# -*- coding: utf-8 -*-

class Scrollbar(Widget):

    """Abstract base class for scrollbars."""

    def __init__(self):

        Widget.__init__(self)

        # Scrolling range is 0 .. _scroll_max

        self._scroll_max = self._get_length() - 3

        # Current position of scrollbar in scrolling range.

        self._scroll_pos = 0

        # Current position of thumb on scrollbar - used for draw.

        self._thumb_pos = 0

        # Auxilliary variable, True when user holds mouse on thumb.

        self._dragging = False

        # Auxilliary variable, 'up' or 'down' depending on last move direction.

        self._move = None

        #: delay before continuous scrolling when user holds mouse on scrollbar arrow

        self.scroll_delay = 0.150

        #: interval for continuous scrolling

        self.scroll_interval = 0.030

        # change event is emitted when user moves scrollbar (even programmatically)

    @property

    def scroll_max(self):

        """Maximum for scrolling position."""

        return self._scroll_max

    @scroll_max.setter

    def scroll_max(self, value):

        if value < 0:

            value = 0

        self._scroll_max = value

        if self._scroll_pos > value:

            self._scroll_pos = value

        self._update_thumb_pos()

    @property

    def scroll_pos(self):

        """Scrolling position.

        Integer number between 0 and 'max'.

        """

        return self._scroll_pos

    @scroll_pos.setter

    def scroll_pos(self, value):

        if self._scroll_pos != value:

            self._scroll_pos = value

            self._update_thumb_pos()

    def move_up(self):

        """Move scrolling position up/left."""

        if self._scroll_pos > 0:

            self.scroll_pos = self._scroll_pos - 1

        self._move = 'up'

    def move_down(self):

        """Move scrolling position down/right."""

        if self._scroll_pos < self._scroll_max:

            self.scroll_pos = self._scroll_pos + 1

        self._move = 'down'

    def drag(self, mouse_pos):

        """Scroll using mouse drag on thumb.

        Args:

            mouse_pos: new position of mouse, in range 0 .. self._get_length()

        """

        new_pos = int(round((mouse_pos - 1) / (self._get_length() - 3) * self._scroll_max))

        if new_pos < 0:

            new_pos = 0

        if new_pos > self._scroll_max:

            new_pos = self._scroll_max

        if self._scroll_pos != new_pos:

            self.scroll_pos = new_pos

    def _get_length(self):

        """Return length of scrollbar.

        This will be widget height for vertical scrollbar,

        width for horizontal scrollbar.

        """

        raise NotImplementedError()

    def _update_thumb_pos(self):

        """Update value of internal variable _thumb_pos."""

        self._thumb_pos = 0

        if self._scroll_max and self._scroll_pos <= self._scroll_max:

            self._thumb_pos = int(round(self._scroll_pos / self._scroll_max * (self._get_length() - 3)))

    def _continuous_scroll(self):

        if self._move == 'up':

            self.move_up()

        if self._move == 'down':

            self.move_down()

        self.add_timeout(self.scroll_interval, self._continuous_scroll)

class VScrollbar(Scrollbar):

    def __init__(self):

        Scrollbar.__init__(self)

        ug = ev.driver.unigraph

        ev.driver.pushcolor('normal')

        ev.driver.putch(ev.x, ev.y, ug.get_char('sb_up'))

        for i in range(1, self.height - 1):

            ev.driver.putch(ev.x, ev.y + i, ug.get_char('sb_vtrack'))

        ev.driver.putch(ev.x, ev.y + 1 + self._thumb_pos, ug.get_char('sb_thumb'))

        ev.driver.putch(ev.x, ev.y + self.height - 1, ug.get_char('sb_down'))

        ev.driver.popcolor()

    def on_mousedown(self, ev):

        self._dragging = False

        self._move = None

        # arrow buttons

        if ev.wy == 0 or ev.wy == self.height - 1:

            if ev.wy == 0:

                self.move_up()

            else:

                self.move_down()

            self.add_timeout(self.scroll_delay, self._continuous_scroll)

            return

        # thumb bar

        if ev.wy == 1 + self._thumb_pos:

            self._dragging = True

            return

    def on_mousemove(self, ev):

        if self._dragging:

            self.drag(ev.wy)

    def on_mouseup(self, ev):

        if self._dragging:

            self.drag(ev.wy)

            self._dragging = False

            return

        if self._move:

            self.remove_timeout(self._continuous_scroll)

            self._move = None

            return

    def _get_length(self):

        return self.height

class HScrollbar(Scrollbar):

    def __init__(self):

        Scrollbar.__init__(self)

    def on_draw(self, ev):

        ug = ev.driver.unigraph

        ev.driver.pushcolor('normal')

        ev.driver.putch(ev.x, ev.y, ug.get_char('sb_left'))

        for i in range(1, self.width - 1):

            ev.driver.putch(ev.x + i, ev.y, ug.get_char('sb_htrack'))

        ev.driver.putch(ev.x + 1 + self._thumb_pos, ev.y, ug.get_char('sb_thumb'))

        ev.driver.putch(ev.x + self.width - 1, ev.y, ug.get_char('sb_right'))

        ev.driver.popcolor()

    def on_mousedown(self, ev):

        self._dragging = False

        self._move = None

        # arrow buttons

        if ev.wx == 0 or ev.wx == self.width - 1:

            if ev.wx == 0:

                self.move_up()

            else:

                self.move_down()

            self.add_timeout(self.scroll_delay, self._continuous_scroll)

            return

        # thumb bar

        if ev.wx == 1 + self._thumb_pos:

            self._dragging = True

            return

    def on_mousemove(self, ev):

        if self._dragging:

            self.drag(ev.wx)

    def on_mouseup(self, ev):

        if self._dragging:

            self.drag(ev.wx)

            self._dragging = False

            return

        if self._move:

            self.remove_timeout(self._continuous_scroll)

            self._move = None

            return

    def _get_length(self):

        return self.width