# osmo_gsm_tester: trial: directory of binaries to be tested
#
# Copyright (C) 2016-2017 by sysmocom - s.f.m.c. GmbH
#
# Author: Neels Hofmeyr <neels@hofmeyr.de>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import os
import time
import shutil
import tarfile

from . import log, util

FILE_MARK_TAKEN = 'taken'
FILE_CHECKSUMS = 'checksums.md5'
TIMESTAMP_FMT = '%Y-%m-%d_%H-%M-%S'
FILE_LAST_RUN = 'last_run'
FILE_LOG = 'log'

class Trial(log.Origin):
    path = None
    dir = None
    _run_dir = None
    bin_tars = None
    log_targets = None

    @staticmethod
    def next(trials_dir):

        with trials_dir.lock('Trial.next'):
            trials = [e for e in trials_dir.children()
                      if trials_dir.isdir(e) and not trials_dir.exists(e, FILE_MARK_TAKEN)]
            if not trials:
                return None
            # sort by time to get the one that waited longest
            trials.sort(key=lambda e: os.path.getmtime(trials_dir.child(e)))
            next_trial = trials[0]
            return Trial(trials_dir.child(next_trial)).take()

    def __init__(self, trial_dir):
        self.path = trial_dir
        self.set_name(os.path.basename(self.path))
        self.set_log_category(log.C_TST)
        self.dir = util.Dir(self.path)
        self.inst_dir = util.Dir(self.dir.child('inst'))
        self.bin_tars = []

    def __repr__(self):
        return self.name()

    def __enter__(self):
        # add a log target to log to the run dir
        run_dir = self.get_run_dir()
        self.log_targets = [
            log.FileLogTarget(run_dir.new_child(FILE_LOG))
              .set_all_levels(log.L_DBG)
              .style_change(trace=True),
            ]
        self.log('Trial start')
        self.take()
        super().__enter__()

    def __exit__(self, *exc_info):
        super().__exit__(*exc_info)
        self.log('Trial end')

        for lt in self.log_targets:
            lt.remove()
        self.log_targets = None

    def take(self):
        self.dir.touch(FILE_MARK_TAKEN)
        return self

    def get_run_dir(self):
        if self._run_dir is not None:
            return self._run_dir
        self._run_dir = util.Dir(self.dir.new_child('run.%s' % time.strftime(TIMESTAMP_FMT)))
        self._run_dir.mkdir()

        last_run = self.dir.child(FILE_LAST_RUN)
        if os.path.islink(last_run):
            os.remove(last_run)
        if not os.path.exists(last_run):
            os.symlink(self.dir.rel_path(self._run_dir.path), last_run)
        return self._run_dir

    def verify(self):
        "verify checksums"

        if not self.dir.exists():
            raise RuntimeError('Trial dir does not exist: %r' % self.dir)
        if not self.dir.isdir():
            raise RuntimeError('Trial dir is not a dir: %r' % self.dir)

        checksums = self.dir.child(FILE_CHECKSUMS)
        if not self.dir.isfile(FILE_CHECKSUMS):
            raise RuntimeError('No checksums file in trial dir: %r', checksums)

        with open(checksums, 'r') as f:
            line_nr = 0
            for line in [l.strip() for l in f.readlines()]:
                line_nr += 1
                if not line:
                    continue
                md5, filename = line.split('  ')
                file_path = self.dir.child(filename)

                if not self.dir.isfile(filename):
                    raise RuntimeError('File listed in checksums file but missing in trials dir:'
                                       ' %r vs. %r line %d' % (file_path, checksums, line_nr))

                if md5 != util.md5_of_file(file_path):
                    raise RuntimeError('Checksum mismatch for %r vs. %r line %d'
                                       % (file_path, checksums, line_nr))

                if filename.endswith('.tgz'):
                    self.bin_tars.append(filename)

    def has_bin_tar(self, bin_name):
        bin_tar_start = '%s.' % bin_name
        matches = [t for t in self.bin_tars if t.startswith(bin_tar_start)]
        self.dbg(bin_name=bin_name, matches=matches)
        if not matches:
            return None
        if len(matches) > 1:
            raise RuntimeError('More than one match for bin name %r: %r' % (bin_name, matches))
        bin_tar = matches[0]
        bin_tar_path = self.dir.child(bin_tar)
        if not os.path.isfile(bin_tar_path):
            raise RuntimeError('Not a file or missing: %r' % bin_tar_path)
        return bin_tar_path

    def get_inst(self, bin_name):
        bin_tar = self.has_bin_tar(bin_name)
        if not bin_tar:
            raise RuntimeError('No such binary available: %r' % bin_name)
        inst_dir = self.inst_dir.child(bin_name)

        if os.path.isdir(inst_dir):
            # already unpacked
            return inst_dir

        t = None
        try:
            os.makedirs(inst_dir)
            t = tarfile.open(bin_tar)
            t.extractall(inst_dir)
            return inst_dir

        except:
            shutil.rmtree(inst_dir)
            raise
        finally:
            if t:
                try:
                    t.close()
                except:
                    pass

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