# Copyright 2015 gRPC authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Run a group of subprocesses and then finish."""

import logging
import multiprocessing
import os
import platform
import re
import signal
import subprocess
import sys
import tempfile
import time
import errno

# cpu cost measurement
measure_cpu_costs = False

_DEFAULT_MAX_JOBS = 16 * multiprocessing.cpu_count()
# Maximum number of bytes of job's stdout that will be stored in the result.
# Only last N bytes of stdout will be kept if the actual output longer.
_MAX_RESULT_SIZE = 64 * 1024


# NOTE: If you change this, please make sure to test reviewing the
# github PR with http://reviewable.io, which is known to add UTF-8
# characters to the PR description, which leak into the environment here
# and cause failures.
def strip_non_ascii_chars(s):
    return ''.join(c for c in s if ord(c) < 128)


def sanitized_environment(env):
    sanitized = {}
    for key, value in env.items():
        sanitized[strip_non_ascii_chars(key)] = strip_non_ascii_chars(value)
    return sanitized


def platform_string():
    if platform.system() == 'Windows':
        return 'windows'
    elif platform.system()[:7] == 'MSYS_NT':
        return 'windows'
    elif platform.system() == 'Darwin':
        return 'mac'
    elif platform.system() == 'Linux':
        return 'linux'
    else:
        return 'posix'


# setup a signal handler so that signal.pause registers 'something'
# when a child finishes
# not using futures and threading to avoid a dependency on subprocess32
if platform_string() == 'windows':
    pass
else:

    def alarm_handler(unused_signum, unused_frame):
        pass

    signal.signal(signal.SIGCHLD, lambda unused_signum, unused_frame: None)
    signal.signal(signal.SIGALRM, alarm_handler)

_SUCCESS = object()
_FAILURE = object()
_RUNNING = object()
_KILLED = object()

_COLORS = {
    'red': [31, 0],
    'green': [32, 0],
    'yellow': [33, 0],
    'lightgray': [37, 0],
    'gray': [30, 1],
    'purple': [35, 0],
    'cyan': [36, 0]
}

_BEGINNING_OF_LINE = '\x1b[0G'
_CLEAR_LINE = '\x1b[2K'

_TAG_COLOR = {
    'FAILED': 'red',
    'FLAKE': 'purple',
    'TIMEOUT_FLAKE': 'purple',
    'WARNING': 'yellow',
    'TIMEOUT': 'red',
    'PASSED': 'green',
    'START': 'gray',
    'WAITING': 'yellow',
    'SUCCESS': 'green',
    'IDLE': 'gray',
    'SKIPPED': 'cyan'
}

_FORMAT = '%(asctime)-15s %(message)s'
logging.basicConfig(level=logging.INFO, format=_FORMAT)


def eintr_be_gone(fn):
    """Run fn until it doesn't stop because of EINTR"""
    while True:
        try:
            return fn()
        except IOError as e:
            if e.errno != errno.EINTR:
                raise


def message(tag, msg, explanatory_text=None, do_newline=False):
    if message.old_tag == tag and message.old_msg == msg and not explanatory_text:
        return
    message.old_tag = tag
    message.old_msg = msg
    while True:
        try:
            if platform_string() == 'windows' or not sys.stdout.isatty():
                if explanatory_text:
                    logging.info(explanatory_text)
                logging.info('%s: %s', tag, msg)
            else:
                sys.stdout.write(
                    '%s%s%s\x1b[%d;%dm%s\x1b[0m: %s%s' %
                    (_BEGINNING_OF_LINE, _CLEAR_LINE, '\n%s' %
                     explanatory_text if explanatory_text is not None else '',
                     _COLORS[_TAG_COLOR[tag]][1], _COLORS[_TAG_COLOR[tag]][0],
                     tag, msg, '\n'
                     if do_newline or explanatory_text is not None else ''))
            sys.stdout.flush()
            return
        except IOError as e:
            if e.errno != errno.EINTR:
                raise


message.old_tag = ''
message.old_msg = ''


def which(filename):
    if '/' in filename:
        return filename
    for path in os.environ['PATH'].split(os.pathsep):
        if os.path.exists(os.path.join(path, filename)):
            return os.path.join(path, filename)
    raise Exception('%s not found' % filename)


class JobSpec(object):
    """Specifies what to run for a job."""

    def __init__(self,
                 cmdline,
                 shortname=None,
                 environ=None,
                 cwd=None,
                 shell=False,
                 timeout_seconds=5 * 60,
                 flake_retries=0,
                 timeout_retries=0,
                 kill_handler=None,
                 cpu_cost=1.0,
                 verbose_success=False,
                 logfilename=None):
        """
    Arguments:
      cmdline: a list of arguments to pass as the command line
      environ: a dictionary of environment variables to set in the child process
      kill_handler: a handler that will be called whenever job.kill() is invoked
      cpu_cost: number of cores per second this job needs
      logfilename: use given file to store job's output, rather than using a temporary file
    """
        if environ is None:
            environ = {}
        self.cmdline = cmdline
        self.environ = environ
        self.shortname = cmdline[0] if shortname is None else shortname
        self.cwd = cwd
        self.shell = shell
        self.timeout_seconds = timeout_seconds
        self.flake_retries = flake_retries
        self.timeout_retries = timeout_retries
        self.kill_handler = kill_handler
        self.cpu_cost = cpu_cost
        self.verbose_success = verbose_success
        self.logfilename = logfilename
        if self.logfilename and self.flake_retries != 0 and self.timeout_retries != 0:
            # Forbidden to avoid overwriting the test log when retrying.
            raise Exception(
                'Cannot use custom logfile when retries are enabled')

    def identity(self):
        return '%r %r' % (self.cmdline, self.environ)

    def __hash__(self):
        return hash(self.identity())

    def __cmp__(self, other):
        return self.identity() == other.identity()

    def __repr__(self):
        return 'JobSpec(shortname=%s, cmdline=%s)' % (self.shortname,
                                                      self.cmdline)

    def __str__(self):
        return '%s: %s %s' % (self.shortname, ' '.join(
            '%s=%s' % kv for kv in self.environ.items()), ' '.join(
                self.cmdline))


class JobResult(object):

    def __init__(self):
        self.state = 'UNKNOWN'
        self.returncode = -1
        self.elapsed_time = 0
        self.num_failures = 0
        self.retries = 0
        self.message = ''
        self.cpu_estimated = 1
        self.cpu_measured = 1


def read_from_start(f):
    f.seek(0)
    return f.read()


class Job(object):
    """Manages one job."""

    def __init__(self,
                 spec,
                 newline_on_success,
                 travis,
                 add_env,
                 quiet_success=False):
        self._spec = spec
        self._newline_on_success = newline_on_success
        self._travis = travis
        self._add_env = add_env.copy()
        self._retries = 0
        self._timeout_retries = 0
        self._suppress_failure_message = False
        self._quiet_success = quiet_success
        if not self._quiet_success:
            message('START', spec.shortname, do_newline=self._travis)
        self.result = JobResult()
        self.start()

    def GetSpec(self):
        return self._spec

    def start(self):
        if self._spec.logfilename:
            # make sure the log directory exists
            logfile_dir = os.path.dirname(
                os.path.abspath(self._spec.logfilename))
            if not os.path.exists(logfile_dir):
                os.makedirs(logfile_dir)
            self._logfile = open(self._spec.logfilename, 'w+')
        else:
            self._logfile = tempfile.TemporaryFile()
        env = dict(os.environ)
        env.update(self._spec.environ)
        env.update(self._add_env)
        env = sanitized_environment(env)
        self._start = time.time()
        cmdline = self._spec.cmdline
        # The Unix time command is finicky when used with MSBuild, so we don't use it
        # with jobs that run MSBuild.
        global measure_cpu_costs
        if measure_cpu_costs and not 'vsprojects\\build' in cmdline[0]:
            cmdline = ['time', '-p'] + cmdline
        else:
            measure_cpu_costs = False
        try_start = lambda: subprocess.Popen(args=cmdline,
                                             stderr=subprocess.STDOUT,
                                             stdout=self._logfile,
                                             cwd=self._spec.cwd,
                                             shell=self._spec.shell,
                                             env=env)
        delay = 0.3
        for i in range(0, 4):
            try:
                self._process = try_start()
                break
            except OSError:
                message(
                    'WARNING', 'Failed to start %s, retrying in %f seconds' %
                    (self._spec.shortname, delay))
                time.sleep(delay)
                delay *= 2
        else:
            self._process = try_start()
        self._state = _RUNNING

    def state(self):
        """Poll current state of the job. Prints messages at completion."""

        def stdout(self=self):
            stdout = read_from_start(self._logfile)
            self.result.message = stdout[-_MAX_RESULT_SIZE:]
            return stdout

        if self._state == _RUNNING and self._process.poll() is not None:
            elapsed = time.time() - self._start
            self.result.elapsed_time = elapsed
            if self._process.returncode != 0:
                if self._retries < self._spec.flake_retries:
                    message('FLAKE',
                            '%s [ret=%d, pid=%d]' %
                            (self._spec.shortname, self._process.returncode,
                             self._process.pid),
                            stdout(),
                            do_newline=True)
                    self._retries += 1
                    self.result.num_failures += 1
                    self.result.retries = self._timeout_retries + self._retries
                    # NOTE: job is restarted regardless of jobset's max_time setting
                    self.start()
                else:
                    self._state = _FAILURE
                    if not self._suppress_failure_message:
                        message('FAILED',
                                '%s [ret=%d, pid=%d, time=%.1fsec]' %
                                (self._spec.shortname, self._process.returncode,
                                 self._process.pid, elapsed),
                                stdout(),
                                do_newline=True)
                    self.result.state = 'FAILED'
                    self.result.num_failures += 1
                    self.result.returncode = self._process.returncode
            else:
                self._state = _SUCCESS
                measurement = ''
                if measure_cpu_costs:
                    m = re.search(
                        r'real\s+([0-9.]+)\nuser\s+([0-9.]+)\nsys\s+([0-9.]+)',
                        stdout())
                    real = float(m.group(1))
                    user = float(m.group(2))
                    sys = float(m.group(3))
                    if real > 0.5:
                        cores = (user + sys) / real
                        self.result.cpu_measured = float('%.01f' % cores)
                        self.result.cpu_estimated = float('%.01f' %
                                                          self._spec.cpu_cost)
                        measurement = '; cpu_cost=%.01f; estimated=%.01f' % (
                            self.result.cpu_measured, self.result.cpu_estimated)
                if not self._quiet_success:
                    message('PASSED',
                            '%s [time=%.1fsec, retries=%d:%d%s]' %
                            (self._spec.shortname, elapsed, self._retries,
                             self._timeout_retries, measurement),
                            stdout() if self._spec.verbose_success else None,
                            do_newline=self._newline_on_success or self._travis)
                self.result.state = 'PASSED'
        elif (self._state == _RUNNING and
              self._spec.timeout_seconds is not None and
              time.time() - self._start > self._spec.timeout_seconds):
            elapsed = time.time() - self._start
            self.result.elapsed_time = elapsed
            if self._timeout_retries < self._spec.timeout_retries:
                message('TIMEOUT_FLAKE',
                        '%s [pid=%d]' %
                        (self._spec.shortname, self._process.pid),
                        stdout(),
                        do_newline=True)
                self._timeout_retries += 1
                self.result.num_failures += 1
                self.result.retries = self._timeout_retries + self._retries
                if self._spec.kill_handler:
                    self._spec.kill_handler(self)
                self._process.terminate()
                # NOTE: job is restarted regardless of jobset's max_time setting
                self.start()
            else:
                message('TIMEOUT',
                        '%s [pid=%d, time=%.1fsec]' %
                        (self._spec.shortname, self._process.pid, elapsed),
                        stdout(),
                        do_newline=True)
                self.kill()
                self.result.state = 'TIMEOUT'
                self.result.num_failures += 1
        return self._state

    def kill(self):
        if self._state == _RUNNING:
            self._state = _KILLED
            if self._spec.kill_handler:
                self._spec.kill_handler(self)
            self._process.terminate()

    def suppress_failure_message(self):
        self._suppress_failure_message = True


class Jobset(object):
    """Manages one run of jobs."""

    def __init__(self, check_cancelled, maxjobs, maxjobs_cpu_agnostic,
                 newline_on_success, travis, stop_on_failure, add_env,
                 quiet_success, max_time):
        self._running = set()
        self._check_cancelled = check_cancelled
        self._cancelled = False
        self._failures = 0
        self._completed = 0
        self._maxjobs = maxjobs
        self._maxjobs_cpu_agnostic = maxjobs_cpu_agnostic
        self._newline_on_success = newline_on_success
        self._travis = travis
        self._stop_on_failure = stop_on_failure
        self._add_env = add_env
        self._quiet_success = quiet_success
        self._max_time = max_time
        self.resultset = {}
        self._remaining = None
        self._start_time = time.time()

    def set_remaining(self, remaining):
        self._remaining = remaining

    def get_num_failures(self):
        return self._failures

    def cpu_cost(self):
        c = 0
        for job in self._running:
            c += job._spec.cpu_cost
        return c

    def start(self, spec):
        """Start a job. Return True on success, False on failure."""
        while True:
            if self._max_time > 0 and time.time(
            ) - self._start_time > self._max_time:
                skipped_job_result = JobResult()
                skipped_job_result.state = 'SKIPPED'
                message('SKIPPED', spec.shortname, do_newline=True)
                self.resultset[spec.shortname] = [skipped_job_result]
                return True
            if self.cancelled(): return False
            current_cpu_cost = self.cpu_cost()
            if current_cpu_cost == 0: break
            if current_cpu_cost + spec.cpu_cost <= self._maxjobs:
                if len(self._running) < self._maxjobs_cpu_agnostic:
                    break
            self.reap(spec.shortname, spec.cpu_cost)
        if self.cancelled(): return False
        job = Job(spec, self._newline_on_success, self._travis, self._add_env,
                  self._quiet_success)
        self._running.add(job)
        if job.GetSpec().shortname not in self.resultset:
            self.resultset[job.GetSpec().shortname] = []
        return True

    def reap(self, waiting_for=None, waiting_for_cost=None):
        """Collect the dead jobs."""
        while self._running:
            dead = set()
            for job in self._running:
                st = eintr_be_gone(lambda: job.state())
                if st == _RUNNING: continue
                if st == _FAILURE or st == _KILLED:
                    self._failures += 1
                    if self._stop_on_failure:
                        self._cancelled = True
                        for job in self._running:
                            job.kill()
                dead.add(job)
                break
            for job in dead:
                self._completed += 1
                if not self._quiet_success or job.result.state != 'PASSED':
                    self.resultset[job.GetSpec().shortname].append(job.result)
                self._running.remove(job)
            if dead: return
            if not self._travis and platform_string() != 'windows':
                rstr = '' if self._remaining is None else '%d queued, ' % self._remaining
                if self._remaining is not None and self._completed > 0:
                    now = time.time()
                    sofar = now - self._start_time
                    remaining = sofar / self._completed * (self._remaining +
                                                           len(self._running))
                    rstr = 'ETA %.1f sec; %s' % (remaining, rstr)
                if waiting_for is not None:
                    wstr = ' next: %s @ %.2f cpu' % (waiting_for,
                                                     waiting_for_cost)
                else:
                    wstr = ''
                message(
                    'WAITING',
                    '%s%d jobs running, %d complete, %d failed (load %.2f)%s' %
                    (rstr, len(self._running), self._completed, self._failures,
                     self.cpu_cost(), wstr))
            if platform_string() == 'windows':
                time.sleep(0.1)
            else:
                signal.alarm(10)
                signal.pause()

    def cancelled(self):
        """Poll for cancellation."""
        if self._cancelled: return True
        if not self._check_cancelled(): return False
        for job in self._running:
            job.kill()
        self._cancelled = True
        return True

    def finish(self):
        while self._running:
            if self.cancelled(): pass  # poll cancellation
            self.reap()
        if platform_string() != 'windows':
            signal.alarm(0)
        return not self.cancelled() and self._failures == 0


def _never_cancelled():
    return False


def tag_remaining(xs):
    staging = []
    for x in xs:
        staging.append(x)
        if len(staging) > 5000:
            yield (staging.pop(0), None)
    n = len(staging)
    for i, x in enumerate(staging):
        yield (x, n - i - 1)


def run(cmdlines,
        check_cancelled=_never_cancelled,
        maxjobs=None,
        maxjobs_cpu_agnostic=None,
        newline_on_success=False,
        travis=False,
        infinite_runs=False,
        stop_on_failure=False,
        add_env={},
        skip_jobs=False,
        quiet_success=False,
        max_time=-1):
    if skip_jobs:
        resultset = {}
        skipped_job_result = JobResult()
        skipped_job_result.state = 'SKIPPED'
        for job in cmdlines:
            message('SKIPPED', job.shortname, do_newline=True)
            resultset[job.shortname] = [skipped_job_result]
        return 0, resultset
    js = Jobset(
        check_cancelled, maxjobs if maxjobs is not None else _DEFAULT_MAX_JOBS,
        maxjobs_cpu_agnostic if maxjobs_cpu_agnostic is not None else
        _DEFAULT_MAX_JOBS, newline_on_success, travis, stop_on_failure, add_env,
        quiet_success, max_time)
    for cmdline, remaining in tag_remaining(cmdlines):
        if not js.start(cmdline):
            break
        if remaining is not None:
            js.set_remaining(remaining)
    js.finish()
    return js.get_num_failures(), js.resultset
