# osmo_gsm_tester: test suite
#
# 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 sys
import time
import copy
import traceback
from . import config, log, template, util, resource, schema, ofono_client, osmo_nitb, event_loop
from . import test

class Timeout(Exception):
    pass

class Failure(Exception):
    '''Test failure exception, provided to be raised by tests. fail_type is
       usually a keyword used to quickly identify the type of failure that
       occurred. fail_msg is a more extensive text containing information about
       the issue.'''

    def __init__(self, fail_type, fail_msg):
        self.fail_type = fail_type
        self.fail_msg = fail_msg

class SuiteDefinition(log.Origin):
    '''A test suite reserves resources for a number of tests.
       Each test requires a specific number of modems, BTSs etc., which are
       reserved beforehand by a test suite. This way several test suites can be
       scheduled dynamically without resource conflicts arising halfway through
       the tests.'''

    CONF_FILENAME = 'suite.conf'

    CONF_SCHEMA = util.dict_add(
        {
            'defaults.timeout': schema.STR,
        },
        dict([('resources.%s' % k, t) for k,t in resource.WANT_SCHEMA.items()])
        )


    def __init__(self, suite_dir):
        self.set_log_category(log.C_CNF)
        self.suite_dir = suite_dir
        self.set_name(os.path.basename(self.suite_dir))
        self.read_conf()

    def read_conf(self):
        with self:
            self.dbg('reading %s' % SuiteDefinition.CONF_FILENAME)
            if not os.path.isdir(self.suite_dir):
                raise RuntimeError('No such directory: %r' % self.suite_dir)
            self.conf = config.read(os.path.join(self.suite_dir,
                                                 SuiteDefinition.CONF_FILENAME),
                                    SuiteDefinition.CONF_SCHEMA)
            self.load_tests()

    def load_tests(self):
        with self:
            self.tests = []
            for basename in sorted(os.listdir(self.suite_dir)):
                if not basename.endswith('.py'):
                    continue
                self.tests.append(Test(self, basename))

    def add_test(self, test):
        with self:
            if not isinstance(test, Test):
                raise ValueError('add_test(): pass a Test() instance, not %s' % type(test))
            if test.suite is None:
                test.suite = self
            if test.suite is not self:
                raise ValueError('add_test(): test already belongs to another suite')
            self.tests.append(test)

class Test(log.Origin):
    UNKNOWN = 'UNKNOWN'
    SKIP = 'SKIP'
    PASS = 'PASS'
    FAIL = 'FAIL'

    def __init__(self, suite, test_basename):
        self.suite = suite
        self.basename = test_basename
        self.path = os.path.join(self.suite.suite_dir, self.basename)
        super().__init__(self.path)
        self.set_name(self.basename)
        self.set_log_category(log.C_TST)
        self.status = Test.UNKNOWN
        self.start_timestamp = 0
        self.duration = 0
        self.fail_type = None
        self.fail_message = None

    def run(self, suite_run):
        assert self.suite is suite_run.definition
        try:
            with self:
                self.status = Test.UNKNOWN
                self.start_timestamp = time.time()
                test.setup(suite_run, self, ofono_client, sys.modules[__name__], event_loop)
                self.log('START')
                with self.redirect_stdout():
                    util.run_python_file('%s.%s' % (self.suite.name(), self.name()),
                                         self.path)
                if self.status == Test.UNKNOWN:
                     self.set_pass()
        except Exception as e:
            self.log_exn()
            if isinstance(e, Failure):
                ftype = e.fail_type
                fmsg =  e.fail_msg + '\n' + traceback.format_exc().rstrip()
            else:
                ftype = type(e).__name__
                fmsg = repr(e) + '\n' + traceback.format_exc().rstrip()
                if isinstance(e, resource.NoResourceExn):
                    fmsg += '\n' + 'Current resource state:\n' + repr(suite_run.reserved_resources)
            self.set_fail(ftype, fmsg, False)

        finally:
            if self.status == Test.PASS or self.status == Test.SKIP:
                self.log(self.status)
            else:
                self.log('%s (%s)' % (self.status, self.fail_type))
        return self.status

    def name(self):
        l = log.get_line_for_src(self.path)
        if l is not None:
            return '%s:%s' % (self._name, l)
        return super().name()

    def set_fail(self, fail_type, fail_message, tb=True):
        self.status = Test.FAIL
        self.duration = time.time() - self.start_timestamp
        self.fail_type = fail_type
        self.fail_message = fail_message
        if tb:
            self.fail_message += '\n' + ''.join(traceback.format_stack()[:-1]).rstrip()

    def set_pass(self):
        self.status = Test.PASS
        self.duration = time.time() - self.start_timestamp

    def set_skip(self):
        self.status = Test.SKIP
        self.duration = 0

class SuiteRun(log.Origin):
    UNKNOWN = 'UNKNOWN'
    PASS = 'PASS'
    FAIL = 'FAIL'

    trial = None
    resources_pool = None
    reserved_resources = None
    _resource_requirements = None
    _config = None
    _processes = None

    def __init__(self, current_trial, suite_scenario_str, suite_definition, scenarios=[]):
        self.trial = current_trial
        self.definition = suite_definition
        self.scenarios = scenarios
        self.set_name(suite_scenario_str)
        self.set_log_category(log.C_TST)
        self.resources_pool = resource.ResourcesPool()

    def mark_start(self):
        self.tests = []
        self.start_timestamp = time.time()
        self.duration = 0
        self.test_failed_ctr = 0
        self.test_skipped_ctr = 0
        self.status = SuiteRun.UNKNOWN

    def combined(self, conf_name):
        self.dbg(combining=conf_name)
        with log.Origin(combining_scenarios=conf_name):
            combination = copy.deepcopy(self.definition.conf.get(conf_name) or {})
            self.dbg(definition_conf=combination)
            for scenario in self.scenarios:
                with scenario:
                    c = scenario.get(conf_name)
                    self.dbg(scenario=scenario.name(), conf=c)
                    if c is None:
                        continue
                    config.combine(combination, c)
            return combination

    def resource_requirements(self):
        if self._resource_requirements is None:
            self._resource_requirements = self.combined('resources')
        return self._resource_requirements

    def config(self):
        if self._config is None:
            self._config = self.combined('config')
        return self._config

    def reserve_resources(self):
        if self.reserved_resources:
            raise RuntimeError('Attempt to reserve resources twice for a SuiteRun')
        self.log('reserving resources in', self.resources_pool.state_dir, '...')
        with self:
            self.reserved_resources = self.resources_pool.reserve(self, self.resource_requirements())

    def run_tests(self, names=None):
        self.log('Suite run start')
        try:
            self.mark_start()
            event_loop.register_poll_func(self.poll)
            if not self.reserved_resources:
                self.reserve_resources()
            for test in self.definition.tests:
                if names and not test.name() in names:
                    test.set_skip()
                    self.test_skipped_ctr += 1
                    self.tests.append(test)
                    continue
                with self:
                    st = test.run(self)
                    if st == Test.FAIL:
                        self.test_failed_ctr += 1
                    self.tests.append(test)
        finally:
            # if sys.exit() called from signal handler (e.g. SIGINT), SystemExit
            # base exception is raised. Make sure to stop processes in this
            # finally section. Resources are automatically freed with 'atexit'.
            self.stop_processes()
        event_loop.unregister_poll_func(self.poll)
        self.duration = time.time() - self.start_timestamp
        if self.test_failed_ctr:
            self.status = SuiteRun.FAIL
        else:
            self.status = SuiteRun.PASS
        self.log(self.status)
        return self.status

    def remember_to_stop(self, process):
        if self._processes is None:
            self._processes = []
        self._processes.insert(0, process)

    def stop_processes(self):
        if not self._processes:
            return
        for process in self._processes:
            process.terminate()

    def nitb_iface(self):
        return self.reserved_resources.get(resource.R_NITB_IFACE)

    def nitb(self, nitb_iface=None):
        if nitb_iface is None:
            nitb_iface = self.nitb_iface()
        return osmo_nitb.OsmoNitb(self, nitb_iface)

    def bts(self):
        return bts_obj(self, self.reserved_resources.get(resource.R_BTS))

    def modem(self):
        return modem_obj(self.reserved_resources.get(resource.R_MODEM))

    def modems(self, count):
        l = []
        for i in range(count):
            l.append(self.modem())
        return l

    def msisdn(self):
        msisdn = self.resources_pool.next_msisdn(self.origin)
        self.log('using MSISDN', msisdn)
        return msisdn

    def poll(self):
        if self._processes:
            for process in self._processes:
                if process.terminated():
                    process.log_stdout_tail()
                    process.log_stderr_tail()
                    process.raise_exn('Process ended prematurely')

    def prompt(self, *msgs, **msg_details):
        'ask for user interaction. Do not use in tests that should run automatically!'
        if msg_details:
            msgs = list(msgs)
            msgs.append('{%s}' %
                        (', '.join(['%s=%r' % (k,v)
                                    for k,v in sorted(msg_details.items())])))
        msg = ' '.join(msgs) or 'Hit Enter to continue'
        self.log('prompt:', msg)
        sys.__stdout__.write('\n\n--- PROMPT ---\n')
        sys.__stdout__.write(msg)
        sys.__stdout__.write('\n')
        sys.__stdout__.flush()
        entered = util.input_polling('> ', self.poll)
        self.log('prompt entered:', repr(entered))
        return entered

loaded_suite_definitions = {}

def load(suite_name):
    global loaded_suite_definitions

    suite = loaded_suite_definitions.get(suite_name)
    if suite is not None:
        return suite

    suites_dir = config.get_suites_dir()
    suite_dir = suites_dir.child(suite_name)
    if not suites_dir.exists(suite_name):
        raise RuntimeError('Suite not found: %r in %r' % (suite_name, suites_dir))
    if not suites_dir.isdir(suite_name):
        raise RuntimeError('Suite name found, but not a directory: %r' % (suite_dir))

    suite_def = SuiteDefinition(suite_dir)
    loaded_suite_definitions[suite_name] = suite_def
    return suite_def

def parse_suite_scenario_str(suite_scenario_str):
    tokens = suite_scenario_str.split(':')
    if len(tokens) > 2:
        raise RuntimeError('invalid combination string: %r' % suite_scenario_str)

    suite_name = tokens[0]
    if len(tokens) <= 1:
        scenario_names = []
    else:
        scenario_names = tokens[1].split('+')

    return suite_name, scenario_names

def load_suite_scenario_str(suite_scenario_str):
    suite_name, scenario_names = parse_suite_scenario_str(suite_scenario_str)
    suite = load(suite_name)
    scenarios = [config.get_scenario(scenario_name) for scenario_name in scenario_names]
    return (suite_scenario_str, suite, scenarios)

def bts_obj(suite_run, conf):
    bts_type = conf.get('type')
    log.dbg(None, None, 'create BTS object', type=bts_type)
    bts_class = resource.KNOWN_BTS_TYPES.get(bts_type)
    if bts_class is None:
        raise RuntimeError('No such BTS type is defined: %r' % bts_type)
    return bts_class(suite_run, conf)

def modem_obj(conf):
    log.dbg(None, None, 'create Modem object', conf=conf)
    return ofono_client.Modem(conf)

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