#include <stdio.h>
#include <string.h>
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include "tcpip_adapter.h"
#include "esp_sntp.h"
#include "lwip/sockets.h"

#define SMTP_SERVER "smtp.gmail.com"
#define SMTP_PORT 587
#define USERNAME "[email protected]"
#define PASSWORD "your_password"

void send_smtp_email()
{
    int sock;
    struct sockaddr_in server_addr;
    char buffer[1024];

    // Step 1: Create socket
    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock < 0) {
        printf("Failed to create socket\n");
        return;
    }

    // Step 2: Configure server address
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(SMTP_PORT);
    server_addr.sin_addr.s_addr = inet_addr(SMTP_SERVER);

    // Step 3: Connect to server
    if (connect(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        printf("Connection failed\n");
        close(sock);
        return;
    }

    // Step 4: Send EHLO command (SMTP initiation)
    snprintf(buffer, sizeof(buffer), "EHLO esp32\r\n");
    send(sock, buffer, strlen(buffer), 0);
    recv(sock, buffer, sizeof(buffer), 0);

    // Step 5: Send STARTTLS command
    snprintf(buffer, sizeof(buffer), "STARTTLS\r\n");
    send(sock, buffer, strlen(buffer), 0);
    recv(sock, buffer, sizeof(buffer), 0);

    // Step 6: Authenticate using USERNAME and PASSWORD
    snprintf(buffer, sizeof(buffer), "AUTH LOGIN\r\n");
    send(sock, buffer, strlen(buffer), 0);
    recv(sock, buffer, sizeof(buffer), 0);

    // Send username in base64
    // (Here you need to encode USERNAME and PASSWORD in base64)
    snprintf(buffer, sizeof(buffer), "your_base64_encoded_username\r\n");
    send(sock, buffer, strlen(buffer), 0);
    recv(sock, buffer, sizeof(buffer), 0);

    snprintf(buffer, sizeof(buffer), "your_base64_encoded_password\r\n");
    send(sock, buffer, strlen(buffer), 0);
    recv(sock, buffer, sizeof(buffer), 0);

    // Step 7: Send MAIL FROM command
    snprintf(buffer, sizeof(buffer), "MAIL FROM:<%s>\r\n", USERNAME);
    send(sock, buffer, strlen(buffer), 0);
    recv(sock, buffer, sizeof(buffer), 0);

    // Step 8: Send RCPT TO command
    snprintf(buffer, sizeof(buffer), "RCPT TO:<[email protected]>\r\n");
    send(sock, buffer, strlen(buffer), 0);
    recv(sock, buffer, sizeof(buffer), 0);

    // Step 9: Send DATA command
    snprintf(buffer, sizeof(buffer), "DATA\r\n");
    send(sock, buffer, strlen(buffer), 0);
    recv(sock, buffer, sizeof(buffer), 0);

    // Step 10: Send email body
    snprintf(buffer, sizeof(buffer),
             "From: <%s>\r\n"
             "To: <[email protected]>\r\n"
             "Subject: Test Email from ESP32\r\n"
             "\r\n"
             "This is a test email sent from ESP32.\r\n"
             ".\r\n", USERNAME);
    send(sock, buffer, strlen(buffer), 0);
    recv(sock, buffer, sizeof(buffer), 0);

    // Step 11: Send QUIT command
    snprintf(buffer, sizeof(buffer), "QUIT\r\n");
    send(sock, buffer, strlen(buffer), 0);
    recv(sock, buffer, sizeof(buffer), 0);

    // Close the socket
    close(sock);
    printf("Email sent successfully!\n");
}

void app_main(void)
{
    // Setup Wi-Fi connection and network initialization here...
    // Once connected, call send_smtp_email()

    send_smtp_email();
}