/* eth2ap (Ethernet to Wi-Fi AP packet forwarding) 

   This code is in the Public Domain (or CC0 licensed, at your option.)


*/
#include <string.h>
#include <stdlib.h>
#include "sdkconfig.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_eth.h"
#include "esp_wifi.h"
#include "nvs_flash.h"
#include "esp_private/wifi.h"
#include "driver/gpio.h"
#if CONFIG_ETH_USE_SPI_ETHERNET
#include "driver/spi_master.h"
#endif

static const char *TAG = "eth_example";
static esp_eth_handle_t s_eth_handle = NULL;
static xQueueHandle flow_control_queue = NULL;
static bool s_sta_is_connected = false;
static bool s_ethernet_is_connected = false;
static uint8_t s_eth_mac[6];

#define FLOW_CONTROL_QUEUE_TIMEOUT_MS (100)
#define FLOW_CONTROL_QUEUE_LENGTH (40)
#define FLOW_CONTROL_WIFI_SEND_TIMEOUT_MS (100)

typedef struct {
    void *packet;
    uint16_t length;
} flow_control_msg_t;

// Forward packets from Wi-Fi to Ethernet
static esp_err_t pkt_wifi2eth(void *buffer, uint16_t len, void *eb)
{
    if (s_ethernet_is_connected) {
        if (esp_eth_transmit(s_eth_handle, buffer, len) != ESP_OK) {
            ESP_LOGE(TAG, "Ethernet send packet failed");
        }
    }
    esp_wifi_internal_free_rx_buffer(eb);
    return ESP_OK;
}

// Forward packets from Ethernet to Wi-Fi
// Note that, Ethernet works faster than Wi-Fi on ESP32,
// so we need to add an extra queue to balance their speed difference.
static esp_err_t pkt_eth2wifi(esp_eth_handle_t eth_handle, uint8_t *buffer, uint32_t len, void *priv)
{
    esp_err_t ret = ESP_OK;
    flow_control_msg_t msg = {
        .packet = buffer,
        .length = len
    };
    if (xQueueSend(flow_control_queue, &msg, pdMS_TO_TICKS(FLOW_CONTROL_QUEUE_TIMEOUT_MS)) != pdTRUE) {
        ESP_LOGE(TAG, "send flow control message failed or timeout");
        free(buffer);
        ret = ESP_FAIL;
    }
    return ret;
}

// This task will fetch the packet from the queue, and then send out through Wi-Fi.
// Wi-Fi handles packets slower than Ethernet, we might add some delay between each transmitting.
static void eth2wifi_flow_control_task(void *args)
{
    flow_control_msg_t msg;
    int res = 0;
    uint32_t timeout = 0;
    while (1) {
        if (xQueueReceive(flow_control_queue, &msg, pdMS_TO_TICKS(FLOW_CONTROL_QUEUE_TIMEOUT_MS)) == pdTRUE) {
            timeout = 0;
            if (s_sta_is_connected && msg.length) {
                do {
                    vTaskDelay(pdMS_TO_TICKS(timeout));
                    timeout += 2;
                    res = esp_wifi_internal_tx(WIFI_IF_AP, msg.packet, msg.length);
                } while (res && timeout < FLOW_CONTROL_WIFI_SEND_TIMEOUT_MS);
                if (res != ESP_OK) {
                    ESP_LOGE(TAG, "WiFi send packet failed: %d", res);
                }
            }
            free(msg.packet);
        }
    }
    vTaskDelete(NULL);
}

// Event handler for Ethernet
static void eth_event_handler(void *arg, esp_event_base_t event_base,
                              int32_t event_id, void *event_data)
{
    switch (event_id) {
    case ETHERNET_EVENT_CONNECTED:
        ESP_LOGI(TAG, "Ethernet Link Up");
        s_ethernet_is_connected = true;
        esp_eth_ioctl(s_eth_handle, ETH_CMD_G_MAC_ADDR, s_eth_mac);
        esp_wifi_set_mac(WIFI_IF_AP, s_eth_mac);
        ESP_ERROR_CHECK(esp_wifi_start());
        break;
    case ETHERNET_EVENT_DISCONNECTED:
        ESP_LOGI(TAG, "Ethernet Link Down");
        s_ethernet_is_connected = false;
        ESP_ERROR_CHECK(esp_wifi_stop());
        break;
    case ETHERNET_EVENT_START:
        ESP_LOGI(TAG, "Ethernet Started");
        break;
    case ETHERNET_EVENT_STOP:
        ESP_LOGI(TAG, "Ethernet Stopped");
        break;
    default:
        break;
    }
}

// Event handler for Wi-Fi
static void wifi_event_handler(void *arg, esp_event_base_t event_base,
                               int32_t event_id, void *event_data)
{
    static uint8_t s_con_cnt = 0;
    switch (event_id) {
    case WIFI_EVENT_AP_STACONNECTED:
        ESP_LOGI(TAG, "Wi-Fi AP got a station connected");
        if (!s_con_cnt) {
            s_sta_is_connected = true;
            esp_wifi_internal_reg_rxcb(WIFI_IF_AP, pkt_wifi2eth);
        }
        s_con_cnt++;
        break;
    case WIFI_EVENT_AP_STADISCONNECTED:
        ESP_LOGI(TAG, "Wi-Fi AP got a station disconnected");
        s_con_cnt--;
        if (!s_con_cnt) {
            s_sta_is_connected = false;
            esp_wifi_internal_reg_rxcb(WIFI_IF_AP, NULL);
        }
        break;
    default:
        break;
    }
}

static void initialize_ethernet(void)
{
    ESP_ERROR_CHECK(esp_event_handler_register(ETH_EVENT, ESP_EVENT_ANY_ID, eth_event_handler, NULL));
    eth_mac_config_t mac_config = ETH_MAC_DEFAULT_CONFIG();
    eth_phy_config_t phy_config = ETH_PHY_DEFAULT_CONFIG();
    phy_config.phy_addr = CONFIG_EXAMPLE_ETH_PHY_ADDR;
    phy_config.reset_gpio_num = CONFIG_EXAMPLE_ETH_PHY_RST_GPIO;
#if CONFIG_EXAMPLE_USE_INTERNAL_ETHERNET
    mac_config.smi_mdc_gpio_num = CONFIG_EXAMPLE_ETH_MDC_GPIO;
    mac_config.smi_mdio_gpio_num = CONFIG_EXAMPLE_ETH_MDIO_GPIO;
    esp_eth_mac_t *mac = esp_eth_mac_new_esp32(&mac_config);
#if CONFIG_EXAMPLE_ETH_PHY_IP101
    esp_eth_phy_t *phy = esp_eth_phy_new_ip101(&phy_config);
#elif CONFIG_EXAMPLE_ETH_PHY_RTL8201
    esp_eth_phy_t *phy = esp_eth_phy_new_rtl8201(&phy_config);
#elif CONFIG_EXAMPLE_ETH_PHY_LAN87XX
    esp_eth_phy_t *phy = esp_eth_phy_new_lan87xx(&phy_config);
#elif CONFIG_EXAMPLE_ETH_PHY_DP83848
    esp_eth_phy_t *phy = esp_eth_phy_new_dp83848(&phy_config);
#elif CONFIG_EXAMPLE_ETH_PHY_KSZ8041
    esp_eth_phy_t *phy = esp_eth_phy_new_ksz8041(&phy_config);
#elif CONFIG_EXAMPLE_ETH_PHY_KSZ8081
    esp_eth_phy_t *phy = esp_eth_phy_new_ksz8081(&phy_config);
#endif
#elif CONFIG_ETH_USE_SPI_ETHERNET
    gpio_install_isr_service(0);
    spi_device_handle_t spi_handle = NULL;
    spi_bus_config_t buscfg = {
        .miso_io_num = CONFIG_EXAMPLE_ETH_SPI_MISO_GPIO,
        .mosi_io_num = CONFIG_EXAMPLE_ETH_SPI_MOSI_GPIO,
        .sclk_io_num = CONFIG_EXAMPLE_ETH_SPI_SCLK_GPIO,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
    };
    ESP_ERROR_CHECK(spi_bus_initialize(CONFIG_EXAMPLE_ETH_SPI_HOST, &buscfg, SPI_DMA_CH_AUTO));

#if CONFIG_EXAMPLE_USE_KSZ8851SNL
    spi_device_interface_config_t devcfg = {
        .mode = 0,
        .clock_speed_hz = CONFIG_EXAMPLE_ETH_SPI_CLOCK_MHZ * 1000 * 1000,
        .spics_io_num = CONFIG_EXAMPLE_ETH_SPI_CS_GPIO,
        .queue_size = 20
    };
    ESP_ERROR_CHECK(spi_bus_add_device(CONFIG_EXAMPLE_ETH_SPI_HOST, &devcfg, &spi_handle));
    /* KSZ8851SNL ethernet driver is based on spi driver */
    eth_ksz8851snl_config_t ksz8851snl_config = ETH_KSZ8851SNL_DEFAULT_CONFIG(spi_handle);
    ksz8851snl_config.int_gpio_num = CONFIG_EXAMPLE_ETH_SPI_INT_GPIO;
    esp_eth_mac_t *mac = esp_eth_mac_new_ksz8851snl(&ksz8851snl_config, &mac_config);
    esp_eth_phy_t *phy = esp_eth_phy_new_ksz8851snl(&phy_config);
#elif CONFIG_EXAMPLE_USE_DM9051
    spi_device_interface_config_t devcfg = {
        .command_bits = 1,
        .address_bits = 7,
        .mode = 0,
        .clock_speed_hz = CONFIG_EXAMPLE_ETH_SPI_CLOCK_MHZ * 1000 * 1000,
        .spics_io_num = CONFIG_EXAMPLE_ETH_SPI_CS_GPIO,
        .queue_size = 20
    };
    ESP_ERROR_CHECK(spi_bus_add_device(CONFIG_EXAMPLE_ETH_SPI_HOST, &devcfg, &spi_handle));
    /* dm9051 ethernet driver is based on spi driver */
    eth_dm9051_config_t dm9051_config = ETH_DM9051_DEFAULT_CONFIG(spi_handle);
    dm9051_config.int_gpio_num = CONFIG_EXAMPLE_ETH_SPI_INT_GPIO;
    esp_eth_mac_t *mac = esp_eth_mac_new_dm9051(&dm9051_config, &mac_config);
    esp_eth_phy_t *phy = esp_eth_phy_new_dm9051(&phy_config);
#elif CONFIG_EXAMPLE_USE_W5500
    spi_device_interface_config_t devcfg = {
        .command_bits = 16, // Actually it's the address phase in W5500 SPI frame
        .address_bits = 8,  // Actually it's the control phase in W5500 SPI frame
        .mode = 0,
        .clock_speed_hz = CONFIG_EXAMPLE_ETH_SPI_CLOCK_MHZ * 1000 * 1000,
        .spics_io_num = CONFIG_EXAMPLE_ETH_SPI_CS_GPIO,
        .queue_size = 20
    };
    ESP_ERROR_CHECK(spi_bus_add_device(CONFIG_EXAMPLE_ETH_SPI_HOST, &devcfg, &spi_handle));
    /* w5500 ethernet driver is based on spi driver */
    eth_w5500_config_t w5500_config = ETH_W5500_DEFAULT_CONFIG(spi_handle);
    w5500_config.int_gpio_num = CONFIG_EXAMPLE_ETH_SPI_INT_GPIO;
    esp_eth_mac_t *mac = esp_eth_mac_new_w5500(&w5500_config, &mac_config);
    esp_eth_phy_t *phy = esp_eth_phy_new_w5500(&phy_config);
#endif
#endif // CONFIG_ETH_USE_SPI_ETHERNET
    esp_eth_config_t config = ETH_DEFAULT_CONFIG(mac, phy);
    config.stack_input = pkt_eth2wifi;
    ESP_ERROR_CHECK(esp_eth_driver_install(&config, &s_eth_handle));
#if !CONFIG_EXAMPLE_USE_INTERNAL_ETHERNET
    /* The SPI Ethernet module might doesn't have a burned factory MAC address, we cat to set it manually.
       02:00:00 is a Locally Administered OUI range so should not be used except when testing on a LAN under your control.
    */
    ESP_ERROR_CHECK(esp_eth_ioctl(s_eth_handle, ETH_CMD_S_MAC_ADDR, (uint8_t[]) {
        0x02, 0x00, 0x00, 0x12, 0x34, 0x56
    }));
#endif
    bool eth_promiscuous = true;
    esp_eth_ioctl(s_eth_handle, ETH_CMD_S_PROMISCUOUS, &eth_promiscuous);
    esp_eth_start(s_eth_handle);
}

static void initialize_wifi(void)
{
    ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, ESP_EVENT_ANY_ID, wifi_event_handler, NULL));
    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
    ESP_ERROR_CHECK(esp_wifi_set_storage(WIFI_STORAGE_RAM));
    wifi_config_t wifi_config = {
        .ap = {
            .ssid = CONFIG_EXAMPLE_WIFI_SSID,
            .ssid_len = strlen(CONFIG_EXAMPLE_WIFI_SSID),
            .password = CONFIG_EXAMPLE_WIFI_PASSWORD,
            .max_connection = CONFIG_EXAMPLE_MAX_STA_CONN,
            .authmode = WIFI_AUTH_WPA_WPA2_PSK,
            .channel = CONFIG_EXAMPLE_WIFI_CHANNEL // default: channel 1
        },
    };
    if (strlen(CONFIG_EXAMPLE_WIFI_PASSWORD) == 0) {
        wifi_config.ap.authmode = WIFI_AUTH_OPEN;
    }
    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_AP));
    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_AP, &wifi_config));
}

static esp_err_t initialize_flow_control(void)
{
    flow_control_queue = xQueueCreate(FLOW_CONTROL_QUEUE_LENGTH, sizeof(flow_control_msg_t));
    if (!flow_control_queue) {
        ESP_LOGE(TAG, "create flow control queue failed");
        return ESP_FAIL;
    }
    BaseType_t ret = xTaskCreate(eth2wifi_flow_control_task, "flow_ctl", 2048, NULL, (tskIDLE_PRIORITY + 2), NULL);
    if (ret != pdTRUE) {
        ESP_LOGE(TAG, "create flow control task failed");
        return ESP_FAIL;
    }
    return ESP_OK;
}

void app_main(void)
{
    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        ret = nvs_flash_init();
    }
    ESP_ERROR_CHECK(ret);
    ESP_ERROR_CHECK(esp_event_loop_create_default());
    ESP_ERROR_CHECK(initialize_flow_control());
    initialize_wifi();
    initialize_ethernet();
}
