// ChirpStack3 Encoder for Combined Downlink Packet
// Format: [heating_enable][room_temp_threshold][floor_temp_threshold]

function Encode(fPort, obj, variables) {
    var bytes = [];

    // Combined packet format (3 bytes)
    if (obj.heating_enable !== undefined && obj.room_temp !== undefined && obj.floor_temp !== undefined) {
        // Byte 0: Heating enable (0=DISABLED, 1=ENABLED)
        bytes[0] = obj.heating_enable ? 1 : 0;

        // Byte 1: Room temperature threshold (°C)
        bytes[1] = parseInt(obj.room_temp);

        // Byte 2: Floor temperature threshold (°C)
        bytes[2] = parseInt(obj.floor_temp);

        return bytes;
    }

    // Send interval format (2 bytes): 'i' + minutes
    if (obj.send_interval !== undefined) {
        bytes[0] = 0x69; // ASCII 'i'
        bytes[1] = parseInt(obj.send_interval);

        return bytes;
    }

    // Load configuration format (3 bytes): 'w' + watts (2 bytes big-endian)
    if (obj.load_watts !== undefined) {
        var w = parseInt(obj.load_watts);
        bytes[0] = 0x77; // ASCII 'w'
        bytes[1] = (w >> 8) & 0xFF;
        bytes[2] = w & 0xFF;

        return bytes;
    }

    return null;
}

// Example usage:
// Combined packet: {"heating_enable": true, "room_temp": 22, "floor_temp": 25}
// Result: [0x01, 0x16, 0x19]

// Send interval: {"send_interval": 5}
// Result: [0x69, 0x05]

// Load configuration: {"load_watts": 400}
// Result: [0x77, 0x01, 0x90]