# 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 ast

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.stding.readline


CONST_BINDCTL_HELP = """BindCtl, version 0.1
usage: <module name> <command name> [param1 = value1 [, param2 = value2]]
Type Tab character to get the hint of module/command/paramters.
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: """

CONST_COMMAND_NODE = "command"

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

    def __init__(self, server_port = 'localhost:8080', pem_file = "bindctl.pem"):
        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.pem_file = pem_file
        self._connect_to_cmd_ctrld()
        self.session_id = self._get_session_id()

    def _connect_to_cmd_ctrld(self):
        '''Connect to cmdctl in SSL context. '''
        try:
            self.conn = http.client.HTTPSConnection(self.server_port,
                          cert_file=self.pem_file)
        except  Exception as e:
            print(e, "can't connect to %s, please make sure cmd-ctrld is running" %
                  self.server_port)

    def _get_session_id(self):
        '''Generate one session id for the connection. '''
        rand = os.urandom(16)
        now = time.time()
        ip = socket.gethostbyname(socket.gethostname())
        session_id = sha1(("%s%s%s" %(rand, now, ip)).encode())
        digest = session_id.hexdigest()
        return digest
    
    def run(self):
        '''Parse commands inputted from user and send them to cmdctl. '''
        try:
            if not self.login_to_cmdctl():
                return False

            # Get all module information from cmd-ctrld
            self.config_data = isc.config.UIModuleCCSession(self)
            self._update_commands()
            self.cmdloop()
        except KeyboardInterrupt:
            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.
        '''
        csvfile = None
        bsuccess = False
        try:
            csvfile = open('default_user.csv')
            users = csv.reader(csvfile)
            for row in users:
                param = {'username': row[0], 'password' : row[1]}
                response = self.send_POST('/login', param)
                data = response.read().decode()
                if response.status == http.client.OK:
                    print(data + ' login as ' + row[0] )
                    bsuccess = True
                    break
        except IOError as e:
            pass
        except Exception as e:
            print(e)
        finally:
            if csvfile:
                csvfile.close()
            if bsuccess:
                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}
            response = self.send_POST('/login', param)
            data = response.read().decode()
            print(data)
            
            if response.status == http.client.OK:
                csvfile = open('default_user.csv', 'w')
                writer = csv.writer(csvfile)
                writer.writerow([username, passwd])
                csvfile.close()
                return True


    def _update_commands(self):
        '''Get the commands of all modules. '''
        cmd_spec = self.send_GET('/command_spec')
        if not cmd_spec:
            return

        for module_name in cmd_spec.keys():
            self._prepare_module_commands(module_name, cmd_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 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_name, module_commands):
        '''Prepare the module commands'''
        module = ModuleInfo(name = module_name,
                            desc = "same here")
        for command in module_commands:
            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"]))
                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

    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":
            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 complete(self, text, state):
        if 0 == state:
            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":
                        # grm text has been stripped of slashes...
                        my_text = self.location + "/" + cur_line.rpartition(" ")[2]
                        print("[XX] completing config part")
                        list = self.config_data.get_config_item_list(my_text.rpartition("/")[0])
                        hints.extend([val for val in list if val.startswith(text)])
            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 BindCtlException as e:
            print("Error! ", e)
            self._print_correct_usage(e)
            
            
    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']
            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 = ast.literal_eval(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 message to cmd-ctrld")        
        reply = self.send_POST(url, cmd.params)
        data = reply.read().decode()
        print("received reply:", data)