#!/usr/bin/env python3
"""
vrrun.py -- live responding board for the custom-DOSBox-X FLYK run.

Phase machine matched to what disassembly of shipped FLYK proved:

  BOOT   : swallow the raw transputer .BTL stream (not framed). When it ends
           (idle gap after a substantial burst), send ONE vr_net frame -- this is
           all start_velocirender's velocirender_input() needs to stop timing out
           (it loops on iserver msgs, returns on the first non-iserver frame with
           count >= 8; the content is ignored). No iserver tag => no exit(666) risk.

  FRAMED : feed everything to vrboard -- discards the framed vr_860* MNG download,
           replies to vr_init, then handles the scene (create/flush/geometry/
           textures/draw). Every message + reply is logged.

Raw bytes also go to capture.raw.bin / capture.hex.log for offline analysis.

    python vrrun.py [prefix]        # listen 127.0.0.1:8620; Ctrl-C to stop
                                    # writes <prefix>.raw.bin / <prefix>.log
    python vrrun.py [prefix] --view # + real-time board-side window: moderngl GPU
                                    # backend (vrview_gl.py, 832x512) by default,
                                    # renders each draw_scene from live wire state,
                                    # ack paced to <=60 Hz so FLYK runs real-time
    python vrrun.py [prefix] --view --soft   # software rasterizer (vrview.py,
                                    # the debugging reference; also VRVIEW_SOFT=1)
"""
import os, socket, struct, time, sys
from vrboard import VirtualBoard, Assembler, pack_vr, A

def make_renderer(soft=False):
    """GPU backend by default; --soft / VRVIEW_SOFT=1 or any GL failure falls
    back to the software rasterizer (the reference implementation)."""
    if not soft and os.environ.get('VRVIEW_SOFT') != '1':
        try:
            from vrview_gl import GLRenderer
            return GLRenderer()
        except Exception as e:
            print(f"[view] GPU backend unavailable ({e}) -- software fallback")
    from vrview import Renderer
    return Renderer()

HOST, PORT = '127.0.0.1', 8620
RSET = b'\x00RSET'
IDLE = 0.5            # seconds of no writes => a phase boundary
MIN_BOOT = 4096       # bytes received before we treat an idle as "BTL done"

def main():
    args = [a for a in sys.argv[1:] if not a.startswith("--")]
    prefix = args[0] if args else "capture"
    view = None
    if "--view" in sys.argv:
        view = make_renderer("--soft" in sys.argv)
    binf = open(prefix + ".raw.bin", "wb")
    log  = open(prefix + ".log", "w")
    def emit(s): log.write(s + "\n"); log.flush(); print(s)

    board = VirtualBoard(); asm = Assembler()
    board._view = view
    phase = "BOOT"; recv_since_reset = 0; handshake_sent = False

    srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    srv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    srv.bind((HOST, PORT)); srv.listen(1)
    emit(f"vrrun listening on {HOST}:{PORT}")
    conn, addr = srv.accept(); emit(f"vrlink connected from {addr}")
    conn.settimeout(IDLE)

    def send_handshake():
        msg = pack_vr(A.init, b'\x00' * 8)   # vr_net, count = 12 (action+8) -- clears the >=8 check
        conn.sendall(msg)
        emit(f"[BOOT] BTL done ({recv_since_reset}B). Sent 1 vr_net handshake frame "
             f"({len(msg)}B) -> velocirender_input should succeed.")

    with conn:
        while True:
            try:
                data = conn.recv(8192)
            except socket.timeout:
                if phase == "BOOT" and recv_since_reset > MIN_BOOT and not handshake_sent:
                    send_handshake(); handshake_sent = True; phase = "FRAMED"
                if view is not None:
                    view.pump()      # keep the window alive while the link idles
                continue
            except ConnectionResetError:
                emit("(peer reset -- FLYK closed)"); break
            if not data:
                break
            binf.write(data); binf.flush()

            # peel RSET control frames (vrlink injects these only on port-0x160 writes,
            # which FLYK does only during boot -- so ignore the marker once past BOOT)
            while phase == "BOOT" and RSET in data:
                i = data.index(RSET)
                pre, data = data[:i], data[i+len(RSET):]
                if pre: recv_since_reset += _consume(pre, phase, asm, board, conn, emit)
                emit("[reset] link reset strobe"); recv_since_reset = 0
                phase = "BOOT"; handshake_sent = False; asm.buf.clear()
            if data:
                recv_since_reset += _consume(data, phase, asm, board, conn, emit)
    emit(f"connection closed. frames drawn={board.frames}, "
         f"nodes={len(board.nodes)}, geom={len(board.geom)}, tex={len(board.tex)}")

def _consume(data, phase, asm, board, conn, emit):
    """Return count of bytes accounted; frame+dispatch when past boot."""
    if phase == "BOOT":
        return len(data)            # swallow BTL raw
    view = getattr(board, '_view', None)
    asm.feed(data)
    for msg in asm:
        board.log.clear()
        is_draw = (not msg.iserver and msg.action == A.draw_scene)
        try:
            reply = board.handle(msg)
        except Exception as e:
            emit(f"  [board error on {msg!r}: {e}]"); reply = b''
        quiet = is_draw and board.frames > 3      # don't spam the log at 60 Hz
        if not quiet:
            for line in board.log: emit("  " + line)
        if is_draw and view is not None:
            # render this frame board-side, then ack -- FLYK's loop is paced by us
            try:
                view.draw(board)
            except KeyboardInterrupt:
                raise
            except Exception as e:
                if board.frames % 300 == 1: emit(f"  [render error: {e}]")
            if board.frames % 300 == 0:
                emit(f"  [frame {board.frames}]")
        if reply:
            conn.sendall(reply)
            if not quiet:
                act = struct.unpack_from('<II', reply, 0)[1]
                try: nm = A(act).name
                except ValueError: nm = f"action_{act:#x}"
                emit(f"    -> reply {nm} ({len(reply)}B)")
    return len(data)

if __name__ == '__main__':
    main()