# -*- coding: utf-8 -*-

# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2018 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT
#

import copy
import re


class PhpConfBaseException(Exception):
    """Base class for all php.conf exceptions"""
    def __init__(self, message):
        super().__init__(message)


class PhpConfReadError(PhpConfBaseException):
    def __init__(self, message=None):
        if message is None:
            message = "File open/read error"
        super().__init__(message)


class PhpConfLoadException(PhpConfBaseException):
    def __init__(self, line_num, reason):
        message = f"Error at line {line_num}: {reason}. Please see " \
            "http://docs.cloudlinux.com/index.html?custom_php_ini_options.html"
        super().__init__(message)


class PhpConfNoSuchAlternativeException(PhpConfBaseException):
    def __init__(self, version):
        self.php_version = version
        message = f'No such alternative version ({version})'
        super().__init__(message)


# For unit tests
def _open(file_name):
    return open(file_name, mode='rb')


class PhpConfReader:
    """
    Class for read and parse /etc/cl.selector/php.conf
    During read this file, its syntax check is performed
    Contains methods for get its data for selectoctl and cagefsctl utilities in required formats
    """
    DIRECTIVES_LIST = ['Directive', 'Default', 'Type', 'Comment', 'Range', 'Remark']
    TYPES_LIST = ['value', 'list', 'bool']

    def __init__(self, phpconf_path):
        self.phpconf_path = phpconf_path
        # /etc/cl.selector/php.conf contents as dictionary
        # Example:
        # { 'safe_mode': {'Default': 'Off', 'Comment': 'Enables PHP safe mode.',
        #                 'Remark': '<5.4.0', 'Type': 'bool'},
        #   'file_uploads': {'Default': 'On', 'Comment': 'Allows uploading files over HTTP.',
        #                    'Type': 'bool'}
        # }
        self._php_conf = None

    def _read_file(self):
        """
        Reads file and returns its content
        :return: List of filelines
        """
        try:
            f = _open(self.phpconf_path)
            conf_lines = f.readlines()
            f.close()
            return conf_lines
        except (OSError, IOError) as e:
            # Open/read error
            raise PhpConfReadError(e.strerror) from e

    def _php_conf_load(self):
        data = {}
        conf_lines = self._read_file()
        try:
            directive = None
            current_section = None
            # Analyze lines
            for line_num, line in enumerate(conf_lines, start=1):
                # line example: 'Directive = upload_max_filesize'
                line = line.strip().decode('utf-8', "ignore")
                # pass comments
                if line.startswith('#'):
                    continue
                # Empty line - separator between directives
                if len(line) == 0:
                    directive = None
                    current_section = None
                    continue
                if '=' not in line:
                    # Separator = not found in line - error
                    raise PhpConfLoadException(line_num, "Required separator = not found")
                line_parts = line.split('=', 1)
                directive_name = line_parts[0].strip()
                directive_value = line_parts[1].strip()
                if directive_name not in self.DIRECTIVES_LIST:
                    # Invalid directive
                    raise PhpConfLoadException(line_num, f"Unknown directive '{directive_name}' found")
                if not directive and directive_name != 'Directive':
                    # No current directive and some other directive found - error
                    raise PhpConfLoadException(line_num, f"'{directive_name}' found, but no 'Directive' before it")
                if directive_name == 'Directive':
                    if directive:
                        # 'Directive' duplicate
                        raise PhpConfLoadException(line_num, f"Directive '{directive_name}' duplicate")
                    # Save current directive name and create placeholder for diirective data
                    directive = directive_value
                    current_section = directive_value
                    data[current_section] = {}
                else:
                    if directive_name in data[current_section]:
                        # Directive already present
                        raise PhpConfLoadException(line_num, f"Directive '{directive_name}' duplicate")
                    if directive_name == 'Type' and directive_value not in self.TYPES_LIST:
                        raise PhpConfLoadException(line_num,
                                                   f"Directive is Type, but it value '{directive_value}' is invalid")
                    data[current_section][directive_name] = directive_value
            # Successfull end
            self._php_conf = data
        except PhpConfLoadException as e:
            # Parsing error
            raise e
        except Exception as e:
            raise PhpConfBaseException(e) from e

    def get_config_for_selectorctl(self, php_version, php_versions_map):
        """
        Retrives php.conf for selectorctl needs
        :param php_version: PHP version to filter options
        :param php_versions_map: Short to full PHP version map. Example: {'4.4', '4.4.9'}
        :return: dict
        Example:
            {'file_uploads': {'default': 'On',
                              'comment': 'Allows uploading files over HTTP.',
                              'type': 'bool'},
             'max_execution_time': {'default': '30',
                                    'comment': 'The maximum time in seconds a script is allowed to run '
                                               'before it is terminated.',
                                    'type': 'value'},
            }
        """
        # if config not loaded - load it
        if not self._php_conf:
            self._php_conf_load()
        out_dict = {}
        for directive_name, directive_data in self._php_conf.items():
            # directive_data example:
            # { 'Default': 'Off', 'Comment': 'Enables PHP safe mode.',
            #   'Remark': '<5.4.0', 'Type': 'bool'}
            # if directive has Remark attribute, compare version with supplied and pass if need
            if 'Remark' in directive_data and not self._check_version(directive_data['Remark'],
                                                                      php_version, php_versions_map):
                continue
            out_dict[directive_name] = {}
            if 'Default' in directive_data:
                out_dict[directive_name]['default'] = directive_data['Default']
            if 'Comment' in directive_data:
                out_dict[directive_name]['comment'] = directive_data['Comment']
            if 'Type' in directive_data:
                out_dict[directive_name]['type'] = directive_data['Type']
            if 'Range' in directive_data:
                out_dict[directive_name]['range'] = directive_data['Range']
        return out_dict

    def get_config_for_cagefsctl(self):
        """
        Retrives php.conf for selectorctl needs
        :return: dict
        Example:
            {'safe_mode': {'Remark': '<5.4.0', 'Type': 'bool'},
             'file_uploads': {'Type': 'bool'}
            }
        """
        # if config not loaded - load it
        if not self._php_conf:
            self._php_conf_load()
        out_dict = {}
        for directive_name, directive_data in self._php_conf.items():
            out_dict[directive_name] = copy.deepcopy(directive_data)
            if 'Comment' in out_dict[directive_name]:
                del out_dict[directive_name]['Comment']
        return out_dict

    @staticmethod
    def _check_version(test, version, php_versions_map):
        """
        Compares version in use and version required by PHP feature
        and return true if PHP feature satisfies
        :param test: Condition to filter from php.conf ('Remark' option value), such as <5.4.0
        :param version: PHP Verson to check filter matching, such as 5.3
        :param php_versions_map: Short to full PHP version map. Example: {'4.4': '4.4.9'}
        :return: bool: true - condition true, false - else
        """
        # if test has 2 section, add third
        if len(test.split('.')) == 2:
            test += '.0'
        patt = re.compile(r'([<>=]{1,2})?(\d+\.\d+\.\d+)\.?')
        m = patt.match(test)
        if not m:
            raise PhpConfNoSuchAlternativeException(test)
        action = m.group(1)
        test_int = PhpConfReader._full_version_string_to_int(m.group(2), action)
        version_int = PhpConfReader._full_version_string_to_int(php_versions_map[version], action)
        if action == r'<' and version_int < test_int:
            return True
        if action == r'<=' and version_int <= test_int:
            return True
        if action == r'>' and version_int > test_int:
            return True
        if action == r'>=' and version_int >= test_int:
            return True
        if not action or action == r'=':
            if version_int == test_int:
                return True
        return False

    @staticmethod
    def _full_version_string_to_int(s_ver_full, action):
        """
        Convert version string (such as '5.3.29') to int (10653)
        :param s_ver_full: PHP version string. Only full, 3-section versions are allowed
        :param action: Compare type. If None or '=' function will not use third section from version
        :return: integer
        """
        v_array = [int(x) for x in s_ver_full.split('.')]
        ver_int = v_array[0] << 11 | v_array[1] << 7
        if not action or action == r'=':
            return ver_int
        return ver_int | v_array[2]