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/// Sankey flow diagram component
use crate::components::svg::sankey_tooltip::SankeyTooltip;
use crate::hooks::use_container_size;
use leptos::prelude::*;
use lodviz_core::algorithms::sankey_layout::layout_sankey;
use lodviz_core::core::data::SankeyData;
use lodviz_core::core::theme::{ChartConfig, ChartTheme};
/// SankeyChart: directed flow diagram with node rectangles and ribbon paths.
///
/// Features:
/// - Automatic column assignment via BFS from source nodes
/// - Node heights proportional to flow magnitude
/// - Cubic Bézier ribbons between nodes
/// - Hover tooltip for nodes and ribbons
/// - Responsive layout via `use_container_size()`
#[component]
pub fn SankeyChart(
/// Sankey data: nodes and directed links
data: Signal<SankeyData>,
/// Pixel width of each node rectangle
#[prop(default = 20.0)]
node_width: f64,
/// Vertical gap between nodes in the same column
#[prop(default = 8.0)]
node_gap: f64,
/// Opacity of ribbon (link) paths
#[prop(default = 0.5)]
link_opacity: f64,
/// Chart configuration
#[prop(default = Signal::derive(|| ChartConfig::default()), into)]
config: Signal<ChartConfig>,
/// Fixed width override
#[prop(optional)]
width: Option<u32>,
/// Fixed height override
#[prop(optional)]
height: Option<u32>,
) -> impl IntoView {
let ctx_theme = use_context::<Signal<ChartTheme>>();
let theme = Memo::new(move |_| {
config
.get()
.theme
.unwrap_or_else(|| ctx_theme.map(|s| s.get()).unwrap_or_default())
});
let (container_width, container_height, container_ref) = use_container_size();
let chart_width = Memo::new(move |_| {
let m = container_width.get();
if m > 0.0 {
return m as u32;
}
config.get().width.or(width).unwrap_or(700)
});
let chart_height = Memo::new(move |_| {
let m = container_height.get();
if m > 0.0 {
return m as u32;
}
config.get().height.or(height).unwrap_or(400)
});
let final_title = Memo::new(move |_| config.get().title);
let margin = 20.0_f64;
let inner_width = Memo::new(move |_| (chart_width.get() as f64 - margin * 2.0).max(10.0));
let inner_height =
Memo::new(move |_| (chart_height.get() as f64 - margin * 2.0 - 30.0).max(10.0));
// Layout result recomputed when data or dimensions change
let layout = Memo::new(move |_| {
let d = data.get();
let iw = inner_width.get();
let ih = inner_height.get();
layout_sankey(&d, iw, ih, node_width, node_gap)
});
// Hover state
let (hover_label, set_hover_label) = signal(None::<String>);
let (hover_value, set_hover_value) = signal(None::<f64>);
let (hover_x, set_hover_x) = signal(0.0_f64);
let (hover_y, set_hover_y) = signal(0.0_f64);
let iw_signal = Signal::derive(move || inner_width.get());
let ih_signal = Signal::derive(move || inner_height.get());
let a11y_title_id = format!("chart-title-{}", uuid::Uuid::new_v4().as_simple());
let a11y_desc_id = format!("chart-desc-{}", uuid::Uuid::new_v4().as_simple());
let a11y_labelledby = format!("{} {}", a11y_title_id, a11y_desc_id);
view! {
<div
class="sankey-chart"
style=move || {
format!(
"width: 100%; height: 100%; display: flex; flex-direction: column; background-color: {};",
theme.get().background_color,
)
}
>
{move || {
final_title
.get()
.map(|t| {
let th = theme.get();
view! {
<h3 style=format!(
"text-align: center; margin: 0; padding-top: {}px; padding-bottom: {}px; font-size: {}px; font-family: {}; color: {}; font-weight: {};",
th.title_padding_top,
th.title_padding_bottom,
th.title_font_size,
th.font_family,
th.text_color,
th.title_font_weight,
)>{t}</h3>
}
})
}}
<div node_ref=container_ref style="flex: 1; position: relative; min-height: 0;">
<svg
role="img"
aria-labelledby=a11y_labelledby
viewBox=move || format!("0 0 {} {}", chart_width.get(), chart_height.get())
style="width: 100%; height: 100%; display: block;"
>
<title id=a11y_title_id>
{move || final_title.get().unwrap_or("Sankey diagram".to_string())}
</title>
<desc id=a11y_desc_id>
"Sankey flow diagram showing directional flow between nodes."
</desc>
<g transform=move || {
format!("translate({margin}, {margin})")
}>
// Ribbons (draw first — behind nodes)
{move || {
let lay = layout.get();
lay.links
.iter()
.map(|ribbon| {
let path = ribbon.path.clone();
let color = ribbon.color.clone();
let value = ribbon.value;
let src = ribbon.source;
let dst = ribbon.target;
let d = data.get();
let src_label = d
.nodes
.get(src)
.map(|n| n.label.clone())
.unwrap_or_default();
let dst_label = d
.nodes
.get(dst)
.map(|n| n.label.clone())
.unwrap_or_default();
view! {
<path
d=path
fill=color
opacity=link_opacity
style="cursor: default;"
on:mousemove=move |ev| {
set_hover_label
.set(Some(format!("{src_label} → {dst_label}")));
set_hover_value.set(Some(value));
set_hover_x.set(ev.offset_x() as f64 - margin);
set_hover_y.set(ev.offset_y() as f64 - margin);
}
on:mouseleave=move |_| {
set_hover_label.set(None);
set_hover_value.set(None);
}
/>
}
})
.collect_view()
}} // Node rectangles + labels
{move || {
let lay = layout.get();
let th = theme.get();
let max_node_x = lay
.nodes
.iter()
.map(|n| (n.x * 1000.0) as i64)
.max()
.unwrap_or(0);
lay.nodes
.iter()
.map(|node| {
let x = node.x;
let y = node.y;
let w = node.width;
let h = node.height;
let color = node.color.clone();
let label = node.label.clone();
let label2 = label.clone();
let is_last_col = (x * 1000.0) as i64 == max_node_x;
let (text_x, text_anchor) = if is_last_col {
(x - 4.0, "end".to_string())
} else {
(x + w + 4.0, "start".to_string())
};
let node_val_flow = {
let d = data.get();
let idx = node.index;
d
.links
.iter()
.filter(|l| l.source == idx || l.target == idx)
.map(|l| l.value)
.sum::<f64>() / 2.0
};
// Detect last column: nodes with the maximum x value
view! {
<rect
x=format!("{x:.2}")
y=format!("{y:.2}")
width=format!("{w:.2}")
height=format!("{h:.2}")
fill=color.clone()
on:mousemove=move |ev| {
set_hover_label.set(Some(label.clone()));
set_hover_value.set(Some(node_val_flow));
set_hover_x.set(ev.offset_x() as f64 - margin);
set_hover_y.set(ev.offset_y() as f64 - margin);
}
on:mouseleave=move |_| {
set_hover_label.set(None);
set_hover_value.set(None);
}
/>
<text
x=format!("{text_x:.2}")
y=format!("{:.2}", y + h / 2.0 + th.axis_font_size * 0.35)
font-size=th.axis_font_size
fill=th.text_color.clone()
text-anchor=text_anchor
pointer-events="none"
>
{label2}
</text>
}
})
.collect_view()
}} // Tooltip
<SankeyTooltip
label=Signal::derive(move || hover_label.get())
value=Signal::derive(move || hover_value.get())
x=Signal::derive(move || hover_x.get())
y=Signal::derive(move || hover_y.get())
inner_width=iw_signal
inner_height=ih_signal
tooltip_bg=Signal::derive(move || theme.get().tooltip_bg.clone())
tooltip_text=Signal::derive(move || theme.get().tooltip_text.clone())
/>
</g>
</svg>
</div>
</div>
}
}