#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_system.h"

#include "esp_nimble_hci.h"
#include "nimble/nimble_port.h"
#include "nimble/nimble_port_freertos.h"
#include "host/ble_hs.h"
#include "host/util/util.h"
#include "services/gap/ble_svc_gap.h"
#include "services/bas/ble_svc_bas.h"
#include "driver/gpio.h"

#include "main.h"
#include "ble.h"
#include "pumps.h"

#define TAG                       "BLE"
#define CONFIG_CACO_MAX_SERVICES (10)
#define CACO_BLE_ADV_PERIOD      (4000)

static const char *device_name = CONFIG_BARBACK_ID;

static uint8_t blehr_addr_type;
static uint8_t callback_handler_count = 0;
static uint16_t conn_handle;
static uint16_t ble_svc_handle;
static uint16_t svc_handle_button;
static event_callback_handle_t callback_handlers[CONFIG_CACO_MAX_SERVICES] = { 0 };

static int ble_gap_event(struct ble_gap_event *event, void *arg);
static int ble_svc_access(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg);
static int svc_access_pump_state(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg);
static int svc_access_pump_enabled(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg);
static int svc_access_pump_duration(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg);
static int svc_access_system(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg);

#define BLE_SERVICE_PUMP_ENABLED        (0x4200)
#define BLE_SERVICE_PUMP_STATE          (0x4300)
#define BLE_SERVICE_PUMP_DURATION       (0x4350)

#define BLE_SERVICE_BARBACK             (0x4400)
#define CHAR_POUR                       (BLE_SERVICE_BARBACK + 1)
#define CHAR_BUTTON                     (BLE_SERVICE_BARBACK + 2)

#define BLE_CHAR_PUMP_ENABLED(idx) {\
			.uuid = BLE_UUID16_DECLARE(BLE_SERVICE_PUMP_ENABLED + idx),\
			.access_cb = svc_access_pump_enabled,\
			.val_handle = &ble_svc_handle,\
			.flags = BLE_GATT_CHR_F_WRITE | BLE_GATT_CHR_F_READ\
		}

#define BLE_CHAR_PUMP_STATE(idx) {\
			.uuid = BLE_UUID16_DECLARE(BLE_SERVICE_PUMP_STATE + idx),\
			.access_cb = svc_access_pump_state,\
			.val_handle = &ble_svc_handle,\
			.flags = BLE_GATT_CHR_F_NOTIFY | BLE_GATT_CHR_F_READ\
		}

#define BLE_CHAR_PUMP_DURATION(idx) {\
			.uuid = BLE_UUID16_DECLARE(BLE_SERVICE_PUMP_DURATION + idx),\
			.access_cb = svc_access_pump_duration,\
			.val_handle = &ble_svc_handle,\
			.flags = BLE_GATT_CHR_F_WRITE | BLE_GATT_CHR_F_READ\
		}

static const struct ble_gatt_svc_def service_defs[] = {
	{
		.type = BLE_GATT_SVC_TYPE_PRIMARY,
		.uuid = BLE_UUID16_DECLARE(BLE_SERVICE_PUMP_ENABLED),

		.characteristics = (struct ble_gatt_chr_def[]) {
			BLE_CHAR_PUMP_ENABLED(1),
			BLE_CHAR_PUMP_ENABLED(2),
			BLE_CHAR_PUMP_ENABLED(3),
			BLE_CHAR_PUMP_ENABLED(4),
			{ 0 }
		},
	}, {
		.type = BLE_GATT_SVC_TYPE_PRIMARY,
		.uuid = BLE_UUID16_DECLARE(BLE_SERVICE_PUMP_STATE),
		.characteristics = (struct ble_gatt_chr_def[]) {
			BLE_CHAR_PUMP_STATE(1),
			BLE_CHAR_PUMP_STATE(2),
			BLE_CHAR_PUMP_STATE(3),
			BLE_CHAR_PUMP_STATE(4),
			{ 0 }
		},
	}, {
		.type = BLE_GATT_SVC_TYPE_PRIMARY,
		.uuid = BLE_UUID16_DECLARE(BLE_SERVICE_PUMP_DURATION),
		.characteristics = (struct ble_gatt_chr_def[]) {
			BLE_CHAR_PUMP_DURATION(1),
			BLE_CHAR_PUMP_DURATION(2),
			BLE_CHAR_PUMP_DURATION(3),
			BLE_CHAR_PUMP_DURATION(4),
			{ 0 }
		},
	}, {
		.type = BLE_GATT_SVC_TYPE_PRIMARY,
		.uuid = BLE_UUID16_DECLARE(BLE_SERVICE_BARBACK),
		.characteristics = (struct ble_gatt_chr_def[]) {
			{
				.uuid = BLE_UUID16_DECLARE(CHAR_POUR),
				.access_cb = svc_access_system,
				.val_handle = &ble_svc_handle,
				.flags = BLE_GATT_CHR_F_WRITE | BLE_GATT_CHR_F_READ
			}, {
				.uuid = BLE_UUID16_DECLARE(CHAR_BUTTON),
				.access_cb = svc_access_system,
				.val_handle = &svc_handle_button,
				.flags = BLE_GATT_CHR_F_READ | BLE_GATT_CHR_F_NOTIFY
			},
			{ 0 }
		}
	},
	{ 0 } // no more services
};

static int gatt_svr_chr_write(struct os_mbuf *om, uint16_t min_len, uint16_t max_len,
                   void *dst, uint16_t *len) {
    uint16_t om_len;
    int rc;

    om_len = OS_MBUF_PKTLEN(om);
    if (om_len < min_len || om_len > max_len) {
        return BLE_ATT_ERR_INVALID_ATTR_VALUE_LEN;
    }

    rc = ble_hs_mbuf_to_flat(om, dst, max_len, len);
    if (rc != 0) {
        return BLE_ATT_ERR_UNLIKELY;
    }

    return 0;
}

static int svc_access_system(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg) {
  uint16_t uuid16 = ble_uuid_u16(ctxt->chr->uuid);
  uint8_t value = 0;

  ESP_LOGI(TAG, "0x%02X access: %d", uuid16, ctxt->op);

  if(ctxt->op == BLE_GATT_ACCESS_OP_READ_CHR) {
  } else if(ctxt->op == BLE_GATT_ACCESS_OP_WRITE_CHR) {
    gatt_svr_chr_write(
        ctxt->om,
        sizeof value,
        sizeof value,
        &value, NULL
    );

    switch(uuid16) {
      case CHAR_POUR:
        if(value == 1) {
          ESP_LOGI(TAG, "starting pump");
          pumps_run();
        } else {
          pumps_stop();
        }
      break;

      case CHAR_BUTTON:
      break;
    }
  }

  return 0;
}

static int svc_access_pump_enabled(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg) {
  uint16_t uuid16 = ble_uuid_u16(ctxt->chr->uuid);
  uint8_t value = 0;

  ESP_LOGI(TAG, "0x%02X access: %d", uuid16, ctxt->op);

  uint8_t idx = uuid16 - (BLE_SERVICE_PUMP_ENABLED + 1);

	if(ctxt->op == BLE_GATT_ACCESS_OP_WRITE_CHR) {
    gatt_svr_chr_write(
        ctxt->om,
        sizeof value,
        sizeof value,
        &value, NULL
    );

    pumps_set_enabled(idx, value);
  } else if(ctxt->op == BLE_GATT_ACCESS_OP_READ_CHR) {
    uint8_t enabled = pumps_get_enabled(idx);

    ESP_LOGI(TAG, "pumps_enabled[%d] = %d", idx, enabled);
    os_mbuf_append(ctxt->om, &enabled, sizeof enabled);
  }

  return 0;
}

static int svc_access_pump_duration(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg) {
  uint16_t uuid16 = ble_uuid_u16(ctxt->chr->uuid);
  uint8_t idx = uuid16 - (BLE_SERVICE_PUMP_DURATION + 1);
  uint8_t value = 0;

  ESP_LOGI(TAG, "0x%02X access: %d", uuid16, ctxt->op);

	if(ctxt->op == BLE_GATT_ACCESS_OP_WRITE_CHR) {
    gatt_svr_chr_write(
        ctxt->om,
        sizeof value,
        sizeof value,
        &value, NULL
    );

    pumps_set_time(idx, value);
  } else if(ctxt->op == BLE_GATT_ACCESS_OP_READ_CHR) {
    uint8_t duration = pumps_get_time(idx);

    ESP_LOGI(TAG, "pumps_duration[%d] = %d", idx, duration);
    os_mbuf_append(ctxt->om, &duration, sizeof duration);
  }

  return 0;
}

static int svc_access_pump_state(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg) {
  uint16_t uuid16 = ble_uuid_u16(ctxt->chr->uuid);
  uint8_t idx = uuid16 - (BLE_SERVICE_PUMP_ENABLED + 1);

  ESP_LOGI(TAG, "0x%02X access: %d", uuid16, ctxt->op);

	if(ctxt->op == BLE_GATT_ACCESS_OP_WRITE_CHR) {
		ESP_LOGW(TAG, "attempting non-read op on read only characteristics");

		return 1;
  } else if(ctxt->op == BLE_GATT_ACCESS_OP_READ_CHR) {
    uint8_t state = pumps_get_state(idx);

    ESP_LOGI(TAG, "pumps_state[%d] = %d", idx, state);
    os_mbuf_append(ctxt->om, &state, sizeof state);
  }

	return 0;
}

static void ble_advertise(void) {
  struct ble_gap_adv_params adv_params;
  struct ble_hs_adv_fields fields;
  int rc;

  /*
   *  Set the advertisement data included in our advertisements:
   *     o Flags (indicates advertisement type and other general info)
   *     o Advertising tx power
   *     o Device name
   */
  memset(&fields, 0, sizeof(fields));

  /*
   * Advertise two flags:
   *      o Discoverability in forthcoming advertisement (general)
   *      o BLE-only (BR/EDR unsupported)
   */
  fields.flags = BLE_HS_ADV_F_DISC_GEN |
    BLE_HS_ADV_F_BREDR_UNSUP;

  /*
   * Indicate that the TX power level field should be included; have the
   * stack fill this value automatically.  This is done by assigning the
   * special value BLE_HS_ADV_TX_PWR_LVL_AUTO.
   */
  fields.tx_pwr_lvl_is_present = 1;
  fields.tx_pwr_lvl = BLE_HS_ADV_TX_PWR_LVL_AUTO;

  fields.name = (uint8_t *)device_name;
  fields.name_len = strlen(device_name);
  fields.name_is_complete = 1;

  rc = ble_gap_adv_set_fields(&fields);
  if (rc != 0) {
    ESP_LOGE(TAG, "error setting advertisement data; rc=%d\n", rc);
    return;
  }

  /* Begin advertising */
  memset(&adv_params, 0, sizeof(adv_params));
  adv_params.conn_mode = BLE_GAP_CONN_MODE_UND;
  adv_params.disc_mode = BLE_GAP_DISC_MODE_GEN;
  rc = ble_gap_adv_start(blehr_addr_type, NULL, BLE_HS_FOREVER,
      &adv_params, ble_gap_event, NULL);
  if (rc != 0) {
    ESP_LOGE(TAG, "error enabling advertisement; rc=%d\n", rc);
    return;
  }
}

static int ble_gap_event(struct ble_gap_event *event, void *arg) {
  switch (event->type) {
    case BLE_GAP_EVENT_CONNECT:
      /* A new connection was established or a connection attempt failed */
      conn_handle = event->connect.conn_handle;

      ESP_LOGI(TAG, "connection %s; conn_handle: %d status=%d\n",
				event->connect.status == 0 ? "established" : "failed",
				conn_handle,
				event->connect.status
			);

      if (event->connect.status != 0) {
        /* Connection failed; resume advertising */
        ble_advertise();
      }

      break;

    case BLE_GAP_EVENT_DISCONNECT:
      ESP_LOGI(TAG, "disconnect; reason=%d\n", event->disconnect.reason);

      /* Connection terminated; resume advertising */
      ble_advertise();

      break;

    case BLE_GAP_EVENT_ADV_COMPLETE:
      ESP_LOGI(TAG, "adv complete\n");

      ble_advertise();
      break;

    case BLE_GAP_EVENT_SUBSCRIBE:
      ESP_LOGI(TAG, "subscribe event; cur_notify=%d\n value handle; "
                    "val_handle=%d\n",
                    event->subscribe.cur_notify, svc_handle_button);

      if(event->subscribe.attr_handle == svc_handle_button) {
      }

      break;

    case BLE_GAP_EVENT_CONN_UPDATE:
      ESP_LOGI(TAG, "BLE_GAP_EVENT_CONN_UPDATE, conn_handle: %d status: %d",
				event->mtu.conn_handle,
				event->enc_change.status
			);

      break;


    case BLE_GAP_EVENT_ENC_CHANGE:
      ESP_LOGI(TAG, "BLE_GAP_EVENT_ENC_CHANGE");

      break;

    case BLE_GAP_EVENT_MTU:
      ESP_LOGI(TAG, "mtu update event; conn_handle=%d mtu=%d\n",
          event->mtu.conn_handle,
          event->mtu.value);
      break;

    default:
      ESP_LOGW(TAG, "unhandled ble_gap_event; conn_handle=%d type=%d\n",
				event->mtu.conn_handle,
				event->type
			);
  }

  return 0;
}

static void on_sync() {
  ESP_LOGI(TAG, "on_sync");

  int err;

  err = ble_hs_id_infer_auto(0, &blehr_addr_type);
  ESP_ERROR_CHECK(err);

  uint8_t addr_val[6] = {0};
  err = ble_hs_id_copy_addr(blehr_addr_type, addr_val, NULL);
  ESP_ERROR_CHECK(err);

  ble_advertise();
}

static void on_reset(int reason) {
  ESP_LOGI(TAG, "on_reset, reason: %d", reason);
}

void nimble_host_task(void *param) {
  nimble_port_run();
}

int8_t ble_send_notification(void *buf, uint8_t size) {
  struct os_mbuf *om;
  om = ble_hs_mbuf_from_flat(buf, size);

  return ble_gattc_notify_custom(conn_handle, svc_handle_button, om);
}

void ble_init() {
  esp_err_t err;

  memset(&callback_handlers, 0, sizeof(event_callback_handle_t) * CONFIG_CACO_MAX_SERVICES);

  ESP_ERROR_CHECK(esp_nimble_hci_and_controller_init());

  nimble_port_init();

  ble_hs_cfg.sync_cb = on_sync;
  ble_hs_cfg.reset_cb = on_reset;

  // initialize services
  err = ble_gatts_count_cfg(service_defs);
  ESP_ERROR_CHECK(err);

  err = ble_gatts_add_svcs(service_defs);
  ESP_ERROR_CHECK(err);

  ESP_LOGI(TAG, "Setting device name: %s", CONFIG_BARBACK_ID);

  err = ble_svc_gap_device_name_set(CONFIG_BARBACK_ID);
  ESP_ERROR_CHECK(err);

  vTaskDelay(500 / portTICK_PERIOD_MS);

  nimble_port_freertos_init(nimble_host_task);
}