#include "sound.h"

#include "pico/stdlib.h"
#include "hardware/pwm.h"
#include "hardware/dma.h"
#include "hardware/irq.h"
#include "hardware/clocks.h"
#include "alarm_sound.h"
#include "pins.h"

#define SAMPLE_RATE 22050   // 22.05kHz
#define PWM_WRAP 255        // 8-bit resolution
volatile float volume_multiplier = 4.0f; // todo load from flash

static uint32_t audio_pos = 0;
static bool audio_playing = false;

// Timer callback for audio playback
bool audio_timer_callback(repeating_timer_t *rt) {
    if (!audio_playing || audio_pos >= alarm_sound_wav_len) {
        audio_playing = false;
        return false; // Stop timer
    }

    // Get the original audio sample
    uint8_t sample = alarm_sound_wav[audio_pos++];

    // Apply volume amplification
    // Convert to float, center around 0, apply multiplier, then center back around 128
    float amplified = ((float)sample - 128.0f) * volume_multiplier + 128.0f;

    // Clamp the result to valid 8-bit range (0-255)
    if (amplified < 0.0f) amplified = 0.0f;
    else if (amplified > 255.0f) amplified = 255.0f;

    // Set PWM duty cycle with amplified sample
    pwm_set_gpio_level(SPEAKER_PIN, (uint8_t)amplified);

    return true; // Continue timer
}

void setup_pwm_audio() {
    // Set up PWM for audio output
    gpio_set_function(SPEAKER_PIN, GPIO_FUNC_PWM);
    uint slice_num = pwm_gpio_to_slice_num(SPEAKER_PIN);

    // Configure PWM for 8-bit resolution
    pwm_config config = pwm_get_default_config();

    // Calculate clock divider for desired PWM frequency
    // PWM frequency should be much higher than audio sample rate
    // Target: ~250kHz PWM frequency for good audio quality
    float clock_div = (float)clock_get_hz(clk_sys) / (PWM_WRAP + 1) / 250000.0f;
    pwm_config_set_clkdiv(&config, clock_div);
    pwm_config_set_wrap(&config, PWM_WRAP);

    pwm_init(slice_num, &config, true);
    pwm_set_gpio_level(SPEAKER_PIN, 128); // Set to middle level (silence)
}

void play_audio() {
    audio_pos = 0;
    audio_playing = true;

    // Set up timer for sample rate (22.05kHz)
    static repeating_timer_t timer;
    int32_t delay_us = -1000000 / SAMPLE_RATE; // Negative for precise timing
    add_repeating_timer_us(delay_us, audio_timer_callback, NULL, &timer);
}

void stop_audio() {
    audio_playing = false;
    pwm_set_gpio_level(SPEAKER_PIN, 128); // Return to silence level
}