// ============================================================================
// audio_demo.c - XAudio2 音频系统演示
// 生成 440Hz 正弦波并播放 2 秒，无需外部 WAV 文件
// ============================================================================

#include "../Engine/Audio/audio.h"
#include "../Engine/Core/logger.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <windows.h>

#pragma comment(lib, "winmm.lib")

// 生成标准 PCM WAV 数据 (44.1kHz, 16bit, 单声道)
static uint8_t* generate_sine_wave_wav(float frequency, float duration_sec, uint32_t* out_size) {
    const uint32_t sample_rate = 44100;
    const uint16_t channels = 1;
    const uint16_t bits_per_sample = 16;
    const uint16_t block_align = channels * bits_per_sample / 8;
    const uint32_t byte_rate = sample_rate * block_align;
    const uint32_t num_samples = (uint32_t)(sample_rate * duration_sec);
    const uint32_t data_size = num_samples * block_align;
    const uint32_t file_size = 44 + data_size;

    uint8_t* wav = (uint8_t*)malloc(file_size);
    if (!wav) return NULL;

    // RIFF 头
    memcpy(wav + 0, "RIFF", 4);
    memcpy(wav + 4, &file_size, 4);
    memcpy(wav + 8, "WAVE", 4);

    // fmt chunk
    memcpy(wav + 12, "fmt ", 4);
    uint32_t fmt_size = 16;
    memcpy(wav + 16, &fmt_size, 4);
    uint16_t audio_format = 1; // PCM
    memcpy(wav + 20, &audio_format, 2);
    memcpy(wav + 22, &channels, 2);
    memcpy(wav + 24, &sample_rate, 4);
    memcpy(wav + 28, &byte_rate, 4);
    memcpy(wav + 32, &block_align, 2);
    memcpy(wav + 34, &bits_per_sample, 2);

    // data chunk
    memcpy(wav + 36, "data", 4);
    memcpy(wav + 40, &data_size, 4);

    // 生成正弦波样本
    int16_t* samples = (int16_t*)(wav + 44);
    float amplitude = 0.3f; // 避免削波
    for (uint32_t i = 0; i < num_samples; i++) {
        float t = (float)i / (float)sample_rate;
        // 简单淡出，避免咔嗒声
        float envelope = 1.0f;
        if (i < 1000) envelope = (float)i / 1000.0f;
        if (i > num_samples - 1000) envelope = (float)(num_samples - i) / 1000.0f;
        float sample = sinf(2.0f * 3.14159265f * frequency * t) * amplitude * envelope;
        samples[i] = (int16_t)(sample * 32767.0f);
    }

    *out_size = file_size;
    return wav;
}

int main(int argc, char* argv[]) {
    (void)argc; (void)argv;

    printf("Lity3D - Audio Demo\n");
    printf("========================\n");

    AudioSystem* audio = audio_create();
    if (!audio) {
        printf("ERROR: Failed to create XAudio2 audio system\n");
        return 1;
    }
    printf("XAudio2 audio system created.\n");

    AudioSource* source = audio_source_create(audio);
    if (!source) {
        printf("ERROR: Failed to create audio source\n");
        audio_destroy(audio);
        return 1;
    }

    uint32_t wav_size = 0;
    uint8_t* wav_data = generate_sine_wave_wav(440.0f, 2.0f, &wav_size);
    if (!wav_data) {
        printf("ERROR: Failed to generate sine wave\n");
        audio_source_destroy(source);
        audio_destroy(audio);
        return 1;
    }

    if (!audio_load_wav_memory(source, wav_data, wav_size)) {
        printf("ERROR: Failed to load generated WAV into audio source\n");
        free(wav_data);
        audio_source_destroy(source);
        audio_destroy(audio);
        return 1;
    }
    free(wav_data);
    printf("Generated 440Hz sine wave loaded.\n");

    printf("Playing 2 seconds...\n");
    audio_source_play(source);

    // 等待播放结束 (约 2 秒 + 缓冲)
    Sleep(2500);

    audio_source_destroy(source);
    audio_destroy(audio);

    printf("Audio demo finished successfully.\n");
    return 0;
}