#include "audio_out.h"

#include <stdlib.h>

#include "esp_ae_rate_cvt.h"
#include "esp_heap_caps.h"
#include "esp_log.h"

#define OUT_RATE        48000
#define CONV_FRAMES     4096            // per rate converter call

static const char *TAG = "audio_out";

struct audio_conv {
    player_src_t src;
    const char *name;
    esp_ae_rate_cvt_handle_t cvt;       // NULL: no conversion (source is 48 kHz)
    uint32_t rate;                      // input rate the converter was opened for
    int32_t *in32, *out32;              // stereo int32 work buffers (PSRAM)
};

audio_conv_t *audio_conv_create(player_src_t src, const char *name)
{
    audio_conv_t *c = calloc(1, sizeof(*c));
    if (!c) {
        return NULL;
    }
    c->src = src;
    c->name = name;
    c->in32 = heap_caps_malloc(CONV_FRAMES * 2 * sizeof(int32_t), MALLOC_CAP_SPIRAM);
    c->out32 = heap_caps_malloc(CONV_FRAMES * 2 * 2 * sizeof(int32_t), MALLOC_CAP_SPIRAM);
    if (!c->in32 || !c->out32) {
        free(c->in32);
        free(c->out32);
        free(c);
        return NULL;
    }
    return c;
}

static void set_rate(audio_conv_t *c, uint32_t rate)
{
    if (c->cvt) {
        esp_ae_rate_cvt_close(c->cvt);
        c->cvt = NULL;
    }
    c->rate = rate;
    if (rate == OUT_RATE) {
        return;
    }
    esp_ae_rate_cvt_cfg_t cfg = {
        .src_rate = rate, .dest_rate = OUT_RATE, .channel = 2, .bits_per_sample = 32,
        .complexity = 3, .perf_type = ESP_AE_RATE_CVT_PERF_TYPE_SPEED,
    };
    if (esp_ae_rate_cvt_open(&cfg, &c->cvt) != ESP_AE_ERR_OK) {
        ESP_LOGE(TAG, "%s: rate converter %lu -> %d Hz: open failed", c->name, (unsigned long)rate, OUT_RATE);
    } else {
        ESP_LOGI(TAG, "%s: rate converter %lu -> %d Hz", c->name, (unsigned long)rate, OUT_RATE);
    }
}

size_t audio_conv_write(audio_conv_t *c, const int16_t *pcm, uint32_t frames, int ch, uint32_t rate)
{
    if (rate != c->rate) {
        set_rate(c, rate);
    }
    size_t produced = 0;
    while (frames) {
        uint32_t n = frames < CONV_FRAMES ? frames : CONV_FRAMES;
        for (uint32_t i = 0; i < n; i++) {      // to stereo int32 (full scale = INT32_MAX)
            int32_t l = (int32_t)pcm[i * ch] << 16;
            c->in32[i * 2] = l;
            c->in32[i * 2 + 1] = ch > 1 ? (int32_t)pcm[i * ch + 1] << 16 : l;
        }
        const int32_t *out = c->in32;
        uint32_t out_n = n;
        if (c->cvt) {
            out_n = CONV_FRAMES * 2;
            if (esp_ae_rate_cvt_process(c->cvt, c->in32, n, c->out32, &out_n) != ESP_AE_ERR_OK) {
                ESP_LOGW(TAG, "%s: rate conversion failed", c->name);
                return produced;
            }
            out = c->out32;
        }
        produced += player_write(c->src, out, out_n);
        pcm += n * ch;
        frames -= n;
    }
    return produced;
}