#include "WebServer.h"
#include "WiFi.h"
#include "esp_camera.h"
#include "esp_timer.h"
#include "img_converters.h"
#include "Arduino.h"
#include "soc/soc.h"           // Disable brownout problems
#include "soc/rtc_cntl_reg.h"  // Disable brownout problems
#include "driver/rtc_io.h"
#include <LittleFS.h>

// OV2640 camera module pins (CAMERA_MODEL_AI_THINKER)
#define PWDN_GPIO_NUM     32
#define RESET_GPIO_NUM    -1
#define XCLK_GPIO_NUM      0
#define SIOD_GPIO_NUM     26
#define SIOC_GPIO_NUM     27
#define Y9_GPIO_NUM       35
#define Y8_GPIO_NUM       34
#define Y7_GPIO_NUM       39
#define Y6_GPIO_NUM       36
#define Y5_GPIO_NUM       21
#define Y4_GPIO_NUM       19
#define Y3_GPIO_NUM       18
#define Y2_GPIO_NUM        5
#define VSYNC_GPIO_NUM    25
#define HREF_GPIO_NUM     23
#define PCLK_GPIO_NUM     22

// Replace with your network credentials
const char* ssid = "...";
const char* password = "...";

// Create AsyncWebServer object on port 80
WebServer server(80);

// Photo File Name to save in LittleFS
#define FILE_PHOTO "/photo.jpg"

//LED flash setup parameters - the LED flash illuminates the meter when the photo is taken
const int freq = 5000;
const int ledChannel = 2;  // Timer 0 is used to generate the camera pixel clock
                           //    so use a different Timer for the LED flash. Use Timer 1 (Channel 2 / Channel 3).
const int res = 8;         // select 8-bit resolution
const int ledPin = 4;      // the flash LED is connected to pin 4
const int brightness = 255; // set the led PWM ( 0 - 255 )

void captureAndSave( void ) {
  camera_fb_t * fb = NULL;
  bool ok = 0;

  do {
    // Take a photo with the camera
    Serial.println("Taking a photo...");

    // Dump first frame
    fb = esp_camera_fb_get();
    esp_camera_fb_return(fb);
    fb = NULL;

    // Configure and turn on the LED flash
    ledcAttachPin(ledPin, ledChannel);
    ledcSetup(ledChannel, freq, res);  
    ledcWrite(ledChannel, brightness);
    delay(1);

    fb = esp_camera_fb_get();

    // Turn off the LED flash
    ledcWrite(ledChannel, 0);
    ledcDetachPin(ledPin);

    if (!fb) {
      Serial.println("Camera capture failed");
      return;
    }

    // Photo file name
    File file = LittleFS.open(FILE_PHOTO, FILE_WRITE);

    // Insert the data in the photo file
    if (!file) {
      Serial.println("Failed to open file in writing mode");
    }
    else {
      file.write(fb->buf, fb->len); // payload (image), payload length
      Serial.println("Photo saved");
    }
    // Close the file
    file.close();
    esp_camera_fb_return(fb);

    // check if file has been correctly saved in LittleFS
    File f_pic = LittleFS.open( FILE_PHOTO );
    unsigned int pic_sz = f_pic.size();
    Serial.print("Saved file is ");
    Serial.print(pic_sz);
    Serial.println(" bytes");
    pic_sz > 100 ? ok = true : ok = false;
  } while ( !ok );
}

void setup() {
  Serial.begin(115200);

  // Connect to Wi-Fi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  if (!LittleFS.begin(true)) {
    Serial.println("An Error has occurred while mounting LittleFS");
    ESP.restart();
  }
  else {
    delay(500);
    Serial.println("LittleFS mounted successfully");
  }

  // Print ESP32 Local IP Address
  Serial.print("IP Address: http://");
  Serial.println(WiFi.localIP());

  // Turn off the 'brownout detector'
  WRITE_PERI_REG(RTC_CNTL_BROWN_OUT_REG, 0);

  // OV2640 camera module
  camera_config_t config;
  config.ledc_channel = LEDC_CHANNEL_0;
  config.ledc_timer = LEDC_TIMER_0;
  config.pin_d0 = Y2_GPIO_NUM;
  config.pin_d1 = Y3_GPIO_NUM;
  config.pin_d2 = Y4_GPIO_NUM;
  config.pin_d3 = Y5_GPIO_NUM;
  config.pin_d4 = Y6_GPIO_NUM;
  config.pin_d5 = Y7_GPIO_NUM;
  config.pin_d6 = Y8_GPIO_NUM;
  config.pin_d7 = Y9_GPIO_NUM;
  config.pin_xclk = XCLK_GPIO_NUM;
  config.pin_pclk = PCLK_GPIO_NUM;
  config.pin_vsync = VSYNC_GPIO_NUM;
  config.pin_href = HREF_GPIO_NUM;
  config.pin_sscb_sda = SIOD_GPIO_NUM;
  config.pin_sscb_scl = SIOC_GPIO_NUM;
  config.pin_pwdn = PWDN_GPIO_NUM;
  config.pin_reset = RESET_GPIO_NUM;
  config.xclk_freq_hz = 20000000;
  config.pixel_format = PIXFORMAT_JPEG;

  config.frame_size = FRAMESIZE_HD;
  config.jpeg_quality = 10;
  config.fb_count = 1;

  // Camera init
  esp_err_t err = esp_camera_init(&config);
  if (err != ESP_OK) {
    Serial.printf("Camera init failed with error 0x%x", err);
    ESP.restart();
  }

  server.on("/", HTTP_GET, []() {
    captureAndSave();
    File file = LittleFS.open(FILE_PHOTO);
    server.streamFile(file, "image/jpeg");
    file.close();
  });

  // Start server
  server.begin();
}

void loop() {
  server.handleClient();
  delay(1);
}