class TextInput(Widget):
    """
    A simple text input widget based on https://github.com/sirfuzzalot/textual-inputs
    Args:
        name (Optional[str]): The unique name of the widget. If None, the widget will be automatically named.
        value (str, optional): Defaults to "". The starting text value.
        placeholder (str, optional), default="".
            Text that appears in the widget when value is "" and the widget is not focused.
        title (str, optional): Defaults to "". A title on the top left of the widget's border.
        password (bool, optional): Defaults to False. Hides the text input, replacing it with bullets.
    Attributes:
        value (str): the value of the text field
        placeholder (str): The placeholder message.
        title (str): The displayed title of the widget.
        has_password (bool): True if the text field masks the input.
        has_focus (bool): True if the widget is focused.
        cursor (Tuple[str, Style]): The character used for the cursor and a rich Style object defining its appearance.
    Messages:
        InputOnChange: Emitted when the contents of the input changes.
        InputOnFocus: Emitted when the widget becomes focused.
    Examples:
    .. code-block:: python
        from textual_inputs import TextInput
        email_input = TextInput(
            name="email",
            placeholder="enter your email address...",
            title="Email",
        )
    """
    value: Reactive[str] = Reactive("")
    cursor: Tuple[str, Style] = ("|", Style(color="white", blink=True, bold=True))
    _cursor_position: Reactive[int] = Reactive(0)
    _has_focus: Reactive[bool] = Reactive(False)

    def __init__(self, *, name: Optional[str] = None, value: str = "", placeholder: str = "",
                 title: str = "", password: bool = False, **kwargs: Any,) -> None:
        super().__init__(name, **kwargs)
        self.value = value
        self.placeholder = placeholder
        self.title = title
        self.has_password = password
        self._cursor_position = len(self.value)

    def __rich_repr__(self):
        yield from (("name", self.name), ("title", self.title), ("value", self._conceal_or_reveal(self.value)))

    @property
    def has_focus(self) -> bool:
        """Produces True if widget is focused"""
        return self._has_focus

    def render(self) -> RenderableType:
        """ Produce a Panel object containing placeholder text or value and cursor. """
        segments = self._render_text_with_cursor() if self.has_focus else\
                   [self._conceal_or_reveal(self.value)] if self.value else\
                   [self.title] if self.title and not self.placeholder else\
                   [self.placeholder]
        text = Text.assemble(*segments)
        title = "" if self.title and not any([self.placeholder, self.value, self.has_focus]) else self.title
        return Panel(text, title=title, title_align="left", height=3, style=self.style or "",
                     border_style=self.border_style or Style(color="blue"),
                     box=rich.box.DOUBLE if self.has_focus else rich.box.SQUARE)

    def _conceal_or_reveal(self, segment: str) -> str:
        """ Produce the segment either concealed like a password or as it was passed. """
        return "•" * len(segment) if self.has_password else segment

    def _render_text_with_cursor(self) -> List[Union[str, Tuple[str, Style]]]:
        """ Produces the renderable Text object combining value and cursor """
        return [self._conceal_or_reveal(self.value[: self._cursor_position]), self.cursor,
                self._conceal_or_reveal(self.value[self._cursor_position+1:])]

    async def on_focus(self, event: events.Focus) -> None:
        self._has_focus = True
        await self._emit_on_focus()

    async def on_blur(self, event: events.Blur) -> None:
        self._has_focus = False

    async def on_key(self, event: events.Key) -> None:
        if event.key == "left":
            if self._cursor_position: self._cursor_position -= 1
        elif event.key == "right":
            if self._cursor_position <= len(self.value): self._cursor_position += 1
        elif event.key == "home":
            self._cursor_position = 0
        elif event.key == "end":
            self._cursor_position = len(self.value)
        elif event.key == "ctrl+h":  # Backspace
            if self._cursor_position:
                self.value = self.value[:self._cursor_position - 1] + self.value[self._cursor_position:]
                self._cursor_position -= 1
                await self._emit_on_change(event)
        elif event.key == "delete":
            if self._cursor_position <= len(self.value):
                self.value = self.value[:self._cursor_position] + self.value[self._cursor_position+1:]
                if self._cursor_position == len(self.value): self._cursor_position -= 1
                await self._emit_on_change(event)
        elif event.key in string.printable:
            self.value = self.value[: self._cursor_position] + event.key + self.value[self._cursor_position :]
            self._cursor_position += 1
            await self._emit_on_change(event)

    async def _emit_on_change(self, event: events.Key) -> None:
        event.stop()
        await self.emit(InputOnChange(self))

    async def _emit_on_focus(self) -> None:
        await self.emit(InputOnFocus(self))