/*
 *  VWE fork: in-fork virtual RIO cockpit board (serial1=rio).
 *
 *  A native DOSBox-X serial backend that *is* the cockpit RIO board: it speaks
 *  the device side of the RIO 9600-8N1 protocol to the game's UART, and sources
 *  its pilot input from an SDL game controller + the host keyboard inside the
 *  emulator. There is no external process and no pipe, so the game<->board
 *  round trip happens entirely in-process at the emulated UART's own byte
 *  cadence -- the same timing a real ISA UART sees on a physical pod, which
 *  removes the whole class of serial / pipe round-trip-latency dropouts
 *  (livelock, TXMAXIDLE, rxburst, 15s retry).
 *
 *  The protocol state machine + input mapping are transcribed from the
 *  validated vRIO app (C:\VWE\vrio VRio.Core: VRioDevice, the Protocol codec,
 *  Input/InputRouter + BindingProfileFormat), minus its transport, wire pacer,
 *  panel UI and thread locks -- CSerial callbacks, the SDL reads and the host
 *  keyboard hook all run on the single emulator thread.
 *
 *  Keyboard field (B1): sdlmain's SDL2 event loop offers every key to
 *  RIO_HostKeyEvent() first. While capture is ON (default; PAUSE or
 *  SCROLL LOCK toggles it -- plus an optional `togglekey:<name>`) a key bound
 *  in the profile presses its RIO address (button 0x00-0x47 / keypad
 *  0x50-0x6F) or drives an axis, and is swallowed before the DOS keyboard
 *  sees it; unbound keys and Ctrl/Alt/Gui chords pass through (bound modifier
 *  keys are exempt from the chord rule), so DOSBox-X host hotkeys keep
 *  working. Toggling capture OFF releases everything held and gives the whole
 *  keyboard back to DOS (needed at the netnub loop / DOS prompts).
 *
 *  Bindings: the built-in default profile = vRIO's pad + button field
 *  (number/QWERTY rows = upper MFD bank, home/bottom rows = lower bank,
 *  F1-F12 = Secondary/Screen columns, arrows+Space = hat+main) plus keyboard
 *  FLIGHT controls (operator 2026-07-22): numpad 8/2/4/6 = stick, 7/9 =
 *  pedals, LShift/LCtrl = throttle slew, numpad-5 = throttle zero; the
 *  internal keypad is unbound (mission-review-only plumbing). A bindings file
 *  in vRIO's grammar (`key <name> button <addr> [toggle]` / `key <name> axis
 *  <axis> deflect|slew|rate|set <n>` / `pad <button> button <addr> [toggle]`
 *  / `padaxis <src> axis <axis> [invert] [deadzone <d>] [rate <n>]`, '#'
 *  comments, sign may be a separate token) REPLACES the default: conf arg
 *  `bindings:<path>`, else env VWE_RIO_BINDINGS. vRIO's .NET key names (D1,
 *  NumPad0, OemMinus, ...) are aliased, so a vRIO bindings.txt ports over.
 *
 *  This is an ADDITIVE dev / standalone backend. Real pods keep the physical
 *  board on `serial1=directserial realport:COM1`; vRIO-over-pipe keeps
 *  `serial1=namedpipe pipe:vrio`. Neither is touched by this file.
 *
 *  Conf:  serial1=rio [pad:<n>] [inverty] [bindings:<path>] [togglekey:<key>]
 *                     [rxpollus:<us>] [rxburst:<n>]
 *         pad:<n>        game-controller index to use (default: first present)
 *         inverty        send the joystick Y in the physical direction (up = +)
 *         bindings:<p>   bindings file (vRIO grammar; replaces the default)
 *         togglekey:<k>  extra capture-toggle key (SDL name, e.g. End, F24)
 *         rx opts        directserial semantics (board->game delivery pacing)
 */

#ifndef DOSBOX_SERIALRIO_H
#define DOSBOX_SERIALRIO_H

#include "dosbox.h"
#include "serialport.h"

#include <deque>
#include <map>
#include <mutex>
#include <set>
#include <string>
#include <utility>
#include <vector>

// ---- host-side hooks (called from sdlmain's SDL2 event loop) ----------------
// Both are cheap no-ops when no serial<n>=rio port is installed.
// RIO_HostKeyEvent returns true when the key was consumed by the cockpit panel
// (bound + captured, or the PAUSE capture toggle) -- the caller must then skip
// its normal keyboard handling for that event.
bool RIO_HostKeyEvent(int sdl_scancode, bool pressed, bool repeat, unsigned int sdl_mods);
void RIO_HostFocusLost(void);

// Current panel state for the in-fork lamp/button bezel (B2): fills lamps[]
// with the host-commanded LampRequest byte and pressed[] with 1 where a button
// address is currently held. Returns false (and touches nothing) when no
// serial<n>=rio port is installed, so the VDB heads render normally.
bool RIO_GetPanelState(uint8_t lamps[72], uint8_t pressed[72]);

// A panel button was clicked (down=true) or released in a VDB head window.
// Called from the VPX render thread (rt_wndproc), so it is thread-safe: the
// event is queued and applied on the emulator's next tick. No-op if no rio port.
void RIO_HostButton(int addr, bool down);

// ---- binding profile (transcribed from vRIO BindingProfile) -----------------
// key-axis modes: DEFLECT holds the axis at value while the key is down and
// springs back; RATE ("slew" in bindings files) walks the axis by value/second
// and the position sticks; SET snaps the axis position to value on key press.
enum { RIO_KAX_DEFLECT = 0, RIO_KAX_RATE = 1, RIO_KAX_SET = 2 };
struct RioKeyButtonBind { int scancode; int addr; bool toggle; };
struct RioKeyAxisBind   { int scancode; int axis; int mode; float value; };
struct RioPadButtonBind { uint16_t bit; int addr; bool toggle; };
struct RioPadAxisBind   { int src; int axis; bool invert; float dz; float rate; };

class CSerialRio : public CSerial {
public:
	CSerialRio(Bitu id, CommandLine* cmd);
	virtual ~CSerialRio();

	void updatePortConfig(uint16_t divider, uint8_t lcr);
	void updateMSR();
	void transmitByte(uint8_t val, bool first);
	void setBreak(bool value);
	void setRTSDTR(bool rts, bool dtr);
	void setRTS(bool val);
	void setDTR(bool val);
	void handleUpperEvent(uint16_t type);

	// host keyboard (forwarded by the RIO_Host* free functions)
	bool hostKeyEvent(int sdl_scancode, bool pressed, bool repeat, unsigned int sdl_mods);
	void hostFocusLost();
	void getPanelState(uint8_t lampsOut[72], uint8_t pressedOut[72]);
	void hostButton(int addr, bool down);   // panel click (VPX thread -> queue)

private:
	// ---- board -> game byte delivery (UART RX pacing; mirrors directserial) --
	bool doReceive();
	std::deque<uint8_t> rxq;       // bytes the board wants to send to the game
	float rx_poll_ms = 1.0f;
	float rx_burst_div = 1.0f;
	Bitu rx_retry = 0;
	Bitu rx_retry_max = 0;
	Bitu rx_state = 0;

	// ---- game -> board protocol RX parser --------------------------------
	void feedByte(uint8_t ch);
	uint8_t parse_buf[16] = {};
	int parse_remaining = 0;       // bytes still expected (0 = not in a packet)
	int parse_count = 0;           // bytes stored for the current packet

	// ---- device (board) state --------------------------------------------
	void onPacket(const uint8_t* body, int bodyLen, bool checksumValid);
	void onControl(uint8_t b);
	void applyReset(uint8_t target);
	void emit(const uint8_t* p, int n);           // queue board->game bytes
	void emitControl(uint8_t c);
	void sendEvent(const uint8_t* p, int n);      // remember (for NAK resend) + emit
	void pressAddress(int addr);
	void releaseAddress(int addr);
	void setAxis(int axis, int value);

	int16_t axes[5] = {};
	uint8_t lamps[72] = {};
	std::vector<uint8_t> lastEventPacket;         // last button/key/test event
	int resends = 0;
	bool analogMuted = false;                     // v4.2 wedge bug -- default OFF
	uint8_t verMajor = 4, verMinor = 2;
	bool invertY = false;
	long analogRequests = 0;
	bool dtr_state = false;

	// ---- input profile + routing state ------------------------------------
	void loadDefaultProfile();
	bool loadBindingsFile(const std::string& path);
	void computeBoundModMask();
	void openPad();
	void pollInput();
	void incHold(int addr);
	void decHold(int addr);
	void toggleAddress(int addr);
	void releaseAllKeys();

	std::vector<RioKeyButtonBind> keyButtons;
	std::vector<RioKeyAxisBind>   keyAxes;
	std::vector<RioPadButtonBind> padButtons;
	std::vector<RioPadAxisBind>   padAxes;

	void* pad = nullptr;                          // SDL_GameController* (opaque here)
	int pad_index = -1;                           // requested index; -1 = first
	double next_pad_open_ms = 0.0;
	double last_tick_ms = 0.0;
	float rate_i[5] = {};                         // rate-integrator per axis
	int last_sent[5] = {};
	bool last_sent_valid[5] = {};
	std::map<int,int> holdCounts;                 // held count per RIO address
	std::mutex panelMx;                           // guards panelQ (VPX thread <-> emu)
	std::vector<std::pair<int,bool>> panelQ;      // pending panel clicks (addr, down)
	std::set<int> heldKeys;                       // scancodes routed to the panel
	std::set<int> toggled;                        // latched (toggle) addresses
	uint16_t prevPadButtons = 0;
	bool captureKeys = true;                      // toggle keys flip panel <-> DOS
	int toggleKeys[3] = { 0, 0, 0 };              // scancodes; defaults Pause+ScrollLock,
	                                              // slot 2 = togglekey:<name> conf arg
	unsigned int boundModMask = 0;                // modifier bits bound as inputs
	                                              // (exempt from chord passthrough)

	bool logv = false;                            // VWE_RIO_LOG stderr trace
	void logf(const char* fmt, ...);
};

#endif // DOSBOX_SERIALRIO_H