futtlui 0.1.6

use futtl::Futtl;
use std::ops::{Add, Sub};

pub const SINGLE_BORDER: BorderStyle = BorderStyle {
    top: '─' as i32,
    bottom: '─' as i32,
    left: '│' as i32,
    right: '│' as i32,
    top_left: '┌' as i32,
    top_right: '┐' as i32,
    bottom_right: '┘' as i32,
    bottom_left: '└' as i32,
};

pub const DOUBLE_BORDER: BorderStyle = BorderStyle {
    top: '═' as i32,
    bottom: '═' as i32,
    left: '║' as i32,
    right: '║' as i32,
    top_left: '╔' as i32,
    top_right: '╗' as i32,
    bottom_right: '╝' as i32,
    bottom_left: '╚' as i32,
};

pub const NO_BORDER: BorderStyle = BorderStyle {
    top: '\0' as i32,
    bottom: '\0' as i32,
    left: '\0' as i32,
    right: '\0' as i32,
    top_left: '\0' as i32,
    top_right: '\0' as i32,
    bottom_right: '\0' as i32,
    bottom_left: '\0' as i32,
};

#[derive(Clone)]
pub enum Layout {
    Vh(i32),
    Vw(i32),
    Percent(i32),
    Cell(i32),
    Auto,

    Add(Box<Layout>, Box<Layout>),
    Sub(Box<Layout>, Box<Layout>),
}

impl Add for Layout {
    type Output = Layout;

    fn add(self, rhs: Layout) -> Layout {
        Layout::Add(Box::new(self), Box::new(rhs))
    }
}

impl Sub for Layout {
    type Output = Layout;

    fn sub(self, rhs: Layout) -> Layout {
        Layout::Sub(Box::new(self), Box::new(rhs))
    }
}

#[derive(Copy, Clone)]
pub enum Alignment {
    Left,
    Center,
    Right
}

#[derive(Copy, Clone)]
pub struct BorderStyle {
    pub top: i32,
    pub bottom: i32,
    pub left: i32,
    pub right: i32,
    pub top_left: i32,
    pub top_right: i32,
    pub bottom_right: i32,
    pub bottom_left: i32,
}

#[derive(Copy, Clone)]
pub enum Border {
    Single,
    Double,
    Custom(BorderStyle),
    None
}

#[derive(Clone)]
pub struct LayoutVec2 {
    pub x: Layout,
    pub y: Layout
}

impl LayoutVec2 {
    pub fn new(x: Layout, y: Layout) -> Self {
        Self {x, y}
    }
}

pub struct Style {
    pub position: LayoutVec2,
    pub size: LayoutVec2,
    pub margin: LayoutVec2,
    pub color: futtl::ColorSet,
    pub attributes: futtl::Attr,
    pub widget_border: Border,
    pub alignment_type: Alignment
}

pub enum WidgetCtx {
    Box(usize),
    None
}

pub struct Text {
    pub text: String,
    pub style: Style
}

pub struct Widget {
    pub ctx: WidgetCtx,
    pub style: Style,
    pub children: Vec<Widget>,
    pub content: Vec<Text>,
    pub pos: futtl::Vec2
}

pub struct Win {
    pub ctx: futtl::Win,
    pub children: Vec<Widget>,
    pub color: futtl::ColorSet
}

impl Style {
    pub fn new() -> Self {
        Self {
            position: LayoutVec2 {x: Layout::Auto, y: Layout::Auto},
            size: LayoutVec2 {x: Layout::Auto, y: Layout::Auto},
            margin: LayoutVec2 {x: Layout::Auto, y: Layout::Auto},
            color: futtl::ColorSet::new_default(),
            attributes: futtl::Attr::NONE,
            widget_border: Border::None,
            alignment_type: Alignment::Left
        }
    }
}

#[derive(Copy, Clone)]
enum Axis {
    X,
    Y,
}

fn evaluate_layout(term_size: futtl::Vec2, parent_size: futtl::Vec2, layout: &Layout, axis: Axis) -> i32 {
    match layout {
        Layout::Auto => 0,

        Layout::Vw(n) => match axis {
            Axis::X => term_size.x * n / 100,
            Axis::Y => 0,
        },

        Layout::Vh(n) => match axis {
            Axis::X => 0,
            Axis::Y => term_size.y * n / 100,
        },

        Layout::Percent(n) => match axis {
            Axis::X => parent_size.x * n / 100,
            Axis::Y => parent_size.y * n / 100,
        },

        Layout::Cell(n) => *n,

        Layout::Add(a, b) => {
            evaluate_layout(term_size, parent_size, a, axis)
                + evaluate_layout(term_size, parent_size, b, axis)
        }

        Layout::Sub(a, b) => {
            evaluate_layout(term_size, parent_size, a, axis)
                - evaluate_layout(term_size, parent_size, b, axis)
        }
    }
}

fn evaluate_size(term_size: futtl::Vec2, parent_size: futtl::Vec2, size_obj: LayoutVec2) -> futtl::Vec2 {
    futtl::Vec2::new(
        evaluate_layout(term_size, parent_size, &size_obj.x, Axis::X),
        evaluate_layout(term_size, parent_size, &size_obj.y, Axis::Y),
    )
}

fn evaluate_pos(term_size: futtl::Vec2, parent_size: futtl::Vec2, pos_obj: LayoutVec2) -> futtl::Vec2 {
    futtl::Vec2::new(
        evaluate_layout(term_size, parent_size, &pos_obj.x, Axis::X),
        evaluate_layout(term_size, parent_size, &pos_obj.y, Axis::Y),
    )
}

impl Win {
    pub fn new() -> Self {
        Self {
            ctx: futtl::Win::new(256, futtl::Attr::NONE),
            children: Vec::new(),
            color: futtl::ColorSet::new(
                futtl::Color::ANSI(futtl::AnsiColor::DefaultFG),
                futtl::Color::ANSI(futtl::AnsiColor::DefaultBG),
            ),
        }
    }

    pub fn pack(&mut self, widget: Widget) {
        self.children.push(widget);
    }

    fn evaluate_members(&mut self) {
        let term_size = self.ctx.get_size();

        let auto_x = self.children
            .iter()
            .filter(|child| matches!(child.style.size.x, Layout::Auto))
            .count();

        let auto_y = self.children
            .iter()
            .filter(|child| matches!(child.style.size.y, Layout::Auto))
            .count();

        let mut remaining_x = term_size.x;
        let mut remaining_y = term_size.y;

        // Calculate the space consumed by non-Auto children.
        for child in &self.children {
            let size = evaluate_size(
                term_size,
                term_size,
                child.style.size.clone(),
            );

            if !matches!(child.style.size.x, Layout::Auto) {
                remaining_x -= size.x;
            }

            if !matches!(child.style.size.y, Layout::Auto) {
                remaining_y -= size.y;
            }
        }

        remaining_x = remaining_x.max(0);
        remaining_y = remaining_y.max(0);

        // Divide the remaining space equally between Auto children.
        let auto_x_size = if auto_x > 0 {
            remaining_x / auto_x as i32
        } else {
            0
        };

        let auto_y_size = if auto_y > 0 {
            remaining_y / auto_y as i32
        } else {
            0
        };

        let mut current_x = 0;
        let mut current_y = 0;

        for child in self.children.iter_mut() {
            let child_size = evaluate_size(
                term_size,
                term_size,
                child.style.size.clone(),
            );

            let x_size = match child.style.size.x {
                Layout::Auto => auto_x_size,
                _ => child_size.x.min(term_size.x),
            };

            let y_size = match child.style.size.y {
                Layout::Auto => auto_y_size,
                _ => child_size.y.min(term_size.y),
            };

            child.pos = evaluate_pos(
                term_size,
                term_size,
                child.style.position.clone(),
            );

            // Auto position means "place me after the previous child".
            if matches!(child.style.position.x, Layout::Auto) {
                child.pos.x = current_x;
            }

            if matches!(child.style.position.y, Layout::Auto) {
                child.pos.y = current_y;
            }

            // Every child consumes space in the flow.
            current_x += x_size;
            current_y += y_size;

            let idx = self.ctx.create_container(x_size, y_size);

            child.ctx = WidgetCtx::Box(idx);
        }
    }

    pub fn mainloop(&mut self) {
        self.evaluate_members();

        for child in self.children.iter_mut() {
            match child.ctx {
                WidgetCtx::None => {},
                WidgetCtx::Box(_) => {
                    child.show(child.pos, &mut self.ctx);
                }
            }
        }

        futtl::flush();

        let c = self.ctx.get_in();
        if !((c == 'q' as i32) || (c == 27)) {
            self.mainloop();
        }
    }
}

pub trait Stylable: Sized {
    fn style(&mut self) -> &mut Style;

    fn foreground(mut self, col: futtl::Color) -> Self {
        self.style().color.fg = col;
        self
    }

    fn background(mut self, col: futtl::Color) -> Self {
        self.style().color.bg = col;
        self
    }

    fn position(mut self, x: Layout, y: Layout) -> Self {
        self.style().position.x = x;
        self.style().position.y = y;
        self
    }

    fn position_x(mut self, x: Layout) -> Self {
        self.style().position.x = x;
        self
    }

    fn position_y(mut self, y: Layout) -> Self {
        self.style().position.y = y;
        self
    }

    fn size(mut self, x: Layout, y: Layout) -> Self {
        self.style().size.x = x;
        self.style().size.y = y;
        self
    }

    fn size_x(mut self, x: Layout) -> Self {
        self.style().size.x = x;
        self
    }

    fn size_y(mut self, y: Layout) -> Self {
        self.style().size.y = y;
        self
    }

    fn margin(mut self, x: Layout, y: Layout) -> Self {
        self.style().margin.x = x;
        self.style().margin.y = y;
        self
    }

    fn margin_x(mut self, x: Layout) -> Self {
        self.style().margin.x = x;
        self
    }

    fn margin_y(mut self, y: Layout) -> Self {
        self.style().margin.y = y;
        self
    }

    fn attribute(mut self, attr: futtl::Attr) -> Self {
        self.style().attributes |= attr;
        self
    }

    fn remove_attribute(mut self, attr: futtl::Attr) -> Self {
        self.style().attributes &= !attr;
        self
    }

    fn border(mut self, border: Border) -> Self {
        self.style().widget_border = border;
        self
    }

    fn color(mut self, cs: futtl::ColorSet) -> Self {
        self.style().color = cs;
        self
    }
    
    fn align(mut self, alignment: Alignment) -> Self {
        self.style().alignment_type = alignment;
        self
    }
}

pub trait BorrowStylable {
    fn style(&mut self) -> &mut Style;

    fn foreground(&mut self, col: futtl::Color) -> &mut Self {
        self.style().color.fg = col;
        self
    }

    fn background(&mut self, col: futtl::Color) -> &mut Self {
        self.style().color.bg = col;
        self
    }

    fn position(&mut self, x: Layout, y: Layout) -> &mut Self {
        self.style().position.x = x;
        self.style().position.y = y;
        self
    }

    fn position_x(&mut self, x: Layout) -> &mut Self {
        self.style().position.x = x;
        self
    }

    fn position_y(&mut self, y: Layout) -> &mut Self {
        self.style().position.y = y;
        self
    }

    fn size(&mut self, x: Layout, y: Layout) -> &mut Self {
        self.style().size.x = x;
        self.style().size.y = y;
        self
    }

    fn size_x(&mut self, x: Layout) -> &mut Self {
        self.style().size.x = x;
        self
    }

    fn size_y(&mut self, y: Layout) -> &mut Self {
        self.style().size.y = y;
        self
    }

    fn margin(&mut self, x: Layout, y: Layout) -> &mut Self {
        self.style().margin.x = x;
        self.style().margin.y = y;
        self
    }

    fn margin_x(&mut self, x: Layout) -> &mut Self {
        self.style().margin.x = x;
        self
    }

    fn margin_y(&mut self, y: Layout) -> &mut Self {
        self.style().margin.y = y;
        self
    }

    fn attribute(&mut self, attr: futtl::Attr) -> &mut Self {
        self.style().attributes |= attr;
        self
    }

    fn remove_attribute(&mut self, attr: futtl::Attr) -> &mut Self {
        self.style().attributes &= !attr;
        self
    }

    fn border(&mut self, border: Border) -> &mut Self {
        self.style().widget_border = border;
        self
    }

    fn color(&mut self, cs: futtl::ColorSet) -> &mut Self {
        self.style().color = cs;
        self
    }

    fn align(&mut self, alignment: Alignment) -> &mut Self {
        self.style().alignment_type = alignment;
        self
    }
}

impl Stylable for Widget {
    fn style(&mut self) -> &mut Style {
        &mut self.style
    }
}

impl BorrowStylable for Text {
    fn style(&mut self) -> &mut Style {
        &mut self.style
    }
}

impl Text {
    pub fn show(&self, parent_ctx: &mut futtl::Container, offset: futtl::Vec2, size: futtl::Vec2, idx: usize) {
        let pos = evaluate_pos(size, size, self.style.position.clone());

        let text_size = futtl::Vec2::new(
            self.text
                .lines()
                .map(|line| line.chars().count())
                .max()
                .unwrap_or(0) as i32,
            self.text.lines().count() as i32,
        );

        let text_offset = match self.style.alignment_type {
            Alignment::Left => futtl::Vec2::new(0, 0),
            Alignment::Right => text_size,
            Alignment::Center => futtl::Vec2::new(text_size.x / 2, text_size.y / 2),
        };

        parent_ctx.set_curs(
            (pos.x - text_offset.x).max(0) + offset.x, 
            pos.y.max(0) + offset.y
        );

        parent_ctx.add_color(self.style.color, idx);
        parent_ctx.set_color(idx);

        parent_ctx.write_str(&self.text);
    }
}

impl Widget {
    pub fn new() -> Self {
        Self {
            ctx: WidgetCtx::None,
            style: Style::new(),
            children: Vec::new(),
            content: Vec::new(),
            pos: futtl::Vec2::new(0, 0)
        }
    }

    pub fn style(&mut self, style: Style) {
        self.style = style;
    }

    pub fn text(&mut self, text: impl Into<String>) -> &mut Text {
        let mut style = Style::new();
        style.color = self.style.color;

        self.content.push(Text {
            text: text.into(),
            style,
        });

        self.content.last_mut().unwrap()
    }

    fn set_border(&mut self, box_ctx: &mut futtl::Container, border: Border) {
        let border = match border {
            Border::Single => SINGLE_BORDER,
            Border::Double => DOUBLE_BORDER,
            Border::Custom(border) => border,
            Border::None => NO_BORDER
        };

        box_ctx.add_color(self.style.color, 255);

        box_ctx.set_border(
            border.top as u32,
            border.right as u32,
            border.bottom as u32,
            border.left as u32,
            border.top_right as u32,
            border.bottom_right as u32,
            border.bottom_left as u32,
            border.top_left as u32,
            255,
        );
    }

    pub fn show(&mut self, widget_pos: futtl::Vec2, f_ctx: &mut futtl::Win) {
        match self.ctx {
            WidgetCtx::None => {}

            WidgetCtx::Box(ctx) => {
                let box_ctx = &mut f_ctx.children()[ctx];

                box_ctx.clear();

                self.set_border(box_ctx, self.style.widget_border);

                let offset = match self.style.widget_border {
                    Border::None => futtl::Vec2::new(0, 0),
                    _ => futtl::Vec2::new(1, 1),
                };

                let size = match self.style.widget_border {
                    Border::None => box_ctx.get_size(),
                    _ => futtl::Vec2::new(box_ctx.get_size().x - 2, box_ctx.get_size().y - 2),
                };

                for (i, item) in self.content.iter().enumerate() {
                    item.show(box_ctx, offset, size, i);
                }

                box_ctx.show(widget_pos.x, widget_pos.y);
            }
        }
    }
}


impl Default for Win {
    fn default() -> Self {
        Self::new()
    }
}

impl Default for Widget {
    fn default() -> Self {
        Self::new()
    }
}

impl Default for Style {
    fn default() -> Self {
        Self::new()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test() {
        let mut ctx = Win::new();

        let mut text_widget = Widget::new()
            .position_x(Layout::Cell(0))
            .position_y(Layout::Cell(0))
            .size_x(Layout::Vw(50))
            .size_y(Layout::Vh(100) - Layout::Cell(2))
            .border(Border::Double)
            .foreground(futtl::Color::ANSI256(69));

        text_widget.text("test")
            .position_x(Layout::Percent(50))
            .align(Alignment::Left);


        ctx.pack(text_widget);

        let mut widget2 = Widget::new()
            .position_x(Layout::Auto)
            .position_y(Layout::Cell(0))
            .size_x(Layout::Vw(50))
            .size_y(Layout::Vh(100) - Layout::Cell(1))
            .border(Border::Single);

        widget2.text("Left".to_string())
            .position_x(Layout::Percent(50))
            .color(futtl::ColorSet::new(
                futtl::Color::ANSI(futtl::AnsiColor::Red),
                futtl::Color::ANSI(futtl::AnsiColor::DefaultBG)
            ));

        widget2.text("Center".to_string())
            .position(
                Layout::Percent(50),
                Layout::Cell(1)
            )
            .color(futtl::ColorSet::new(
                futtl::Color::ANSI(futtl::AnsiColor::Green),
                futtl::Color::ANSI(futtl::AnsiColor::DefaultBG)
            ))
            .align(Alignment::Center);

        widget2.text("Right".to_string())
            .position(
                Layout::Percent(50),
                Layout::Cell(2)
            )
            .color(futtl::ColorSet::new(
                futtl::Color::ANSI(futtl::AnsiColor::Blue),
                futtl::Color::ANSI(futtl::AnsiColor::DefaultBG)
            ))
            .align(Alignment::Right);


        ctx.pack(widget2);

        ctx.mainloop();
    }
}