windows.py

# Copyright 2010-2011 Florent Le Coz <louiz@louiz.org>
#
# This file is part of Poezio.
#
# Poezio is free software: you can redistribute it and/or modify
# it under the terms of the zlib license. See the COPYING file.

"""
Define all the windows.
A window is a little part of the screen, for example the input window,
the text window, the roster window, etc.
A Tab (see tab.py) is composed of multiple Windows
"""

from gettext import (bindtextdomain, textdomain, bind_textdomain_codeset,
                     gettext as _)

import logging
log = logging.getLogger(__name__)

import curses
import string
from datetime import datetime
from math import ceil, log10
from config import config

from threading import RLock

from contact import Contact, Resource
from roster import RosterGroup
import poopt

from sleekxmpp import JID
from common import safeJID
import common

import core
import singleton
import collections

from theming import get_theme, to_curses_attr, read_tuple, dump_tuple

allowed_color_digits = ('0', '1', '2', '3', '4', '5', '6', '7')
# msg is a reference to the corresponding Message tuple. text_start and text_end are the position
# delimiting the text in this line.
# first is a bool telling if this is the first line of the message.
Line = collections.namedtuple('Line', 'msg start_pos end_pos prepend')

g_lock = RLock()

LINES_NB_LIMIT = 4096

def truncate_nick(nick, size=None):
    size = size or config.get('max_nick_length', 25)
    if size < 1:
        size = 1
    if nick and len(nick) > size:
        return nick[:size]+'…'
    return nick

def parse_attrs(text, previous=None):
    next_attr_char = text.find('\x19')
    if previous:
        attrs = previous
    else:
        attrs = []
    while next_attr_char != -1 and text:
        if next_attr_char + 1 < len(text):
            attr_char = text[next_attr_char+1].lower()
        else:
            attr_char = str()
        if attr_char == 'o':
            attrs = []
        elif attr_char == 'u':
            attrs.append('u')
        elif attr_char == 'b':
            attrs.append('b')
        if attr_char in string.digits and attr_char != '':
            color_str = text[next_attr_char+1:text.find('}', next_attr_char)]
            if color_str:
                attrs.append(color_str + '}')
            text = text[next_attr_char+len(color_str)+2:]
        else:
            text = text[next_attr_char+2:]
        next_attr_char = text.find('\x19')
    return attrs


class Win(object):
    _win_core = None
    _tab_win = None
    def __init__(self):
        self._win = None

    def _resize(self, height, width, y, x):
        if height == 0 or width == 0:
            self.height, self.width = height, width
            return
        self.height, self.width, self.x, self.y = height, width, x, y
        try:
            self._win = Win._tab_win.derwin(height, width, y, x)
        except:
            log.debug('DEBUG: mvwin returned ERR. Please investigate')

        # If this ever fail, uncomment that ^

    def resize(self, height, width, y, x):
        """
        Override if something has to be done on resize
        """
        with g_lock:
            self._resize(height, width, y, x)

    def _refresh(self):
        self._win.noutrefresh()

    def addnstr(self, *args):
        """
        Safe call to addnstr
        """
        try:
            self._win.addnstr(*args)
        except:
            pass

    def addstr(self, *args):
        """
        Safe call to addstr
        """
        try:
            self._win.addstr(*args)
        except:
            pass

    def move(self, y, x):
        try:
            self._win.move(y, x)
        except:
            self._win.move(0, 0)

    def addstr_colored(self, text, y=None, x=None):
        """
        Write a string on the window, setting the
        attributes as they are in the string.
        For example:
        \x19bhello → hello in bold
        \x191}Bonj\x192}our → 'Bonj' in red and 'our' in green
        next_attr_char is the \x19 delimiter
        attr_char is the char following it, it can be
        one of 'u', 'b', 'c[0-9]'
        """
        if y is not None and x is not None:
            self.move(y, x)
        next_attr_char = text.find('\x19')
        while next_attr_char != -1 and text:
            if next_attr_char + 1 < len(text):
                attr_char = text[next_attr_char+1].lower()
            else:
                attr_char = str()
            if next_attr_char != 0:
                self.addstr(text[:next_attr_char])
            if attr_char == 'o':
                self._win.attrset(0)
            elif attr_char == 'u':
                self._win.attron(curses.A_UNDERLINE)
            elif attr_char == 'b':
                self._win.attron(curses.A_BOLD)
            if (attr_char in string.digits or attr_char == '-') and attr_char != '':
                color_str = text[next_attr_char+1:text.find('}', next_attr_char)]
                if ',' in color_str:
                    tup, char = read_tuple(color_str)
                    self._win.attron(to_curses_attr(tup))
                    if char:
                        if char == 'o':
                            self._win.attrset(0)
                        elif char == 'u':
                            self._win.attron(curses.A_UNDERLINE)
                        elif char == 'b':
                            self._win.attron(curses.A_BOLD)
                elif color_str:
                    self._win.attron(to_curses_attr((int(color_str), -1)))
                text = text[next_attr_char+len(color_str)+2:]
            else:
                text = text[next_attr_char+2:]
            next_attr_char = text.find('\x19')
        self.addstr(text)

    def addstr_colored_lite(self, text, y=None, x=None):
        """
        Just like addstr_colored, but only handles colors with one digit.
        \x193 is the 3rd color. We do not use any } char in this version
        """
        if y is not None and x is not None:
            self.move(y, x)
        next_attr_char = text.find('\x19')
        while next_attr_char != -1:
            if next_attr_char + 1 < len(text):
                attr_char = text[next_attr_char+1].lower()
            else:
                attr_char = str()
            if next_attr_char != 0:
                self.addstr(text[:next_attr_char])
            text = text[next_attr_char+2:]
            if attr_char == 'o':
                self._win.attrset(0)
            elif attr_char == 'u':
                self._win.attron(curses.A_UNDERLINE)
            elif attr_char == 'b':
                self._win.attron(curses.A_BOLD)
            elif attr_char in string.digits and attr_char != '':
                self._win.attron(to_curses_attr((int(attr_char), -1)))
            next_attr_char = text.find('\x19')
        self.addstr(text)

    def finish_line(self, color=None):
        """
        Write colored spaces until the end of line
        """
        (y, x) = self._win.getyx()
        size = self.width-x
        if color:
            self.addnstr(' '*size, size, to_curses_attr(color))
        else:
            self.addnstr(' '*size, size)

    @property
    def core(self):
        if not Win._win_core:
            Win._win_core = singleton.Singleton(core.Core)
        return Win._win_core

class UserList(Win):
    def __init__(self):
        Win.__init__(self)
        self.pos = 0

    def scroll_up(self):
        self.pos += self.height-1
        return True

    def scroll_down(self):
        pos = self.pos
        self.pos -= self.height-1
        if self.pos < 0:
            self.pos = 0
        return self.pos != pos

    def draw_plus(self, y):
        self.addstr(y, self.width-2, '++', to_curses_attr(get_theme().COLOR_MORE_INDICATOR))

    def refresh(self, users):
        log.debug('Refresh: %s',self.__class__.__name__)
        if config.get("hide_user_list", "false") == "true":
            return # do not refresh if this win is hidden.
        with g_lock:
            self._win.erase()
            if config.get('user_list_sort', 'desc').lower() == 'asc':
                y, x = self._win.getmaxyx()
                y -= 1
                users = sorted(users, reverse=True)
            else:
                y = 0
                users = sorted(users)

            if len(users) < self.height:
                self.pos = 0
            elif self.pos >= len(users) - self.height and self.pos != 0:
                self.pos = len(users) - self.height
            for user in users[self.pos:]:
                self.draw_role_affiliation(y, user)
                self.draw_status_chatstate(y, user)
                self.addstr(y, 2, poopt.cut_by_columns(user.nick, self.width-2), to_curses_attr(user.color))
                if config.get('user_list_sort', 'desc').lower() == 'asc':
                    y -= 1
                else:
                    y += 1
                if y == self.height:
                    break
            # draw indicators of position in the list
            if self.pos > 0:
                if config.get('user_list_sort', 'desc').lower() == 'asc':
                    self.draw_plus(self.height-1)
                else:
                    self.draw_plus(0)
            if self.pos + self.height < len(users):
                if config.get('user_list_sort', 'desc').lower() == 'asc':
                    self.draw_plus(0)
                else:
                    self.draw_plus(self.height-1)
            self._refresh()

    def draw_role_affiliation(self, y, user):
        theme = get_theme()
        color = theme.color_role(user.role)
        symbol = theme.char_affiliation(user.affiliation)
        self.addstr(y, 1, symbol, to_curses_attr(color))

    def draw_status_chatstate(self, y, user):
        show_col = get_theme().color_show(user.show)
        if user.chatstate == 'composing':
            char = get_theme().CHAR_CHATSTATE_COMPOSING
        elif user.chatstate == 'active':
            char = get_theme().CHAR_CHATSTATE_ACTIVE
        elif user.chatstate == 'paused':
            char = get_theme().CHAR_CHATSTATE_PAUSED
        else:
            char = get_theme().CHAR_STATUS
        self.addstr(y, 0, char, to_curses_attr(show_col))

    def resize(self, height, width, y, x):
        with g_lock:
            self._resize(height, width, y, x)
            self._win.attron(to_curses_attr(get_theme().COLOR_VERTICAL_SEPARATOR))
            self._win.vline(0, 0, curses.ACS_VLINE, self.height)
            self._win.attroff(to_curses_attr(get_theme().COLOR_VERTICAL_SEPARATOR))

class Topic(Win):
    def __init__(self):
        Win.__init__(self)
        self._message = ''

    def refresh(self, topic=None):
        log.debug('Refresh: %s',self.__class__.__name__)
        with g_lock:
            self._win.erase()
            if topic:
                msg = topic[:self.width-1]
            else:
                msg = self._message[:self.width-1]
            self.addstr(0, 0, msg, to_curses_attr(get_theme().COLOR_TOPIC_BAR))
            (y, x) = self._win.getyx()
            remaining_size = self.width - x
            if remaining_size:
                self.addnstr(' '*remaining_size, remaining_size,
                             to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
            self._refresh()

    def set_message(self, message):
        self._message = message

class GlobalInfoBar(Win):
    def __init__(self):
        Win.__init__(self)

    def refresh(self):
        log.debug('Refresh: %s',self.__class__.__name__)
        with g_lock:
            self._win.erase()
            self.addstr(0, 0, "[", to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

            create_gaps = config.getl('create_gaps', 'false') == 'true'
            show_names = config.getl('show_tab_names', 'false') == 'true'
            show_nums = config.getl('show_tab_numbers', 'true') != 'false'
            use_nicks = config.getl('use_tab_nicks', 'true') != 'false'
            # ignore any remaining gap tabs if the feature is not enabled
            sorted_tabs = [tab for tab in self.core.tabs if tab] if not create_gaps else self.core.tabs[:]
            for nb, tab in enumerate(sorted_tabs):
                if not tab: continue
                color = tab.color
                if config.get('show_inactive_tabs', 'true') == 'false' and\
                        color is get_theme().COLOR_TAB_NORMAL:
                    continue
                try:
                    if show_nums or not show_names:
                        self.addstr("%s" % str(nb), to_curses_attr(color))
                        if show_names:
                            self.addstr(' ', to_curses_attr(color))
                    if show_names:
                        if use_nicks:
                            self.addstr("%s" % str(tab.get_nick()), to_curses_attr(color))
                        else:
                            self.addstr("%s" % str(tab.get_name()), to_curses_attr(color))
                    self.addstr("|", to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
                except:             # end of line
                    break
            (y, x) = self._win.getyx()
            self.addstr(y, x-1, '] ', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
            (y, x) = self._win.getyx()
            remaining_size = self.width - x
            self.addnstr(' '*remaining_size, remaining_size,
                         to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
            self._refresh()

class VerticalGlobalInfoBar(Win):
    def __init__(self, scr):
        Win.__init__(self)
        self._win = scr

    def refresh(self):
        with g_lock:
            height, width = self._win.getmaxyx()
            self._win.erase()
            sorted_tabs = [tab for tab in self.core.tabs if tab]
            if config.get('show_inactive_tabs', 'true') == 'false':
                sorted_tabs = [tab for tab in sorted_tabs if\
                                   tab.vertical_color != get_theme().COLOR_VERTICAL_TAB_NORMAL]
            nb_tabs = len(sorted_tabs)
            use_nicks = config.getl('use_tab_nicks', 'true') != 'false'
            if nb_tabs >= height:
                for y, tab in enumerate(sorted_tabs):
                    if tab.vertical_color == get_theme().COLOR_VERTICAL_TAB_CURRENT:
                        pos = y
                        break
                # center the current tab as much as possible
                if pos < height//2:
                    sorted_tabs = sorted_tabs[:height]
                elif nb_tabs - pos <= height//2:
                    sorted_tabs = sorted_tabs[-height:]
                else:
                    sorted_tabs = sorted_tabs[pos-height//2 : pos+height//2]
            for y, tab in enumerate(sorted_tabs):
                color = tab.vertical_color
                self.addstr(y if config.get('vertical_tab_list_sort', 'desc') != 'asc' else height - y - 1, 0, "%2d" % tab.nb, to_curses_attr(get_theme().COLOR_VERTICAL_TAB_NUMBER))
                self.addstr('.')
                if use_nicks:
                    self.addnstr("%s" % tab.get_nick(), width - 4, to_curses_attr(color))
                else:
                    self.addnstr("%s" % tab.get_name(), width - 4, to_curses_attr(color))
            self._win.attron(to_curses_attr(get_theme().COLOR_VERTICAL_SEPARATOR))
            self._win.vline(0, width-1, curses.ACS_VLINE, height)
            self._win.attroff(to_curses_attr(get_theme().COLOR_VERTICAL_SEPARATOR))
            self._refresh()

class InfoWin(Win):
    """
    Base class for all the *InfoWin, used in various tabs. For example
    MucInfoWin, etc. Provides some useful methods.
    """
    def __init__(self):
        Win.__init__(self)

    def print_scroll_position(self, window):
        """
        Print, like in Weechat, a -MORE(n)- where n
        is the number of available lines to scroll
        down
        """
        if window.pos > 0:
            plus = ' -MORE(%s)-' % window.pos
            self.addstr(plus, to_curses_attr(get_theme().COLOR_SCROLLABLE_NUMBER))

class XMLInfoWin(InfoWin):
    """
    Info about the latest xml filter used and the state of the buffer.
    """
    def __init__(self):
        InfoWin.__init__(self)

    def refresh(self, filter_t='', filter='', window=None):
        log.debug('Refresh: %s', self.__class__.__name__)
        with g_lock:
            self._win.erase()
            if not filter_t:
                self.addstr('[No filter]', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
            else:
                info = '[%s] %s' % (filter_t, filter)
                self.addstr(info, to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
            self.print_scroll_position(window)
            self.finish_line(get_theme().COLOR_INFORMATION_BAR)
            self._refresh()

class PrivateInfoWin(InfoWin):
    """
    The line above the information window, displaying informations
    about the MUC user we are talking to
    """
    def __init__(self):
        InfoWin.__init__(self)

    def refresh(self, name, window, chatstate):
        log.debug('Refresh: %s',self.__class__.__name__)
        with g_lock:
            self._win.erase()
            self.write_room_name(name)
            self.print_scroll_position(window)
            self.write_chatstate(chatstate)
            self.finish_line(get_theme().COLOR_INFORMATION_BAR)
            self._refresh()

    def write_room_name(self, name):
        jid = safeJID(name)
        room_name, nick = jid.bare, jid.resource
        self.addstr(nick, to_curses_attr(get_theme().COLOR_PRIVATE_NAME))
        txt = ' from room %s' % room_name
        self.addstr(txt, to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

    def write_chatstate(self, state):
        if state:
            self.addstr(' %s' % (state,), to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

class MucListInfoWin(InfoWin):
    """
    The live above the information window, displaying informations
    about the muc server being listed
    """
    def __init__(self, message=''):
        InfoWin.__init__(self)
        self.message = message

    def refresh(self, name=None):
        log.debug('Refresh: %s',self.__class__.__name__)
        with g_lock:
            self._win.erase()
            if name:
                self.addstr(name, to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
            else:
                self.addstr(self.message, to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
            self.finish_line(get_theme().COLOR_INFORMATION_BAR)
            self._refresh()

class ConversationInfoWin(InfoWin):
    """
    The line above the information window, displaying informations
    about the user we are talking to
    """

    def __init__(self):
        InfoWin.__init__(self)

    def refresh(self, jid, contact, window, chatstate, informations):
        # contact can be None, if we receive a message
        # from someone not in our roster. In this case, we display
        # only the maximum information from the message we can get.
        log.debug('Refresh: %s',self.__class__.__name__)
        jid = safeJID(jid)
        if contact:
            if jid.resource:
                resource = contact[jid.full]
            else:
                resource = contact.get_highest_priority_resource()
        else:
            resource = None
        # if contact is None, then resource is None too: user is not in the roster
        # so we know almost nothing about it
        # If contact is a Contact, then
        # resource can now be a Resource: user is in the roster and online
        # or resource is None: user is in the roster but offline
        with g_lock:
            self._win.erase()
            self.write_contact_jid(jid)
            self.write_contact_informations(contact)
            self.write_resource_information(resource)
            self.print_scroll_position(window)
            self.write_chatstate(chatstate)
            self.write_additional_informations(informations, jid)
            self.finish_line(get_theme().COLOR_INFORMATION_BAR)
            self._refresh()

    def write_additional_informations(self, informations, jid):
        """
        Write all informations added by plugins by getting the
        value returned by the callbacks.
        """
        for key in informations:
            self.addstr(informations[key](jid), to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

    def write_resource_information(self, resource):
        """
        Write the informations about the resource
        """
        if not resource:
            presence = "unavailable"
        else:
            presence = resource.presence
        color = get_theme().color_show(presence)
        self.addstr('[', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
        self.addstr(get_theme().CHAR_STATUS, to_curses_attr(color))
        self.addstr(']', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

    def write_contact_informations(self, contact):
        """
        Write the informations about the contact
        """
        if not contact:
            self.addstr("(contact not in roster)", to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
            return
        display_name = contact.name
        if display_name:
            self.addstr('%s '%(display_name), to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

    def write_contact_jid(self, jid):
        """
        Just write the jid that we are talking to
        """
        self.addstr('[', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
        self.addstr(jid.full, to_curses_attr(get_theme().COLOR_CONVERSATION_NAME))
        self.addstr('] ', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

    def write_chatstate(self, state):
        if state:
            self.addstr(' %s' % (state,), to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

class DynamicConversationInfoWin(ConversationInfoWin):
    def write_contact_jid(self, jid):
        """
        Just displays the resource in an other color
        """
        log.debug("write_contact_jid DynamicConversationInfoWin, jid: %s" % jid.resource)
        self.addstr('[', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
        self.addstr(jid.bare, to_curses_attr(get_theme().COLOR_CONVERSATION_NAME))
        if jid.resource:
            self.addstr("/%s" % (jid.resource,), to_curses_attr(get_theme().COLOR_CONVERSATION_RESOURCE))
        self.addstr('] ', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

class ConversationStatusMessageWin(InfoWin):
    """
    The upper bar displaying the status message of the contact
    """
    def __init__(self):
        InfoWin.__init__(self)

    def refresh(self, jid, contact):
        log.debug('Refresh: %s',self.__class__.__name__)
        jid = safeJID(jid)
        if contact:
            if jid.resource:
                resource = contact[jid.full]
            else:
                resource = contact.get_highest_priority_resource()
        else:
            resource = None
        with g_lock:
            self._win.erase()
            if resource:
                self.write_status_message(resource)
            self.finish_line(get_theme().COLOR_INFORMATION_BAR)
            self._refresh()

    def write_status_message(self, resource):
        self.addstr(resource.status, to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

class MucInfoWin(InfoWin):
    """
    The line just above the information window, displaying informations
    about the MUC we are viewing
    """
    def __init__(self):
        InfoWin.__init__(self)

    def refresh(self, room, window=None):
        log.debug('Refresh: %s',self.__class__.__name__)
        with g_lock:
            self._win.erase()
            self.write_room_name(room)
            self.write_participants_number(room)
            self.write_own_nick(room)
            self.write_disconnected(room)
            self.write_role(room)
            if window:
                self.print_scroll_position(window)
            self.finish_line(get_theme().COLOR_INFORMATION_BAR)
            self._refresh()

    def write_room_name(self, room):
        self.addstr('[', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
        self.addstr(room.name, to_curses_attr(get_theme().COLOR_GROUPCHAT_NAME))
        self.addstr(']', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

    def write_participants_number(self, room):
        self.addstr('{', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))
        self.addstr(str(len(room.users)), to_curses_attr(get_theme().COLOR_GROUPCHAT_NAME))
        self.addstr('} ', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

    def write_disconnected(self, room):
        """
        Shows a message if the room is not joined
        """
        if not room.joined:
            self.addstr(' -!- Not connected ', to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

    def write_own_nick(self, room):
        """
        Write our own nick in the info bar
        """
        nick = room.own_nick
        if not nick:
            return
        self.addstr(truncate_nick(nick, 13), to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

    def write_role(self, room):
        """
        Write our own role and affiliation
        """
        own_user = None
        for user in room.users:
            if user.nick == room.own_nick:
                own_user = user
                break
        if not own_user:
            return
        txt = ' ('
        if own_user.affiliation != 'none':
            txt += own_user.affiliation+', '
        txt += own_user.role+')'
        self.addstr(txt, to_curses_attr(get_theme().COLOR_INFORMATION_BAR))

class TextWin(Win):
    def __init__(self, lines_nb_limit=config.get('max_lines_in_memory', 2048)):
        Win.__init__(self)
        self.lines_nb_limit = lines_nb_limit
        self.pos = 0
        self.built_lines = []   # Each new message is built and kept here.
        # on resize, we rebuild all the messages

        self.lock = False
        self.lock_buffer = []

        # the Lines of the highlights in that buffer
        self.highlights = []
        # the current HL position in that list NaN means that we’re not on
        # an hl. -1 is a valid position (it's before the first hl of the
        # list. i.e the separator, in the case where there’s no hl before
        # it.)
        self.hl_pos = float('nan')

        # Keep track of the number of hl after the separator.
        # This is useful to make “go to next highlight“ work after a “move to separator”.
        self.nb_of_highlights_after_separator = 0

        self.separator_after = None

    def toggle_lock(self):
        if self.lock:
            self.release_lock()
        else:
            self.acquire_lock()
        return self.lock

    def acquire_lock(self):
        self.lock = True

    def release_lock(self):
        for line in self.lock_buffer:
            self.built_lines.append(line)
        self.lock = False

    def next_highlight(self):
        """
        Go to the next highlight in the buffer.
        (depending on which highlight was selected before)
        if the buffer is already positionned on the last, of if there are no
        highlights, scroll to the end of the buffer.
        """
        log.debug('Going to the next highlight…')
        if not self.highlights or self.hl_pos != self.hl_pos or \
                self.hl_pos == len(self.highlights)-1:
            self.hl_pos = float('nan')
            self.pos = 0
            return
        hl_size = len(self.highlights) - 1
        if self.hl_pos < hl_size:
            self.hl_pos += 1
        else:
            self.hl_pos = hl_size
        log.debug("self.hl_pos = %s" % self.hl_pos)
        hl = self.highlights[self.hl_pos]
        pos = None
        while not pos:
            try:
                pos = self.built_lines.index(hl)
            except ValueError:
                self.highlights = self.highlights[self.hl_pos+1:]
                if not self.highlights:
                    self.hl_pos = float('nan')
                    self.pos = 0
                    return
                hl = self.highlights[0]
        self.pos =  len(self.built_lines) - pos - self.height
        if self.pos < 0 or self.pos >= len(self.built_lines):
            self.pos = 0

    def previous_highlight(self):
        """
        Go to the previous highlight in the buffer.
        (depending on which highlight was selected before)
        if the buffer is already positionned on the first, or if there are no
        highlights, scroll to the end of the buffer.
        """
        log.debug('Going to the previous highlight…')
        if not self.highlights or self.hl_pos <= 0:
            self.hl_pos = float('nan')
            self.pos =  0
            return
        if self.hl_pos != self.hl_pos:
            self.hl_pos = len(self.highlights) - 1
        elif self.hl_pos > 0:
            self.hl_pos -= 1
        log.debug("self.hl_pos = %s" % self.hl_pos)
        hl = self.highlights[self.hl_pos]
        pos = None
        while not pos:
            try:
                pos = self.built_lines.index(hl)
            except ValueError:
                self.highlights = self.highlights[self.hl_pos+1:]
                if not self.highlights:
                    self.hl_pos = float('nan')
                    self.pos = 0
                    return
                hl = self.highlights[0]
        self.pos = len(self.built_lines) - pos - self.height
        if self.pos < 0 or self.pos >= len(self.built_lines):
            self.pos = 0

    def scroll_up(self, dist=14):
        pos = self.pos
        self.pos += dist
        if self.pos + self.height > len(self.built_lines):
            self.pos = len(self.built_lines) - self.height
            if self.pos < 0:
                self.pos = 0
        return self.pos != pos

    def scroll_down(self, dist=14):
        pos = self.pos
        self.pos -= dist
        if self.pos <= 0:
            self.pos = 0
        return self.pos != pos

    def scroll_to_separator(self):
        """
        Scroll until separator is centered. If no separator is
        present, scroll at the top of the window
        """
        if None in self.built_lines:
            self.pos = len(self.built_lines) - self.built_lines.index(None) - self.height + 1
            if self.pos < 0:
                self.pos = 0
        else:
            self.pos = len(self.built_lines) - self.height + 1
        # Chose a proper position (not too high)
        self.scroll_up(0)
        # Make “next highlight” work afterwards. This makes it easy to
        # review all the highlights since the separator was placed, in
        # the correct order.
        self.hl_pos = len(self.highlights) - self.nb_of_highlights_after_separator - 1
        log.debug("self.hl_pos = %s" % self.hl_pos)

    def remove_line_separator(self):
        """
        Remove the line separator
        """
        log.debug('remove_line_separator')
        if None in self.built_lines:
            self.built_lines.remove(None)
            self.separator_after = None

    def add_line_separator(self, room=None):
        """
        add a line separator at the end of messages list
        room is a textbuffer that is needed to get the previous message
        (in case of resize)
        """
        if None not in self.built_lines:
            self.built_lines.append(None)
            self.nb_of_highlights_after_separator = 0
            log.debug("Reseting number of highlights after separator")
            if room and room.messages:
                self.separator_after = room.messages[-1]

    def build_new_message(self, message, history=None, clean=True, highlight=False, timestamp=False):
        """
        Take one message, build it and add it to the list
        Return the number of lines that are built for the given
        message.
        """
        lines = self.build_message(message, timestamp=timestamp)
        if self.lock:
            self.lock_buffer.extend(lines)
        else:
            self.built_lines.extend(lines)
        if not lines or not lines[0]:
            return 0
        if highlight:
            self.highlights.append(lines[0])
            self.nb_of_highlights_after_separator += 1
            log.debug("Number of highlights after separator is now %s" % \
                          self.nb_of_highlights_after_separator)
        if clean:
            while len(self.built_lines) > self.lines_nb_limit:
                self.built_lines.pop(0)
        return len(lines)

    def build_message(self, message, timestamp=False):
        """
        Build a list of lines from a message, without adding it
        to a list
        """
        if message is None:  # line separator
            return [None]
        txt = message.txt
        if not txt:
            return []
        ret = []
        nick = truncate_nick(message.nickname)
        offset = 0
        if nick:
            offset += poopt.wcswidth(nick) + 2 # + nick + '> ' length
        if message.revisions > 0:
            offset += ceil(log10(message.revisions + 1))
        if message.me:
            offset += 1 # '* ' before and ' ' after
        if timestamp:
            if message.str_time:
                offset += 1 + len(message.str_time)
            if get_theme().CHAR_TIME_LEFT and message.str_time:
                offset += 1
            if get_theme().CHAR_TIME_RIGHT and message.str_time:
                offset += 1
        lines = poopt.cut_text(txt, self.width-offset-1)
        prepend = ''
        attrs = []
        for line in lines:
            saved = Line(msg=message, start_pos=line[0], end_pos=line[1], prepend=prepend)
            attrs = parse_attrs(message.txt[line[0]:line[1]], attrs)
            if attrs:
                prepend = '\x19' + '\x19'.join(attrs)
            else:
                prepend = ''
            ret.append(saved)
        return ret

    def refresh<