#
# Handler library for Linux IaaS
#
# Copyright 2014 Microsoft Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


"""
JSON def:
HandlerEnvironment.json
[{
  "name": "ExampleHandlerLinux",
  "seqNo": "seqNo",
  "version": "1.0",
  "handlerEnvironment": {
    "logFolder": "<your log folder location>",
    "configFolder": "<your config folder location>",
    "statusFolder": "<your status folder location>",
    "heartbeatFile": "<your heartbeat file location>",

  }
}]

Example ./config/1.settings
"{"runtimeSettings":[{"handlerSettings":{"protectedSettingsCertThumbprint":"1BE9A13AA1321C7C515EF109746998BAB6D86FD1","protectedSettings":
"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","publicSettings":{"port":"3000"}}}]}"


Example HeartBeat
{
"version": 1.0,
    "heartbeat" : {
        "status": "ready",
        "code": 0,
        "Message": "Sample Handler running. Waiting for a new configuration from user."
    }
}
Example Status Report:
[{"version":"1.0","timestampUTC":"2014-05-29T04:20:13Z","status":{"name":"Chef Extension Handler","operation":"chef-client-run","status":"success","code":0,"formattedMessage":{"lang":"en-US","message":"Chef-client run success"}}}]

"""

import os
import os.path
import sys
import base64
import json
import time
import re

from xml.etree import ElementTree
from os.path import join
from Utils.WAAgentUtil import waagent
from waagent import LoggerInit

DateTimeFormat = "%Y-%m-%dT%H:%M:%SZ"

MANIFEST_XML = "manifest.xml"


class HandlerContext:
    def __init__(self, name):
        self._name = name
        self._version = '0.0'
        self._config_dir = None
        self._log_dir = None
        self._log_file = None
        self._status_dir = None
        self._heartbeat_file = None
        self._seq_no = -1
        self._status_file = None
        self._settings_file = None
        self._config = None
        return


class HandlerUtility:
    def __init__(self, log, error, s_name=None, l_name=None, extension_version=None, logFileName='extension.log',
                 console_logger=None, file_logger=None):
        self._log = log
        self._log_to_con = console_logger
        self._log_to_file = file_logger
        self._error = error
        self._logFileName = logFileName
        if s_name is None or l_name is None or extension_version is None:
            (l_name, s_name, extension_version) = self._get_extension_info()

        self._short_name = s_name
        self._extension_version = extension_version
        self._log_prefix = '[%s-%s] ' % (l_name, extension_version)

    def get_extension_version(self):
        return self._extension_version

    def _get_log_prefix(self):
        return self._log_prefix

    def _get_extension_info(self):
        if os.path.isfile(MANIFEST_XML):
            return self._get_extension_info_manifest()

        ext_dir = os.path.basename(os.getcwd())
        (long_name, version) = ext_dir.split('-')
        short_name = long_name.split('.')[-1]

        return long_name, short_name, version

    def _get_extension_info_manifest(self):
        with open(MANIFEST_XML) as fh:
            doc = ElementTree.parse(fh)
            namespace = doc.find('{http://schemas.microsoft.com/windowsazure}ProviderNameSpace').text
            short_name = doc.find('{http://schemas.microsoft.com/windowsazure}Type').text
            version = doc.find('{http://schemas.microsoft.com/windowsazure}Version').text

            long_name = "%s.%s" % (namespace, short_name)
            return (long_name, short_name, version)

    def _get_current_seq_no(self, config_folder):
        seq_no = -1
        cur_seq_no = -1
        freshest_time = None
        for subdir, dirs, files in os.walk(config_folder):
            for file in files:
                try:
                    cur_seq_no = int(os.path.basename(file).split('.')[0])
                    if (freshest_time == None):
                        freshest_time = os.path.getmtime(join(config_folder, file))
                        seq_no = cur_seq_no
                    else:
                        current_file_m_time = os.path.getmtime(join(config_folder, file))
                        if (current_file_m_time > freshest_time):
                            freshest_time = current_file_m_time
                            seq_no = cur_seq_no
                except ValueError:
                    continue
        return seq_no

    def log(self, message):
        self._log(self._get_log_prefix() + message)

    def log_to_console(self, message):
        if self._log_to_con is not None:
            self._log_to_con(self._get_log_prefix() + message)
        else:
            self.error("Unable to log to console, console log method not set")

    def log_to_file(self, message):
        if self._log_to_file is not None:
            self._log_to_file(self._get_log_prefix() + message)
        else:
            self.error("Unable to log to file, file log method not set")

    def error(self, message):
        self._error(self._get_log_prefix() + message)

    @staticmethod
    def redact_protected_settings(content):
        redacted_tmp = re.sub('"protectedSettings":\s*"[^"]+=="', '"protectedSettings": "*** REDACTED ***"', content)
        redacted = re.sub('"protectedSettingsCertThumbprint":\s*"[^"]+"', '"protectedSettingsCertThumbprint": "*** REDACTED ***"', redacted_tmp)
        return redacted

    def _parse_config(self, ctxt):
        config = None
        try:
            config = json.loads(ctxt)
        except:
            self.error('JSON exception decoding ' + HandlerUtility.redact_protected_settings(ctxt))

        if config is None:
            self.error("JSON error processing settings file:" + HandlerUtility.redact_protected_settings(ctxt))
        else:
            handlerSettings = config['runtimeSettings'][0]['handlerSettings']
            if 'protectedSettings' in handlerSettings and \
                    'protectedSettingsCertThumbprint' in handlerSettings and \
                    handlerSettings['protectedSettings'] is not None and \
                    handlerSettings["protectedSettingsCertThumbprint"] is not None:
                protectedSettings = handlerSettings['protectedSettings']
                thumb = handlerSettings['protectedSettingsCertThumbprint']
                cert = waagent.LibDir + '/' + thumb + '.crt'
                pkey = waagent.LibDir + '/' + thumb + '.prv'
                unencodedSettings = base64.standard_b64decode(protectedSettings)
                openSSLcmd = "openssl smime -inform DER -decrypt -recip {0} -inkey {1}"
                cleartxt = waagent.RunSendStdin(openSSLcmd.format(cert, pkey), unencodedSettings)[1]
                if cleartxt is None:
                    self.error("OpenSSL decode error using  thumbprint " + thumb)
                    self.do_exit(1, "Enable", 'error', '1', 'Failed to decrypt protectedSettings')
                jctxt = ''
                try:
                    jctxt = json.loads(cleartxt)
                except:
                    self.error('JSON exception decoding ' + HandlerUtility.redact_protected_settings(cleartxt))
                handlerSettings['protectedSettings']=jctxt
                self.log('Config decoded correctly.')
        return config

    def do_parse_context(self, operation):
        _context = self.try_parse_context()
        if not _context:
            self.do_exit(1, operation, 'error', '1', operation + ' Failed')
        return _context

    def try_parse_context(self):
        self._context = HandlerContext(self._short_name)
        handler_env = None
        config = None
        ctxt = None
        code = 0
        # get the HandlerEnvironment.json. According to the extension handler spec, it is always in the ./ directory
        self.log('cwd is ' + os.path.realpath(os.path.curdir))
        handler_env_file = './HandlerEnvironment.json'
        if not os.path.isfile(handler_env_file):
            self.error("Unable to locate " + handler_env_file)
            return None
        ctxt = waagent.GetFileContents(handler_env_file)
        if ctxt == None:
            self.error("Unable to read " + handler_env_file)
        try:
            handler_env = json.loads(ctxt)
        except:
            pass
        if handler_env == None:
            self.log("JSON error processing " + handler_env_file)
            return None
        if type(handler_env) == list:
            handler_env = handler_env[0]

        self._context._name = handler_env['name']
        self._context._version = str(handler_env['version'])
        self._context._config_dir = handler_env['handlerEnvironment']['configFolder']
        self._context._log_dir = handler_env['handlerEnvironment']['logFolder']

        self._context._log_file = os.path.join(handler_env['handlerEnvironment']['logFolder'], self._logFileName)
        self._change_log_file()
        self._context._status_dir = handler_env['handlerEnvironment']['statusFolder']
        self._context._heartbeat_file = handler_env['handlerEnvironment']['heartbeatFile']
        self._context._seq_no = self._get_current_seq_no(self._context._config_dir)
        if self._context._seq_no < 0:
            self.error("Unable to locate a .settings file!")
            return None
        self._context._seq_no = str(self._context._seq_no)
        self.log('sequence number is ' + self._context._seq_no)
        self._context._status_file = os.path.join(self._context._status_dir, self._context._seq_no + '.status')
        self._context._settings_file = os.path.join(self._context._config_dir, self._context._seq_no + '.settings')
        self.log("setting file path is" + self._context._settings_file)
        ctxt = None
        ctxt = waagent.GetFileContents(self._context._settings_file)
        if ctxt == None:
            error_msg = 'Unable to read ' + self._context._settings_file + '. '
            self.error(error_msg)
            return None

        self.log("JSON config: " + HandlerUtility.redact_protected_settings(ctxt))
        self._context._config = self._parse_config(ctxt)
        return self._context

    def _change_log_file(self):
        self.log("Change log file to " + self._context._log_file)
        LoggerInit(self._context._log_file, '/dev/stdout')
        self._log = waagent.Log
        self._error = waagent.Error

    def set_verbose_log(self, verbose):
        if (verbose == "1" or verbose == 1):
            self.log("Enable verbose log")
            LoggerInit(self._context._log_file, '/dev/stdout', verbose=True)
        else:
            self.log("Disable verbose log")
            LoggerInit(self._context._log_file, '/dev/stdout', verbose=False)

    def is_seq_smaller(self):
        return int(self._context._seq_no) <= self._get_most_recent_seq()

    def save_seq(self):
        self._set_most_recent_seq(self._context._seq_no)
        self.log("set most recent sequence number to " + self._context._seq_no)

    def exit_if_enabled(self, remove_protected_settings=False):
        self.exit_if_seq_smaller(remove_protected_settings)

    def exit_if_seq_smaller(self, remove_protected_settings):
        if(self.is_seq_smaller()):
            self.log("Current sequence number, " + self._context._seq_no + ", is not greater than the sequence number of the most recent executed configuration. Exiting...")
            sys.exit(0)
        self.save_seq()

        if remove_protected_settings:
            self.scrub_settings_file()

    def _get_most_recent_seq(self):
        if (os.path.isfile('mrseq')):
            seq = waagent.GetFileContents('mrseq')
            if (seq):
                return int(seq)

        return -1

    def is_current_config_seq_greater_inused(self):
        return int(self._context._seq_no) > self._get_most_recent_seq()

    def get_inused_config_seq(self):
        return self._get_most_recent_seq()

    def set_inused_config_seq(self, seq):
        self._set_most_recent_seq(seq)

    def _set_most_recent_seq(self, seq):
        waagent.SetFileContents('mrseq', str(seq))

    def do_status_report(self, operation, status, status_code, message):
        self.log("{0},{1},{2},{3}".format(operation, status, status_code, message))
        tstamp = time.strftime(DateTimeFormat, time.gmtime())
        stat = [{
            "version": self._context._version,
            "timestampUTC": tstamp,
            "status": {
                "name": self._context._name,
                "operation": operation,
                "status": status,
                "code": status_code,
                "formattedMessage": {
                    "lang": "en-US",
                    "message": message
                }
            }
        }]
        stat_rept = json.dumps(stat)
        if self._context._status_file:
            tmp = "%s.tmp" % (self._context._status_file)
            with open(tmp, 'w+') as f:
                f.write(stat_rept)
            os.rename(tmp, self._context._status_file)

    def do_heartbeat_report(self, heartbeat_file, status, code, message):
        # heartbeat
        health_report = '[{"version":"1.0","heartbeat":{"status":"' + status + '","code":"' + code + '","Message":"' + message + '"}}]'
        if waagent.SetFileContents(heartbeat_file, health_report) == None:
            self.error('Unable to wite heartbeat info to ' + heartbeat_file)

    def do_exit(self, exit_code, operation, status, code, message):
        try:
            self.do_status_report(operation, status, code, message)
        except Exception as e:
            self.log("Can't update status: " + str(e))
        sys.exit(exit_code)

    def get_name(self):
        return self._context._name

    def get_seq_no(self):
        return self._context._seq_no

    def get_log_dir(self):
        return self._context._log_dir

    def get_handler_settings(self):
        if (self._context._config != None):
            return self._context._config['runtimeSettings'][0]['handlerSettings']
        return None

    def get_protected_settings(self):
        if (self._context._config != None):
            return self.get_handler_settings().get('protectedSettings')
        return None

    def get_public_settings(self):
        handlerSettings = self.get_handler_settings()
        if (handlerSettings != None):
            return self.get_handler_settings().get('publicSettings')
        return None

    def scrub_settings_file(self):
        content = waagent.GetFileContents(self._context._settings_file)
        redacted = HandlerUtility.redact_protected_settings(content)

        waagent.SetFileContents(self._context._settings_file, redacted)