#!/usr/bin/env python3
# _._ coding:utf-8 _._


import os
import sys
import time
import shutil
import traceback
import configparser


class MonitorRun:
    @classmethod
    def monitor_run_time(cls, function):
        """
        监控运行时间
        :param function:
        :return:
        """
        def wrapper(*args, **kwargs):
            clock = time.clock()
            print('start run. clock time is :{0}'.format(clock))
            function(*args, **kwargs)
            clock_end = time.clock()
            print('end run. clock time is :{0}'.format(clock_end))

        return wrapper


class Service:

    cp = None
    path = os.path.split(os.path.realpath(__file__))[0]
    conf_path = os.path.join(path, 'conf')
    data_path = os.path.join(path, 'data')
    commands = {}

    # system
    stdin = '/dev/null'
    stdout = 'dev/null'
    stderr = 'dev/null'

    # user
    user = 'root'
    group = 'root'

    # dirs
    source_dir = None
    target_dir = None

    # filter_list
    filter_dirs = []

    si = None
    so = None
    se = None

    def __init__(self):
        self.commands = {'reload': self.reload, 'stop': self.stop, 'restart': self.restart}
        self.cp = configparser.ConfigParser()
        self.cp.read(os.path.join(self.conf_path, 'monitor.conf'), 'utf-8')

        try:
            self._valid_config()
        except OSError as e:
            print("valid config fail. error: {0}".format(e.strerror))
            sys.exit(1)

        if not os.path.exists(self.source_dir) or not os.path.isdir(self.source_dir):
            raise NotADirectoryError(self.source_dir + '不是一个有效的目录')
        if not os.path.exists(self.target_dir) and not os.path.isdir(self.target_dir):
            os.makedirs(self.target_dir)

    def _valid_config(self):
        """
        检查配置文件
        :return:
        """
        if not self.cp.has_section('system'):
            raise configparser.NoSectionError("缺少系统配置模块")
        if not self.cp.has_section('user'):
            raise configparser.NoSectionError("缺少权限配置模块")
        if not self.cp.has_section('dirs'):
            raise configparser.NoSectionError("没有配置监控目录与目标目录")

        # dirs
        self.source_dir = self.cp.get('dirs', 'source_dir')
        self.target_dir = self.cp.get('dirs', 'target_dir')

        # system
        if self.cp.has_option('system', 'std_in'):
            self.stdin = self.cp.get('system', 'std_in')
        if self.cp.has_option('system', 'std_out'):
            self.stdout = self.cp.get('system', 'std_out')
        if self.cp.has_option('system', 'std_err'):
            self.stderr = self.cp.get('system', 'std_err')

        # user
        if self.cp.has_option('user', 'user'):
            self.user = self.cp.get('user', 'user')
        if self.cp.has_option('user', 'group'):
            self.group = self.cp.get('user', 'group')

        # filters
        if self.cp.has_section('filter') and self.cp.has_option('filter', 'filter_list'):
            with open(os.path.join(self.conf_path, self.cp.get('filter', 'filter_list'))) as f:
                for line in f:
                    self.filter_dirs.append(line.strip("\n"))

    def start(self) -> None:
        """
        创建守护进程，主进程退出，开始监控
        :return:
        """
        if self.valid_service() != -1:
            return -1
        print("monitor dir: {0}".format(self.source_dir))
        print("start service...")
        try:
            pid = os.fork()
            if pid > 0:
                print("start service success")
                sys.exit(0)
        except OSError as e:
            print("start service failed. errorInfo: {0} {1}".format(e.errno, e.strerror))
            sys.exit(1)

        os.chdir('/')
        os.setsid()
        os.umask(0)

        try:
            pid = os.fork()
            if pid > 0:
                sys.exit(0)
        except OSError as e:
            sys.stderr.write("start service failed. errorInfo: {0} {1}".format(e.errno, e.strerror))
            sys.exit(1)

        sys.stdout.flush()
        sys.stderr.flush()

        self.si = open(self.stdin, 'r')
        self.so = open(self.stdout, 'a+')
        self.se = open(self.stderr, 'a+')
        os.dup2(self.si.fileno(), sys.stdin.fileno())
        os.dup2(self.so.fileno(), sys.stdout.fileno())
        os.dup2(self.se.fileno(), sys.stderr.fileno())

        with open(os.path.join(self.data_path, '.pid'), 'w') as f:
            f.write(str(os.getpid()))
        with open(os.path.join(self.data_path, '.status'), 'w') as f:
            f.write('1')
        open(os.path.join(self.data_path, '.command'), 'w').close()

        self._monitor()

    def reload(self):
        """
        重新加载配置文件
        :return:
        """
        if self.valid_service() == -1:
            return -1

        try:
            self._valid_config()
        except OSError:
            traceback.print_exc(file=self.se)
            return -1
        return 1

    def stop(self):
        """
        结束服务进程
        :return:
        """
        if self.valid_service() == -1:
            return -1

        with open(os.path.join(self.data_path, '.status'), 'w') as f:
            f.write('1')
        open(os.path.join(self.data_path, '.command'), 'w').close()
        open(os.path.join(self.data_path, '.pid'), 'w').close()

        sys.exit(0)

    def restart(self):
        pass

    def error(self):
        pass

    def valid_service(self):
        """
        检查服务是否在运行
        :return:
        """
        pid_path = os.path.join(self.data_path, '.pid')
        try:
            if os.path.exists(pid_path):
                with open(pid_path, 'r') as f:
                    if f.readline() == str(os.getpid()):
                        return os.getpid()
                    else:
                        return -1
            else:
                return -1
        except OSError:
            traceback.print_exc(file=self.se)
            return -1

    def _monitor(self):
        """
        开启监听
        :return:
        """
        while True:
            self._flush_log()

            self._command_line()

            self._contrast(self.source_dir)

            time.sleep(1)

    def _flush_log(self):
        """
        刷新日志文件
        :return:
        """
        if time.localtime(time.time()).tm_min == 1 and self.stdout != '/dev/null':
            self.so.close()
            os.remove(self.stdout)
            self.so = open(self.stdout, 'a+')
            os.dup2(self.so.fileno(), sys.stdout.fileno())

    def _command_line(self):
        """
        执行外部命令
        :return:
        """
        command_path = os.path.join(self.data_path, '.command')
        status_path = os.path.join(self.data_path, '.status')
        try:
            if os.path.exists(command_path):
                with open(command_path, 'r') as f:
                    command = f.readline()
                    status = self.commands.get(command, self.error)()
                    with open(status_path, 'w') as sf:
                        sf.write(str(status))
                        open(command_path, 'w').close()
            else:
                open(command_path, 'w').close()
        except OSError:
            with open(status_path, 'w') as sf:
                sf.write('-1')
            traceback.print_exc(file=self.se)

    def _contrast(self, source_dir: str) -> None:
        """
        递归遍历目录，检查每个文件
        :param source_dir:
        :return:
        """
        # 检查源目录，更新文件及目录
        try:
            for source_path, dirs, files in os.walk(source_dir):
                target_path = self._get_target(source_path)

                # 跳过filter_dirs中的目录
                filter_path_list = [os.path.join(source_path, filter_dir) for filter_dir in dirs]
                for filter_path in filter_path_list:
                    if filter_path in self.filter_dirs:
                        dirs[:] = [dir_path for dir_path in dirs if dir_path != os.path.split(filter_path)[-1]]
                        filter_target_path = self._get_target(filter_path)
                        if not os.path.exists(filter_target_path):
                            os.makedirs(filter_target_path)
                            shutil.chown(filter_target_path, self.user, self.group)
                            print("create dir: {0}".format(filter_target_path))
                            continue

                # 对比目录差异
                if os.path.exists(target_path):
                    list_target_path = os.listdir(target_path)
                    list_diff_path = list(set(dirs + files) ^ set(list_target_path))
                    for path in list_diff_path:
                        target_path = os.path.join(target_path, path)
                        if os.path.exists(target_path) and self._get_source(target_path) not in self.filter_dirs:
                            shutil.rmtree(target_path) if os.path.isdir(target_path) else os.remove(target_path)
                            print("remove path: {0}".format(target_path))

                # 同步文件
                for file in files:
                    source = os.path.join(source_path, file)
                    target = self._get_target(source)
                    if self._contrast_file(source, target):
                        self._copy_file(source, target)
        except OSError:
            traceback.print_exc(file=self.se)

    def _get_target(self, source: str):
        """
        获取目标路径
        :param source:
        :return:
        """
        return source.replace(self.source_dir, self.target_dir)

    def _get_source(self, target: str):
        """
        获取源路径
        :param target:
        :return:
        """
        return target.replace(self.target_dir, self.source_dir)

    def _contrast_file(self, source: str, target: str) -> bool:
        """
        对比文件的mtime属性
        :param source:
        :param target:
        :return:
        """
        if not os.path.exists(target):
            return True
        source = os.stat(source)
        target = os.stat(target)
        if int(source.st_mtime) > int(target.st_mtime):
            return True
        else:
            return False

    def _copy_file(self, source: str, target: str, user: str = None, group: str = None) -> None:
        """
        拷贝文件并更改权限
        :param source:
        :param target:
        :param user:
        :param group:
        :return:
        """
        if not user:
            user = self.user
        if not group:
            group = self.group
        try:
            target_path = os.path.dirname(target)
            if not os.path.exists(target_path):
                os.makedirs(target_path)
                shutil.chown(target_path, user, group)
                print("create dirs: {0}".format(target_path))
            shutil.copy(source, target)
            st = os.stat(source)
            os.utime(target, (int(st.st_atime), int(st.st_mtime)))
            shutil.chown(target, user, group)
            print("copy file {0} to {1}".format(source, target))
        except FileNotFoundError:
            traceback.print_exc(file=self.se)

    def _remove_file(self, source: str, target: str) -> None:
        """
        移除文件并重新拷贝
        :param source:
        :param target:
        :return:
        """
        os.remove(target)
        self._copy_file(source, target)