# Copyright (C) 2009  Internet Systems Consortium.
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SYSTEMS CONSORTIUM
# DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
# INTERNET SYSTEMS CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
# FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
# WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

"""This module holds the BindCmdInterpreter class. This provides the
   core functionality for bindctl. It maintains a session with
   b10-cmdctl, holds local configuration and module information, and
   handles command line interface commands"""

import sys
from cmd import Cmd
from bindctl.exception import *
from bindctl.moduleinfo import *
from bindctl.cmdparse import BindCmdParse
from xml.dom import minidom
import isc
import isc.cc.data
import http.client
import json
import inspect
import pprint
import ssl, socket
import os, time, random, re
import getpass
from hashlib import sha1
import csv
import pwd
import getpass

try:
    from collections import OrderedDict
except ImportError:
    from bindctl.mycollections import OrderedDict

# if we have readline support, use that, otherwise use normal stdio
try:
    import readline
    my_readline = readline.get_line_buffer
except ImportError:
    my_readline = sys.stdin.readline

CSV_FILE_NAME = 'default_user.csv'
FAIL_TO_CONNECT_WITH_CMDCTL = "Fail to connect with b10-cmdctl module, is it running?"
CONFIG_MODULE_NAME = 'config'
CONST_BINDCTL_HELP = """
usage: <module name> <command name> [param1 = value1 [, param2 = value2]]
Type Tab character to get the hint of module/command/parameters.
Type \"help(? h)\" for help on bindctl.
Type \"<module_name> help\" for help on the specific module.
Type \"<module_name> <command_name> help\" for help on the specific command.
\nAvailable module names: """

class ValidatedHTTPSConnection(http.client.HTTPSConnection):
    '''Overrides HTTPSConnection to support certification 
    validation. '''
    def __init__(self, host, ca_certs):
        http.client.HTTPSConnection.__init__(self, host)
        self.ca_certs = ca_certs

    def connect(self):
        ''' Overrides the connect() so that we do 
        certificate validation. '''
        sock = socket.create_connection((self.host, self.port),
                                        self.timeout)
        if self._tunnel_host:
            self.sock = sock
            self._tunnel()
       
        req_cert = ssl.CERT_NONE
        if self.ca_certs:
            req_cert = ssl.CERT_REQUIRED
        self.sock = ssl.wrap_socket(sock, self.key_file,
                                    self.cert_file,
                                    cert_reqs=req_cert,
                                    ca_certs=self.ca_certs)

class BindCmdInterpreter(Cmd):
    """simple bindctl example."""    

    def __init__(self, server_port = 'localhost:8080', pem_file = None):
        Cmd.__init__(self)
        self.location = ""
        self.prompt_end = '> '
        self.prompt = self.prompt_end
        self.ruler = '-'
        self.modules = OrderedDict()
        self.add_module_info(ModuleInfo("help", desc = "Get help for bindctl"))
        self.server_port = server_port
        self.conn = ValidatedHTTPSConnection(self.server_port,
                                             ca_certs=pem_file)
        self.session_id = self._get_session_id()
        self.config_data = None
        
    def _get_session_id(self):
        '''Generate one session id for the connection. '''
        rand = os.urandom(16)
        now = time.time()
        session_id = sha1(("%s%s%s" %(rand, now,
                                      socket.gethostname())).encode())
        digest = session_id.hexdigest()
        return digest
    
    def run(self):
        '''Parse commands from user and send them to cmdctl. '''
        try:
            if not self.login_to_cmdctl():
                return 

            self.cmdloop()
        except FailToLogin as err:
            print(err)
            print(FAIL_TO_CONNECT_WITH_CMDCTL)
        except KeyboardInterrupt:
            print('\nExit from bindctl')

    def _get_saved_user_info(self, dir, file_name):
        ''' Read all the available username and password pairs saved in 
        file(path is "dir + file_name"), Return value is one list of elements
        ['name', 'password'], If get information failed, empty list will be 
        returned.'''
        if (not dir) or (not os.path.exists(dir)):
            return []

        try:
            csvfile = None
            users = []
            csvfile = open(dir + file_name)
            users_info = csv.reader(csvfile)
            for row in users_info:
                users.append([row[0], row[1]])
        except (IOError, IndexError) as err:
            print("Error reading saved username and password from %s%s: %s" % (dir, file_name, err))
        finally:
            if csvfile:
                csvfile.close()
            return users

    def _save_user_info(self, username, passwd, dir, file_name):
        ''' Save username and password in file "dir + file_name"
        If it's saved properly, return True, or else return False. '''
        try:
            if not os.path.exists(dir):
                os.mkdir(dir, 0o700)

            csvfilepath = dir + file_name 
            csvfile = open(csvfilepath, 'w')
            os.chmod(csvfilepath, 0o600)
            writer = csv.writer(csvfile)
            writer.writerow([username, passwd])
            csvfile.close()
        except IOError as err:
            print("Error saving user information:", err)
            print("user info file name: %s%s" % (dir, file_name))
            return False

        return True

    def login_to_cmdctl(self):
        '''Login to cmdctl with the username and password inputted 
        from user. After the login is sucessful, the username and
        password will be saved in 'default_user.csv', when run the next
        time, username and password saved in 'default_user.csv' will be
        used first.
        '''
        csv_file_dir = pwd.getpwnam(getpass.getuser()).pw_dir
        csv_file_dir += os.sep + '.bind10' + os.sep
        users = self._get_saved_user_info(csv_file_dir, CSV_FILE_NAME)
        for row in users:
            param = {'username': row[0], 'password' : row[1]}
            try:
                response = self.send_POST('/login', param)
                data = response.read().decode()
            except socket.error as err:
                print("Socket error while sending login information:", err)
                raise FailToLogin()

            if response.status == http.client.OK:
                print(data + ' login as ' + row[0] )
                return True 

        count = 0
        print("[TEMP MESSAGE]: username :root  password :bind10")
        while True:
            count = count + 1
            if count > 3:
                print("Too many authentication failures")
                return False

            username = input("Username:")
            passwd = getpass.getpass()
            param = {'username': username, 'password' : passwd}
            try:
                response = self.send_POST('/login', param)
                data = response.read().decode()
                print(data)
            except socket.error as err:
                print("Socket error while sending login information:", err)
                raise FailToLogin()

            if response.status == http.client.OK:
                self._save_user_info(username, passwd, csv_file_dir, CSV_FILE_NAME)
                return True

    def _update_commands(self):
        '''Update the commands of all modules. '''
        for module_name in self.config_data.get_config_item_list():
            self._prepare_module_commands(self.config_data.get_module_spec(module_name))

    def send_GET(self, url, body = None):
        '''Send GET request to cmdctl, session id is send with the name
        'cookie' in header.
        '''
        headers = {"cookie" : self.session_id}
        self.conn.request('GET', url, body, headers)
        res = self.conn.getresponse()
        reply_msg = res.read()
        if reply_msg:
           return json.loads(reply_msg.decode())
        else:
            return {}
       

    def send_POST(self, url, post_param = None): 
        '''Send POST request to cmdctl, session id is send with the name
        'cookie' in header.
        Format: /module_name/command_name
        parameters of command is encoded as a map
        '''
        param = None
        if (len(post_param) != 0):
            param = json.dumps(post_param)

        headers = {"cookie" : self.session_id}
        self.conn.request('POST', url, param, headers)
        return self.conn.getresponse()

    def _update_all_modules_info(self):
        ''' Get all modules' information from cmdctl, including
        specification file and configuration data. This function
        should be called before interpreting command line or complete-key
        is entered. This may not be the best way to keep bindctl
        and cmdctl share same modules information, but it works.'''
        if self.config_data is not None:
            self.config_data.update_specs_and_config()
        else:
            self.config_data = isc.config.UIModuleCCSession(self)
        self._update_commands()

    def precmd(self, line):
        self._update_all_modules_info()
        return line 

    def postcmd(self, stop, line):
        '''Update the prompt after every command'''
        self.prompt = self.location + self.prompt_end
        return stop

    def _prepare_module_commands(self, module_spec):
        '''Prepare the module commands'''
        module = ModuleInfo(name = module_spec.get_module_name(),
                            desc = module_spec.get_module_description())
        for command in module_spec.get_commands_spec():
            cmd = CommandInfo(name = command["command_name"],
                              desc = command["command_description"])
            for arg in command["command_args"]:
                param = ParamInfo(name = arg["item_name"],
                                  type = arg["item_type"],
                                  optional = bool(arg["item_optional"]),
                                  param_spec = arg)
                if ("item_default" in arg):
                    param.default = arg["item_default"]
                cmd.add_param(param)
            module.add_command(cmd)
        self.add_module_info(module)

    def _validate_cmd(self, cmd):
        '''validate the parameters and merge some parameters together,
        merge algorithm is based on the command line syntax, later, if
        a better command line syntax come out, this function should be 
        updated first.        
        '''
        if not cmd.module in self.modules:
            raise CmdUnknownModuleSyntaxError(cmd.module)
        
        module_info = self.modules[cmd.module]
        if not module_info.has_command_with_name(cmd.command):
            raise CmdUnknownCmdSyntaxError(cmd.module, cmd.command)

        command_info = module_info.get_command_with_name(cmd.command)
        manda_params = command_info.get_mandatory_param_names()
        all_params = command_info.get_param_names()
        
        # If help is entered, don't do further parameter validation.
        for val in cmd.params.keys():
            if val == "help":
                return
        
        params = cmd.params.copy()       
        if not params and manda_params:            
            raise CmdMissParamSyntaxError(cmd.module, cmd.command, manda_params[0])            
        elif params and not all_params:
            raise CmdUnknownParamSyntaxError(cmd.module, cmd.command, 
                                             list(params.keys())[0])
        elif params:
            param_name = None
            param_count = len(params)
            for name in params:
                # either the name of the parameter must be known, or
                # the 'name' must be an integer (ie. the position of
                # an unnamed argument
                if type(name) == int:
                    # lump all extraneous arguments together as one big final one
                    # todo: check if last param type is a string?
                    if (param_count > 2):
                        while (param_count > len(command_info.params) - 1):
                            params[param_count - 2] += params[param_count - 1]
                            del(params[param_count - 1])
                            param_count = len(params)
                            cmd.params = params.copy()

                    # (-1, help is always in the all_params list)
                    if name >= len(all_params) - 1:
                        # add to last known param
                        if param_name:
                            cmd.params[param_name] += cmd.params[name]
                        else:
                            raise CmdUnknownParamSyntaxError(cmd.module, cmd.command, cmd.params[name])
                    else:
                        # replace the numbered items by named items
                        param_name = command_info.get_param_name_by_position(name, param_count)
                        cmd.params[param_name] = cmd.params[name]
                        del cmd.params[name]
                        
                elif not name in all_params:
                    raise CmdUnknownParamSyntaxError(cmd.module, cmd.command, name)

            param_nr = 0
            for name in manda_params:
                if not name in params and not param_nr in params:
                    raise CmdMissParamSyntaxError(cmd.module, cmd.command, name)
                param_nr += 1
        
        # Convert parameter value according parameter spec file.
        # Ignore check for commands belongs to module 'config'
        if cmd.module != CONFIG_MODULE_NAME:
            for param_name in cmd.params:
                param_spec = command_info.get_param_with_name(param_name).param_spec
                try:
                    cmd.params[param_name] = isc.config.config_data.convert_type(param_spec, cmd.params[param_name])
                except isc.cc.data.DataTypeError as e:
                    raise isc.cc.data.DataTypeError('Invalid parameter value for \"%s\", the type should be \"%s\" \n' 
                                                     % (param_name, param_spec['item_type']) + str(e))
    
    def _handle_cmd(self, cmd):
        '''Handle a command entered by the user'''
        if cmd.command == "help" or ("help" in cmd.params.keys()):
            self._handle_help(cmd)
        elif cmd.module == CONFIG_MODULE_NAME:
            self.apply_config_cmd(cmd)
        else:
            self.apply_cmd(cmd)

    def add_module_info(self, module_info):
        '''Add the information about one module'''
        self.modules[module_info.name] = module_info
        
    def get_module_names(self):
        '''Return the names of all known modules'''
        return list(self.modules.keys())

    #override methods in cmd
    def default(self, line):
        self._parse_cmd(line)

    def emptyline(self):
        pass

    def do_help(self, name):
        print(CONST_BINDCTL_HELP)
        for k in self.modules.keys():
            print("\t", self.modules[k])
                
    
    def onecmd(self, line):
        if line == 'EOF' or line.lower() == "quit":
            self.conn.close()
            return True
            
        if line == 'h':
            line = 'help'
        
        Cmd.onecmd(self, line)

    def remove_prefix(self, list, prefix):
        return [(val[len(prefix):]) for val in list]

    def complete(self, text, state):
        if 0 == state:
            self._update_all_modules_info()
            text = text.strip()
            hints = []
            cur_line = my_readline()
            try:
                cmd = BindCmdParse(cur_line)
                if not cmd.params and text:
                    hints = self._get_command_startswith(cmd.module, text)
                else:                       
                    hints = self._get_param_startswith(cmd.module, cmd.command,
                                                       text)
                    if cmd.module == CONFIG_MODULE_NAME:
                        # grm text has been stripped of slashes...
                        my_text = self.location + "/" + cur_line.rpartition(" ")[2]
                        list = self.config_data.get_config_item_list(my_text.rpartition("/")[0], True)
                        hints.extend([val for val in list if val.startswith(my_text[1:])])
                        # remove the common prefix from the hints so we don't get it twice
                        hints = self.remove_prefix(hints, my_text.rpartition("/")[0])
            except CmdModuleNameFormatError:
                if not text:
                    hints = self.get_module_names()

            except CmdMissCommandNameFormatError as e:
                if not text.strip(): # command name is empty
                    hints = self.modules[e.module].get_command_names()                    
                else: 
                    hints = self._get_module_startswith(text)

            except CmdCommandNameFormatError as e:
                if e.module in self.modules:
                    hints = self._get_command_startswith(e.module, text)

            except CmdParamFormatError as e:
                hints = self._get_param_startswith(e.module, e.command, text)

            except BindCtlException:
                hints = []

            self.hint = hints
            #self._append_space_to_hint()

        if state < len(self.hint):
            return self.hint[state]
        else:
            return None
            

    def _get_module_startswith(self, text):       
        return [module
                for module in self.modules 
                if module.startswith(text)]


    def _get_command_startswith(self, module, text):
        if module in self.modules:            
            return [command
                    for command in self.modules[module].get_command_names() 
                    if command.startswith(text)]
        
        return []                    
                        

    def _get_param_startswith(self, module, command, text):        
        if module in self.modules:
            module_info = self.modules[module]            
            if command in module_info.get_command_names():                
                cmd_info = module_info.get_command_with_name(command)
                params = cmd_info.get_param_names() 
                hint = []
                if text:    
                    hint = [val for val in params if val.startswith(text)]
                else:
                    hint = list(params)
                
                if len(hint) == 1 and hint[0] != "help":
                    hint[0] = hint[0] + " ="    
                
                return hint

        return []

    def _parse_cmd(self, line):
        try:
            cmd = BindCmdParse(line)
            self._validate_cmd(cmd)
            self._handle_cmd(cmd)
        except (IOError, http.client.HTTPException) as err:
            print('Error!', err)
            print(FAIL_TO_CONNECT_WITH_CMDCTL)
        except BindCtlException as err:
            print("Error! ", err)
            self._print_correct_usage(err)
        except isc.cc.data.DataTypeError as err:
            print("Error! ", err)
            
    def _print_correct_usage(self, ept):        
        if isinstance(ept, CmdUnknownModuleSyntaxError):
            self.do_help(None)
            
        elif isinstance(ept, CmdUnknownCmdSyntaxError):
            self.modules[ept.module].module_help()
            
        elif isinstance(ept, CmdMissParamSyntaxError) or \
             isinstance(ept, CmdUnknownParamSyntaxError):
             self.modules[ept.module].command_help(ept.command)
                 
                
    def _append_space_to_hint(self):
        """Append one space at the end of complete hint."""
        self.hint = [(val + " ") for val in self.hint]
            
            
    def _handle_help(self, cmd):
        if cmd.command == "help":
            self.modules[cmd.module].module_help()
        else:
            self.modules[cmd.module].command_help(cmd.command)


    def apply_config_cmd(self, cmd):
        '''Handles a configuration command.
           Raises a DataTypeError if a wrong value is set.
           Raises a DataNotFoundError if a wrong identifier is used.
           Raises a KeyError if the command was not complete
        '''
        identifier = self.location
        try:
            if 'identifier' in cmd.params:
                if not identifier.endswith("/"):
                    identifier += "/"
                if cmd.params['identifier'].startswith("/"):
                    identifier = cmd.params['identifier']
                else:
                    identifier += cmd.params['identifier']

                # Check if the module is known; for unknown modules
                # we currently deny setting preferences, as we have
                # no way yet to determine if they are ok.
                module_name = identifier.split('/')[1]
                if self.config_data is None or \
                   not self.config_data.have_specification(module_name):
                    print("Error: Module '" + module_name + "' unknown or not running")
                    return

            if cmd.command == "show":
                values = self.config_data.get_value_maps(identifier)
                for value_map in values:
                    line = value_map['name']
                    if value_map['type'] in [ 'module', 'map', 'list' ]:
                        line += "/"
                    else:
                        line += ":\t" + str(value_map['value'])
                    line += "\t" + value_map['type']
                    line += "\t"
                    if value_map['default']:
                        line += "(default)"
                    if value_map['modified']:
                        line += "(modified)"
                    print(line)
            elif cmd.command == "add":
                self.config_data.add_value(identifier, cmd.params['value'])
            elif cmd.command == "remove":
                self.config_data.remove_value(identifier, cmd.params['value'])
            elif cmd.command == "set":
                if 'identifier' not in cmd.params:
                    print("Error: missing identifier or value")
                else:
                    parsed_value = None
                    try:
                        parsed_value = json.loads(cmd.params['value'])
                    except Exception as exc:
                        # ok could be an unquoted string, interpret as such
                        parsed_value = cmd.params['value']
                    self.config_data.set_value(identifier, parsed_value)
            elif cmd.command == "unset":
                self.config_data.unset(identifier)
            elif cmd.command == "revert":
                self.config_data.clear_local_changes()
            elif cmd.command == "commit":
                self.config_data.commit()
            elif cmd.command == "diff":
                print(self.config_data.get_local_changes());
            elif cmd.command == "go":
                self.go(identifier)
        except isc.cc.data.DataTypeError as dte:
            print("Error: " + str(dte))
        except isc.cc.data.DataNotFoundError as dnfe:
            print("Error: " + identifier + " not found")
        except KeyError as ke:
            print("Error: missing " + str(ke))
            raise ke

    def go(self, identifier):
        '''Handles the config go command, change the 'current' location
           within the configuration tree'''
        # this is just to see if it exists
        self.config_data.get_value(identifier)
        # some sanitizing
        identifier = identifier.replace("//", "/")
        if not identifier.startswith("/"):
            identifier = "/" + identifier
        if identifier.endswith("/"):
            identifier = identifier[:-1]
        self.location = identifier

    def apply_cmd(self, cmd):
        '''Handles a general module command'''
        url = '/' + cmd.module + '/' + cmd.command
        cmd_params = None
        if (len(cmd.params) != 0):
            cmd_params = json.dumps(cmd.params)

        print("send the command to cmd-ctrld")        
        reply = self.send_POST(url, cmd.params)
        data = reply.read().decode()
        print("received reply:", data)