#pragma once

#include "vendor/shim/IPAddress.h"

#include "lwip/udp.h"
#include "lwip/pbuf.h"

// Arduino WiFiUDP-compatible wrapper around lwIP raw UDP API.
// Template parameter for AppleMIDISession<LwIPUDP>.

class LwIPUDP {
public:
    LwIPUDP();
    ~LwIPUDP();

    bool begin(uint16_t port);
    void stop();

    // Rx — packet-oriented read
    int available();
    int parsePacket();
    int read(uint8_t *buf, size_t len);
    int read();
    IPAddress remoteIP();
    uint16_t remotePort();

    // Tx — packet-oriented write
    int beginPacket(IPAddress ip, uint16_t port);
    size_t write(const uint8_t *buf, size_t len);
    int endPacket();
    void flush() {}  // no-op; UDP sends are immediate

private:
    static constexpr uint8_t RX_QUEUE_SIZE = 4;

    struct RxPacket {
        ip_addr_t addr;
        uint16_t port;
        struct pbuf *p;
        uint16_t offset;
    };

    struct udp_pcb *pcb_;
    RxPacket rxQueue_[RX_QUEUE_SIZE];
    volatile uint8_t rxHead_;
    volatile uint8_t rxTail_;

    // Current packet being read
    RxPacket *current_;
    void advanceRx();

    // Outgoing
    ip_addr_t txAddr_;
    uint16_t txPort_;
    struct pbuf *txBuf_;

    static void recvCb(void *arg, struct udp_pcb *pcb,
                       struct pbuf *p, const ip_addr_t *addr, u16_t port);
};