#include "http.h"
#include "esp_sntp.h"
#include "wifi.h"
#include <math.h>
#include <stdlib.h>
#include "esp_log.h"
#include "esp_http_server.h"

const static char *TAG = "HTTP";

// 2 Days worth of samples
#define NUM_SAMPLES_TO_STORE (((24 * 60) / 10) * 2)

httpd_handle_t server = NULL;

typedef struct {
  uint8_t myt_sec;   // 0 -> 61
  uint8_t myt_min;   // 0 -> 59
  uint8_t myt_hour;  // 0 -> 23
  uint8_t myt_day;   // 1 -> 31
  uint8_t myt_month; // 0 -> 11 !!
  uint8_t myt_year;  // years since 1900
} my_time;

typedef struct {
  deci_percent rh;
  deci_degrees_c temp;
  my_time time;
} my_dht22_data;


// I know this is asking for a race condition...
static my_dht22_data *dht22_buffer = NULL;
static int dht22_num = 0;

my_time get_time() {
  time_t epoch;
  time(&epoch);
  struct tm *timeinfo = localtime(&epoch);
  my_time my_current_time;

  // There must be a better way - I couldn't figure out how to do it
  // nicely all at once
  my_current_time.myt_sec = timeinfo->tm_sec;
  // -5 to get the middle of the averaged window
  my_current_time.myt_min = timeinfo->tm_min;
  my_current_time.myt_hour = timeinfo->tm_hour;
  my_current_time.myt_day = timeinfo->tm_mday;
  my_current_time.myt_month = timeinfo->tm_mon;
  my_current_time.myt_year = timeinfo->tm_year;
  return my_current_time;
}


esp_err_t dht22_data_get_handler(httpd_req_t *req) {
//  if (dht22_num == 0) {
//    httpd_resp_send(req, resp, HTTPD_RESP_USE_STRLEN);
//  }
  char *resp;

  size_t size_of_csv_line = strlen("YY:MM:DD HH:MM:SS,XXXX,YYYY\n");

  resp = calloc(dht22_num, size_of_csv_line + 1);

  for (int i = 0; i < dht22_num; i++) {
    // FIXME - there are random NULL characters that seem to appear
    // in the data - I think the snprintf could be modified slightly
    // FIXME - For some reason the data string starts with a '1'
    // unsure whether it's from the year or what
    my_dht22_data d = dht22_buffer[i];
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-truncation"
    snprintf(resp + (i * size_of_csv_line), size_of_csv_line,
             "%02d:%02d:%02d %02d:%02d:%02d\t%04d\t%04d\n", d.time.myt_year,
             d.time.myt_month, d.time.myt_day, d.time.myt_hour, d.time.myt_min,
             d.time.myt_sec, d.rh, d.temp);
#pragma GCC diagnostic pop
  }
  // shouldn't need to null terminate this becuase of calloc

  httpd_resp_send(req, resp, dht22_num * size_of_csv_line + 1);
  return ESP_OK;
}

/* URI handler structure for GET /uri */
httpd_uri_t dht22_data_get = {
    .uri      = "/dht22.csv",
    .method   = HTTP_GET,
    .handler  = dht22_data_get_handler,
    .user_ctx = NULL
};

void init_dht22_data() {
  dht22_buffer = malloc(NUM_SAMPLES_TO_STORE * sizeof(my_dht22_data));
  httpd_register_uri_handler(server, &dht22_data_get);
}

void add_dht22_data(float rh, float temp) {
  if (dht22_buffer == NULL) {
    return;
  }
  my_dht22_data dht22_data;
  dht22_data.time = get_time();
  dht22_data.time.myt_min -= 5;
  dht22_data.temp = round(temp);
  dht22_data.rh = round(rh);
  dht22_buffer[dht22_num] = dht22_data;
  dht22_num += 1;
  ESP_LOGI(TAG, "Logged %i dht22 values", dht22_num);
  // TODO: handle if dht22_num == MAX
  //  use a circular buffer or something maybe?
}

void start_server() {
  httpd_config_t config = HTTPD_DEFAULT_CONFIG();

  ESP_LOGI(TAG, "Starting server on port: '%d'", config.server_port);
  httpd_start(&server, &config);
}