#! /somewhere/python3

from contextlib import contextmanager
from xml.sax.saxutils import XMLGenerator
import _thread
import atexit
import json
import os
import ptpython.repl
import pty
import queue
import re
import shutil
import socket
import subprocess
import sys
import tempfile
import time
import unicodedata

CHAR_TO_KEY = {
    "A": "shift-a",
    "N": "shift-n",
    "-": "0x0C",
    "_": "shift-0x0C",
    "B": "shift-b",
    "O": "shift-o",
    "=": "0x0D",
    "+": "shift-0x0D",
    "C": "shift-c",
    "P": "shift-p",
    "[": "0x1A",
    "{": "shift-0x1A",
    "D": "shift-d",
    "Q": "shift-q",
    "]": "0x1B",
    "}": "shift-0x1B",
    "E": "shift-e",
    "R": "shift-r",
    ";": "0x27",
    ":": "shift-0x27",
    "F": "shift-f",
    "S": "shift-s",
    "'": "0x28",
    '"': "shift-0x28",
    "G": "shift-g",
    "T": "shift-t",
    "`": "0x29",
    "~": "shift-0x29",
    "H": "shift-h",
    "U": "shift-u",
    "\\": "0x2B",
    "|": "shift-0x2B",
    "I": "shift-i",
    "V": "shift-v",
    ",": "0x33",
    "<": "shift-0x33",
    "J": "shift-j",
    "W": "shift-w",
    ".": "0x34",
    ">": "shift-0x34",
    "K": "shift-k",
    "X": "shift-x",
    "/": "0x35",
    "?": "shift-0x35",
    "L": "shift-l",
    "Y": "shift-y",
    " ": "spc",
    "M": "shift-m",
    "Z": "shift-z",
    "\n": "ret",
    "!": "shift-0x02",
    "@": "shift-0x03",
    "#": "shift-0x04",
    "$": "shift-0x05",
    "%": "shift-0x06",
    "^": "shift-0x07",
    "&": "shift-0x08",
    "*": "shift-0x09",
    "(": "shift-0x0A",
    ")": "shift-0x0B",
}


def eprint(*args, **kwargs):
    print(*args, file=sys.stderr, **kwargs)


def create_vlan(vlan_nr):
    global log
    log.log("starting VDE switch for network {}".format(vlan_nr))
    vde_socket = os.path.abspath("./vde{}.ctl".format(vlan_nr))
    pty_master, pty_slave = pty.openpty()
    vde_process = subprocess.Popen(
        ["vde_switch", "-s", vde_socket, "--dirmode", "0777"],
        bufsize=1,
        stdin=pty_slave,
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
        shell=False,
    )
    fd = os.fdopen(pty_master, "w")
    fd.write("version\n")
    # TODO: perl version checks if this can be read from
    # an if not, dies. we could hang here forever. Fix it.
    vde_process.stdout.readline()
    if not os.path.exists(os.path.join(vde_socket, "ctl")):
        raise Exception("cannot start vde_switch")

    return (vlan_nr, vde_socket, vde_process, fd)


def retry(fn):
    """Call the given function repeatedly, with 1 second intervals,
    until it returns True or a timeout is reached.
    """

    for _ in range(900):
        if fn(False):
            return
        time.sleep(1)

    if not fn(True):
        raise Exception("action timed out")


class Logger:
    def __init__(self):
        self.logfile = os.environ.get("LOGFILE", "/dev/null")
        self.logfile_handle = open(self.logfile, "wb")
        self.xml = XMLGenerator(self.logfile_handle, encoding="utf-8")
        self.queue = queue.Queue(1000)

        self.xml.startDocument()
        self.xml.startElement("logfile", attrs={})

    def close(self):
        self.xml.endElement("logfile")
        self.xml.endDocument()
        self.logfile_handle.close()

    def sanitise(self, message):
        return "".join(ch for ch in message if unicodedata.category(ch)[0] != "C")

    def maybe_prefix(self, message, attributes):
        if "machine" in attributes:
            return "{}: {}".format(attributes["machine"], message)
        return message

    def log_line(self, message, attributes):
        self.xml.startElement("line", attributes)
        self.xml.characters(message)
        self.xml.endElement("line")

    def log(self, message, attributes={}):
        eprint(self.maybe_prefix(message, attributes))
        self.drain_log_queue()
        self.log_line(message, attributes)

    def enqueue(self, message):
        self.queue.put(message)

    def drain_log_queue(self):
        try:
            while True:
                item = self.queue.get_nowait()
                attributes = {"machine": item["machine"], "type": "serial"}
                self.log_line(self.sanitise(item["msg"]), attributes)
        except queue.Empty:
            pass

    @contextmanager
    def nested(self, message, attributes={}):
        eprint(self.maybe_prefix(message, attributes))

        self.xml.startElement("nest", attrs={})
        self.xml.startElement("head", attributes)
        self.xml.characters(message)
        self.xml.endElement("head")

        tic = time.time()
        self.drain_log_queue()
        yield
        self.drain_log_queue()
        toc = time.time()
        self.log("({:.2f} seconds)".format(toc - tic))

        self.xml.endElement("nest")


class Machine:
    def __init__(self, args):
        if "name" in args:
            self.name = args["name"]
        else:
            self.name = "machine"
            try:
                cmd = args["startCommand"]
                self.name = re.search("run-(.+)-vm$", cmd).group(1)
            except KeyError:
                pass
            except AttributeError:
                pass

        self.script = args.get("startCommand", self.create_startcommand(args))

        tmp_dir = os.environ.get("TMPDIR", tempfile.gettempdir())

        def create_dir(name):
            path = os.path.join(tmp_dir, name)
            os.makedirs(path, mode=0o700, exist_ok=True)
            return path

        self.state_dir = create_dir("vm-state-{}".format(self.name))
        self.shared_dir = create_dir("xchg-shared")

        self.booted = False
        self.connected = False
        self.pid = None
        self.socket = None
        self.monitor = None
        self.logger = args["log"]
        self.allow_reboot = args.get("allowReboot", False)

    @staticmethod
    def create_startcommand(args):
        net_backend = "-netdev user,id=net0"
        net_frontend = "-device virtio-net-pci,netdev=net0"

        if "netBackendArgs" in args:
            net_backend += "," + args["netBackendArgs"]

        if "netFrontendArgs" in args:
            net_frontend += "," + args["netFrontendArgs"]

        start_command = (
            "qemu-kvm -m 384 " + net_backend + " " + net_frontend + " $QEMU_OPTS "
        )

        if "hda" in args:
            hda_path = os.path.abspath(args["hda"])
            if args.get("hdaInterface", "") == "scsi":
                start_command += (
                    "-drive id=hda,file="
                    + hda_path
                    + ",werror=report,if=none "
                    + "-device scsi-hd,drive=hda "
                )
            else:
                start_command += (
                    "-drive file="
                    + hda_path
                    + ",if="
                    + args["hdaInterface"]
                    + ",werror=report "
                )

        if "cdrom" in args:
            start_command += "-cdrom " + args["cdrom"] + " "

        if "usb" in args:
            start_command += (
                "-device piix3-usb-uhci -drive "
                + "id=usbdisk,file="
                + args["usb"]
                + ",if=none,readonly "
                + "-device usb-storage,drive=usbdisk "
            )
        if "bios" in args:
            start_command += "-bios " + args["bios"] + " "

        start_command += args.get("qemuFlags", "")

        return start_command

    def is_up(self):
        return self.booted and self.connected

    def log(self, msg):
        self.logger.log(msg, {"machine": self.name})

    def nested(self, msg, attrs={}):
        my_attrs = {"machine": self.name}
        my_attrs.update(attrs)
        return self.logger.nested(msg, my_attrs)

    def wait_for_monitor_prompt(self):
        while True:
            answer = self.monitor.recv(1024).decode()
            if answer.endswith("(qemu) "):
                return answer

    def send_monitor_command(self, command):
        message = ("{}\n".format(command)).encode()
        self.log("sending monitor command: {}".format(command))
        self.monitor.send(message)
        return self.wait_for_monitor_prompt()

    def wait_for_unit(self, unit, user=None):
        while True:
            info = self.get_unit_info(unit, user)
            state = info["ActiveState"]
            if state == "failed":
                raise Exception('unit "{}" reached state "{}"'.format(unit, state))

            if state == "inactive":
                status, jobs = self.systemctl("list-jobs --full 2>&1", user)
                if "No jobs" in jobs:
                    info = self.get_unit_info(unit, user)
                    if info["ActiveState"] == state:
                        raise Exception(
                            (
                                'unit "{}" is inactive and there ' "are no pending jobs"
                            ).format(unit)
                        )
            if state == "active":
                return True

    def get_unit_info(self, unit, user=None):
        status, lines = self.systemctl('--no-pager show "{}"'.format(unit), user)
        if status != 0:
            raise Exception(
                'retrieving systemctl info for unit "{}" {} failed with exit code {}'.format(
                    unit, "" if user is None else 'under user "{}"'.format(user), status
                )
            )

        line_pattern = re.compile(r"^([^=]+)=(.*)$")

        def tuple_from_line(line):
            match = line_pattern.match(line)
            return match[1], match[2]

        return dict(
            tuple_from_line(line)
            for line in lines.split("\n")
            if line_pattern.match(line)
        )

    def systemctl(self, q, user=None):
        if user is not None:
            q = q.replace("'", "\\'")
            return self.execute(
                (
                    "su -l {} -c "
                    "$'XDG_RUNTIME_DIR=/run/user/`id -u` "
                    "systemctl --user {}'"
                ).format(user, q)
            )
        return self.execute("systemctl {}".format(q))

    def require_unit_state(self, unit, require_state="active"):
        with self.nested(
            "checking if unit ‘{}’ has reached state '{}'".format(unit, require_state)
        ):
            info = self.get_unit_info(unit)
            state = info["ActiveState"]
            if state != require_state:
                raise Exception(
                    "Expected unit ‘{}’ to to be in state ".format(unit)
                    + "'active' but it is in state ‘{}’".format(state)
                )

    def execute(self, command):
        self.connect()

        out_command = "( {} ); echo '|!EOF' $?\n".format(command)
        self.shell.send(out_command.encode())

        output = ""
        status_code_pattern = re.compile(r"(.*)\|\!EOF\s+(\d+)")

        while True:
            chunk = self.shell.recv(4096).decode()
            match = status_code_pattern.match(chunk)
            if match:
                output += match[1]
                status_code = int(match[2])
                return (status_code, output)
            output += chunk

    def succeed(self, *commands):
        """Execute each command and check that it succeeds."""
        output = ""
        for command in commands:
            with self.nested("must succeed: {}".format(command)):
                (status, out) = self.execute(command)
                if status != 0:
                    self.log("output: {}".format(out))
                    raise Exception(
                        "command `{}` failed (exit code {})".format(command, status)
                    )
                output += out
        return output

    def fail(self, *commands):
        """Execute each command and check that it fails."""
        for command in commands:
            with self.nested("must fail: {}".format(command)):
                status, output = self.execute(command)
                if status == 0:
                    raise Exception(
                        "command `{}` unexpectedly succeeded".format(command)
                    )

    def wait_until_succeeds(self, command):
        with self.nested("waiting for success: {}".format(command)):
            while True:
                status, output = self.execute(command)
                if status == 0:
                    return output

    def wait_until_fails(self, command):
        with self.nested("waiting for failure: {}".format(command)):
            while True:
                status, output = self.execute(command)
                if status != 0:
                    return output

    def wait_for_shutdown(self):
        if not self.booted:
            return

        with self.nested("waiting for the VM to power off"):
            sys.stdout.flush()
            self.process.wait()

            self.pid = None
            self.booted = False
            self.connected = False

    def get_tty_text(self, tty):
        status, output = self.execute(
            "fold -w$(stty -F /dev/tty{0} size | "
            "awk '{{print $2}}') /dev/vcs{0}".format(tty)
        )
        return output

    def wait_until_tty_matches(self, tty, regexp):
        matcher = re.compile(regexp)
        with self.nested("waiting for {} to appear on tty {}".format(regexp, tty)):
            while True:
                text = self.get_tty_text(tty)
                if len(matcher.findall(text)) > 0:
                    return True

    def send_chars(self, chars):
        with self.nested("sending keys ‘{}‘".format(chars)):
            for char in chars:
                self.send_key(char)

    def wait_for_file(self, filename):
        with self.nested("waiting for file ‘{}‘".format(filename)):
            while True:
                status, _ = self.execute("test -e {}".format(filename))
                if status == 0:
                    return True

    def wait_for_open_port(self, port):
        def port_is_open(_):
            status, _ = self.execute("nc -z localhost {}".format(port))
            return status == 0

        with self.nested("waiting for TCP port {}".format(port)):
            retry(port_is_open)

    def wait_for_closed_port(self, port):
        def port_is_closed(_):
            status, _ = self.execute("nc -z localhost {}".format(port))
            return status != 0

        retry(port_is_closed)

    def start_job(self, jobname, user=None):
        return self.systemctl("start {}".format(jobname), user)

    def stop_job(self, jobname, user=None):
        return self.systemctl("stop {}".format(jobname), user)

    def wait_for_job(self, jobname):
        return self.wait_for_unit(jobname)

    def connect(self):
        if self.connected:
            return

        with self.nested("waiting for the VM to finish booting"):
            self.start()

            tic = time.time()
            self.shell.recv(1024)
            # TODO: Timeout
            toc = time.time()

            self.log("connected to guest root shell")
            self.log("(connecting took {:.2f} seconds)".format(toc - tic))
            self.connected = True

    def screenshot(self, filename):
        out_dir = os.environ.get("out", os.getcwd())
        word_pattern = re.compile(r"^\w+$")
        if word_pattern.match(filename):
            filename = os.path.join(out_dir, "{}.png".format(filename))
        tmp = "{}.ppm".format(filename)

        with self.nested(
            "making screenshot {}".format(filename),
            {"image": os.path.basename(filename)},
        ):
            self.send_monitor_command("screendump {}".format(tmp))
            ret = subprocess.run("pnmtopng {} > {}".format(tmp, filename), shell=True)
            os.unlink(tmp)
            if ret.returncode != 0:
                raise Exception("Cannot convert screenshot")

    def dump_tty_contents(self, tty):
        """Debugging: Dump the contents of the TTY<n>
        """
        self.execute("fold -w 80 /dev/vcs{} | systemd-cat".format(tty))

    def get_screen_text(self):
        if shutil.which("tesseract") is None:
            raise Exception("get_screen_text used but enableOCR is false")

        magick_args = (
            "-filter Catrom -density 72 -resample 300 "
            + "-contrast -normalize -despeckle -type grayscale "
            + "-sharpen 1 -posterize 3 -negate -gamma 100 "
            + "-blur 1x65535"
        )

        tess_args = "-c debug_file=/dev/null --psm 11 --oem 2"

        with self.nested("performing optical character recognition"):
            with tempfile.NamedTemporaryFile() as tmpin:
                self.send_monitor_command("screendump {}".format(tmpin.name))

                cmd = "convert {} {} tiff:- | tesseract - - {}".format(
                    magick_args, tmpin.name, tess_args
                )
                ret = subprocess.run(cmd, shell=True, capture_output=True)
                if ret.returncode != 0:
                    raise Exception(
                        "OCR failed with exit code {}".format(ret.returncode)
                    )

                return ret.stdout.decode("utf-8")

    def wait_for_text(self, regex):
        def screen_matches(last):
            text = self.get_screen_text()
            m = re.search(regex, text)

            if last and not m:
                self.log("Last OCR attempt failed. Text was: {}".format(text))

            return m

        with self.nested("waiting for {} to appear on screen".format(regex)):
            retry(screen_matches)

    def send_key(self, key):
        key = CHAR_TO_KEY.get(key, key)
        self.send_monitor_command("sendkey {}".format(key))

    def start(self):
        if self.booted:
            return

        self.log("starting vm")

        def create_socket(path):
            if os.path.exists(path):
                os.unlink(path)
            s = socket.socket(family=socket.AF_UNIX, type=socket.SOCK_STREAM)
            s.bind(path)
            s.listen(1)
            return s

        monitor_path = os.path.join(self.state_dir, "monitor")
        self.monitor_socket = create_socket(monitor_path)

        shell_path = os.path.join(self.state_dir, "shell")
        self.shell_socket = create_socket(shell_path)

        qemu_options = (
            " ".join(
                [
                    "" if self.allow_reboot else "-no-reboot",
                    "-monitor unix:{}".format(monitor_path),
                    "-chardev socket,id=shell,path={}".format(shell_path),
                    "-device virtio-serial",
                    "-device virtconsole,chardev=shell",
                    "-device virtio-rng-pci",
                    "-serial stdio" if "DISPLAY" in os.environ else "-nographic",
                ]
            )
            + " "
            + os.environ.get("QEMU_OPTS", "")
        )

        environment = {
            "QEMU_OPTS": qemu_options,
            "SHARED_DIR": self.shared_dir,
            "USE_TMPDIR": "1",
        }
        environment.update(dict(os.environ))

        self.process = subprocess.Popen(
            self.script,
            bufsize=1,
            stdin=subprocess.DEVNULL,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,
            shell=True,
            cwd=self.state_dir,
            env=environment,
        )
        self.monitor, _ = self.monitor_socket.accept()
        self.shell, _ = self.shell_socket.accept()

        def process_serial_output():
            for line in self.process.stdout:
                line = line.decode("unicode_escape").replace("\r", "").rstrip()
                eprint("{} # {}".format(self.name, line))
                self.logger.enqueue({"msg": line, "machine": self.name})

        _thread.start_new_thread(process_serial_output, ())

        self.wait_for_monitor_prompt()

        self.pid = self.process.pid
        self.booted = True

        self.log("QEMU running (pid {})".format(self.pid))

    def shutdown(self):
        if not self.booted:
            return

        self.shell.send("poweroff\n".encode())
        self.wait_for_shutdown()

    def crash(self):
        if not self.booted:
            return

        self.log("forced crash")
        self.send_monitor_command("quit")
        self.wait_for_shutdown()

    def wait_for_x(self):
        """Wait until it is possible to connect to the X server.  Note that
        testing the existence of /tmp/.X11-unix/X0 is insufficient.
        """
        with self.nested("waiting for the X11 server"):
            while True:
                cmd = (
                    "journalctl -b SYSLOG_IDENTIFIER=systemd | "
                    + 'grep "Reached target Current graphical"'
                )
                status, _ = self.execute(cmd)
                if status != 0:
                    continue
                status, _ = self.execute("[ -e /tmp/.X11-unix/X0 ]")
                if status == 0:
                    return

    def get_window_names(self):
        return self.succeed(
            r"xwininfo -root -tree | sed 's/.*0x[0-9a-f]* \"\([^\"]*\)\".*/\1/; t; d'"
        ).splitlines()

    def wait_for_window(self, regexp):
        pattern = re.compile(regexp)

        def window_is_visible(last_try):
            names = self.get_window_names()
            if last_try:
                self.log(
                    "Last chance to match {} on the window list,".format(regexp)
                    + " which currently contains: "
                    + ", ".join(names)
                )
            return any(pattern.search(name) for name in names)

        with self.nested("Waiting for a window to appear"):
            retry(window_is_visible)

    def sleep(self, secs):
        time.sleep(secs)

    def forward_port(self, host_port=8080, guest_port=80):
        """Forward a TCP port on the host to a TCP port on the guest.
        Useful during interactive testing.
        """
        self.send_monitor_command(
            "hostfwd_add tcp::{}-:{}".format(host_port, guest_port)
        )

    def block(self):
        """Make the machine unreachable by shutting down eth1 (the multicast
        interface used to talk to the other VMs).  We keep eth0 up so that
        the test driver can continue to talk to the machine.
        """
        self.send_monitor_command("set_link virtio-net-pci.1 off")

    def unblock(self):
        """Make the machine reachable.
        """
        self.send_monitor_command("set_link virtio-net-pci.1 on")


def create_machine(args):
    global log
    args["log"] = log
    args["redirectSerial"] = os.environ.get("USE_SERIAL", "0") == "1"
    return Machine(args)


def start_all():
    with log.nested("starting all VMs"):
        for machine in machines:
            machine.start()


def join_all():
    with log.nested("waiting for all VMs to finish"):
        for machine in machines:
            machine.wait_for_shutdown()


def test_script():
    exec(os.environ["testScript"])


def run_tests():
    tests = os.environ.get("tests", None)
    if tests is not None:
        with log.nested("running the VM test script"):
            try:
                exec(tests)
            except Exception as e:
                eprint("error: {}".format(str(e)))
                sys.exit(1)
    else:
        ptpython.repl.embed(locals(), globals())

    # TODO: Collect coverage data

    for machine in machines:
        if machine.is_up():
            machine.execute("sync")

    if nr_tests != 0:
        log.log("{} out of {} tests succeeded".format(nr_succeeded, nr_tests))


@contextmanager
def subtest(name):
    global nr_tests
    global nr_succeeded

    with log.nested(name):
        nr_tests += 1
        try:
            yield
            nr_succeeded += 1
            return True
        except Exception as e:
            log.log("error: {}".format(str(e)))

    return False


if __name__ == "__main__":
    global log
    log = Logger()

    vlan_nrs = list(dict.fromkeys(os.environ["VLANS"].split()))
    vde_sockets = [create_vlan(v) for v in vlan_nrs]
    for nr, vde_socket, _, _ in vde_sockets:
        os.environ["QEMU_VDE_SOCKET_{}".format(nr)] = vde_socket

    vm_scripts = sys.argv[1:]
    machines = [create_machine({"startCommand": s}) for s in vm_scripts]
    machine_eval = [
        "{0} = machines[{1}]".format(m.name, idx) for idx, m in enumerate(machines)
    ]
    exec("\n".join(machine_eval))

    nr_tests = 0
    nr_succeeded = 0

    @atexit.register
    def clean_up():
        with log.nested("cleaning up"):
            for machine in machines:
                if machine.pid is None:
                    continue
                log.log("killing {} (pid {})".format(machine.name, machine.pid))
                machine.process.kill()

            for _, _, process, _ in vde_sockets:
                process.kill()
        log.close()

    tic = time.time()
    run_tests()
    toc = time.time()
    print("test script finished in {:.2f}s".format(toc - tic))
