mod build;
mod edit;

pub use build::*;
pub use edit::*;
use iris_core::util::MutDetect;

use crate::prelude::*;
use std::ops::{Deref, DerefMut};

pub struct Text {
    pub content: MutDetect<String>,
    view: TextView,
}

pub struct TextView {
    pub attrs: MutDetect<TextAttrs>,
    pub buf: MutDetect<TextBuffer>,
    // cache
    tex: Option<RenderedText>,
    width: Option<f32>,
    pub hint: Option<StrongWidget>,
}

impl TextView {
    fn is_empty(&self) -> bool {
        self.buf.is_empty()
    }

    pub fn wrap_width(&self) -> Option<f32> {
        self.width
    }
}

impl TextView {
    pub fn new(buf: TextBuffer, attrs: TextAttrs, hint: Option<StrongWidget>) -> Self {
        Self {
            attrs: attrs.into(),
            buf: buf.into(),
            tex: None,
            width: None,
            hint,
        }
    }

    /// region where the text should be draw
    /// does not include extra height or width from weird unicode
    pub fn region(&self) -> UiRegion {
        self.tex()
            .map(|t| t.size)
            .unwrap_or(Vec2::ZERO)
            .align(self.align)
    }

    fn render(&mut self, painter: &mut Painter) -> &RenderedText {
        let width = if self.attrs.wrap {
            Some(painter.px_size().x)
        } else {
            None
        };
        if width != self.width || self.tex.is_none() || self.attrs.changed || self.buf.changed {
            self.width = width;
            self.tex = Some(painter.render_text(&mut self.buf, &self.attrs, width));
            self.attrs.changed = false;
            self.buf.changed = false;
        }
        self.tex.as_ref().unwrap()
    }
    pub fn tex(&self) -> Option<&RenderedText> {
        self.tex.as_ref()
    }
    /// Draws the text, and says where the glyphs went and what they use.
    pub fn draw(&mut self, painter: &mut Painter) -> (UiRegion, Size) {
        let align = self.align;
        if self.is_empty() && self.hint.is_some() {
            let region = self.render(painter).size.align(align);
            let size = match &self.hint {
                Some(hint) => painter.widget(hint).size(),
                None => Size::ZERO,
            };
            return (region, size);
        }

        let tex = self.render(painter);
        let region = tex.size.align(align);
        let size = Size::abs(tex.size);
        let within = region.within(&painter.region());
        painter.glyphs(tex, within);
        (region, size)
    }

    /// Wrapping reads the width it is offered, so a wider box reshapes it and
    /// a taller one does not. Alignment matters too, and separately: glyphs
    /// anchored to the start of an axis stay put when that extent changes,
    /// but centred or end-aligned ones move even though the shaping stands.
    pub fn on_resize(&self, axis: Axis) -> OnResize {
        let reshapes = axis == Axis::X && self.attrs.wrap;
        let anchored = match axis {
            Axis::X => self.align.x,
            Axis::Y => self.align.y,
        } == AxisAlign::Neg;
        match reshapes || !anchored {
            true => OnResize::Redraw,
            false => OnResize::Translate,
        }
    }

    pub fn content(&self) -> String {
        self.buf.text().to_string()
    }
}

impl Text {
    pub fn new(content: impl Into<String>) -> Self {
        let content: String = content.into();
        Self {
            view: TextView::new(TextBuffer::new(&content), TextAttrs::default(), None),
            content: content.into(),
        }
    }
    fn update_buf(&mut self) {
        if self.content.changed {
            self.content.changed = false;
            self.view.buf.set_text(self.content.as_str());
        }
    }
}

impl Widget for Text {
    fn draw(&mut self, painter: &mut Painter) -> Size {
        self.update_buf();
        self.view.draw(painter).1
    }

    fn on_resize(&self, axis: Axis) -> OnResize {
        self.view.on_resize(axis)
    }
}

impl Deref for Text {
    type Target = TextAttrs;

    fn deref(&self) -> &Self::Target {
        &self.view
    }
}

impl DerefMut for Text {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.view
    }
}

impl Deref for TextView {
    type Target = TextAttrs;

    fn deref(&self) -> &Self::Target {
        &self.attrs
    }
}

impl DerefMut for TextView {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.attrs
    }
}