rl 0.4.0

#![allow(unused)]
use std::cmp::max;

use unicode_width::UnicodeWidthStr;

use points::Points;
use ratatui::{
    prelude::*,
    style::Styled,
    widgets::{canvas::Canvas, Block, LegendPosition, WidgetRef},
};

mod points;

#[derive(Clone, Copy, PartialEq, Default, Debug)]
pub struct Hsl(pub f64, pub f64, pub f64);

impl From<Hsl> for Style {
    fn from(value: Hsl) -> Self {
        let Hsl(h, s, l) = value;
        Self::default().fg(Color::from_hsl(h, s, l))
    }
}

/// See [`ratatui::widgets::Axis`]
#[derive(Debug, Default, Clone, PartialEq)]
pub struct Axis<'a> {
    /// Title displayed next to axis end
    title: Option<Line<'a>>,
    /// Bounds for the axis (all data points outside these limits will not be represented)
    bounds: [f64; 2],
    /// A list of labels to put to the left or below the axis
    labels: Option<Vec<Span<'a>>>,
    /// The style used to draw the axis itself
    style: Style,
    /// The alignment of the labels of the Axis
    labels_alignment: Alignment,
}

impl<'a> Axis<'a> {
    /// See [`Axis::title`](ratatui::widgets::Axis::title)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub fn title<T>(mut self, title: T) -> Self
    where
        T: Into<Line<'a>>,
    {
        self.title = Some(title.into());
        self
    }

    /// See [`Axis::bounds`](ratatui::widgets::Axis::bounds)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub const fn bounds(mut self, bounds: [f64; 2]) -> Self {
        self.bounds = bounds;
        self
    }

    /// See [`Axis::labels`](ratatui::widgets::Axis::labels)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub fn labels(mut self, labels: Vec<Span<'a>>) -> Self {
        self.labels = Some(labels);
        self
    }

    /// See [`Axis::style`](ratatui::widgets::Axis::style)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub fn style<S: Into<Style>>(mut self, style: S) -> Self {
        self.style = style.into();
        self
    }

    /// See [`Axis::labels_alignment`](ratatui::widgets::Axis::labels_alignment)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub const fn labels_alignment(mut self, alignment: Alignment) -> Self {
        self.labels_alignment = alignment;
        self
    }
}

/// The same as [`ratatui::widgets::Dataset`], with the addition of the gradient tuple.
#[derive(Debug, Default, Clone, PartialEq)]
pub struct Dataset<'a> {
    /// Name of the dataset (used in the legend if shown)
    name: Option<Line<'a>>,
    /// A reference to the actual data
    data: &'a [(f64, f64)],
    /// Symbol used for each points of this dataset
    marker: symbols::Marker,
    /// Style used to plot this dataset
    style: Style,
    /// Start and end HSL colors of density gradient
    gradient: (Hsl, Hsl),
}

impl<'a> Dataset<'a> {
    /// See [`Dataset::name`](ratatui::widgets::Dataset::name)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub fn name<S>(mut self, name: S) -> Self
    where
        S: Into<Line<'a>>,
    {
        self.name = Some(name.into());
        self
    }

    /// See [`Dataset::data`](ratatui::widgets::Dataset::data)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub const fn data(mut self, data: &'a [(f64, f64)]) -> Self {
        self.data = data;
        self
    }

    /// See [`Dataset::marker`](ratatui::widgets::Dataset::marker)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub const fn marker(mut self, marker: symbols::Marker) -> Self {
        self.marker = marker;
        self
    }

    /// See [`Dataset::style`](ratatui::widgets::Dataset::style)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub fn style<S: Into<Style>>(mut self, style: S) -> Self {
        self.style = style.into();
        self
    }

    /// Set the gradient colors of this dataset
    #[must_use = "method moves the value of self and returns the modified value"]
    pub fn gradient(mut self, gradient: (Hsl, Hsl)) -> Self {
        self.gradient = gradient;
        self
    }
}

/// A container that holds all the infos about where to display each elements of the chart (axis,
/// labels, legend, ...).
struct ChartLayout {
    /// Location of the title of the x axis
    title_x: Option<(u16, u16)>,
    /// Location of the title of the y axis
    title_y: Option<(u16, u16)>,
    /// Location of the first label of the x axis
    label_x: Option<u16>,
    /// Location of the first label of the y axis
    label_y: Option<u16>,
    /// Y coordinate of the horizontal axis
    axis_x: Option<u16>,
    /// X coordinate of the vertical axis
    axis_y: Option<u16>,
    /// Area of the legend
    legend_area: Option<Rect>,
    /// Area of the graph
    graph_area: Rect,
}

/// The same as [`ratatui::widgets::Chart`], but limited to scatter plot, and colors each point on a gradient relative to
/// the number of samples collapsed into that point.
#[derive(Debug, Default, Clone, PartialEq)]
pub struct HeatmapScatterPlot<'a> {
    /// A block to display around the widget eventually
    block: Option<Block<'a>>,
    /// The horizontal axis
    x_axis: Axis<'a>,
    /// The vertical axis
    y_axis: Axis<'a>,
    /// A reference to the dataset
    dataset: Dataset<'a>,
    /// The widget base style
    style: Style,
    /// Constraints used to determine whether the legend should be shown or not
    hidden_legend_constraints: (Constraint, Constraint),
    /// The position determine where the length is shown or hide regardless of
    /// `hidden_legend_constraints`
    legend_position: Option<LegendPosition>,
}

impl<'a> HeatmapScatterPlot<'a> {
    /// See [`Chart::new`](ratatui::widgets::Chart::new)
    pub fn new(dataset: Dataset<'a>) -> Self {
        Self {
            block: None,
            x_axis: Axis::default(),
            y_axis: Axis::default(),
            style: Style::default(),
            dataset,
            hidden_legend_constraints: (Constraint::Ratio(1, 4), Constraint::Ratio(1, 4)),
            legend_position: Some(LegendPosition::default()),
        }
    }

    /// See [`Chart::block`](ratatui::widgets::Chart::block)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub fn block(mut self, block: Block<'a>) -> Self {
        self.block = Some(block);
        self
    }

    /// See [`Chart::style`](ratatui::widgets::Chart::style)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub fn style<S: Into<Style>>(mut self, style: S) -> Self {
        self.style = style.into();
        self
    }

    /// See [`Chart::x_axis`](ratatui::widgets::Chart::x_axis)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub fn x_axis(mut self, axis: Axis<'a>) -> Self {
        self.x_axis = axis;
        self
    }

    /// See [`Chart::y_axis`](ratatui::widgets::Chart::y_axis)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub fn y_axis(mut self, axis: Axis<'a>) -> Self {
        self.y_axis = axis;
        self
    }

    /// See [`Chart::hidden_legend_constraints`](ratatui::widgets::Chart::hidden_legend_constraints)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub const fn hidden_legend_constraints(
        mut self,
        constraints: (Constraint, Constraint),
    ) -> Self {
        self.hidden_legend_constraints = constraints;
        self
    }

    /// See [`Chart::legend_position`](ratatui::widgets::Chart::legend_position)
    #[must_use = "method moves the value of self and returns the modified value"]
    pub const fn legend_position(mut self, position: Option<LegendPosition>) -> Self {
        self.legend_position = position;
        self
    }

    /// See [`Chart::layout`](ratatui::widgets::Chart::layout)
    fn layout(&self, area: Rect) -> Option<ChartLayout> {
        if area.height == 0 || area.width == 0 {
            return None;
        }
        let mut x = area.left();
        let mut y = area.bottom() - 1;

        let mut label_x = None;
        if self.x_axis.labels.is_some() && y > area.top() {
            label_x = Some(y);
            y -= 1;
        }

        let label_y = self.y_axis.labels.as_ref().and(Some(x));
        x += self.max_width_of_labels_left_of_y_axis(area, self.y_axis.labels.is_some());

        let mut axis_x = None;
        if self.x_axis.labels.is_some() && y > area.top() {
            axis_x = Some(y);
            y -= 1;
        }

        let mut axis_y = None;
        if self.y_axis.labels.is_some() && x + 1 < area.right() {
            axis_y = Some(x);
            x += 1;
        }

        let graph_width = area.right().saturating_sub(x);
        let graph_height = y.saturating_sub(area.top()).saturating_add(1);
        debug_assert_ne!(
            graph_width, 0,
            "Axis and labels should have been hidden due to the small area"
        );
        debug_assert_ne!(
            graph_height, 0,
            "Axis and labels should have been hidden due to the small area"
        );
        let graph_area = Rect::new(x, area.top(), graph_width, graph_height);

        let mut title_x = None;
        if let Some(ref title) = self.x_axis.title {
            let w = title.width() as u16;
            if w < graph_area.width && graph_area.height > 2 {
                title_x = Some((x + graph_area.width - w, y));
            }
        }

        let mut title_y = None;
        if let Some(ref title) = self.y_axis.title {
            let w = title.width() as u16;
            if w + 1 < graph_area.width && graph_area.height > 2 {
                title_y = Some((x, area.top()));
            }
        }

        let legend_area = None;
        // if let Some(legend_position) = self.legend_position {
        //     let legends = self
        //         .datasets
        //         .iter()
        //         .filter_map(|d| Some(d.name.as_ref()?.width() as u16));

        //     if let Some(inner_width) = legends.clone().max() {
        //         let legend_width = inner_width + 2;
        //         let legend_height = legends.count() as u16 + 2;

        //         let [max_legend_width] = Layout::horizontal([self.hidden_legend_constraints.0])
        //             .flex(Flex::Start)
        //             .areas(graph_area);

        //         let [max_legend_height] = Layout::vertical([self.hidden_legend_constraints.1])
        //             .flex(Flex::Start)
        //             .areas(graph_area);

        //         if inner_width > 0
        //             && legend_width <= max_legend_width.width
        //             && legend_height <= max_legend_height.height
        //         {
        //             legend_area = legend_position.layout(
        //                 graph_area,
        //                 legend_width,
        //                 legend_height,
        //                 title_x
        //                     .and(self.x_axis.title.as_ref())
        //                     .map(|t| t.width() as u16)
        //                     .unwrap_or_default(),
        //                 title_y
        //                     .and(self.y_axis.title.as_ref())
        //                     .map(|t| t.width() as u16)
        //                     .unwrap_or_default(),
        //             );
        //         }
        //     }
        // }
        Some(ChartLayout {
            title_x,
            title_y,
            label_x,
            label_y,
            axis_x,
            axis_y,
            legend_area,
            graph_area,
        })
    }

    fn max_width_of_labels_left_of_y_axis(&self, area: Rect, has_y_axis: bool) -> u16 {
        let mut max_width = self
            .y_axis
            .labels
            .as_ref()
            .map(|l| l.iter().map(Span::width).max().unwrap_or_default() as u16)
            .unwrap_or_default();

        if let Some(first_x_label) = self
            .x_axis
            .labels
            .as_ref()
            .and_then(|labels| labels.first())
        {
            let first_label_width = first_x_label.content.width() as u16;
            let width_left_of_y_axis = match self.x_axis.labels_alignment {
                Alignment::Left => {
                    // The last character of the label should be below the Y-Axis when it exists,
                    // not on its left
                    let y_axis_offset = u16::from(has_y_axis);
                    first_label_width.saturating_sub(y_axis_offset)
                }
                Alignment::Center => first_label_width / 2,
                Alignment::Right => 0,
            };
            max_width = max(max_width, width_left_of_y_axis);
        }
        // labels of y axis and first label of x axis can take at most 1/3rd of the total width
        max_width.min(area.width / 3)
    }

    fn render_x_labels(
        &self,
        buf: &mut Buffer,
        layout: &ChartLayout,
        chart_area: Rect,
        graph_area: Rect,
    ) {
        let Some(y) = layout.label_x else { return };
        let labels = self.x_axis.labels.as_ref().unwrap();
        let labels_len = labels.len() as u16;
        if labels_len < 2 {
            return;
        }

        let width_between_ticks = graph_area.width / labels_len;

        let label_area = self.first_x_label_area(
            y,
            labels.first().unwrap().width() as u16,
            width_between_ticks,
            chart_area,
            graph_area,
        );

        let label_alignment = match self.x_axis.labels_alignment {
            Alignment::Left => Alignment::Right,
            Alignment::Center => Alignment::Center,
            Alignment::Right => Alignment::Left,
        };

        Self::render_label(buf, labels.first().unwrap(), label_area, label_alignment);

        for (i, label) in labels[1..labels.len() - 1].iter().enumerate() {
            // We add 1 to x (and width-1 below) to leave at least one space before each
            // intermediate labels
            let x = graph_area.left() + (i + 1) as u16 * width_between_ticks + 1;
            let label_area = Rect::new(x, y, width_between_ticks.saturating_sub(1), 1);

            Self::render_label(buf, label, label_area, Alignment::Center);
        }

        let x = graph_area.right() - width_between_ticks;
        let label_area = Rect::new(x, y, width_between_ticks, 1);
        // The last label should be aligned Right to be at the edge of the graph area
        Self::render_label(buf, labels.last().unwrap(), label_area, Alignment::Right);
    }

    fn first_x_label_area(
        &self,
        y: u16,
        label_width: u16,
        max_width_after_y_axis: u16,
        chart_area: Rect,
        graph_area: Rect,
    ) -> Rect {
        let (min_x, max_x) = match self.x_axis.labels_alignment {
            Alignment::Left => (chart_area.left(), graph_area.left()),
            Alignment::Center => (
                chart_area.left(),
                graph_area.left() + max_width_after_y_axis.min(label_width),
            ),
            Alignment::Right => (
                graph_area.left().saturating_sub(1),
                graph_area.left() + max_width_after_y_axis,
            ),
        };

        Rect::new(min_x, y, max_x - min_x, 1)
    }

    fn render_label(buf: &mut Buffer, label: &Span, label_area: Rect, alignment: Alignment) {
        let label_width = label.width() as u16;
        let bounded_label_width = label_area.width.min(label_width);

        let x = match alignment {
            Alignment::Left => label_area.left(),
            Alignment::Center => label_area.left() + label_area.width / 2 - bounded_label_width / 2,
            Alignment::Right => label_area.right() - bounded_label_width,
        };

        buf.set_span(x, label_area.top(), label, bounded_label_width);
    }

    fn render_y_labels(
        &self,
        buf: &mut Buffer,
        layout: &ChartLayout,
        chart_area: Rect,
        graph_area: Rect,
    ) {
        let Some(x) = layout.label_y else { return };
        let labels = self.y_axis.labels.as_ref().unwrap();
        let labels_len = labels.len() as u16;
        for (i, label) in labels.iter().enumerate() {
            let dy = i as u16 * (graph_area.height - 1) / (labels_len - 1);
            if dy < graph_area.bottom() {
                let label_area = Rect::new(
                    x,
                    graph_area.bottom().saturating_sub(1) - dy,
                    (graph_area.left() - chart_area.left()).saturating_sub(1),
                    1,
                );
                Self::render_label(buf, label, label_area, self.y_axis.labels_alignment);
            }
        }
    }
}

impl Widget for HeatmapScatterPlot<'_> {
    fn render(self, area: Rect, buf: &mut Buffer) {
        self.render_ref(area, buf);
    }
}

impl WidgetRef for HeatmapScatterPlot<'_> {
    #[allow(clippy::too_many_lines)]
    fn render_ref(&self, area: Rect, buf: &mut Buffer) {
        buf.set_style(area, self.style);

        self.block.render_ref(area, buf);
        let chart_area = self.block.inner_if_some(area);
        let Some(layout) = self.layout(chart_area) else {
            return;
        };
        let graph_area = layout.graph_area;

        // Sample the style of the entire widget. This sample will be used to reset the style of
        // the cells that are part of the components put on top of the grah area (i.e legend and
        // axis names).
        let original_style = buf.get(area.left(), area.top()).style();

        self.render_x_labels(buf, &layout, chart_area, graph_area);
        self.render_y_labels(buf, &layout, chart_area, graph_area);

        if let Some(y) = layout.axis_x {
            for x in graph_area.left()..graph_area.right() {
                buf.get_mut(x, y)
                    .set_symbol(symbols::line::HORIZONTAL)
                    .set_style(self.x_axis.style);
            }
        }

        if let Some(x) = layout.axis_y {
            for y in graph_area.top()..graph_area.bottom() {
                buf.get_mut(x, y)
                    .set_symbol(symbols::line::VERTICAL)
                    .set_style(self.y_axis.style);
            }
        }

        if let Some(y) = layout.axis_x {
            if let Some(x) = layout.axis_y {
                buf.get_mut(x, y)
                    .set_symbol(symbols::line::BOTTOM_LEFT)
                    .set_style(self.x_axis.style);
            }
        }

        Canvas::default()
            .background_color(self.style.bg.unwrap_or(Color::Reset))
            .x_bounds(self.x_axis.bounds)
            .y_bounds(self.y_axis.bounds)
            .marker(self.dataset.marker)
            .paint(|ctx| {
                ctx.draw(&Points {
                    coords: self.dataset.data,
                    gradient: self.dataset.gradient,
                });
            })
            .render(graph_area, buf);

        if let Some((x, y)) = layout.title_x {
            let title = self.x_axis.title.as_ref().unwrap();
            let width = graph_area
                .right()
                .saturating_sub(x)
                .min(title.width() as u16);
            buf.set_style(
                Rect {
                    x,
                    y,
                    width,
                    height: 1,
                },
                original_style,
            );
            buf.set_line(x, y, title, width);
        }

        if let Some((x, y)) = layout.title_y {
            let title = self.y_axis.title.as_ref().unwrap();
            let width = graph_area
                .right()
                .saturating_sub(x)
                .min(title.width() as u16);
            buf.set_style(
                Rect {
                    x,
                    y,
                    width,
                    height: 1,
                },
                original_style,
            );
            buf.set_line(x, y, title, width);
        }

        // if let Some(legend_area) = layout.legend_area {
        //     buf.set_style(legend_area, original_style);
        //     Block::bordered().render(legend_area, buf);

        //     for (i, (dataset_name, dataset_style)) in self
        //         .datasets
        //         .iter()
        //         .filter_map(|ds| Some((ds.name.as_ref()?, ds.style())))
        //         .enumerate()
        //     {
        //         let name = dataset_name.clone().patch_style(dataset_style);
        //         name.render(
        //             Rect {
        //                 x: legend_area.x + 1,
        //                 y: legend_area.y + 1 + i as u16,
        //                 width: legend_area.width - 2,
        //                 height: 1,
        //             },
        //             buf,
        //         );
        //     }
        // }
    }
}

impl<'a> Styled for Axis<'a> {
    type Item = Self;

    fn style(&self) -> Style {
        self.style
    }

    fn set_style<S: Into<Style>>(self, style: S) -> Self::Item {
        self.style(style)
    }
}

impl<'a> Styled for Dataset<'a> {
    type Item = Self;

    fn style(&self) -> Style {
        self.style
    }

    fn set_style<S: Into<Style>>(self, style: S) -> Self::Item {
        self.style(style)
    }
}

impl<'a> Styled for HeatmapScatterPlot<'a> {
    type Item = Self;

    fn style(&self) -> Style {
        self.style
    }

    fn set_style<S: Into<Style>>(self, style: S) -> Self::Item {
        self.style(style)
    }
}