import locale

from tuikit.core.widget import Widget


class TextField(Widget):

    def __init__(self, value=''):
        Widget.__init__(self)
        self.allow_focus = True
        self.sizereq.update(10, 1)

        self.code = locale.getpreferredencoding()
        if not isinstance(value, str):
            value = str(value, self.code)

        self.value = value
        self.maxlen = None   # unlimited

        self.tw = 0       # real width of text field (minus space for arrows)
        self.curspos = len(value)      # position of cursor in value
        self.ofs = 0      # position of value beginning on screen

    def resize(self, w, h):
        self.tw = self.width - 2

    def draw(self, buffer):
        color = self.theme.active if self.has_focus() else self.theme.normal
        with buffer.attr(color):
            # draw value
            val = self.value + ' ' * self.tw         # add spaces to fill rest of field
            val = val[self.ofs : self.ofs + self.tw]  # cut value - begin from ofs, limit to tw chars
            buffer.puts(val.encode(self.code), 1)

            # draw arrows if content overflows
            c = ' '
            if self.ofs > 0:
                c = '<'
            buffer.putch(c)

            c = ' '
            if len(self.value[self.ofs:]) > self.tw:
                c = '>'
            buffer.putch(c, self.width-1, 0)

            self._cursor = (1 + self.curspos - self.ofs, 0)

    def keypress(self, keyname, char, mod=0):
        consumed = True
        if keyname == 'left':
            self.move_left()
        elif keyname == 'right':
            self.move_right()
        elif keyname == 'backspace':
            if self.curspos > 0:
                self.move_left()
                self.del_char()
        elif keyname == 'delete':
            self.del_char()
        else:
            consumed = False

        if not keyname and char:
            self.add_char(char)
            self.move_right()
            consumed = True

        if consumed:
            #self.redraw()
            return True
        Widget.keypress(self, keyname, char, mod)

    def move_left(self):
        if self.curspos - self.ofs > 1 or (self.ofs == 0 and self.curspos == 1):
            # move cursor
            self.curspos -= 1
        else:
            # move content in field
            if self.ofs > 0:
                self.curspos -= 1
                self.ofs -= 1

    def move_right(self):
        if self.curspos < len(self.value):
            if self.curspos - self.ofs < self.tw - 2 \
            or (self.curspos - self.ofs == self.tw - 2 and self.curspos == len(self.value)-1):
                # move cursor
                self.curspos += 1
            else:
                # move content in field
                self.curspos += 1
                self.ofs += 1

    def add_char(self, c):
        self.value = self.value[:self.curspos] + c + self.value[self.curspos:]

    def del_char(self):
        self.value = self.value[:self.curspos] + self.value[self.curspos+1:]