#include <stdlib.h>
#include <stdint.h>
#include <string.h>

#include <freertos/FreeRTOS.h>
#include <freertos/task.h>

#include <esp_system.h>
#include <esp_event.h>
#include <esp_event_loop.h>
#include <esp_log.h>
#include <esp_err.h>
#include <esp_wifi.h>

#include "eos.h"
#include "net.h"
#include "wifi.h"

// XXX: WiFi fail due to no DHCP server

#define WIFI_MAX_SCAN_RECORDS       20
#define WIFI_MAX_CONNECT_ATTEMPTS   3

#define WIFI_STATE_STOPPED          0
#define WIFI_STATE_SCANNING         1
#define WIFI_STATE_CONNECTING       2
#define WIFI_STATE_CONNECTED        3
#define WIFI_STATE_DISCONNECTING    4
#define WIFI_STATE_DISCONNECTED     5

#define WIFI_ACTION_NONE            0
#define WIFI_ACTION_SCAN            1
#define WIFI_ACTION_CONNECT         2
#define WIFI_ACTION_DISCONNECT      3

static const char *TAG = "EOS WIFI";

static SemaphoreHandle_t mutex;

static wifi_config_t wifi_sta_config;
static wifi_scan_config_t wifi_scan_config;

static int wifi_connect_cnt = 0;
static uint8_t wifi_action;
static uint8_t wifi_state;

static esp_err_t wifi_event_handler(void *ctx, system_event_t *event) {
    esp_err_t ret = ESP_OK;
    char _disconnect;
    uint8_t _action, _state;
    unsigned char *rbuf;
    wifi_ap_record_t scan_r[WIFI_MAX_SCAN_RECORDS];
    uint16_t scan_n = WIFI_MAX_SCAN_RECORDS;

    switch(event->event_id) {
        case WIFI_EVENT_SCAN_DONE:
            memset(scan_r, 0, sizeof(scan_r));
            esp_wifi_scan_get_ap_records(&scan_n, scan_r);

            xSemaphoreTake(mutex, portMAX_DELAY);
            _state = wifi_state;
            if (wifi_state == WIFI_STATE_CONNECTED) wifi_action = WIFI_ACTION_NONE;
            xSemaphoreGive(mutex);

            if (_state != WIFI_STATE_CONNECTED) ret = esp_wifi_stop();
            break;

        case WIFI_EVENT_STA_START:
            xSemaphoreTake(mutex, portMAX_DELAY);
            _action = wifi_action;
            xSemaphoreGive(mutex);

            switch (_action) {
                case WIFI_ACTION_SCAN:
                    ret = esp_wifi_scan_start(&wifi_scan_config, 0);
                    break;

                case WIFI_ACTION_CONNECT:
                    ret = esp_wifi_connect();
                    break;

                default:
                    break;
            }
            break;

        case WIFI_EVENT_STA_STOP:
            xSemaphoreTake(mutex, portMAX_DELAY);
            wifi_state = WIFI_STATE_STOPPED;
            wifi_action = WIFI_ACTION_NONE;
            xSemaphoreGive(mutex);
            break;

        case WIFI_EVENT_STA_CONNECTED:
            xSemaphoreTake(mutex, portMAX_DELAY);
            wifi_state = WIFI_STATE_CONNECTED;
            wifi_action = WIFI_ACTION_NONE;
            wifi_connect_cnt = WIFI_MAX_CONNECT_ATTEMPTS;
            xSemaphoreGive(mutex);
            break;

        case WIFI_EVENT_STA_DISCONNECTED:
            xSemaphoreTake(mutex, portMAX_DELAY);
            if (wifi_connect_cnt) wifi_connect_cnt--;
            _action = wifi_action;
            _disconnect = (wifi_connect_cnt == 0);
            if (_disconnect) wifi_state = WIFI_STATE_DISCONNECTED;
            xSemaphoreGive(mutex);

            if (_disconnect) {
                rbuf = eos_net_alloc();
                if (_action == WIFI_ACTION_CONNECT) {
                    rbuf[0] = EOS_WIFI_MTYPE_CONNECT;
                    rbuf[1] = EOS_ERR;
                    eos_net_send(EOS_NET_MTYPE_WIFI, rbuf, 2);
                } else {
                    rbuf[0] = EOS_WIFI_MTYPE_DISCONNECT;
                    eos_net_send(EOS_NET_MTYPE_WIFI, rbuf, 1);
                }
                if (!_action) ret = esp_wifi_stop();
            } else {
                ret = esp_wifi_connect();
            }
            break;

        case IP_EVENT_STA_GOT_IP:
            ESP_LOGI(TAG, "IP address: " IPSTR, IP2STR(&event->event_info.got_ip.ip_info.ip));
            if (event->event_info.got_ip.ip_changed) {
                // send wifi reconnect
            } else {
                rbuf = eos_net_alloc();
                rbuf[0] = EOS_WIFI_MTYPE_CONNECT;
                rbuf[1] = EOS_OK;
                eos_net_send(EOS_NET_MTYPE_WIFI, rbuf, 2);
            }
            break;

        default: // Ignore the other event types
            break;
    }
    if (ret != ESP_OK) ESP_LOGE(TAG, "EVT HANDLER ERR:%d EVT:%d", ret, event->event_id);

    return ESP_OK;
}

static void wifi_handler(unsigned char _mtype, unsigned char *buffer, uint16_t size) {
    int rv = EOS_OK;
    uint8_t mtype = buffer[0];
    char *ssid, *pass;

    switch (mtype) {
        case EOS_WIFI_MTYPE_SCAN:
            rv = eos_wifi_scan();
            break;

        case EOS_WIFI_MTYPE_CONNECT:
            ssid = (char *)buffer+1;
            pass = ssid+strlen(ssid)+1;
            rv = eos_wifi_set_auth(ssid, pass);
            if (!rv) rv = eos_wifi_connect();
            break;

        case EOS_WIFI_MTYPE_DISCONNECT:
            rv = eos_wifi_disconnect();
            break;
    }
    if (rv) ESP_LOGE(TAG, "MSG HANDLER ERR:%d MSG:%d", rv, mtype);
}

void eos_wifi_init(void) {
    esp_err_t ret;
    wifi_init_config_t wifi_config = WIFI_INIT_CONFIG_DEFAULT();

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

    ret = esp_event_loop_init(wifi_event_handler, NULL);
    assert(ret == ESP_OK);

    ret = esp_wifi_init(&wifi_config);
    assert(ret == ESP_OK);

    ret = esp_wifi_set_storage(WIFI_STORAGE_RAM);
    assert(ret == ESP_OK);

    ret = esp_wifi_set_mode(WIFI_MODE_STA);
    assert(ret == ESP_OK);

    ret = esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_sta_config);
    assert(ret == ESP_OK);

    ret = esp_wifi_stop();
    assert(ret == ESP_OK);

    mutex = xSemaphoreCreateBinary();
    xSemaphoreGive(mutex);

    eos_net_set_handler(EOS_NET_MTYPE_WIFI, wifi_handler);
    ESP_LOGI(TAG, "INIT");
}

int eos_wifi_scan(void) {
    int rv = EOS_OK;
    esp_err_t ret = ESP_OK;
    uint8_t _wifi_state = 0;

    xSemaphoreTake(mutex, portMAX_DELAY);
    if (!wifi_action) {
        _wifi_state = wifi_state;

        wifi_action = WIFI_ACTION_SCAN;
        if (wifi_state == WIFI_STATE_STOPPED) wifi_state = WIFI_STATE_SCANNING;

        memset(&wifi_scan_config, 0, sizeof(wifi_scan_config));
    } else {
        rv = EOS_ERR_BUSY;
    }
    xSemaphoreGive(mutex);

    if (rv) return rv;

    if (_wifi_state == WIFI_STATE_STOPPED) {
        ret = esp_wifi_start();
    } else {
        ret = esp_wifi_scan_start(&wifi_scan_config, 0);
    }
    if (ret != ESP_OK) rv = EOS_ERR;

    return rv;
}

int eos_wifi_set_auth(char *ssid, char *pass) {
    int rv = EOS_OK;

    xSemaphoreTake(mutex, portMAX_DELAY);
    if (!wifi_action) {
        if (ssid) strncpy((char *)wifi_sta_config.sta.ssid, ssid, sizeof(wifi_sta_config.sta.ssid) - 1);
        if (pass) strncpy((char *)wifi_sta_config.sta.password, pass, sizeof(wifi_sta_config.sta.password) - 1);
    } else {
        rv = EOS_ERR_BUSY;

    }
    xSemaphoreGive(mutex);

    return rv;
}

int eos_wifi_connect(void) {
    int rv = EOS_OK;
    esp_err_t ret = ESP_OK;
    uint8_t _wifi_state = 0;

    xSemaphoreTake(mutex, portMAX_DELAY);
    if (!wifi_action) {
        _wifi_state = wifi_state;

        wifi_action = WIFI_ACTION_CONNECT;
        wifi_state = WIFI_STATE_CONNECTING;
        wifi_connect_cnt = WIFI_MAX_CONNECT_ATTEMPTS;
    } else {
        rv = EOS_ERR_BUSY;
    }
    xSemaphoreGive(mutex);

    if (rv) return rv;

    esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_sta_config);

    if (_wifi_state == WIFI_STATE_STOPPED) {
        ret = esp_wifi_start();
    } else {
        ret = esp_wifi_connect();
    }
    if (ret != ESP_OK) rv = EOS_ERR;

    return rv;
}

int eos_wifi_disconnect(void) {
    int rv = EOS_OK;
    esp_err_t ret = ESP_OK;

    xSemaphoreTake(mutex, portMAX_DELAY);
    if (!wifi_action) {
        wifi_action = WIFI_ACTION_DISCONNECT;
        wifi_state = WIFI_STATE_DISCONNECTING;
        wifi_connect_cnt = 0;

        memset(wifi_sta_config.sta.ssid, 0, sizeof(wifi_sta_config.sta.ssid));
        memset(wifi_sta_config.sta.password, 0, sizeof(wifi_sta_config.sta.password));
    } else {
        rv = EOS_ERR_BUSY;
    }
    xSemaphoreGive(mutex);

    if (rv) return rv;

    ret = esp_wifi_stop();
    if (ret != ESP_OK) rv = EOS_ERR;

    return rv;
}