use crate::prelude::*;
use std::marker::PhantomData;

pub struct TextBuilder<State, O = TextOutput, H: WidgetOption<State> = ()> {
    pub content: String,
    pub attrs: TextAttrs,
    pub hint: H,
    pub output: O,
    state: PhantomData<State>,
}

impl<State, O, H: WidgetOption<State>> TextBuilder<State, O, H> {
    pub fn size(mut self, size: impl UiNum) -> Self {
        self.attrs.font_size = size.to_f32();
        self.attrs.line_height = self.attrs.font_size * LINE_HEIGHT_MULT;
        self
    }
    pub fn color(mut self, color: UiColor) -> Self {
        self.attrs.color = color;
        self
    }
    pub fn family(mut self, family: Family) -> Self {
        self.attrs.family = family;
        self
    }
    pub fn line_height(mut self, height: f32) -> Self {
        self.attrs.line_height = height;
        self
    }
    pub fn text_align(mut self, align: impl Into<RegionAlign>) -> Self {
        self.attrs.align = align.into();
        self
    }
    pub fn center_text(mut self) -> Self {
        self.attrs.align = Align::CENTER;
        self
    }
    pub fn wrap(mut self, wrap: bool) -> Self {
        self.attrs.wrap = wrap;
        self
    }
    pub fn editable(self, mode: EditMode) -> TextBuilder<State, TextEditOutput, H> {
        TextBuilder {
            content: self.content,
            attrs: self.attrs,
            hint: self.hint,
            output: TextEditOutput { mode },
            state: PhantomData,
        }
    }
}

impl<Rsc: UiRsc, O> TextBuilder<Rsc, O> {
    pub fn hint<W: WidgetLike<Rsc, Tag>, Tag>(
        self,
        hint: W,
    ) -> TextBuilder<Rsc, O, impl WidgetOption<Rsc>> {
        TextBuilder {
            content: self.content,
            attrs: self.attrs,
            hint: move |rsc: &mut Rsc| Some(hint.add_strong(rsc).any()),
            output: self.output,
            state: PhantomData,
        }
    }
}

pub trait TextBuilderOutput<State>: Sized {
    type Output;
    fn run<H: WidgetOption<State>>(
        state: &mut State,
        builder: TextBuilder<State, Self, H>,
    ) -> Self::Output;
}

pub struct TextOutput;
impl<Rsc: UiRsc> TextBuilderOutput<Rsc> for TextOutput {
    type Output = Text;

    fn run<H: WidgetOption<Rsc>>(
        state: &mut Rsc,
        builder: TextBuilder<Rsc, Self, H>,
    ) -> Self::Output {
        let buf = TextBuffer::new(&builder.content);
        let hint = builder.hint.get(state);
        let mut text = Text {
            content: builder.content.into(),
            view: TextView::new(buf, builder.attrs, hint),
        };
        text.content.changed = false;
        text
    }
}

pub struct TextEditOutput {
    mode: EditMode,
}

impl<State: UiRsc> TextBuilderOutput<State> for TextEditOutput {
    type Output = TextEdit;

    fn run<H: WidgetOption<State>>(
        state: &mut State,
        builder: TextBuilder<State, Self, H>,
    ) -> Self::Output {
        let buf = TextBuffer::new(&builder.content);
        TextEdit::new(
            TextView::new(buf, builder.attrs, builder.hint.get(state)),
            builder.output.mode,
        )
    }
}

impl<State, O: TextBuilderOutput<State>, H: WidgetOption<State>> FnOnce<(&mut State,)>
    for TextBuilder<State, O, H>
{
    type Output = O::Output;

    extern "rust-call" fn call_once(self, args: (&mut State,)) -> Self::Output {
        O::run(args.0, self)
    }
}

pub fn wtext<State>(content: impl Into<String>) -> TextBuilder<State> {
    TextBuilder {
        content: content.into(),
        attrs: TextAttrs::default(),
        hint: (),
        output: TextOutput,
        state: PhantomData,
    }
}