rho-coding-agent 1.15.0

// Adapted from Grok Build's terminal Mermaid renderer:
// https://github.com/xai-org/grok-build/blob/b189869b7755d2b482969acf6c92da3ecfeffd36/crates/codegen/xai-grok-markdown/src/mermaid.rs
// Copyright 2023-2026 SpaceXAI. Licensed under Apache-2.0.
use unicode_width::UnicodeWidthStr;

use super::ordering::assign_positions;
use super::{NodeSizes, Placed};
use crate::tui::markdown::mermaid::{
    model::Graph,
    painter::{GAP_X, GAP_Y, MAX_LABEL},
};

fn bus_spans_td(
    graph: &Graph,
    ranks: &[usize],
    centers: &[usize],
    r: usize,
    exact: bool,
) -> Vec<(usize, usize, usize, usize, usize)> {
    graph
        .edges
        .iter()
        .enumerate()
        .filter(|(_, e)| {
            let jogs = if exact {
                centers[e.from] != centers[e.to]
            } else {
                centers[e.from].abs_diff(centers[e.to]) > 1
            };
            e.from != e.to && ranks[e.from] == r && ranks[e.to] == r + 1 && jogs
        })
        .map(|(i, e)| {
            let a = centers[e.from].min(centers[e.to]);
            let b = centers[e.from].max(centers[e.to]);
            (a, b, e.from, e.to, i)
        })
        .collect()
}

fn lane_spans(
    graph: &Graph,
    ranks: &[usize],
    placed: &[Placed],
    vertical: bool,
) -> Vec<(usize, usize, usize, usize, usize)> {
    graph
        .edges
        .iter()
        .enumerate()
        .filter(|(_, e)| e.from != e.to && ranks[e.to] != ranks[e.from] + 1)
        .map(|(i, e)| {
            let (pf, pt) = (&placed[e.from], &placed[e.to]);
            let (a, b) = if vertical {
                (pf.cy.min(pt.cy), pf.cy.max(pt.cy))
            } else {
                (pf.cx.min(pt.cx), pf.cx.max(pt.cx))
            };
            (a, b, e.from, e.to, i)
        })
        .collect()
}

pub(super) fn place_td(
    ranks: &[usize],
    max_rank: usize,
    by_rank: &[Vec<usize>],
    sizes: &NodeSizes,
    graph: &Graph,
    placed: &mut [Placed],
) -> RoutePlan {
    let centers = assign_positions(by_rank, &sizes.lay_w, GAP_X, &graph.edges, ranks);

    let mut edge_bus = vec![0usize; graph.edges.len()];
    let mut bus_tracks = vec![0usize; max_rank + 1];
    for (r, tracks) in bus_tracks.iter_mut().enumerate().take(max_rank) {
        let spans = bus_spans_td(graph, ranks, &centers, r, false);
        if spans.is_empty() {
            continue;
        }
        let (assigned, count) = assign_tracks(&spans);
        for (idx, slot) in assigned {
            edge_bus[idx] = slot;
        }
        *tracks = count;
    }

    let rank_h: Vec<usize> = by_rank
        .iter()
        .map(|row| {
            row.iter()
                .map(|&i| sizes.box_h[i] + sizes.extra_h[i])
                .max()
                .unwrap_or(3)
        })
        .collect();
    let mut rank_y = vec![0usize; max_rank + 1];
    for r in 1..=max_rank {
        let gap = GAP_Y.max(bus_tracks[r - 1] + 1);
        rank_y[r] = rank_y[r - 1] + rank_h[r - 1] + gap;
    }
    let canvas_h = rank_y[max_rank] + rank_h[max_rank];
    let band_end: Vec<usize> = (0..=max_rank).map(|r| rank_y[r] + rank_h[r]).collect();

    let mut diagram_w = 1;
    for (r, row) in by_rank.iter().enumerate() {
        for &idx in row {
            let w = sizes.box_w[idx];
            let h = sizes.box_h[idx];
            let cx = centers[idx];
            let x = cx.saturating_sub(w / 2);
            let y = rank_y[r] + (rank_h[r] - h - sizes.extra_h[idx]) / 2;
            placed[idx] = Placed {
                x,
                y,
                w,
                h,
                cx,
                cy: y + h / 2,
                rank: r,
            };
            diagram_w = diagram_w.max(x + w);
            if sizes.extra_h[idx] > 0 && sizes.self_label_w[idx] > 0 {
                diagram_w = diagram_w.max(x + w + 2 + sizes.self_label_w[idx]);
            }
        }
    }

    let mut content_w = diagram_w;
    for e in &graph.edges {
        if e.from == e.to {
            continue;
        }
        if let Some(label) = &e.label {
            let lw = label.width().min(MAX_LABEL);
            if ranks[e.to] == ranks[e.from] + 1 {
                content_w = content_w.max(placed[e.to].cx + 2 + lw);
            } else {
                content_w = content_w.max(diagram_w + lw + 1);
            }
        }
    }

    let mut edge_lane = vec![0usize; graph.edges.len()];
    let lanes = lane_spans(graph, ranks, placed, true);
    let (canvas_w, lane_base) = if lanes.is_empty() {
        (content_w, 0)
    } else {
        let (assigned, count) = assign_tracks(&lanes);
        for (idx, slot) in assigned {
            edge_lane[idx] = slot;
        }
        (content_w + 1 + count, content_w + 1)
    };

    RoutePlan {
        canvas: (canvas_w, canvas_h),
        band_end,
        edge_bus,
        lane_base,
        edge_lane,
    }
}

pub(super) fn place_lr(
    ranks: &[usize],
    max_rank: usize,
    by_rank: &[Vec<usize>],
    sizes: &NodeSizes,
    graph: &Graph,
    placed: &mut [Placed],
) -> RoutePlan {
    let col_w: Vec<usize> = by_rank
        .iter()
        .map(|row| row.iter().map(|&i| sizes.box_w[i]).max().unwrap_or(0))
        .collect();

    let max_label = graph
        .edges
        .iter()
        .filter(|e| e.from == e.to || ranks[e.to] == ranks[e.from] + 1)
        .filter_map(|e| e.label.as_ref().map(|l| l.width().min(MAX_LABEL)))
        .max()
        .unwrap_or(0);
    let base_gap = (GAP_X + 1).max(max_label + 3);

    let centers = assign_positions(by_rank, &sizes.lay_h, 1, &graph.edges, ranks);

    let mut edge_bus = vec![0usize; graph.edges.len()];
    let mut bus_tracks = vec![0usize; max_rank + 1];
    for (r, tracks) in bus_tracks.iter_mut().enumerate().take(max_rank) {
        let spans = bus_spans_td(graph, ranks, &centers, r, true);
        if spans.is_empty() {
            continue;
        }
        let (assigned, count) = assign_tracks(&spans);
        for (idx, slot) in assigned {
            edge_bus[idx] = slot;
        }
        *tracks = count;
    }

    let mut rank_x = vec![0usize; max_rank + 1];
    for r in 1..=max_rank {
        let gap = base_gap.max(bus_tracks[r - 1] + 1);
        rank_x[r] = rank_x[r - 1] + col_w[r - 1] + gap;
    }
    let canvas_w = rank_x[max_rank]
        + col_w[max_rank]
        + by_rank[max_rank]
            .iter()
            .filter(|&&i| sizes.extra_h[i] > 0 && sizes.self_label_w[i] > 0)
            .map(|&i| 2 + sizes.self_label_w[i])
            .max()
            .unwrap_or(0);
    let band_end: Vec<usize> = (0..=max_rank).map(|r| rank_x[r] + col_w[r]).collect();

    let mut diagram_h = 1;
    for (r, row) in by_rank.iter().enumerate() {
        let x = rank_x[r];
        for &idx in row {
            let w = sizes.box_w[idx];
            let h = sizes.box_h[idx];
            let cy = centers[idx];
            let y = cy.saturating_sub((h + sizes.extra_h[idx]) / 2);
            placed[idx] = Placed {
                x,
                y,
                w,
                h,
                cx: x + w / 2,
                cy: y + h / 2,
                rank: r,
            };
            diagram_h = diagram_h.max(y + h + sizes.extra_h[idx]);
        }
    }

    let mut edge_lane = vec![0usize; graph.edges.len()];
    let lanes = lane_spans(graph, ranks, placed, false);
    let (canvas_h, lane_base) = if lanes.is_empty() {
        (diagram_h, 0)
    } else {
        let (assigned, count) = assign_tracks(&lanes);
        for (idx, slot) in assigned {
            edge_lane[idx] = slot;
        }
        (diagram_h + 1 + count, diagram_h + 1)
    };

    RoutePlan {
        canvas: (canvas_w, canvas_h),
        band_end,
        edge_bus,
        lane_base,
        edge_lane,
    }
}

pub(super) struct RoutePlan {
    pub(super) canvas: (usize, usize),
    pub(super) band_end: Vec<usize>,
    pub(super) edge_bus: Vec<usize>,
    pub(super) lane_base: usize,
    pub(super) edge_lane: Vec<usize>,
}

fn assign_tracks(spans: &[(usize, usize, usize, usize, usize)]) -> (Vec<(usize, usize)>, usize) {
    let mut sorted = spans.to_vec();
    sorted.sort_unstable();
    let mut tracks: Vec<Vec<(usize, usize, usize, usize)>> = Vec::new();
    let mut out = Vec::with_capacity(sorted.len());
    for &(s, e, f, t, idx) in &sorted {
        let compatible = |members: &Vec<(usize, usize, usize, usize)>| {
            members
                .iter()
                .all(|&(s2, e2, f2, t2)| e2 + 2 <= s || e + 2 <= s2 || f2 == f || t2 == t)
        };
        let slot = match tracks.iter().position(compatible) {
            Some(x) => x,
            None => {
                tracks.push(Vec::new());
                tracks.len() - 1
            }
        };
        tracks[slot].push((s, e, f, t));
        out.push((idx, slot));
    }
    (out, tracks.len())
}