin wave to full range of 8-bit values.
		uint8_t wav_8bit = Math::fast_ftoi(((wav + 1) / 2) * UINT8_MAX);
		// Unlike the .wav format, AudioStreamWAV expects signed 8-bit wavs.
		uint8_t wav_8bit_signed = wav_8bit - (INT8_MAX + 1);
		write_ptr[i] = wav_8bit_signed;
	}

	return buffer;
}

// Same as gen_pcm8_test but with 16-bit wavs.
Vector<uint8_t> gen_pcm16_test(float wav_rate, int wav_count, bool stereo) {
	Vector<uint8_t> buffer;
	buffer.resize(stereo ? wav_count * 4 : wav_count * 2);

	uint8_t *write_ptr = buffer.ptrw();
	for (int i = 0; i < buffer.size() / 2; i++) {
		float wav;
		if (stereo) {
			if (i % 2 == 0) {
				wav = gen_wav(440, wav_rate, i / 2);
			} else {
				wav = gen_wav(261.63, wav_rate, i / 2);
			}
		} else {
			wav = gen_wav(440, wav_rate, i);
		}

		// Map sin wave to full range of 16-bit values.
		uint16_t wav_16bit = Math::fast_ftoi(((wav + 1) / 2) * UINT16_MAX);
		// The .wav format expects wavs larger than 8 bits to be signed.
		uint16_t wav_16bit_signed = wav_16bit - (INT16_MAX + 1);
		encode_uint16(wav_16bit_signed, write_ptr + (i * 2));
	}

	return buffer;
}

void run_test(String file_name, AudioStreamWAV::Format data_format, bool stereo, float wav_rate, float wav_count) {
	String save_path = TestUtils::get_temp_path(file_name);

	Vector<uint8_t> test_data;
	if (data_format == AudioStreamWAV::FORMAT_8_BITS) {
		test_data = gen_pcm8_test(wav_rate, wav_count, stereo);
	} else {
		test_data = gen_pcm16_test(wav_rate, wav_count, stereo);
	}

	Ref<AudioStreamWAV> stream = memnew(AudioStreamWAV);
	stream->set_mix_rate(wav_rate);
	CHECK(stream->get_mix_rate() == wav_rate);

	stream->set_format(data_format);
	CHECK(stream->get_format() == data_format);

	stream->set_stereo(stereo);
	CHECK(stream->is_stereo() == stereo);

	stream->set_data(test_data);
	CHECK(stream->get_data() == test_data);

	SUBCASE("Stream length is computed properly") {
		CHECK(stream->get_length() == doctest::Approx(double(wav_count / wav_rate)));
	}

	SUBCASE("Stream can be saved as .wav") {
		REQUIRE(stream->save_to_wav(save_path) == OK);

		Error error;
		Ref<FileAccess> wav_file = FileAccess::open(save_path, FileAccess::READ, &error);
		REQUIRE(error == OK);

		Dictionary options;
		Ref<AudioStreamWAV> loaded_stream = AudioStreamWAV::load_from_file(save_path, options);

		CHECK(loaded_stream->get_format() == stream->get_format());
		CHECK(loaded_stream->get_loop_mode() == stream->get_loop_mode());
		CHECK(loaded_stream->get_loop_begin() == stream->get_loop_begin());
		CHECK(loaded_stream->get_loop_end() == stream->get_loop_end());
		CHECK(loaded_stream->get_mix_rate() == stream->get_mix_rate());
		CHECK(loaded_stream->is_stereo() == stream->is_stereo());
		CHECK(loaded_stream->get_length() == stream->get_length());
		CHECK(loaded_stream->is_monophonic() == stream->is_monophonic());
		CHECK(loaded_stream->get_data() == stream->get_data());
	}
}

TEST_CASE("[Audio][AudioStreamWAV] Mono PCM8 format") {
	run_test("test_pcm8_mono.wav", AudioStreamWAV::FORMAT_8_BITS, false, WAV_RATE, WAV_COUNT);
}

TEST_CASE("[Audio][AudioStreamWAV] Mono PCM16 format") {
	run_test("test_pcm16_mono.wav", AudioStreamWAV::FORMAT_16_BITS, false, WAV_RATE, WAV_COUNT);
}

TEST_CASE("[Audio][AudioStreamWAV] Stereo PCM8 format") {
	run_test("test_pcm8_stereo.wav", AudioStreamWAV::FORMAT_8_BITS, true, WAV_RATE, WAV_COUNT);
}

TEST_CASE("[Audio][AudioStreamWAV] Stereo PCM16 format") {
	run_test("test_pcm16_stereo.wav", AudioStreamWAV::FORMAT_16_BITS, true, WAV_RATE, WAV_COUNT);
}

TEST_CASE("[Audio][AudioStreamWAV] Alternate mix rate") {
	run_test("test_pcm16_stereo_38000Hz.wav", AudioStreamWAV::FORMAT_16_BITS, true, 38000, 38000);
}

TEST_CASE("[Audio][AudioStreamWAV] save_to_wav() adds '.wav' file extension automatically") {
	String save_path = TestUtils::get_temp_path("test_wav_extension");
	Vector<uint8_t> test_data = gen_pcm8_test(WAV_RATE, WAV_COUNT, false);
	Ref<AudioStreamWAV> stream = memnew(AudioStreamWAV);
	stream->set_data(test_data);

	REQUIRE(stream->save_to_wav(save_path) == OK);
	Error error;
	Ref<FileAccess> wav_file = FileAccess::open(save_path + ".wav", FileAccess::READ, &error);
	CHECK(error == OK);
}

TEST_CASE("[Audio][AudioStreamWAV] Default values") {
	Ref<AudioStreamWAV> stream = memnew(AudioStreamWAV);
	CHECK(stream->get_format() == AudioStreamWAV::FORMAT_8_BITS);
	CHECK(stream->get_loop_mode() == AudioStreamWAV::LOOP_DISABLED);
	CHECK(stream->get_loop_begin() == 0);
	CHECK(stream->get_loop_end() == 0);
	CHECK(stream->get_mix_rate() == 44100);
	CHECK(stream->is_stereo() == false);
	CHECK(stream->get_length() == 0);
	CHECK(stream->is_monophonic() == false);
	CHECK(stream->get_data() == Vector<uint8_t>{});
	CHECK(stream->get_stream_name() == "");
}

TEST_CASE("[Audio][AudioStreamWAV] Save empty file") {
	run_test("test_empty.wav", AudioStreamWAV::FORMAT_8_BITS, false, WAV_RATE, 0);
}

TEST_CASE("[Audio][AudioStreamWAV] Saving IMA ADPCM is not supported") {
	String save_path = TestUtils::get_temp_path("test_adpcm.wav");
	Ref<AudioStreamWAV> stream = memnew(AudioStreamWAV);
	stream->set_format(AudioStreamWAV::FORMAT_IMA_ADPCM);
	ERR_PRINT_OFF;
	CHECK(stream->save_to_wav(save_path) == ERR_UNAVAILABLE);
	ERR_PRINT_ON;
}

} // namespace TestAudioStreamWAV
