#pragma once
// BMW I/K-Bus protocol handler
// Extracted from IbusEsp32 — FSM, source filtering, packet callback.
// Reads from a KLineTransport's RX ring buffer, delegates TX to transport.

#include <Arduino.h>
#include <functional>
#include "KLineTransport.h"

#ifndef IBUS_MIN_LENGTH
#define IBUS_MIN_LENGTH 0x03
#endif
#ifndef IBUS_MAX_LENGTH
#define IBUS_MAX_LENGTH 0x24
#endif
#ifndef IBUS_MAX_MSG
#define IBUS_MAX_MSG 40
#endif

class IbusHandler {
public:
    using PacketCallback = std::function<void(const uint8_t* packet, uint8_t length)>;

    explicit IbusHandler(KLineTransport& transport);

    // Run the receive FSM — call from loop() after transport.drainUart()
    void process();

    // Queue a BMW I/K-Bus message for TX (checksum appended by transport)
    void write(const uint8_t* message, uint8_t size);

    // Register callback for received packets
    void onPacket(PacketCallback callback);

    // Source address filtering
    void setFilterEnabled(bool enabled);
    void setFilterAddress(uint8_t addr);
    void setFilterAddresses(const uint8_t* addrs, uint8_t count);

private:
    enum FsmState {
        FIND_SOURCE,
        FIND_LENGTH,
        FIND_MESSAGE,
        GOOD_CHECKSUM,
        BAD_CHECKSUM,
    };

    KLineTransport& _transport;

    FsmState _state;
    uint8_t _source;
    uint8_t _length;
    uint8_t _msgBuf[IBUS_MAX_MSG];
    unsigned long _findMsgEnteredMs;

    PacketCallback _callback;

    bool _filterEnabled;
    uint8_t _filterAddrs[16];
    uint8_t _filterCount;
};