#!/usr/bin/env bash
'''':;
if [[ "$OSTYPE" == "darwin"* ]]; then
    export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES
fi
exec "$(command -v python || command -v python3 || command -v python2 ||
echo "ERROR python IS NOT AVAILABLE IN THIS SYSTEM")" "$0" "$@" # '''

# -*- coding: utf-8 -*-
# Description:
# Author: Pawel Krupa (paulfantom)
# Author: Ilya Mashchenko (l2isbad)
# SPDX-License-Identifier: GPL-3.0-or-later


import collections
import copy
import gc
import multiprocessing
import os
import re
import sys
import time
import threading
import types

PY_VERSION = sys.version_info[:2]

if PY_VERSION > (3, 1):
    from importlib.machinery import SourceFileLoader
else:
    from imp import load_source as SourceFileLoader


ENV_NETDATA_USER_CONFIG_DIR = 'NETDATA_USER_CONFIG_DIR'
ENV_NETDATA_STOCK_CONFIG_DIR = 'NETDATA_STOCK_CONFIG_DIR'
ENV_NETDATA_PLUGINS_DIR = 'NETDATA_PLUGINS_DIR'
ENV_NETDATA_UPDATE_EVERY = 'NETDATA_UPDATE_EVERY'


def dirs():
    user_config = os.getenv(
        ENV_NETDATA_USER_CONFIG_DIR,
        '/etc/netdata',
    )
    stock_config = os.getenv(
        ENV_NETDATA_STOCK_CONFIG_DIR,
        '/usr/lib/netdata/conf.d',
    )
    modules_user_config = os.path.join(user_config, 'python.d')
    modules_stock_config = os.path.join(stock_config, 'python.d')

    modules = os.path.abspath(
        os.getenv(
            ENV_NETDATA_PLUGINS_DIR,
            os.path.dirname(__file__),
        ) + '/../python.d'
    )
    pythond_packages = os.path.join(modules, 'python_modules')

    return collections.namedtuple(
        'Dirs',
        [
            'user_config',
            'stock_config',
            'modules_user_config',
            'modules_stock_config',
            'modules',
            'pythond_packages',
        ]
    )(
        user_config,
        stock_config,
        modules_user_config,
        modules_stock_config,
        modules,
        pythond_packages,
    )


DIRS = dirs()

sys.path.append(DIRS.pythond_packages)


from bases.collection import safe_print
from bases.loggers import PythonDLogger
from bases.loaders import load_config

try:
    from collections import OrderedDict
except ImportError:
    from third_party.ordereddict import OrderedDict


END_TASK_MARKER = None

IS_ATTY = sys.stdout.isatty()

PLUGIN_CONF_FILE = 'python.d.conf'

MODULE_SUFFIX = '.chart.py'

OBSOLETED_MODULES = (
    'apache_cache',        # replaced by web_log
    'cpuidle',             # rewritten in C
    'cpufreq',             # rewritten in C
    'gunicorn_log',        # replaced by web_log
    'linux_power_supply',  # rewritten in C
    'nginx_log',           # replaced by web_log
    'mdstat',              # rewritten in C
    'sslcheck',            # memory leak bug https://github.com/netdata/netdata/issues/5624
)


AVAILABLE_MODULES = [
    m[:-len(MODULE_SUFFIX)] for m in sorted(os.listdir(DIRS.modules))
    if m.endswith(MODULE_SUFFIX) and m[:-len(MODULE_SUFFIX)] not in OBSOLETED_MODULES
]

PLUGIN_BASE_CONF = {
    'enabled': True,
    'default_run': True,
    'gc_run': True,
    'gc_interval': 300,
}

JOB_BASE_CONF = {
    'update_every': os.getenv(ENV_NETDATA_UPDATE_EVERY, 1),
    'priority': 60000,
    'autodetection_retry': 0,
    'chart_cleanup': 10,
    'penalty': True,
    'name': str(),
}


def heartbeat():
    if IS_ATTY:
        return
    safe_print('\n')


class HeartBeat(threading.Thread):
    def __init__(self, every):
        threading.Thread.__init__(self)
        self.daemon = True
        self.every = every

    def run(self):
        while True:
            time.sleep(self.every)
            heartbeat()


def load_module(name):
    abs_path = os.path.join(DIRS.modules, '{0}{1}'.format(name, MODULE_SUFFIX))
    module = SourceFileLoader(name, abs_path)
    if isinstance(module, types.ModuleType):
        return module
    return module.load_module()


def multi_path_find(name, paths):
    for path in paths:
        abs_name = os.path.join(path, name)
        if os.path.isfile(abs_name):
            return abs_name
    return ''


Task = collections.namedtuple(
    'Task',
    [
        'module_name',
        'explicitly_enabled',
    ],
)

Result = collections.namedtuple(
    'Result',
    [
        'module_name',
        'jobs_configs',
    ],
)


class ModuleChecker(multiprocessing.Process):
    def __init__(
            self,
            task_queue,
            result_queue,
    ):
        multiprocessing.Process.__init__(self)
        self.log = PythonDLogger()
        self.log.job_name = 'checker'
        self.task_queue = task_queue
        self.result_queue = result_queue

    def run(self):
        self.log.info('starting...')
        HeartBeat(1).start()
        while self.run_once():
            pass
        self.log.info('terminating...')

    def run_once(self):
        task = self.task_queue.get()

        if task is END_TASK_MARKER:
            # TODO: find better solution, understand why heartbeat thread doesn't work
            heartbeat()
            self.task_queue.task_done()
            self.result_queue.put(END_TASK_MARKER)
            return False

        result = self.do_task(task)
        if result:
            self.result_queue.put(result)
        self.task_queue.task_done()

        return True

    def do_task(self, task):
        self.log.info("{0} : checking".format(task.module_name))

        # LOAD SOURCE
        module = Module(task.module_name)
        try:
            module.load_source()
        except Exception as error:
            self.log.warning("{0} : error on loading source : {1}, skipping module".format(
                task.module_name,
                error,
            ))
            return None
        else:
            self.log.info("{0} : source successfully loaded".format(task.module_name))

        if module.is_disabled_by_default() and not task.explicitly_enabled:
            self.log.info("{0} : disabled by default".format(task.module_name))
            return None

        # LOAD CONFIG
        paths = [
            DIRS.modules_user_config,
            DIRS.modules_stock_config,
        ]

        conf_abs_path = multi_path_find(
            name='{0}.conf'.format(task.module_name),
            paths=paths,
        )

        if conf_abs_path:
            self.log.info("{0} : found config file '{1}'".format(task.module_name, conf_abs_path))
            try:
                module.load_config(conf_abs_path)
            except Exception as error:
                self.log.warning("{0} : error on loading config : {1}, skipping module".format(
                    task.module_name, error))
                return None
        else:
            self.log.info("{0} : config was not found in '{1}', using default 1 job config".format(
                task.module_name, paths))

        # CHECK JOBS
        jobs = module.create_jobs()
        self.log.info("{0} : created {1} job(s) from the config".format(task.module_name, len(jobs)))

        successful_jobs_configs = list()
        for job in jobs:
            if job.autodetection_retry() > 0:
                successful_jobs_configs.append(job.config)
                self.log.info("{0}[{1}]: autodetection job, will be checked in main".format(task.module_name, job.name))
                continue

            try:
                job.init()
            except Exception as error:
                self.log.warning("{0}[{1}] : unhandled exception on init : {2}, skipping the job)".format(
                    task.module_name, job.name, error))
                continue

            try:
                ok = job.check()
            except Exception as error:
                self.log.warning("{0}[{1}] : unhandled exception on check : {2}, skipping the job".format(
                    task.module_name, job.name, error))
                continue

            if not ok:
                self.log.info("{0}[{1}] : check failed, skipping the job".format(task.module_name, job.name))
                continue

            self.log.info("{0}[{1}] : check successful".format(task.module_name, job.name))

            job.config['autodetection_retry'] = job.config['update_every']
            successful_jobs_configs.append(job.config)

        if not successful_jobs_configs:
            self.log.info("{0} : all jobs failed, skipping module".format(task.module_name))
            return None

        return Result(module.source.__name__, successful_jobs_configs)


class JobConf(OrderedDict):
    def __init__(self, *args):
        OrderedDict.__init__(self, *args)

    def set_defaults_from_module(self, module):
        for k in [k for k in JOB_BASE_CONF if hasattr(module, k)]:
            self[k] = getattr(module, k)

    def set_defaults_from_config(self, module_config):
        for k in [k for k in JOB_BASE_CONF if k in module_config]:
            self[k] = module_config[k]

    def set_job_name(self, name):
        self['job_name'] = re.sub(r'\s+', '_', name)

    def set_override_name(self, name):
        self['override_name'] = re.sub(r'\s+', '_', name)

    def as_dict(self):
        return copy.deepcopy(OrderedDict(self))


class Job:
    def __init__(
            self,
            service,
            module_name,
            config,
    ):
        self.service = service
        self.config = config
        self.module_name = module_name
        self.name = config['job_name']
        self.override_name = config['override_name']
        self.wrapped = None

    def init(self):
        self.wrapped = self.service(configuration=self.config.as_dict())

    def check(self):
        return self.wrapped.check()

    def post_check(self, min_update_every):
        if self.wrapped.update_every < min_update_every:
            self.wrapped.update_every = min_update_every

    def create(self):
        return self.wrapped.create()

    def autodetection_retry(self):
        return self.config['autodetection_retry']

    def run(self):
        self.wrapped.run()


class Module:
    def __init__(self, name):
        self.name = name
        self.source = None
        self.config = dict()

    def is_disabled_by_default(self):
        return bool(getattr(self.source, 'disabled_by_default', False))

    def load_source(self):
        self.source = load_module(self.name)

    def load_config(self, abs_path):
        self.config = load_config(abs_path) or dict()

    def gather_jobs_configs(self):
        job_names = [v for v in self.config if isinstance(self.config[v], dict)]

        if len(job_names) == 0:
            job_conf = JobConf(JOB_BASE_CONF)
            job_conf.set_defaults_from_module(self.source)
            job_conf.update(self.config)
            job_conf.set_job_name(self.name)
            job_conf.set_override_name(job_conf.pop('name'))
            return [job_conf]

        configs = list()
        for job_name in job_names:
            raw_job_conf = self.config[job_name]
            job_conf = JobConf(JOB_BASE_CONF)
            job_conf.set_defaults_from_module(self.source)
            job_conf.set_defaults_from_config(self.config)
            job_conf.update(raw_job_conf)
            job_conf.set_job_name(job_name)
            job_conf.set_override_name(job_conf.pop('name'))
            configs.append(job_conf)

        return configs

    def create_jobs(self, jobs_conf=None):
        return [Job(self.source.Service, self.name, conf) for conf in jobs_conf or self.gather_jobs_configs()]


class JobRunner(threading.Thread):
    def __init__(self, job):
        threading.Thread.__init__(self)
        self.daemon = True
        self.wrapped = job

    def run(self):
        self.wrapped.run()


class PluginConf(dict):
    def __init__(self, *args):
        dict.__init__(self, *args)

    def is_module_enabled(self, module_name, explicit):
        if module_name in self:
            return self[module_name]
        if explicit:
            return False
        return self['default_run']


class Plugin:
    def __init__(
            self,
            min_update_every=1,
            modules_to_run=tuple(AVAILABLE_MODULES),
    ):
        self.log = PythonDLogger()
        self.config = PluginConf(PLUGIN_BASE_CONF)
        self.task_queue = multiprocessing.JoinableQueue()
        self.result_queue = multiprocessing.JoinableQueue()
        self.min_update_every = min_update_every
        self.modules_to_run = modules_to_run
        self.auto_detection_jobs = list()
        self.tasks = list()
        self.results = list()
        self.checked_jobs = collections.defaultdict(list)
        self.runs = 0

    @staticmethod
    def shutdown():
        safe_print('DISABLE')
        exit(0)

    def run(self):
        jobs = self.create_jobs()
        if not jobs:
            return

        for job in self.prepare_jobs(jobs):
            self.log.info('{0}[{1}] : started in thread'.format(job.module_name, job.name))
            JobRunner(job).start()

        self.serve()

    def enqueue_tasks(self):
        for task in self.tasks:
            self.task_queue.put(task)
        self.task_queue.put(END_TASK_MARKER)

    def dequeue_results(self):
        while True:
            result = self.result_queue.get()
            self.result_queue.task_done()
            if result is END_TASK_MARKER:
                break
            self.results.append(result)

    def load_config(self):
        paths = [
            DIRS.user_config,
            DIRS.stock_config,
        ]

        self.log.info("checking for config in {0}".format(paths))
        abs_path = multi_path_find(name=PLUGIN_CONF_FILE, paths=paths)
        if not abs_path:
            self.log.warning('config was not found, using defaults')
            return True

        self.log.info("config found, loading config '{0}'".format(abs_path))
        try:
            config = load_config(abs_path) or dict()
        except Exception as error:
            self.log.error('error on loading config : {0}'.format(error))
            return False

        self.log.info('config successfully loaded')
        self.config.update(config)
        return True

    def setup(self):
        self.log.info('starting setup')
        if not self.load_config():
            return False

        if not self.config['enabled']:
            self.log.info('disabled in configuration file')
            return False

        for mod in self.modules_to_run:
            if self.config.is_module_enabled(mod, False):
                task = Task(mod, self.config.is_module_enabled(mod, True))
                self.tasks.append(task)
            else:
                self.log.info("{0} : disabled in configuration file".format(mod))

        if not self.tasks:
            self.log.info('no modules to run')
            return False

        worker = ModuleChecker(self.task_queue, self.result_queue)
        self.log.info('starting checker process ({0} module(s) to check)'.format(len(self.tasks)))
        worker.start()

        # TODO: timeouts?
        self.enqueue_tasks()
        self.task_queue.join()
        self.dequeue_results()
        self.result_queue.join()
        self.task_queue.close()
        self.result_queue.close()
        self.log.info('stopping checker process')
        worker.join()

        if not self.results:
            self.log.info('no modules to run')
            return False

        self.log.info("setup complete, {0} active module(s) : '{1}'".format(
            len(self.results),
            [v.module_name for v in self.results])
        )

        return True

    def create_jobs(self):
        jobs = list()
        for result in self.results:
            module = Module(result.module_name)
            try:
                module.load_source()
            except Exception as error:
                self.log.warning("{0} : error on loading module source : {1}, skipping module".format(
                    result.module_name, error))
                continue

            module_jobs = module.create_jobs(result.jobs_configs)
            self.log.info("{0} : created {1} job(s)".format(module.name, len(module_jobs)))
            jobs.extend(module_jobs)

        return jobs

    def prepare_jobs(self, jobs):
        prepared = list()

        for job in jobs:
            check_name = job.override_name or job.name
            if check_name in self.checked_jobs[job.module_name]:
                self.log.info('{0}[{1}] : already served by another job, skipping the job'.format(
                    job.module_name, job.name))
                continue

            try:
                job.init()
            except Exception as error:
                self.log.warning("{0}[{1}] : unhandled exception on init : {2}, skipping the job".format(
                    job.module_name, job.name, error))
                continue

            self.log.info("{0}[{1}] : init successful".format(job.module_name, job.name))

            try:
                ok = job.check()
            except Exception as error:
                self.log.warning("{0}[{1}] : unhandled exception on check : {2}, skipping the job".format(
                    job.module_name, job.name, error))
                continue

            if not ok:
                self.log.info('{0}[{1}] : check failed'.format(job.module_name, job.name))
                if job.autodetection_retry() > 0:
                    self.log.info('{0}[{1}] : will recheck every {2} second(s)'.format(
                        job.module_name, job.name, job.autodetection_retry()))
                    self.auto_detection_jobs.append(job)
                continue

            self.log.info('{0}[{1}] : check successful'.format(job.module_name, job.name))

            job.post_check(int(self.min_update_every))

            if not job.create():
                self.log.info('{0}[{1}] : create failed'.format(job.module_name, job.name))

            self.checked_jobs[job.module_name].append(check_name)
            prepared.append(job)

        return prepared

    def serve(self):
        gc_run = self.config['gc_run']
        gc_interval = self.config['gc_interval']

        while True:
            self.runs += 1

            # threads: main + heartbeat
            if threading.active_count() <= 2 and not self.auto_detection_jobs:
                return

            time.sleep(1)

            if gc_run and self.runs % gc_interval == 0:
                v = gc.collect()
                self.log.debug('GC collection run result: {0}'.format(v))

            self.auto_detection_jobs = [job for job in self.auto_detection_jobs if not self.retry_job(job)]

    def retry_job(self, job):
        stop_retrying = True
        retry_later = False

        if self.runs % job.autodetection_retry() != 0:
            return retry_later

        check_name = job.override_name or job.name
        if check_name in self.checked_jobs[job.module_name]:
            self.log.info("{0}[{1}]: already served by another job, give up on retrying".format(
                job.module_name, job.name))
            return stop_retrying

        try:
            ok = job.check()
        except Exception as error:
            self.log.warning("{0}[{1}] : unhandled exception on recheck : {2}, give up on retrying".format(
                job.module_name, job.name, error))
            return stop_retrying

        if not ok:
            self.log.info('{0}[{1}] : recheck failed, will retry in {2} second(s)'.format(
                job.module_name, job.name, job.autodetection_retry()))
            return retry_later
        self.log.info('{0}[{1}] : recheck successful'.format(job.module_name, job.name))

        if not job.create():
            return stop_retrying

        job.post_check(int(self.min_update_every))
        self.checked_jobs[job.module_name].append(check_name)
        JobRunner(job).start()

        return stop_retrying


def parse_cmd():
    opts = sys.argv[:][1:]
    debug = False
    trace = False
    update_every = 1
    modules_to_run = list()

    v = next((opt for opt in opts if opt.isdigit() and int(opt) >= 1), None)
    if v:
        update_every = v
        opts.remove(v)
    if 'debug' in opts:
        debug = True
        opts.remove('debug')
    if 'trace' in opts:
        trace = True
        opts.remove('trace')
    if opts:
        modules_to_run = list(opts)

    return collections.namedtuple(
        'CMD',
        [
            'update_every',
            'debug',
            'trace',
            'modules_to_run',
        ],
    )(
        update_every,
        debug,
        trace,
        modules_to_run,
    )


def main():
    cmd = parse_cmd()
    logger = PythonDLogger()

    if cmd.debug:
        logger.logger.severity = 'DEBUG'
    if cmd.trace:
        logger.log_traceback = True

    logger.info('using python v{0}'.format(PY_VERSION[0]))

    unknown_modules = set(cmd.modules_to_run) - set(AVAILABLE_MODULES)
    if unknown_modules:
        logger.error('unknown modules : {0}'.format(sorted(list(unknown_modules))))
        safe_print('DISABLE')
        return

    plugin = Plugin(
        cmd.update_every,
        cmd.modules_to_run or AVAILABLE_MODULES,
    )

    HeartBeat(1).start()

    if not plugin.setup():
        safe_print('DISABLE')
        return

    plugin.run()
    logger.info('exiting from main...')
    plugin.shutdown()


if __name__ == '__main__':
    main()