"""Easy to use python subprocess interface."""
from sbvirtualdisplay.unicodeutil import (
    split_command,
    unidecode,
    uniencode,
)
import logging
import os.path
import platform
import signal
import subprocess
import tempfile
import threading
import time

log = logging.getLogger(__name__)
log.setLevel(logging.ERROR)
SECTION_LINK = "link"
POLL_TIME = 0.1
USE_POLL = 0


class EasyProcessError(Exception):
    def __init__(self, easy_process, msg=""):
        self.easy_process = easy_process
        self.msg = msg

    def __str__(self):
        return self.msg + " " + repr(self.easy_process)


template = """cmd=%s
OSError=%s
Program install error! """


class EasyProcessCheckInstalledError(Exception):
    """This exception is raised when a process run by check() returns
    a non-zero exit status or OSError is raised."""

    def __init__(self, easy_process):
        self.easy_process = easy_process

    def __str__(self):
        msg = template % (
            self.easy_process.cmd,
            self.easy_process.oserror,
        )
        if self.easy_process.url:
            msg += "\nhome page: " + self.easy_process.url
        if platform.dist()[0].lower() == "ubuntu":
            if self.easy_process.ubuntu_package:
                msg += "\nYou can install it in terminal:\n"
                msg += (
                    "sudo apt-get install "
                    "%s" % self.easy_process.ubuntu_package
                )
        return msg


class EasyProcess(object):
    """
    .. module:: easyprocess

    simple interface for :mod:`subprocess`

    :param cmd: string ('ls -l') or list of strings (['ls','-l'])
    :param cwd: working directory
    :param use_temp_files: use temp files instead of pipes for
                           stdout and stderr,
                           pipes can cause deadlock in some cases
                           (see unit tests)
    :param env: If *env* is not ``None``, it must be a mapping that defines
                the environment variables for the new process;
                these are used instead of inheriting the current
                process' environment, which is the default behavior.
                (check :mod:`subprocess`  for more information)
    """
    def __init__(
        self,
        cmd,
        ubuntu_package=None,
        url=None,
        cwd=None,
        use_temp_files=True,
        env=None,
    ):
        self.use_temp_files = use_temp_files
        self._outputs_processed = False
        self.env = env
        self.popen = None
        self.stdout = None
        self.stderr = None
        self._stdout_file = None
        self._stderr_file = None
        self.url = url
        self.ubuntu_package = ubuntu_package
        self.is_started = False
        self.oserror = None
        self.cmd_param = cmd
        self._thread = None
        self._stop_thread = False
        self.timeout_happened = False
        self.cwd = cwd
        cmd = split_command(cmd)
        self.cmd = cmd
        self.cmd_as_string = " ".join(self.cmd)
        log.debug('param: "%s" ', self.cmd_param)
        log.debug("command: %s", self.cmd)
        log.debug("joined command: %s", self.cmd_as_string)
        if not len(cmd):
            raise EasyProcessError(self, "empty command!")

    def __repr__(self):
        msg = (
            "<%s cmd_param=%s cmd=%s oserror=%s return_code=%s"
            ' stdout="%s" stderr="%s" timeout_happened=%s>'
            % (
                self.__class__.__name__,
                self.cmd_param,
                self.cmd,
                self.oserror,
                self.return_code,
                self.stdout,
                self.stderr,
                self.timeout_happened,
            )
        )
        return msg

    @property
    def pid(self):
        """
        PID (:attr:`subprocess.Popen.pid`)
        :rtype: int
        """
        if self.popen:
            return self.popen.pid

    @property
    def return_code(self):
        """
        returncode (:attr:`subprocess.Popen.returncode`)
        :rtype: int
        """
        if self.popen:
            return self.popen.returncode

    def check(self, return_code=0):
        """Run command with arguments. Wait for command to complete. If the
        exit code was as expected and there is no exception then return,
        otherwise raise EasyProcessError.
        :param return_code: int, expected return code
        :rtype: self
        """
        ret = self.call().return_code
        ok = ret == return_code
        if not ok:
            raise EasyProcessError(
                self,
                "check error, return code is not {0}!".format(return_code),
            )
        return self

    def check_installed(self):
        """Used for testing if program is installed.
        Run command with arguments. Wait for command to complete.
        If OSError raised, then raise :class:`EasyProcessCheckInstalledError`
        with information about program installation.
        :param return_code: int, expected return code
        :rtype: self
        """
        try:
            self.call()
        except Exception:
            raise EasyProcessCheckInstalledError(self)
        return self

    def call(self, timeout=None):
        """Run command with arguments. Wait for command to complete.
        same as:
         1. :meth:`start`
         2. :meth:`wait`
         3. :meth:`stop`
        :rtype: self
        """
        self.start().wait(timeout=timeout)
        if self.is_alive():
            self.stop()
        return self

    def start(self):
        """start command in background and does not wait for it.
        :rtype: self
        """
        if self.is_started:
            raise EasyProcessError(self, "process was started twice!")
        if self.use_temp_files:
            self._stdout_file = tempfile.TemporaryFile(prefix="stdout_")
            self._stderr_file = tempfile.TemporaryFile(prefix="stderr_")
            stdout = self._stdout_file
            stderr = self._stderr_file
        else:
            stdout = subprocess.PIPE
            stderr = subprocess.PIPE
        cmd = list(map(uniencode, self.cmd))
        try:
            self.popen = subprocess.Popen(
                cmd,
                stdout=stdout,
                stderr=stderr,
                cwd=self.cwd,
                env=self.env,
            )
        except OSError as oserror:
            log.debug("OSError exception: %s", oserror)
            self.oserror = oserror
            raise EasyProcessError(self, "start error")
        self.is_started = True
        log.debug("process was started (pid=%s)", self.pid)
        return self

    def is_alive(self):
        """
        poll process using :meth:`subprocess.Popen.poll`
        :rtype: bool
        """
        if self.popen:
            return self.popen.poll() is None
        else:
            return False

    def wait(self, timeout=None):
        if timeout is not None:
            if not self._thread:
                self._thread = threading.Thread(target=self._wait4process)
                self._thread.daemon = 1
                self._thread.start()

        if self._thread:
            self._thread.join(timeout=timeout)
            self.timeout_happened = (
                self.timeout_happened or self._thread.isAlive()
            )
        else:
            self._wait4process()
        return self

    def _wait4process(self):
        if self._outputs_processed:
            return

        def remove_ending_lf(s):
            if s.endswith("\n"):
                return s[:-1]
            else:
                return s

        if self.popen:
            if self.use_temp_files:
                if USE_POLL:
                    while True:
                        if self.popen.poll() is not None:
                            break
                        if self._stop_thread:
                            return
                        time.sleep(POLL_TIME)
                else:
                    self.popen.wait()
                self._outputs_processed = True
                self._stdout_file.seek(0)
                self._stderr_file.seek(0)
                self.stdout = self._stdout_file.read()
                self.stderr = self._stderr_file.read()
                self._stdout_file.close()
                self._stderr_file.close()
            else:
                self._outputs_processed = True
                (self.stdout, self.stderr) = self.popen.communicate()
            log.debug("process has ended")
            self.stdout = remove_ending_lf(unidecode(self.stdout))
            self.stderr = remove_ending_lf(unidecode(self.stderr))
            log.debug("return code=%s", self.return_code)
            log.debug("stdout=%s", self.stdout)
            log.debug("stderr=%s", self.stderr)

    def stop(self):
        return self.sendstop().wait()

    def sendstop(self):
        """
        Kill process (:meth:`subprocess.Popen.terminate`).
        Do not wait for command to complete.
        :rtype: self
        """
        if not self.is_started:
            raise EasyProcessError(self, "process was not started!")

        log.debug('stopping process (pid=%s cmd="%s")', self.pid, self.cmd)
        if self.popen:
            if self.is_alive():
                log.debug("process is active -> sending SIGTERM")
                try:
                    try:
                        self.popen.terminate()
                    except AttributeError:
                        os.kill(self.popen.pid, signal.SIGKILL)
                except OSError as oserror:
                    log.debug("exception in terminate:%s", oserror)
            else:
                log.debug("process was already stopped")
        else:
            log.debug("process was not started")
        return self

    def sleep(self, sec):
        time.sleep(sec)
        return self

    def wrap(self, func, delay=0):
        """
        returns a function which:
         1. start process
         2. call func, save result
         3. stop process
         4. returns result
        similar to :keyword:`with` statement
        :rtype:
        """
        def wrapped():
            self.start()
            if delay:
                self.sleep(delay)
            x = None
            try:
                x = func()
            except OSError as oserror:
                log.debug("OSError exception:%s", oserror)
                self.oserror = oserror
                raise EasyProcessError(self, "wrap error!")
            finally:
                self.stop()
            return x
        return wrapped

    def __enter__(self):
        """used by the :keyword:`with` statement"""
        self.start()
        return self

    def __exit__(self, *exc_info):
        """used by the :keyword:`with` statement"""
        self.stop()


def extract_version(txt):
    """This function tries to extract the version
    from the help text of any program."""
    words = txt.replace(",", " ").split()
    version = None
    for x in reversed(words):
        if len(x) > 2:
            if x[0].lower() == "v":
                x = x[1:]
            if "." in x and x[0].isdigit():
                version = x
                break
    return version


Proc = EasyProcess
