#!/usr/bin/env python3
"""console.py -- the visitor's terminal joined to the demo machine's serial console, once the
machine is running (issue #112).

    console.py <qmp.sock> <console.sock>

A resumed machine takes a moment to load. Anything typed meanwhile would reach a serial port
whose state is about to be replaced, and be lost half-way through a line ("3 4 + ." arriving as
"4 + ."). So: wait until QEMU says the machine is running, throw away what was typed before,
say so, and only then pass bytes both ways. Ends when either side closes.
"""
import json, os, select, socket, sys, termios, time, tty

qmp_path, con_path = sys.argv[1], sys.argv[2]

def connect(path, limit=30):
    end = time.time() + limit
    while True:
        try:
            s = socket.socket(socket.AF_UNIX); s.connect(path); return s
        except OSError:
            if time.time() > end: raise
            time.sleep(0.1)

qmp = connect(qmp_path).makefile("rw")
qmp.readline()
qmp.write(json.dumps({"execute": "qmp_capabilities"}) + "\n"); qmp.flush(); qmp.readline()
end = time.time() + 60
while True:                                   # until the machine runs
    qmp.write(json.dumps({"execute": "query-status"}) + "\n"); qmp.flush()
    while True:
        r = json.loads(qmp.readline())
        if "return" in r or "error" in r: break   # skip events
    if r.get("return", {}).get("status") == "running": break
    if time.time() > end: sys.exit("The machine did not start.")
    time.sleep(0.1)

con = connect(con_path)
stdin, stdout = sys.stdin.fileno(), sys.stdout.fileno()
saved = None
if os.isatty(stdin):
    termios.tcflush(stdin, termios.TCIFLUSH)  # what was typed while the machine was loading
    saved = termios.tcgetattr(stdin)
    tty.setraw(stdin)                         # the machine echoes and edits the line itself
os.write(stdout, b"Ready -- type a line and press Enter.\r\n")
try:
    while True:
        r, _, _ = select.select([stdin, con], [], [])
        if stdin in r:
            data = os.read(stdin, 1024)
            if not data: break
            con.sendall(data)
        if con in r:
            data = con.recv(4096)
            if not data: break
            os.write(stdout, data)
except OSError:
    pass                                      # the visitor's terminal went away
finally:
    if saved: termios.tcsetattr(stdin, termios.TCSADRAIN, saved)