render_regex 0.0.0

use crate::graph::{VisualEdge, VisualGraph, VisualNode, ShapeHint, NodeType, EdgeStyle};
use rusty_regex::dfa::DFA;

/// Convert DFA into a VisualGraph
pub fn dfa_to_graph(dfa: &DFA) -> VisualGraph {
    use std::collections::HashMap;

    let mut graph = VisualGraph::new();
    let mut edge_buckets: HashMap<(usize, usize), Vec<(char, EdgeStyle)>> = HashMap::new();

    for (id, state) in dfa.states.iter().enumerate() {
        let node = VisualNode {
            id,
            label: format!("{}", id),
            is_accept: dfa.accept_states.contains(&id),
            shape: ShapeHint::Circle,
            node_type: NodeType::Generic,
        };
        graph.nodes.push(node);

        for (&ch, &to) in &state.transitions {
            edge_buckets.entry((id, to)).or_default().push((ch, EdgeStyle::Solid));
        }
    }

    for ((from, to), entries) in edge_buckets {
        let n = entries.len();
        let mid = (n - 1) as f32 / 2.0;

        for (i, (ch, style)) in entries.into_iter().enumerate() {
            let bend_offset = if n == 1 {
                0.0
            } else {
                (i as f32 - mid) * 0.5
            };

            graph.edges.push(VisualEdge {
                from,
                to,
                label: ch.to_string(),
                style,
                bend_offset,
            });
        }
    }


    graph
}