/**
 * @file RailCom.h
 * @brief RailCom Feedback Controller
 * 
 * Implements RailCom channel 1 and 2 for bidirectional communication
 * with the command station. Sends locomotive address and status information.
 */

#ifndef RAILCOM_H
#define RAILCOM_H

#include <Arduino.h>

// RailCom timing (in microseconds)
#define RAILCOM_CHANNEL1_START 26
#define RAILCOM_CHANNEL1_END   177
#define RAILCOM_CHANNEL2_START 193
#define RAILCOM_CHANNEL2_END   454

// RailCom 4bit to 8bit encoding table
#define RAILCOM_4BIT_TO_8BIT_SIZE 16

class RailCom {
public:
    RailCom();
    
    /**
     * @brief Initialize RailCom
     * @param txPin GPIO for RailCom transmit (UART TX)
     * @param cutoutDetectPin GPIO to detect DCC cutout (optional, 255 = disabled)
     * @return true if successful
     */
    bool begin(uint8_t txPin, uint8_t cutoutDetectPin = 255);
    
    /**
     * @brief Enable/disable RailCom
     * @param enable true to enable
     */
    void setEnabled(bool enable);
    
    /**
     * @brief Check if RailCom is enabled
     */
    bool isEnabled() const { return enabled; }
    
    /**
     * @brief Send RailCom data during cutout window
     * This should be called when DCC cutout is detected
     */
    void sendRailComData();
    
    /**
     * @brief Set locomotive address for RailCom reporting
     * @param address Locomotive address
     */
    void setAddress(uint16_t address);
    
    /**
     * @brief Set decoder state information
     * @param speed Current speed
     * @param direction Current direction
     */
    void setDecoderState(uint8_t speed, bool direction);
    
    /**
     * @brief Update RailCom (call regularly from loop)
     */
    void update();

private:
    uint8_t txPin;
    uint8_t cutoutPin;
    bool enabled;
    
    uint16_t locoAddress;
    uint8_t currentSpeed;
    bool currentDirection;
    
    HardwareSerial* railcomSerial;
    
    // RailCom encoding
    uint8_t encode4to8(uint8_t data);
    void sendChannel1();
    void sendChannel2();
    
    // Timing
    unsigned long lastCutoutTime;
    bool inCutout;
    
    static const uint8_t railcom4to8[16];
};

#endif // RAILCOM_H