# ===========================================================================
# This file is part of Pwman3.
#
# Pwman3 is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License, version 2
# as published by the Free Software Foundation;
#
# Pwman3 is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Pwman3; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
# ============================================================================
# Copyright (C) 2013, 2014 Oz Nahum Tiram <nahumoz@gmail.com>
# ============================================================================
from __future__ import print_function
import sys
import os
import getpass
import ast
import csv
import time
import re
import select as uselect
from colorama import Fore
from pwman.data.nodes import Node
from pwman.ui import tools
from pwman.util.crypto_engine import CryptoEngine
from .base import HelpUIMixin, AliasesMixin

if sys.version_info.major > 2:  # pragma: no cover
    raw_input = input


def _heard_enter():  # pragma: no cover
    i, o, e = uselect.select([sys.stdin], [], [], 0.0001)
    for s in i:
        if s == sys.stdin:
            sys.stdin.readline()
            return True
        return False


def _wait_until_enter(predicate, timeout, period=0.25):  # pragma: no cover
    mustend = time.time() + timeout
    while time.time() < mustend:
        cond = predicate()
        if cond:
            break
        time.sleep(period)


class BaseCommands(HelpUIMixin, AliasesMixin):

    @property
    def _xsel(self):  # pragma: no cover
        if self.hasxsel:
            return True

    def _get_ids(self, args):
        """
        Command can get a single ID or
        a range of IDs, with begin-end.
        e.g. 1-3 , will get 1 to 3.
        """
        ids = []
        rex = re.compile("^(?P<begin>\d+)(?:-(?P<end>\d+))?$")
        rex = rex.match(args)
        if hasattr(rex, 'groupdict'):
            try:
                begin = int(rex.groupdict()['begin'])
                end = int(rex.groupdict()['end'])
                if not end > begin:
                    print("Start node should be smaller than end node")
                    return ids
                ids += range(begin, end+1)
                return ids
            except TypeError:
                ids.append(int(begin))
        else:
            print("Could not understand your input...")
        return ids

    def error(self, exception):  # pragma: no cover
        if (isinstance(exception, KeyboardInterrupt)):
            print('')
        else:
            print("Error: {0} ".format(exception))

    def do_copy(self, args):  # pragma: no cover
        """copy item to clipboard"""
        if not self._xsel:
            return
        if not args.isdigit():
            print("Copy accepts only IDs ...")
            return

        ids = args.split()
        if len(ids) > 1:
            print("Can copy only 1 password at a time...")
            return

        nodes = self._db.getnodes(ids)
        for node in nodes:
            ce = CryptoEngine.get()
            password = ce.decrypt(node[2])
            tools.text_to_clipboards(password)
            print("erasing in 10 sec...")
            time.sleep(10)  # TODO: this should be configurable!
            tools.text_to_clipboards("")

    def do_open(self, args):  # pragma: no cover
        ids = self._get_ids(args)
        if not args:
            self.help_open()
            return

        nodes = self._db.getnodes(ids)
        for node in nodes:
            ce = CryptoEngine.get()
            url = ce.decrypt(node[3])
            tools.open_url(url)

    def do_exit(self, args):  # pragma: no cover
        """close the text console"""
        self._db.close()
        return True

    def do_cls(self, args):  # pragma: no cover
        """clear the screen"""
        os.system("clear")

    def do_edit(self, args):
        """edit a node"""
        pass

    def do_export(self, args):
        """export the database to a given format"""
        try:
            args = ast.literal_eval(args)
        except Exception:
            args = {}

        filename = args.get('filename', 'pwman-export.csv')
        delim = args.get('delimiter', ';')
        nodeids = self._db.listnodes()
        nodes = self._db.getnodes(nodeids)
        with open(filename, 'w') as csvfile:
            writer = csv.writer(csvfile, delimiter=delim)
            writer.writerow(['Username', 'URL', 'Password', 'Notes',
                             'Tags'])
            for node in nodes:
                n = Node.from_encrypted_entries(node[1], node[2], node[3],
                                                node[4],
                                                node[5:])
                tags = n.tags
                tags = ','.join(t.strip().decode() for t in tags)
                r = list(map(bytes.decode, [n.username, n.url, n.password,
                                            n.notes]))
                writer.writerow(r + [tags])

        print("Successfuly exported database to {}".format(
            os.path.join(os.getcwd(), filename)))

    def do_forget(self, args):
        """
        drop saved key forcing the user to re-enter the master
        password
        """
        enc = CryptoEngine.get()
        enc.forget()

    def do_passwd(self, args):  # pragma: no cover
        """change the master password of the database"""
        pass

    def do_tags(self, args):
        """
        print all existing tags
        """
        ce = CryptoEngine.get()
        print("Tags:")
        tags = self._db.listtags()
        for t in tags:
            print(ce.decrypt(t).decode())

    def _get_tags(self, default=None, reader=raw_input):
        """
        Read tags from user input.
        Tags are simply returned as a list
        """
        # TODO: add method to read tags from db, so they
        # could be used for tab completer
        print("Tags: ", end="")
        sys.stdout.flush()
        taglist = sys.stdin.readline()
        tagstrings = taglist.split()
        tags = [tn for tn in tagstrings]
        return tags

    def _prep_term(self):
        self.do_cls('')
        if sys.platform != 'win32':
            rows, cols = tools.gettermsize()
        else:  # pragma: no cover
            rows, cols = 18, 80  # fix this !

        cols -= 8
        return rows, cols

    def _format_line(self, tag_pad, nid="ID", user="USER", url="URL",
                     tags="TAGS"):
        return ("{ID:<3} {USER:<{us}}{URL:<{ur}}{Tags:<{tg}}"
                "".format(ID=nid, USER=user,
                          URL=url, Tags=tags, us=12,
                          ur=20, tg=tag_pad - 32))

    def _print_node_line(self, node, rows, cols):
        tagstring = ','.join([t.decode() for t in node.tags])
        fmt = self._format_line(cols - 32, node._id, node.username.decode(),
                                node.url.decode(),
                                tagstring)
        formatted_entry = tools.typeset(fmt, Fore.YELLOW, False)
        print(formatted_entry)

    def _get_node_ids(self, args):
        filter = None
        if args:
            filter = args.split()[0]
            ce = CryptoEngine.get()
            filter = ce.encrypt(filter)
        nodeids = self._db.listnodes(filter=filter)
        return nodeids

    def _db_entries_to_nodes(self, raw_nodes):
        _nodes_inst = []
        # user, pass, url, notes
        for node in raw_nodes:
            _nodes_inst.append(Node.from_encrypted_entries(
                node[1],
                node[2],
                node[3],
                node[4],
                node[5:]))
            _nodes_inst[-1]._id = node[0]
        return _nodes_inst

    def do_list(self, args):
        """list all existing nodes in database"""
        rows, cols = self._prep_term()
        nodeids = self._get_node_ids(args)
        raw_nodes = self._db.getnodes(nodeids)
        _nodes_inst = self._db_entries_to_nodes(raw_nodes)
        head = self._format_line(cols-32)
        print(tools.typeset(head, Fore.YELLOW, False))
        for idx, node in enumerate(_nodes_inst):
            self._print_node_line(node, rows, cols)

    def _get_input(self, prompt):
        print(prompt, end="")
        sys.stdout.flush()
        return sys.stdin.readline().strip()

    def _get_secret(self):
        # TODO: enable old functionallity, with password generator.
        if sys.stdin.isatty():  # pragma: no cover
            p = getpass.getpass()
        else:
            p = sys.stdin.readline().rstrip()
        return p

    def _do_new(self, args):
        node = {}
        node['username'] = self._get_input("Username: ")
        node['password'] = self._get_secret()
        node['url'] = self._get_input("Url: ")
        node['notes'] = self._get_input("Notes: ")
        node['tags'] = self._get_tags()
        node = Node(clear_text=True, **node)
        self._db.add_node(node)
        return node

    def do_new(self, args):  # pragma: no cover
        # The cmd module stops if and of do_* return something
        # else than None ...
        # This is bad for testing, so everything that is do_*
        # should call _do_* method which is testable
        self._do_new(args)

    def do_print(self, args):
        if not args.isdigit():
            print("print accepts only a single ID ...")
            return
        nodes = self._db.getnodes([args])
        node = self._db_entries_to_nodes(nodes)[0]

        print(node)

        flushtimeout = self.config.get_value('Global', 'cls_timeout')
        flushtimeout = flushtimeout or 10

        print("Type Enter to flush screen or wait %s sec. " % flushtimeout)

        _wait_until_enter(_heard_enter, float(flushtimeout))
        self.do_cls('')

    def _do_rm(self, args):
        for i in args.split():
            if not i.isdigit():
                print("%s is not a node ID" % i)
                return None

        for i in args.split():
            ans = tools.getinput(("Are you sure you want to delete node {}"
                                  " [y/N]?".format(i)))
            if ans.lower() == 'y':
                self._db.removenodes([i])

    def do_delete(self, args):  # pragma: no cover
        CryptoEngine.get()
        self._do_rm(args)