#include <WiFi.h>
#include <stdint.h>

// WiFi credentials
const char* WIFI_SSID = "Wokwi-GUEST";
const char* WIFI_PASS = "";

// CallOnAlarm configuration
const char* SIA_HOST = "sia.callonalarm.io";
const uint16_t SIA_PORT = 5001;
const char* ACCOUNT = "12345678"; // Your connection account number ID there

// CRC16 Table
static const uint16_t CRC16_TABLE[256] PROGMEM = {
    0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
    0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
    0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
    0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
    0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
    0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
    0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
    0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
    0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
    0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
    0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
    0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
    0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
    0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
    0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
    0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
    0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
    0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
    0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
    0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
    0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
    0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
    0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
    0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
    0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
    0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
    0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
    0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
    0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
    0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
    0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
    0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040
};

static uint16_t sequence = 1;

uint16_t crc16(const char* data, size_t len) {
    uint16_t crc = 0;
    for (size_t i = 0; i < len; i++) {
        uint16_t table_val = pgm_read_word(&CRC16_TABLE[(crc ^ data[i]) & 0xFF]);
        crc = (crc >> 8) ^ table_val;
    }
    return crc;
}

bool send_alarm(const char* event_code, const char* zone) {
    WiFiClient client;
    
    Serial.printf("Connecting to %s:%u...\n", SIA_HOST, SIA_PORT);
    
    if (!client.connect(SIA_HOST, SIA_PORT)) {
        Serial.println("Connection failed!");
        return false;
    }
    
    // Build content
    char content[128];
    snprintf(content, sizeof(content), 
             "\"SIA-DCS\"%04uL0#%s[#%s|%s%s]", 
             sequence, ACCOUNT, ACCOUNT, event_code, zone);
    
    // Calculate CRC and length
    uint16_t crc_value = crc16(content, strlen(content));
    uint16_t length = strlen(content);
    
    // Build full message
    char message[256];
    snprintf(message, sizeof(message), 
             "\n%04X%04X%s\r", crc_value, length, content);
    
    // Send
    Serial.printf("Sending: %s\n", message);
    client.print(message);
    
    // Wait for ACK (5 second timeout)
    unsigned long timeout = millis() + 5000;
    while (client.available() == 0 && millis() < timeout) {
        delay(10);
    }
    
    bool success = false;
    if (client.available()) {
        String response = client.readString();
        Serial.printf("Received: %s\n", response.c_str());
        
        if (response.indexOf("ACK") >= 0) {
            Serial.println("✓ Alarm acknowledged!");
            success = true;
        } else {
            Serial.println("✗ Invalid response");
        }
    } else {
        Serial.println("✗ Timeout waiting for ACK");
    }
    
    client.stop();
    
    // Increment sequence for next message
    sequence = (sequence % 9999) + 1;
    
    return success;
}

void setup() {
    Serial.begin(115200);
    delay(1000);
    
    Serial.println("Connecting to WiFi...");
    WiFi.begin(WIFI_SSID, WIFI_PASS);
    
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    
    Serial.println("\nWiFi connected!");
    Serial.printf("IP: %s\n", WiFi.localIP().toString().c_str());
}

void loop() {
    // Example: Send a period test or any SIA/Custom code
    // In real application, trigger this on sensor event
    
    if (send_alarm("RP", "0000")) {
        Serial.println("Event (periodic test) sent successfully!");
    } else {
        Serial.println("Failed to send event");
    }
    
    // Wait before next test (remove in production)
    delay(60000);
}