/**
 * Audio Router - Verwaltet Audio-Quellen und -Routing
 *
 * USB hat Priorität über Bluetooth
 * Automatischer Wechsel bei Verbindungsänderungen
 */

#include <string.h>
#include "audio_router.h"
#include "bluetooth/bt_manager.h"
#include "usb_audio/usb_audio_host.h"
#include "esp_log.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"

static const char* TAG = "AUDIO_RT";

// State
static bool s_initialized = false;
static audio_source_t s_active_source = AUDIO_SOURCE_NONE;
static bool s_call_active = false;
static uint8_t s_volume = 80;
static bool s_muted = false;
static audio_stats_t s_stats;
static SemaphoreHandle_t s_mutex = NULL;

// Callbacks
static audio_from_headset_callback_t s_input_callback = NULL;
static headset_button_callback_t s_button_callback = NULL;
static audio_source_change_callback_t s_source_change_callback = NULL;

// Forward Declarations
static void update_active_source(void);
static void bt_audio_data_handler(const uint8_t* data, size_t len);
static void bt_button_handler(bt_button_event_t event);
static void usb_audio_data_handler(const uint8_t* data, size_t len);
static void usb_button_handler(usb_button_event_t event);
static void usb_state_handler(usb_audio_state_t state);

// Callback von Bluetooth Manager
static void bt_audio_data_handler(const uint8_t* data, size_t len)
{
    if (s_active_source != AUDIO_SOURCE_BLUETOOTH || !s_call_active) {
        return;
    }

    s_stats.packets_received++;

    // An SIP weiterleiten
    if (s_input_callback) {
        audio_format_t format = {
            .sample_rate = 8000,  // HFP Standard
            .channels = 1,
            .bits_per_sample = 16
        };
        s_input_callback(data, len, &format);
    }
}

static void bt_button_handler(bt_button_event_t event)
{
    headset_button_t button;

    switch (event) {
        case BT_BUTTON_ANSWER:
            button = HEADSET_BUTTON_ANSWER;
            break;
        case BT_BUTTON_REJECT:
            button = HEADSET_BUTTON_REJECT;
            break;
        case BT_BUTTON_HANGUP:
            button = HEADSET_BUTTON_HANGUP;
            break;
        case BT_BUTTON_VOLUME_UP:
            button = HEADSET_BUTTON_VOLUME_UP;
            break;
        case BT_BUTTON_VOLUME_DOWN:
            button = HEADSET_BUTTON_VOLUME_DOWN;
            break;
        case BT_BUTTON_MUTE:
            button = HEADSET_BUTTON_MUTE;
            break;
        default:
            return;
    }

    if (s_button_callback) {
        s_button_callback(button, AUDIO_SOURCE_BLUETOOTH);
    }
}

// Callback von USB Audio
static void usb_audio_data_handler(const uint8_t* data, size_t len)
{
    if (s_active_source != AUDIO_SOURCE_USB || !s_call_active) {
        return;
    }

    s_stats.packets_received++;

    // An SIP weiterleiten
    if (s_input_callback) {
        audio_format_t format = {
            .sample_rate = 16000,  // USB typisch
            .channels = 1,
            .bits_per_sample = 16
        };
        s_input_callback(data, len, &format);
    }
}

static void usb_button_handler(usb_button_event_t event)
{
    headset_button_t button;

    switch (event) {
        case USB_BUTTON_ANSWER:
            button = HEADSET_BUTTON_ANSWER;
            break;
        case USB_BUTTON_HANGUP:
            button = HEADSET_BUTTON_HANGUP;
            break;
        case USB_BUTTON_MUTE:
            button = HEADSET_BUTTON_MUTE;
            break;
        case USB_BUTTON_VOLUME_UP:
            button = HEADSET_BUTTON_VOLUME_UP;
            break;
        case USB_BUTTON_VOLUME_DOWN:
            button = HEADSET_BUTTON_VOLUME_DOWN;
            break;
        default:
            return;
    }

    if (s_button_callback) {
        s_button_callback(button, AUDIO_SOURCE_USB);
    }
}

static void usb_state_handler(usb_audio_state_t state)
{
    ESP_LOGI(TAG, "USB Audio State: %d", state);

    // Bei USB Verbindungsänderung Quelle neu evaluieren
    update_active_source();
}

static void update_active_source(void)
{
    audio_source_t new_source = AUDIO_SOURCE_NONE;

    xSemaphoreTake(s_mutex, portMAX_DELAY);

    // USB hat höchste Priorität
    if (usb_audio_host_is_connected()) {
        new_source = AUDIO_SOURCE_USB;
    }
    // Bluetooth als Fallback
    else if (bt_manager_is_connected()) {
        new_source = AUDIO_SOURCE_BLUETOOTH;
    }

    if (new_source != s_active_source) {
        audio_source_t old_source = s_active_source;
        s_active_source = new_source;

        const char* sources[] = {"Keine", "USB", "Bluetooth"};
        ESP_LOGI(TAG, "Audio-Quelle: %s -> %s", sources[old_source], sources[new_source]);

        // Bei aktivem Anruf: Streaming anpassen
        if (s_call_active) {
            // Altes Audio stoppen
            if (old_source == AUDIO_SOURCE_USB) {
                usb_audio_host_stop_stream();
            }
            // Neues Audio starten
            if (new_source == AUDIO_SOURCE_USB) {
                usb_audio_host_start_stream();
            }
        }

        xSemaphoreGive(s_mutex);

        // Callback aufrufen
        if (s_source_change_callback) {
            s_source_change_callback(old_source, new_source);
        }
    } else {
        xSemaphoreGive(s_mutex);
    }
}

esp_err_t audio_router_init(void)
{
    if (s_initialized) {
        return ESP_OK;
    }

    ESP_LOGI(TAG, "Initialisiere Audio Router");

    s_mutex = xSemaphoreCreateMutex();
    if (!s_mutex) {
        ESP_LOGE(TAG, "Mutex erstellen fehlgeschlagen");
        return ESP_ERR_NO_MEM;
    }

    // Callbacks bei Audio-Quellen registrieren
    bt_manager_register_audio_data_callback(bt_audio_data_handler);
    bt_manager_register_button_callback(bt_button_handler);

    usb_audio_host_register_data_callback(usb_audio_data_handler);
    usb_audio_host_register_button_callback(usb_button_handler);
    usb_audio_host_register_state_callback(usb_state_handler);

    memset(&s_stats, 0, sizeof(s_stats));

    s_initialized = true;

    // Initial die Quelle bestimmen
    update_active_source();

    ESP_LOGI(TAG, "Audio Router initialisiert");
    return ESP_OK;
}

esp_err_t audio_router_deinit(void)
{
    if (!s_initialized) return ESP_OK;

    ESP_LOGI(TAG, "Deinitalisiere Audio Router");

    if (s_call_active) {
        audio_router_stop_call();
    }

    if (s_mutex) {
        vSemaphoreDelete(s_mutex);
        s_mutex = NULL;
    }

    s_initialized = false;
    return ESP_OK;
}

audio_source_t audio_router_get_active_source(void)
{
    return s_active_source;
}

bool audio_router_is_source_available(audio_source_t source)
{
    switch (source) {
        case AUDIO_SOURCE_USB:
            return usb_audio_host_is_connected();
        case AUDIO_SOURCE_BLUETOOTH:
            return bt_manager_is_connected();
        default:
            return false;
    }
}

esp_err_t audio_router_start_call(void)
{
    if (s_call_active) {
        return ESP_OK;
    }

    ESP_LOGI(TAG, "Starte Audio für Anruf");

    xSemaphoreTake(s_mutex, portMAX_DELAY);

    s_call_active = true;
    memset(&s_stats, 0, sizeof(s_stats));

    // Audio-Streaming auf aktiver Quelle starten
    if (s_active_source == AUDIO_SOURCE_USB) {
        usb_audio_host_start_stream();
    } else if (s_active_source == AUDIO_SOURCE_BLUETOOTH) {
        // BT Audio wird automatisch über HFP gestartet
        // bt_hfp_audio_connect() wird vom SIP-Client aufgerufen
    }

    xSemaphoreGive(s_mutex);

    return ESP_OK;
}

esp_err_t audio_router_stop_call(void)
{
    if (!s_call_active) {
        return ESP_OK;
    }

    ESP_LOGI(TAG, "Stoppe Audio für Anruf");

    xSemaphoreTake(s_mutex, portMAX_DELAY);

    s_call_active = false;

    // Audio-Streaming stoppen
    if (s_active_source == AUDIO_SOURCE_USB) {
        usb_audio_host_stop_stream();
    }

    xSemaphoreGive(s_mutex);

    return ESP_OK;
}

esp_err_t audio_router_send_to_headset(const uint8_t* data, size_t len, const audio_format_t* format)
{
    if (!s_call_active || s_active_source == AUDIO_SOURCE_NONE) {
        return ESP_ERR_INVALID_STATE;
    }

    if (s_muted) {
        return ESP_OK;  // Muted - nichts senden
    }

    s_stats.packets_sent++;

    // TODO: Lautstärke anwenden
    // TODO: Format-Konvertierung wenn nötig

    esp_err_t ret = ESP_OK;

    if (s_active_source == AUDIO_SOURCE_USB) {
        ret = usb_audio_host_send(data, len);
    } else if (s_active_source == AUDIO_SOURCE_BLUETOOTH) {
        ret = bt_manager_send_audio(data, len);
    }

    if (ret != ESP_OK) {
        s_stats.underruns++;
    }

    return ret;
}

void audio_router_register_input_callback(audio_from_headset_callback_t callback)
{
    s_input_callback = callback;
}

void audio_router_register_button_callback(headset_button_callback_t callback)
{
    s_button_callback = callback;
}

void audio_router_register_source_change_callback(audio_source_change_callback_t callback)
{
    s_source_change_callback = callback;
}

esp_err_t audio_router_set_volume(uint8_t volume)
{
    if (volume > 100) volume = 100;
    s_volume = volume;

    ESP_LOGI(TAG, "Lautstärke: %d%%", volume);

    // Lautstärke an aktive Quelle weitergeben
    if (s_active_source == AUDIO_SOURCE_USB) {
        usb_audio_host_set_volume(volume);
    }
    // BT: Volume wird über HFP AG gehandhabt

    return ESP_OK;
}

uint8_t audio_router_get_volume(void)
{
    return s_volume;
}

esp_err_t audio_router_set_mute(bool mute)
{
    s_muted = mute;

    ESP_LOGI(TAG, "Mute: %s", mute ? "an" : "aus");

    if (s_active_source == AUDIO_SOURCE_USB) {
        usb_audio_host_set_mute(mute);
    }

    return ESP_OK;
}

bool audio_router_is_muted(void)
{
    return s_muted;
}

esp_err_t audio_router_get_stats(audio_stats_t* stats)
{
    if (!stats) return ESP_ERR_INVALID_ARG;
    memcpy(stats, &s_stats, sizeof(audio_stats_t));
    return ESP_OK;
}