import gtk
import os
import math
import data_monitor
import pybInkscape


class _dragger(object):
    _node = None
    _start_x = None
    _start_y = None
    _state = 0
    
    def __init__(self):
        pass
    
    ## \brief Mouse event handler
    #
    # This is a placeholder for mouse vent handlers.  This attribute
    # of instances is switched between _mouse_event_waiting and
    # _mouse_event_pressed.
    #
    def mouse_event(self, evtype, button, x, y):
        raise RuntimeError, 'should not be here'
    
    def _mouse_event_waiting(self, evtype, button, x, y):
        if evtype == pybInkscape.PYSPItem.PYB_EVENT_BUTTON_PRESS and \
                button == 1:
            self._start_x = x
            self._start_y = y
            self.mouse_event = self._mouse_event_pressed
            self.start_drag()
            pass
        pass
    
    def _mouse_event_pressed(self, evtype, button, x, y):
        rx = x - self._start_x
        ry = y - self._start_y
        
        if evtype == pybInkscape.PYSPItem.PYB_EVENT_BUTTON_RELEASE:
            self.mouse_event = self._mouse_event_waiting
            self.stop_drag(rx, ry)
            pass

        self.update(rx, ry)
        pass

    def start(self):
        self.mouse_event = self._mouse_event_waiting
        pass

    def stop(self):
        pass

    def connect(self, node):
        self.start()
        
        def handler(item, evtype, button, x, y):
            self.mouse_event(evtype, button, x, y)
            pass
        
        self._node = node
        hdl_id = node.spitem.connect('mouse-event', handler)
        self._hdl_id = hdl_id
        pass

    def disconnect(self):
        self.stop()
        node = self._node
        hdl_id = self._hdl_id
        node.disconnect(hdl_id)
        pass

    def start_drag(self):
        pass

    def stop_drag(self, rx, ry):
        pass

    def update(self, rx, ry):
        pass
    pass


class FSM_window_base(object):
    _add_state_button = None
    _move_state_button = None
    
    _state_editor = None
    _state_name = None
    _state_radius = None

    _error_dialog = None
    _error_dialog_label = None

    _state_menu = None
    
    def __init__(self):
        super(FSM_window_base, self).__init__()
        
        dirname = os.path.dirname(__file__)
        fname = os.path.join(dirname, 'FSM_window.glade')

        builder = gtk.Builder()
        builder.add_from_file(fname)

        main_win = builder.get_object("FSM_main_win")
        view_box = builder.get_object("view_box")
        add_state_button = builder.get_object('add_state')
        move_state_button = builder.get_object('move_state')
        
        state_editor = builder.get_object("state_editor")
        state_name = builder.get_object('state_name')
        state_radius = builder.get_object('state_radius')
        state_entry_action = builder.get_object('state_entry_action')

        error_dialog = builder.get_object('error_dialog')
        error_dialog_label = builder.get_object('error_dialog_label')

        transition_editor = builder.get_object('transition_editor')
        transition_cond = builder.get_object('transition_cond')
        transition_action = builder.get_object('transition_action')

        state_menu = builder.get_object('state_menu')
        transition_menu = builder.get_object('transition_menu')

        builder.connect_signals(self)
        
        self._builder = builder
        self._main_win = main_win
        self._view_box = view_box
        self._add_state_button = add_state_button
        self._move_state_button = move_state_button

        self._state_editor = state_editor
        self._state_name = state_name
        self._state_radius = state_radius
        self._state_entry_action = state_entry_action

        self._transition_editor = transition_editor
        self._transition_cond = transition_cond
        self._transition_action = transition_action

        self._error_dialog = error_dialog
        self._error_dialog_label = error_dialog_label

        self._state_menu = state_menu
        self._transition_menu = transition_menu
        pass

    def show_error(self, msg):
        error_dialog = self._error_dialog
        error_dialog_label = self._error_dialog_label
        
        error_dialog_label.set_text(msg)
        error_dialog.show()
        pass

    def hide_error(self):
        error_dialog = self._error_dialog
        error_dialog.hide()
        pass

    def show_state_editor(self, state_name=''):
        state_name_inp = self._state_name
        state_radius_inp = self._state_radius
        state_editor = self._state_editor
        
        state_name_inp.set_text(state_name)
        state_radius_inp.set_text('30')
        state_editor.show()
        pass

    def hide_state_editor(self):
        state_editor = self._state_editor
        state_editor.hide()
        pass

    def popup_state_menu(self):
        menu = self._state_menu
        menu.popup(None, None, None, 0, 0)
        pass

    def popup_transition_menu(self):
        menu = self._transition_menu
        menu.popup(None, None, None, 0, 0)
        pass
    
    def show(self):
        self._main_win.show()
        self._add_state_button.set_active(True)
        pass

    def hide(self):
        self._main_win.hide()
        pass

    def gtk_widget_hide(self, widget, event, *data):
        widget.hide()
        return True
    
    def on_start_state_activate(self, *args):
        pass
    
    def on_rename_state_activate(self, *args):
        pass
    
    def on_remove_state_activate(self, *args):
        pass
    
    def on_zoom_out_clicked(self, *args):
        pass
    
    def on_zoom_in_clicked(self, *args):
        pass
    
    def on_move_state_toggled(self, *args):
        pass
    
    def on_add_state_toggled(self, *args):
        pass
    
    def on_close_window_activate(self, *args):
        pass

    def on_FSM_main_win_destroy_event(self, *args):
        pass

    def on_state_apply_clicked(self, *args):
        pass
    
    def on_state_cancel_clicked(self, *args):
        state_editor = self._state_editor
        state_editor.hide()
        pass

    def on_error_dialog_ok_clicked(self, *args):
        error_dialog = self._error_dialog
        error_dialog.hide()
        pass

    def on_add_transition_activate(self, *args):
        pass

    def on_del_state_activate(self, *args):
        pass

    def on_edit_state_activate(self, *args):
        pass

    def on_transition_apply_clicked(self, *args):
        pass

    def on_transition_cancel_clicked(self, *args):
        pass

    def on_del_transition_activate(self, *args):
        pass

    def on_edit_transition_activate(self, *args):
        pass
    pass


class FSM_transition(object):
    _doc = None
    _domview = None
    _fsm_layer = None
    _control_layer = None
    _state = None
    _states = None
    trn_cond = None
    trn_g = None
    _arrow_node = None
    _path_node = None
    _control_points = None

    def __init__(self, trn_cond):
       self.trn_cond = trn_cond
       pass

    def init(self, doc, domview, state, states, fsm_layer, control_layer):
        self._doc = doc
        self._domview = domview
        self._state = state
        self._states = states
        self._fsm_layer = fsm_layer
        self._control_layer = control_layer
        pass

    @staticmethod
    def _update_graph(path, arrow_node, path_node):
        path_txt = 'M %f,%f C %f,%f %f,%f %f,%f' % tuple(path)
        path_node.setAttribute('d', path_txt)
        path_node.setAttribute('style', 'stroke: #000000; stroke-width: 1; '
                               'fill: none')

        # c0 c1 c2 c3 of cubic curve
        c3 = (path[6], path[7])
        c2 = (path[4], path[5])
        c23_v = (c3[0] - c2[0], c3[1] - c2[1])
        c23_len = math.sqrt(c23_v[0] * c23_v[0] + c23_v[1] * c23_v[1])
        adir = (c23_v[0] / c23_len, c23_v[1] / c23_len) # arrow direction
        odir = (-adir[1], adir[0]) # othogonal direction
        arrow_pts = (c3[0], c3[1],
                     -adir[0] * 10 + odir[0] * 4, -adir[1] * 10 + odir[1] * 4,
                     -odir[0] * 8, -odir[1] * 8)
        arrow_txt = 'M %f,%f l %f,%f l %f,%f z' % arrow_pts
        arrow_node.setAttribute('d', arrow_txt)
        arrow_node.setAttribute('style', 'stroke: #000000; stroke-width: 1; '
                                'fill: #000000')
        pass
    
    def _draw_transition_real(self, parent, path):
        doc = self._doc

        trn_g = doc.createElement('svg:g')

        path_node = doc.createElement('svg:path')
        arrow_node = doc.createElement('svg:path')
        self._update_graph(path, arrow_node, path_node)

        trn_g.appendChild(path_node)
        trn_g.appendChild(arrow_node)

        parent.appendChild(trn_g)

        return trn_g, path_node, arrow_node

    def _gen_path(self):
        states = self._states
        target_name = self.target
        target_state = states[target_name]
        src_state = self._state

        src_x, src_y = src_state.xy
        src_r = src_state.r
        target_x, target_y = target_state.xy
        target_r = target_state.r

        src_target_v = (target_x - src_x, target_y - src_y)
        src_target_len = \
            math.sqrt(src_target_v[0] ** 2 + src_target_v[1] ** 2)
        distance = src_target_len - src_r - target_r
        distance3 = distance / 3
        src_target_uv = (src_target_v[0] / src_target_len,
                         src_target_v[1] / src_target_len)

        c0x = src_x + src_target_uv[0] * src_r
        c0y = src_y + src_target_uv[1] * src_r
        c1x = c0x + src_target_uv[0] * distance3
        c1y = c0y + src_target_uv[1] * distance3
        c3x = target_x - src_target_uv[0] * target_r
        c3y = target_y - src_target_uv[1] * target_r
        c2x = c3x - src_target_uv[0] * distance3
        c2y = c3y - src_target_uv[1] * distance3

        path = [c0x, c0y, c1x, c1y, c2x, c2y, c3x, c3y]
        return path

    @property
    def path(self):
        domview = self._domview
        state_name = self._state.state_name
        trn_cond = self.trn_cond
        trn = domview.get_transition(state_name, trn_cond)
        path = trn[3]

        if not path:
            path = self._gen_path()
            pass
        
        return path

    @property
    def target(self):
        domview = self._domview
        state_name = self._state.state_name
        trn_cond = self.trn_cond
        trn = domview.get_transition(state_name, trn_cond)
        return trn[1]

    @property
    def state(self):
        return self._state

    def draw(self, parent):
        path = self.path
        trn_g, path_node, arrow_node = self._draw_transition_real(parent, path)
        self.trn_g = trn_g
        self._arrow_node = arrow_node
        self._path_node = path_node
        pass

    def clear(self):
        trn_g = self.trn_g
        parent = trn_g.parent()
        parent.removeChild(trn_g)
        pass

    def update(self):
        path = self.path
        arrow_node = self._arrow_node
        path_node = self._path_node
        self._update_graph(path, arrow_node, path_node)
        pass

    def adjust_by_ends(self):
        states = self._states

        state = self._state
        state_name = state.state_name
        trn_cond = self.trn_cond
        
        path = self.path
        
        start_state = self._state
        start_x, start_y = start_state.xy
        start_r = start_state.r

        target_name = self.target
        stop_state = states[target_name]
        stop_x, stop_y = stop_state.xy
        stop_r = stop_state.r

        c0x, c0y, c1x, c1y, c2x, c2y, c3x, c3y = tuple(path)

        c0c1 = (c1x - c0x, c1y - c0y)
        c0c1_len = math.sqrt(c0c1[0] ** 2 + c0c1[1] ** 2)
        start_v = (c0c1[0] / c0c1_len, c0c1[1] / c0c1_len)

        c3c2 = (c2x - c3x, c2y - c3y)
        c3c2_len = math.sqrt(c3c2[0] ** 2 + c3c2[1] ** 2)
        stop_v = (c3c2[0] / c3c2_len, c3c2[1] / c3c2_len)

        c0x = start_v[0] * start_r + start_x
        c0y = start_v[1] * start_r + start_y
        c1x = start_v[0] * c0c1_len + c0x
        c1y = start_v[1] * c0c1_len + c0y
        c3x = stop_v[0] * stop_r + stop_x
        c3y = stop_v[1] * stop_r + stop_y
        c2x = stop_v[0] * c3c2_len + c3x
        c2y = stop_v[1] * c3c2_len + c3y
        new_path = [c0x, c0y, c1x, c1y, c2x, c2y, c3x, c3y]
        
        domview = self._domview
        domview.set_transition_path(state_name, trn_cond, new_path)
        pass

    def show_control_points(self):
        if not self._control_points:
            doc = self._doc
            
            c1 = doc.createElement('svg:circle')
            c1.setAttribute('r', '3')
            c1.setAttribute('style', 'stroke: black; stroke-width: 1; '
                            'fill: white')
            l01 = doc.createElement('svg:line')
            l01.setAttribute('style', 'stroke: black; stroke-width: 1; '
                             'stroke-dasharray: 3 2')

            c2 = doc.createElement('svg:circle')
            c2.setAttribute('r', '3')
            c2.setAttribute('style', 'stroke: black; stroke-width: 1; '
                            'fill: white')
            l32 = doc.createElement('svg:line')
            l32.setAttribute('style', 'stroke: black; stroke-width: 1; '
                             'stroke-dasharray: 3 2')

            control_layer = self._control_layer
            
            control_layer.appendChild(c1)
            control_layer.appendChild(l01)
            control_layer.appendChild(c2)
            control_layer.appendChild(l32)
            self._control_points = (c1, l01, c2, l32)
            pass

        c1, l01, c2, l32 = self._control_points
        path = self.path
        c0x, c0y, c1x, c1y, c2x, c2y, c3x, c3y = tuple(path)
        
        c1.setAttribute('cx', str(c1x))
        c1.setAttribute('cy', str(c1y))
        l01.setAttribute('x1', str(c0x))
        l01.setAttribute('y1', str(c0y))
        l01.setAttribute('x2', str(c1x))
        l01.setAttribute('y2', str(c1y))
        
        c2.setAttribute('cx', str(c2x))
        c2.setAttribute('cy', str(c2y))
        l32.setAttribute('x1', str(c3x))
        l32.setAttribute('y1', str(c3y))
        l32.setAttribute('x2', str(c2x))
        l32.setAttribute('y2', str(c2y))
        pass

    def hide_control_points(self):
        if not self._control_points:
            return

        control_layer = self._control_layer
        for node in self._control_points:
            control_layer.removeChild(node)
            pass
        self._control_points = None
        pass

    def start_hint(self):
        path_node = self._path_node
        arrow_node = self._arrow_node
        if path_node:
            path_node.setAttribute('style',
                                   'stroke: #404040; stroke-width: 3; '
                                   'fill: none')
            arrow_node.setAttribute('style',
                                    'stroke: #404040; stroke-width: 2; '
                                    'fill: #404040')
            pass
        pass

    def stop_hint(self):
        path_node = self._path_node
        arrow_node = self._arrow_node
        if path_node:
            path_node.setAttribute('style',
                                   'stroke: #000000; stroke-width: 1; ' \
                                       'fill: none')
            arrow_node.setAttribute('style',
                                    'stroke: #000000; stroke-width: 1; ' \
                                        'fill: #000000')
            pass
        pass
    pass

class FSM_state(object):
    _doc = None
    _domview = None
    _states = None
    _fsm_layer = None
    _control_layer = None
    state_name = None
    state_g = None
    _text_node = None
    _circle_node = None
    transitions = None
    from_states = None          # There is one or more transitions
                                # from these states (name).

    _state_g_hdl_id = None
    _selected_rect = None
    
    def __init__(self, state_name):
        self.state_name = state_name
        self.transitions = {}
        self.from_states = set()
        pass

    def init(self, doc, domview, states, fsm_layer, control_layer):
        self._doc = doc
        self._domview = domview
        self._states = states
        self._fsm_layer = fsm_layer
        self._control_layer = control_layer
        pass

    def _update_graph(self, text_node, text_content, circle_node,
                      state_name, r, x, y):
        circle_node.setAttribute('r', str(r))
        circle_node.setAttribute('cx', str(x))
        circle_node.setAttribute('cy', str(y))
        circle_node.setAttribute('style', 'stroke: #000000; stroke-width: 1; '
                                 'fill: #ffffff')

        text_node.setAttribute('style', 'stroke: #000000; fill: #000000; '
                               'font-size: 16px')

        text_content.setContent(state_name)

        doc = self._doc
        spdoc = doc.spdoc
        spdoc.ensureUpToDate()
        tx, ty, tw, th = text_node.getBBox()
        text_node.setAttribute('x', str(x - tw / 2))
        text_node.setAttribute('y', str(y + th / 2))
        pass

    def grab(self, callback):
        assert not self._state_g_hdl_id
        
        state_g = self.state_g
        state_g_spitem = state_g.spitem
        state_g_hdl_id = state_g_spitem.connect('mouse-event', callback)
        self._state_g_hdl_id = state_g_hdl_id
        pass

    def ungrab(self):
        if not self._state_g_hdl:
            return
        state_g = self.state_g
        state_g_hdl_id = self._state_g_hdl_id
        state_g.disconnect(state_g_hdl_id)
        pass

    def _translate_page_xy(self, x, y):
        doc = self._doc
        root = doc.root()
        page_h_txt = root.getAttribute('height')
        page_h = float(page_h_txt)
        svgx = x
        svgy = page_h - y
        return svgx, svgy

    def show_selected(self):
        if not self._selected_rect:
            doc = self._doc
            rect = doc.createElement('svg:rect')
            control_layer = self._control_layer
            rect.setAttribute('style',
                              'stroke: #404040; stroke-width: 1; '
                              'stroke-dasharray: 6 4; fill: none')
            control_layer.appendChild(rect)
            self._selected_rect = rect
            pass

        state_g = self.state_g
        rect = self._selected_rect
        
        px, py, pw, ph = state_g.getBBox()
        x, y = self._translate_page_xy(px, py)
        y = y - ph              # px, py is left-bottom corner
        
        rect.setAttribute('x', str(x - 2))
        rect.setAttribute('y', str(y - 2))
        rect.setAttribute('width', str(pw + 4))
        rect.setAttribute('height', str(ph + 4))
        pass

    def hide_selected(self):
        if not self._selected_rect:
            return

        control_layer = self._control_layer
        rect = self._selected_rect
        control_layer.removeChild(rect)
        self._selected_rect = None
        pass
    
    def _draw_state_real(self, parent, state_name, r, x, y):
        doc = self._doc
        
        state_g = doc.createElement('svg:g')
        
        text = doc.createElement('svg:text')
        circle = doc.createElement('svg:circle')
        text_content = doc.createTextNode(state_name)

        text.appendChild(text_content)
        state_g.appendChild(circle)
        state_g.appendChild(text)
        parent.appendChild(state_g)

        self._update_graph(text, text_content, circle, state_name, r, x, y)

        return state_g, text, text_content, circle

    @property
    def r(self):
        domview = self._domview
        state_name = self.state_name
        r = domview.get_state_r(state_name)
        return r

    @property
    def xy(self):
        domview = self._domview
        state_name = self.state_name
        xy = domview.get_state_xy(state_name)
        return xy

    @property
    def all_transitions(self):
        domview = self._domview
        state_name = self.state_name
        conds = domview.all_transitions(state_name)
        return conds

    def _load_transition_domview(self, parent, condition):
        domview = self._domview
        states = self._states
        
        trn = FSM_transition(condition)
        trn.init(self._doc, domview, self, states,
                 self._fsm_layer, self._control_layer)
        trn.draw(parent)
        self.transitions[condition] = trn
        pass

    def draw(self, parent):
        state_name = self.state_name

        r = self.r
        x, y = self.xy
        state_g, text_node, text_content, circle_node = \
            self._draw_state_real(parent, state_name, r, x, y)
        self.state_g = state_g
        self._text_node = text_node
        self._text_content = text_content
        self._circle_node = circle_node

        for trn_cond in self.all_transitions:
            self._load_transition_domview(parent, trn_cond)
            pass
        pass

    def clear(self):
        state_g = self.state_g
        parent = state_g.parent()
        parent.removeChild(state_g)
        pass

    def update(self):
        text_node = self._text_node
        text_content = self._text_content
        circle_node = self._circle_node
        state_name = self.state_name
        r = self.r
        x, y = self.xy
        self._update_graph(text_node, text_content, circle_node, state_name,
                           r, x, y)
        pass

    ## \brief Tell states there are transitions to them.
    #
    # This function is only called when loading states of a FSM from
    # domview.  When loading, not all states was loaded that target
    # state may not in the memory.  So, we call this function after
    # all states being loaded.  Transitions added later does need to
    # call this function to notify end state.
    #
    def tell_target_states(self):
        states = self._states
        transitions = self.transitions
        target_state_names = [trn.target for trn in transitions.values()]
        target_states = [states[target_name]
                         for target_name in target_state_names]
        state_name = self.state_name
        for target_state in target_states:
            target_state.from_states.add(state_name)
            pass
        pass

    def adjust_transitions(self):
        import itertools

        states = self._states
        
        for trn in self.transitions.values():
            trn.adjust_by_ends()
            trn.update()
            pass

        state_name = self.state_name
        from_states = [states[from_state_name]
                      for from_state_name in self.from_states]
        states_transitions = [state.transitions.values()
                              for state in from_states]
        in_state_transitions = [[trn for trn in state_transitions
                                 if trn.target == state_name]
                                for state_transitions in states_transitions]
        in_transitions = itertools.chain(*in_state_transitions)
        for trn in in_transitions:
            trn.adjust_by_ends()
            trn.update()
            pass
        pass

    def add_transition(self, parent, condition, target_state):
        domview = self._domview
        
        state_name = self.state_name
        target_name = target_state.state_name
        domview.add_transition(state_name, condition, target_name)
        
        self._load_transition_domview(parent, condition)

        states = self._states
        target_state = states[target_name]
        target_state.from_states.add(state_name)
        pass
    pass


class _FSM_move_state_mode(object):
    __metaclass__ = data_monitor.data_monitor
    __data_monitor_prefix__ = 'on_'
    
    _window = None
    _domview = None
    _selected_cleaner = None
    
    _select_transition = None
    
    def __init__(self, window, domview_ui):
        super(_FSM_move_state_mode, self).__init__()
        
        self._window = window
        self._domview = domview_ui
        self._locker = domview_ui
        pass

    def on_move_state_background(self, item, evtype, button, x, y):
        if self._selected_cleaner is None:
            return

        if evtype == pybInkscape.PYSPItem.PYB_EVENT_BUTTON_RELEASE:
            self._deselect_state()
            pass
        pass

    def _select_state(self, state):
        self._deselect_state()
        self._selected_cleaner = state.hide_selected
        state.show_selected()
        pass

    def _deselect_state(self):
        if self._selected_cleaner:
            self._selected_cleaner()
            pass
        self._selected_cleaner = None
        pass

    def _handle_move_state_state(self, state, evtype, button, x, y):
        window = self._window

        def moving_state(item, evtype, button, x, y):
            if evtype == pybInkscape.PYSPItem.PYB_EVENT_BUTTON_RELEASE:
                window.ungrab_mouse()
                pass
            new_state_x = orign_state_x + start_x - x
            new_state_y = orign_state_y + start_y - y

            domview = self._domview
            domview.set_state_xy(state.state_name, x, y)
            state.update()
            state.adjust_transitions()
            state.show_selected()
            pass
        
        window = self._window
        
        if evtype == pybInkscape.PYSPItem.PYB_EVENT_BUTTON_PRESS and \
                button == 1:
            start_x = x
            start_y = y
            orign_state_x, orign_state_y = state.xy
            
            self._select_state(state)
            window.grab_mouse(moving_state)
            pass
        
        if evtype == pybInkscape.PYSPItem.PYB_EVENT_BUTTON_RELEASE and \
                button == 1:
            window.ungrab_mouse()
            pass
        pass

    ## \brief Install event handler for control points of a transitions.
    #
    def _install_trn_cps_mouse(self, trn):
        c1, l01, c2, l32 = trn._control_points
        path = trn.path
        c0x, c0y, c1x, c1y, c2x, c2y, c3x, c3y = tuple(path)

        state_src = trn.state
        target_name = trn.target
        states = trn._states
        state_target = states[target_name]
        domview = self._domview
        window = self._window

        def c1_update(rx, ry):
            nc1x = c1x + rx
            nc1y = c1y + ry
            cx, cy = state_src.xy
            r = state_src.r
            
            cv = nc1x - cx, nc1y - cy
            cv_len = math.sqrt(cv[0] ** 2 + cv[1] ** 2)
            nc0x = cx + cv[0] * r / cv_len
            nc0y = cy + cv[1] * r / cv_len
            
            path = list(trn.path)
            path[:4] = [nc0x, nc0y, nc1x, nc1y]

            state_name = state_src.state_name
            cond = trn.trn_cond
            domview.set_transition_path(state_name, cond, path)

            trn.show_control_points()
            trn.update()
            pass

        def c1_start():
            def relay_event(item, evtype, button, x, y):
                c1_dragger.mouse_event(evtype, button, x, y)
                pass
            
            window.ungrab_bg()
            window.grab_bg(relay_event)
            pass
        
        def c1_stop(rx, ry):
            window.ungrab_bg()
            window.grab_bg(self.on_move_state_background)
            pass
        
        def c2_update(rx, ry):
            nc2x = c2x + rx
            nc2y = c2y + ry
            cx, cy = state_target.xy
            r = state_target.r
            
            cv = nc2x - cx, nc2y - cy
            cv_len = math.sqrt(cv[0] ** 2 + cv[1] ** 2)
            nc3x = cx + cv[0] * r / cv_len
            nc3y = cy + cv[1] * r / cv_len
            
            path = list(trn.path)
            path[4:] = [nc2x, nc2y, nc3x, nc3y]

            state_name = state_src.state_name
            cond = trn.trn_cond
            domview.set_transition_path(state_name, cond, path)

            trn.show_control_points()
            trn.update()
            pass

        def c2_start():
            def relay_event(item, evtype, button, x, y):
                c2_dragger.mouse_event(evtype, button, x, y)
                pass
            
            window.ungrab_bg()
            window.grab_bg(relay_event)
            pass

        def c2_stop(rx, ry):
            window.ungrab_bg()
            window.grab_bg(self.on_move_state_background)
            pass
        
        c1_dragger = _dragger()
        c1_dragger.update = c1_update
        c1_dragger.start_drag = c1_start
        c1_dragger.stop_drag = c1_stop
        c1_dragger.connect(c1)

        c2_dragger = _dragger()
        c2_dragger.update = c2_update
        c2_dragger.start_drag = c2_start
        c2_dragger.stop_drag = c2_stop
        c2_dragger.connect(c2)
        pass

    ## \brief A transition was selected.
    #
    def _select_transition(self, trn):
        def deselect():
            trn.hide_control_points()
            del self._hint_transition # enable _hint_transition
            pass
        
        self._hint_transition = lambda *args: None # disable _hint_transition
        
        self._deselect_state()
        self._selected_cleaner = deselect
        trn.show_control_points()
        
        trn.stop_hint()
        window = self._window
        window.ungrab_bg()
        
        self._install_trn_cps_mouse(trn)
        pass

    ## \brief Hint for mouse over a transition.
    #
    def _hint_transition(self, trn):
        def stop_hint(*args):
            trn.stop_hint()
            window.ungrab_bg()
            window.grab_bg(self.on_move_state_background)
            pass

        trn.start_hint()
        
        window = self._window
        window.ungrab_bg()
        window.grab_bg(stop_hint)
        pass

    def on_del_transition_activate(self, *args):
        pass

    def on_edit_transition_activate(self, *args):
        pass

    def _show_transition_menu(self, trn):
        self._select_transition = trn
        
        window = self._window
        window.popup_transition_menu()
        pass

    ## \brief Handle mouse events when selecting no transition.
    #
    def _handle_transitoin_mouse_events(self, trn, evtype, button, x, y):
        if evtype == pybInkscape.PYSPItem.PYB_EVENT_BUTTON_RELEASE and \
                button == 1:
            self._select_transition(trn)
        elif evtype == pybInkscape.PYSPItem.PYB_EVENT_MOUSE_ENTER:
            self._hint_transition(trn)
            pass
        elif evtype == pybInkscape.PYSPItem.PYB_EVENT_BUTTON_PRESS and \
                button == 3:
            self._show_transition_menu(trn)
            pass
        pass

    def activate(self):
        window = self._window
        window._emit_leave_mode()
        window._clear_leave_mode_cb()
        window.ungrab_all()
        
        window.grab_bg(self.on_move_state_background)
        window.grab_state(self._handle_move_state_state)
        window.grab_transition(self._handle_transitoin_mouse_events)
        pass

    def deactivate(self):
        self._deselect_state()
        pass
    pass


class _FSM_add_state_mode(object):
    __metaclass__ = data_monitor.data_monitor
    __data_monitor_prefix__ = 'on_'

    _window = None
    _domview = None

    _saved_x = 0
    _saved_y = 0

    _select_state = None
    _candidate_state = None
    
    def __init__(self, window, domview_ui):
        super(_FSM_add_state_mode, self).__init__()
        
        self._window = window
        self._domview = domview_ui
        self._locker = domview_ui
        pass

    def handle_new_state(self):
        import traceback
        
        domview = self._domview
        window = self._window
        x, y = window._translate_xy(self._saved_x, self._saved_y)

        state_name = window._state_name.get_text()
        r_txt = window._state_radius.get_text()
        try:
            r = float(r_txt)
        except ValueError:
            traceback.print_exc()
            window.show_error('Invalid value: "%s" is not a valid value '
                              'for radius.' % (r_txt))
            return
        
        try:
            domview.add_state(state_name)
        except:
            traceback.print_exc()
            window.show_error('Invalid state name: "%s" is existing' %
                              (state_name))
            return
        domview.set_state_xy(state_name, x, y)
        domview.set_state_r(state_name, r)

        window._load_new_state_incr(state_name)

        window.hide_state_editor()
        pass
    
    def on_add_state_background(self, item, evtype, button, x, y):
        window = self._window
        
        if evtype == pybInkscape.PYSPItem.PYB_EVENT_BUTTON_RELEASE and \
                button == 1:
            self._saved_x = x
            self._saved_y = y
            window.show_state_editor()
            pass
        pass

    def _stop_select_target(self):
        self.deactivate()
        self.activate()
        pass

    def _handle_select_transition_target(self, state, evtype, button, x, y):
        if self._candidate_state != state and self._select_state != state:
            if self._candidate_state:
                self._candidate_state.hide_selected()
                pass
            self._candidate_state = state
            state.show_selected()
            pass

        if evtype != pybInkscape.PYSPItem.PYB_EVENT_BUTTON_RELEASE:
            return
        if button != 1:
            return
        
        if state == self._select_state:
            self._stop_select_target()
            return
        
        window = self._window
        fsm_layer = window._fsm_layer
        
        target_state = state
        src_state = self._select_state
        cond = ''
        src_state.add_transition(fsm_layer, cond, target_state)
        
        self._stop_select_target()
        pass

    def _handle_add_transition(self, *args):
        def restore_bg(item, evtype, *args):
            if evtype != pybInkscape.PYSPItem.PYB_EVENT_BUTTON_PRESS:
                if self._candidate_state:
                    self._candidate_state.hide_selected()
                    self._candidate_state = None
                    pass
                return
            self._stop_select_target()
            pass
        
        window = self._window
        window.ungrab_bg()
        window.grab_bg(restore_bg)

        window.ungrab_state()
        window.grab_state(self._handle_select_transition_target)
        self._select_state.show_selected()
        pass

    def _handle_state_mouse_events(self, state, evtype, button, x, y):
        if evtype == pybInkscape.PYSPItem.PYB_EVENT_BUTTON_RELEASE and \
                button == 3:
            self._select_state = state
            
            window = self._window
            window.popup_state_menu()
            pass
        pass

    def activate(self):
        window = self._window
        
        window._emit_leave_mode()
        window.ungrab_all()
        
        window.grab_bg(self.on_add_state_background)
        window.grab_state(self._handle_state_mouse_events)
        window.grab_add_transition(self._handle_add_transition)
        pass

    def deactivate(self):
        if self._select_state:
            self._select_state.hide_selected()
            pass
        if self._candidate_state:
            self._candidate_state.hide_selected()
            self._candidate_state = None
            pass
        pass
    pass

class FSM_window(FSM_window_base):
    __metaclass__ = data_monitor.data_monitor
    __data_monitor_prefix__ = 'on_'

    _background = None
    _fsm_layer = None
    _control_layer = None
    width = 1024
    height = 768

    _grab_mouse_hdl = None
    _bg_hdl = None

    _leave_mode_cb = None
    _move_state_mode = None
    _add_state_mode = None
    _state_mouse_event_handler = None
    _add_transition_cb = None
    _transition_mouse_event_handler = None
    
    def __init__(self, domview_ui, close_cb, destroy_cb):
        super(FSM_window, self).__init__()

        self._locker = domview_ui

        self._domview = domview_ui
        self._states = {}
        
        self._close_cb = close_cb # callback to close editor window (hide)
        self._destroy_cb = destroy_cb # callback to destroy editor window

        self._move_state_mode = _FSM_move_state_mode(self, domview_ui)
        self._add_state_mode = _FSM_add_state_mode(self, domview_ui)
        pass

    def _init_layers(self):
        doc = self._doc()
        root = self._root()
        
        root.setAttribute('inkscape:groupmode', 'layer')
        
        background = doc.createElement('svg:rect')
        background.setAttribute('x', '0')
        background.setAttribute('y', '0')
        background.setAttribute('width', str(self.width))
        background.setAttribute('height', str(self.height))
        background.setAttribute('style', 'fill: #ffffff')
        root.appendChild(background)
        self._background = background
        
        fsm_layer = doc.createElement('svg:g')
        fsm_layer.setAttribute('inkscape:groupmode', 'layer')
        root.appendChild(fsm_layer)
        self._fsm_layer = fsm_layer

        control_layer = doc.createElement('svg:g')
        control_layer.setAttribute('inkscape:groupmode', 'layer')
        root.appendChild(control_layer)
        self._control_layer = control_layer
        pass

    def _doc(self):
        view_widget = self._view_widget
        view = view_widget.view
        doc = view.doc().rdoc
        return doc

    def _root(self):
        doc = self._doc()
        root = doc.root()
        return root

    def _translate_xy(self, x, y):
        return x, y

    def _clear_view(self):
        if not self._background:
            self._init_layers()
            return
        
        children = [child for child in self._fsm_layer.childList()] + \
            [child for child in self._control_layer.childList()]
        for child in children:
            parent = child.parent()
            parent.removeChild(child)
            pass

        self._states = {}
        pass

    def _draw_state_domview(self, state_name):
        domview = self._domview
        doc = self._doc()
        fsm_layer = self._fsm_layer
        states = self._states
        
        state = FSM_state(state_name)
        state.init(doc, domview, states, self._fsm_layer, self._control_layer)
        self._states[state_name] = state
        
        state.draw(fsm_layer)
        pass

    def _set_leave_mode_cb(self, callback):
        self._leave_mode_cb = callback
        pass

    def _clear_leave_mode_cb(self):
        self._leave_mode_cb = None
        pass

    def _emit_leave_mode(self):
        if self._leave_mode_cb:
            self._leave_mode_cb()
            self._leave_mode_cb = None
            pass
        pass

    def ungrab_all(self):
        self.ungrab_bg()
        self.ungrab_mouse()
        self.ungrab_state()
        self.ungrab_add_transition()
        self.ungrab_transition()
        pass

    def on_state_mouse_event(self, state, evtype, button, x, y):
        if self._state_mouse_event_handler:
            self._state_mouse_event_handler(state, evtype, button, x, y)
            pass
        pass

    def _install_state_event_handler(self, state):
        def mouse_event_handler(item, evtype, button, x, y):
            self.on_state_mouse_event(state, evtype, button, x, y)
            pass
        state.grab(mouse_event_handler)
        pass

    def on_transition_mouse_event(self, trn, evtype, button, x, y):
        if self._transition_mouse_event_handler:
            self._transition_mouse_event_handler(trn, evtype, button, x, y)
            pass
        pass

    def _install_transition_event_handler(self, trn):
        def mouse_event_handler(item, evtype, button, x, y):
            self.on_transition_mouse_event(trn, evtype, button, x, y)
            pass
        trn_g = trn.trn_g
        trn_g.spitem.connect('mouse-event', mouse_event_handler)
        pass

    def grab_transition(self, callback):
        assert self._transition_mouse_event_handler is None
        self._transition_mouse_event_handler = callback
        pass

    def ungrab_transition(self):
        self._transition_mouse_event_handler = None
        pass

    def grab_state(self, callback):
        assert self._state_mouse_event_handler is None
        self._state_mouse_event_handler = callback
        pass

    def ungrab_state(self):
        self._state_mouse_event_handler = None
        pass

    def grab_add_transition(self, callback):
        assert self._add_transition_cb is None
        self._add_transition_cb = callback
        pass

    def ungrab_add_transition(self):
        self._add_transition_cb = None
        pass

    def _load_new_state(self, state_name):
        states = self._states
        
        self._draw_state_domview(state_name)
        state = states[state_name]
        self._install_state_event_handler(state)

        for trn in state.transitions.values():
            self._install_transition_event_handler(trn)
            pass
        pass

    ## \brief Load new state incrementally.
    #
    def _load_new_state_incr(self, state_name):
        self._load_new_state(state_name)
        states = self._states
        state = states[state_name]
        state.tell_target_states()
        pass
    
    def _rebuild_from_states(self):
        states = self._states
        domview = self._domview
        state_names = domview.all_state_names()
        for state_name in state_names:
            state = states[state_name]
            state.tell_target_states()
            pass
        pass
    
    def _update_view(self):
        self._clear_view()
        states = self._states
        
        domview = self._domview
        
        state_names = domview.all_state_names()
        for state_name in state_names:
            self._load_new_state(state_name)
            pass
        self._rebuild_from_states()
        pass

    def set_svg_view(self, view):
        self._view_box.add(view)
        self._view_widget = view
        
        root = self._root()
        root.setAttribute('width', '1024')
        root.setAttribute('height', '768')
        view.setResize(True, 800, 600)
        pass

    def on_close_window_activate(self, *args):
        self._emit_leave_mode()
        self._close_cb()
        pass
    
    def on_FSM_main_win_destroy_event(self, *args):
        self._emit_leave_mode()
        self._destroy_cb()
        pass
    
    def on_FSM_main_win_delete_event(self, *args):
        self._emit_leave_mode()
        self._destroy_cb()
        pass

    def on_add_state_toggled(self, *args):
        mode = self._add_state_mode
        mode.activate()
        self._set_leave_mode_cb(lambda: mode.deactivate())
        pass

    def on_move_state_toggled(self, *args):
        mode = self._move_state_mode
        mode.activate()
        self._set_leave_mode_cb(lambda: mode.deactivate())
        pass

    def on_state_apply_clicked(self, *args):
        self._add_state_mode.handle_new_state()
        pass

    def on_add_transition_activate(self, *args):
        if self._add_transition_cb:
            self._add_transition_cb(*args)
            pass
        pass

    def _install_test_data(self):
        self._init_layers()
        
        domview = self._domview
        
        view = self._view_widget.view
        doc = view.doc()
        rdoc = doc.rdoc
        root_node = doc.root().repr

        line_node = rdoc.createElement('svg:line')
        line_node.setAttribute('x1', '10')
        line_node.setAttribute('y1', '10')
        line_node.setAttribute('x2', '100')
        line_node.setAttribute('y2', '100')
        line_node.setAttribute('style', 'stroke: #000000; stroke-width:2')
        
        root_node.appendChild(line_node)

        def show_msg(*args, **kws):
            print 'mouse_event'
            print args
            pass
        print 'before connect'
        hdl_id = line_node.spitem.connect('mouse-event', show_msg)
        print hdl_id

        state1 = 'state 1'
        domview.add_state(state1)
        domview.set_state_r(state1, 50)
        domview.set_state_xy(state1, 200, 100)
        state2 = 'state 2'
        domview.add_state(state2)
        domview.set_state_r(state2, 30)
        domview.set_state_xy(state2, 300, 100)
        domview.add_transition(state1, 'event1', state2)
        domview.set_transition_path(state1, 'event1', (200, 150,
                                                       240, 180,
                                                       260, 180,
                                                       300, 130))
        pass

    def show(self):
        self._install_test_data()
        self._install_test_data = lambda: None
        self._update_view()
        self._add_state_mode.activate()
        super(FSM_window, self).show()
        pass

    def grab_mouse(self, callback):
        assert self._grab_mouse_hdl is None
        
        root = self._root()
        root.setAttribute('inkscape:groupmode', '')
        self._grab_mouse_hdl = root.spitem.connect('mouse-event', callback)
        pass

    def ungrab_mouse(self):
        if not self._grab_mouse_hdl:
            return
        
        root = self._root()
        root.spitem.disconnect(self._grab_mouse_hdl)
        self._grab_mouse_hdl = None
        root.setAttribute('inkscape:groupmode', 'layer')
        pass

    def grab_bg(self, callback):
        assert self._bg_hdl is None
        assert self._background

        background = self._background
        bg_hdl = background.spitem.connect('mouse-event', callback)
        self._bg_hdl = bg_hdl
        pass

    def ungrab_bg(self):
        if not self._bg_hdl:
            return

        background = self._background
        bg_hdl = self._bg_hdl
        background.spitem.disconnect(bg_hdl)
        self._bg_hdl = None
        pass
    pass

if __name__ == '__main__':
    win = FSM_window()
    win._main_win.connect('destroy', gtk.main_quit)
    win.show()
    gtk.main()
    pass