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 = 0  # position of cursor in value

        self.ofs = 0      # position of value beginning on screen

        self._cursor_visible = True

        self.move_end()

    def resize(self, w, h):

        self.tw = self.width - 2

        if self.curspos >= self.tw:

            self.ofs = self.curspos - self.tw

    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.update(1 + self.curspos - self.ofs, 0)

    def keypress_event(self, ev):

        map_keyname_to_func = {

            'left':       self.move_left,

            'right':      self.move_right,

            'home':       self.move_home,

            'end':        self.move_end,

            'backspace':  self.move_left_and_del,

            'delete':     self.del_char,

        }

        if not ev.keyname and ev.char:

            self.add_char(ev.char)

            self.move_right()

            consumed = True

        if consumed:

            #self.redraw()

            return True

        Widget.keypress_event(self, ev)

    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 - 1 \

            or (self.curspos - self.ofs == self.tw - 1 and self.curspos == len(self.value)-1):

                # move cursor

                self.curspos += 1

            else:

                # move content in field

                self.curspos += 1

                self.ofs += 1

    def move_home(self):

        self.curspos = 0

        self.ofs = 0

    def move_end(self):

        self.curspos = len(self.value)

        if self.curspos >= self.tw:

            self.ofs = self.curspos - self.tw

    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:]

    def move_left_and_del(self):

        if self.curspos > 0:

            self.move_left()

            self.del_char()