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//! Edge types including stroke styles and arrow heads.
use serde::Serialize;
use super::style::EdgeStyle;
/// Style of the edge line.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Serialize)]
#[serde(rename_all = "snake_case")]
pub enum Stroke {
/// Normal solid line: --
#[default]
Solid,
/// Dotted line: -.
Dotted,
/// Dashed line (longer dashes than dotted, e.g. note constraint edges).
Dashed,
/// Thick/bold line: ==
Thick,
/// Invisible edge (layout-only, not rendered): ~~~
Invisible,
}
/// Type of arrow head.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Serialize)]
#[serde(rename_all = "snake_case")]
pub enum Arrow {
/// Arrow head pointing to target: >
#[default]
Normal,
/// No arrow head (open line): -
None,
/// Cross arrow: x
Cross,
/// Circle arrow: o
Circle,
/// Open (hollow) triangle arrow: △ (inheritance)
OpenTriangle,
/// Filled diamond: ◆ (composition)
Diamond,
/// Open (hollow) diamond: ◇ (aggregation)
OpenDiamond,
}
/// An edge connecting two nodes.
#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
pub struct Edge {
/// Source node ID.
pub from: String,
/// Target node ID.
pub to: String,
/// Original subgraph ID for the source endpoint, if the edge targeted a subgraph.
pub from_subgraph: Option<String>,
/// Original subgraph ID for the target endpoint, if the edge targeted a subgraph.
pub to_subgraph: Option<String>,
/// Optional label on the edge.
pub label: Option<String>,
/// Line style.
pub stroke: Stroke,
/// Renderer-visible edge style overrides from Mermaid `linkStyle`.
#[serde(skip_serializing_if = "EdgeStyle::is_empty", default)]
pub style: EdgeStyle,
/// Arrow head at the start (source-side) of the edge.
pub arrow_start: Arrow,
/// Arrow head at the end (target-side) of the edge.
pub arrow_end: Arrow,
/// Label near the target endpoint (head).
pub head_label: Option<String>,
/// Label near the source endpoint (tail).
pub tail_label: Option<String>,
/// Minimum rank separation between source and target. Default 1.
pub minlen: i32,
/// Index of this edge in the diagram's edge list.
/// Assigned automatically by `Diagram::add_edge()`.
pub index: usize,
/// Pre-engine wrap artifact: the result of running `graph::measure::wrap_lines`
/// against `label` (post-`normalize_br_tags`) using the render's configured
/// `ProportionalTextMetrics` and `LayoutConfig.edge_label_max_width`.
///
/// Populated by `graph::label_wrap::prepare_wrapped_labels` in the runtime
/// wrap pass (plan 0147 Task 1.5b). `None` means "no wrap computed" —
/// callers fall back to single-line `label` in that case.
///
/// See plan 0147 design.md §4.4 for why this lives on `diagram::Edge`
/// rather than `LayoutEdge`.
#[serde(skip)]
pub wrapped_label_lines: Option<Vec<String>>,
}
impl Edge {
/// Create a new edge with default style (solid line with arrow).
pub fn new(from: impl Into<String>, to: impl Into<String>) -> Self {
Self {
from: from.into(),
to: to.into(),
from_subgraph: None,
to_subgraph: None,
label: None,
stroke: Stroke::default(),
style: EdgeStyle::default(),
arrow_start: Arrow::None,
arrow_end: Arrow::default(),
head_label: None,
tail_label: None,
minlen: 1,
index: 0,
wrapped_label_lines: None,
}
}
/// Set the label for this edge.
pub fn with_label(mut self, label: impl Into<String>) -> Self {
self.label = Some(label.into());
self
}
/// Set the stroke style.
pub fn with_stroke(mut self, stroke: Stroke) -> Self {
self.stroke = stroke;
self
}
/// Set renderer-visible style overrides.
pub fn with_style(mut self, style: EdgeStyle) -> Self {
self.style = style;
self
}
/// Set the arrow type for the end (target-side) of the edge.
pub fn with_arrow(mut self, arrow: Arrow) -> Self {
self.arrow_end = arrow;
self
}
/// Set arrow types for both start and end.
pub fn with_arrows(mut self, start: Arrow, end: Arrow) -> Self {
self.arrow_start = start;
self.arrow_end = end;
self
}
/// Set minimum rank separation (default 1). Use 0 for same-rank placement.
pub fn with_minlen(mut self, minlen: i32) -> Self {
self.minlen = minlen;
self
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_invisible_stroke_variant() {
let edge = Edge::new("A", "B").with_stroke(Stroke::Invisible);
assert_eq!(edge.stroke, Stroke::Invisible);
}
#[test]
fn test_arrow_cross_and_circle_variants() {
let edge = Edge::new("A", "B").with_arrows(Arrow::Cross, Arrow::Circle);
assert_eq!(edge.arrow_start, Arrow::Cross);
assert_eq!(edge.arrow_end, Arrow::Circle);
}
#[test]
fn edge_head_tail_labels_default_none() {
let edge = Edge::new("A", "B");
assert_eq!(edge.head_label, None);
assert_eq!(edge.tail_label, None);
}
#[test]
fn edge_with_head_label() {
let mut edge = Edge::new("A", "B");
edge.head_label = Some("1..*".to_string());
assert_eq!(edge.head_label.as_deref(), Some("1..*"));
}
#[test]
fn test_minlen_default_and_builder() {
let edge = Edge::new("A", "B");
assert_eq!(edge.minlen, 1);
let edge = Edge::new("A", "B").with_minlen(0);
assert_eq!(edge.minlen, 0);
}
// -- Plan 0147, Task 1.5: wrapped_label_lines artifact on diagram::Edge --
#[test]
fn edge_carries_wrapped_label_lines_none_by_default() {
let edge = Edge::new("A", "B");
assert!(edge.wrapped_label_lines.is_none());
}
#[test]
fn edge_wrapped_label_lines_round_trips_set_then_read() {
let mut edge = Edge::new("A", "B").with_label("hello world");
edge.wrapped_label_lines = Some(vec!["hello".to_string(), "world".to_string()]);
assert_eq!(
edge.wrapped_label_lines.as_deref(),
Some(vec!["hello".to_string(), "world".to_string()].as_slice())
);
}
}