# Copyright (c) 2016, Intel Corporation.
#
# This program is free software; you can redistribute it and/or modify it
# under the terms and conditions of the GNU General Public License,
# version 2, as published by the Free Software Foundation.
#
# This program is distributed in the hope it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
# more details.
#
"""Build performance test base classes and functionality"""
import glob
import logging
import os
import re
import shutil
import tempfile
import time
from datetime import datetime, timedelta

from oeqa.utils.commands import runCmd, get_bb_vars

# Get logger for this module
log = logging.getLogger('build-perf')


class KernelDropCaches(object):
    """Container of the functions for dropping kernel caches"""
    sudo_passwd = None

    @classmethod
    def check(cls):
        """Check permssions for dropping kernel caches"""
        from getpass import getpass
        from locale import getdefaultlocale
        cmd = ['sudo', '-k', '-n', 'tee', '/proc/sys/vm/drop_caches']
        ret = runCmd(cmd, ignore_status=True, data=b'0')
        if ret.output.startswith('sudo:'):
            pass_str = getpass(
                "\nThe script requires sudo access to drop caches between "
                "builds (echo 3 > /proc/sys/vm/drop_caches).\n"
                "Please enter your sudo password: ")
            cls.sudo_passwd = bytes(pass_str, getdefaultlocale()[1])

    @classmethod
    def drop(cls):
        """Drop kernel caches"""
        cmd = ['sudo', '-k']
        if cls.sudo_passwd:
            cmd.append('-S')
            input_data = cls.sudo_passwd + b'\n'
        else:
            cmd.append('-n')
            input_data = b''
        cmd += ['tee', '/proc/sys/vm/drop_caches']
        input_data += b'3'
        runCmd(cmd, data=input_data)


def time_cmd(cmd, **kwargs):
    """TIme a command"""
    with tempfile.NamedTemporaryFile(mode='w+') as tmpf:
        timecmd = ['/usr/bin/time', '-v', '-o', tmpf.name]
        if isinstance(cmd, str):
            timecmd = ' '.join(timecmd) + ' '
        timecmd += cmd
        # TODO: 'ignore_status' could/should be removed when globalres.log is
        # deprecated. The function would just raise an exception, instead
        ret = runCmd(timecmd, ignore_status=True, **kwargs)
        timedata = tmpf.file.read()
    return ret, timedata


class BuildPerfTest(object):
    """Base class for build performance tests"""
    SYSRES = 'sysres'

    name = None
    description = None

    def __init__(self, out_dir):
        self.out_dir = out_dir
        self.results = {'name':self.name,
                        'description': self.description,
                        'status': 'NOTRUN',
                        'start_time': None,
                        'elapsed_time': None,
                        'measurements': []}
        if not os.path.exists(self.out_dir):
            os.makedirs(self.out_dir)
        if not self.name:
            self.name = self.__class__.__name__
        self.bb_vars = get_bb_vars()
        # TODO: remove the _failed flag when globalres.log is ditched as all
        # failures should raise an exception
        self._failed = False
        self.cmd_log = os.path.join(self.out_dir, 'commands.log')

    def run(self):
        """Run test"""
        self.results['status'] = 'FAILED'
        self.results['start_time'] = datetime.now()
        self._run()
        self.results['elapsed_time'] = (datetime.now() -
                                        self.results['start_time'])
        # Test is regarded as completed if it doesn't raise an exception
        if not self._failed:
            self.results['status'] = 'COMPLETED'

    def _run(self):
        """Actual test payload"""
        raise NotImplementedError

    def log_cmd_output(self, cmd):
        """Run a command and log it's output"""
        with open(self.cmd_log, 'a') as fobj:
            runCmd(cmd, stdout=fobj)

    def measure_cmd_resources(self, cmd, name, legend):
        """Measure system resource usage of a command"""
        def str_time_to_timedelta(strtime):
            """Convert time strig from the time utility to timedelta"""
            split = strtime.split(':')
            hours = int(split[0]) if len(split) > 2 else 0
            mins = int(split[-2])
            secs, frac = split[-1].split('.')
            secs = int(secs)
            microsecs = int(float('0.' + frac) * pow(10, 6))
            return timedelta(0, hours*3600 + mins*60 + secs, microsecs)

        cmd_str = cmd if isinstance(cmd, str) else ' '.join(cmd)
        log.info("Timing command: %s", cmd_str)
        with open(self.cmd_log, 'a') as fobj:
            ret, timedata = time_cmd(cmd, stdout=fobj)
        if ret.status:
            log.error("Time will be reported as 0. Command failed: %s",
                      ret.status)
            etime = timedelta(0)
            self._failed = True
        else:
            match = re.search(r'.*wall clock.*: (?P<etime>.*)\n', timedata)
            etime = str_time_to_timedelta(match.group('etime'))

        measurement = {'type': self.SYSRES,
                       'name': name,
                       'legend': legend}
        measurement['values'] = {'elapsed_time': etime}
        self.results['measurements'].append(measurement)
        nlogs = len(glob.glob(self.out_dir + '/results.log*'))
        results_log = os.path.join(self.out_dir,
                                   'results.log.{}'.format(nlogs + 1))
        with open(results_log, 'w') as fobj:
            fobj.write(timedata)

    @staticmethod
    def force_rm(path):
        """Equivalent of 'rm -rf'"""
        if os.path.isfile(path) or os.path.islink(path):
            os.unlink(path)
        elif os.path.isdir(path):
            shutil.rmtree(path)

    def rm_tmp(self):
        """Cleanup temporary/intermediate files and directories"""
        log.debug("Removing temporary and cache files")
        for name in ['bitbake.lock', 'conf/sanity_info',
                     self.bb_vars['TMPDIR']]:
            self.force_rm(name)

    def rm_sstate(self):
        """Remove sstate directory"""
        log.debug("Removing sstate-cache")
        self.force_rm(self.bb_vars['SSTATE_DIR'])

    def rm_cache(self):
        """Drop bitbake caches"""
        self.force_rm(self.bb_vars['PERSISTENT_DIR'])

    @staticmethod
    def sync():
        """Sync and drop kernel caches"""
        log.debug("Syncing and dropping kernel caches""")
        KernelDropCaches.drop()
        os.sync()
        # Wait a bit for all the dirty blocks to be written onto disk
        time.sleep(3)