Commit Graph

6 Commits

Author SHA1 Message Date
dayuan.jiang
526f1e14e7 refactor(diagram-engine): apply review findings, fix vertical pool phases
Four reviewers went over the previous commit (three Claude, one Codex). Their
findings, verified independently before applying:

A REAL BUG. A vertical pool with milestone labels drew the label strip outside
the pool frame. The measure pass reserves width as padding + content + strip with
no gap between the last two; the renderer placed the strip one gap further out.
No test caught it because every vertical case omitted phases and every phases
case was horizontal — both regression cases added.

Duplicated logic, now single-sourced:
  - messageCount existed byte-identically in layout.ts and render.ts. Two copies
    that had to agree or the lifelines stop reaching the last message.
  - sequenceMetrics was called twice per sequence container, once inside the
    chrome builder and again for the message positions. Same drift hazard, in the
    file whose own comment warns about it.

Dead code, each verified unreachable rather than assumed:
  - Placed.extent: declared and documented, never written or read. Every .extent
    access belongs to RadialTree.
  - SequenceMetrics.top: computed, returned, no reader.
  - spread()'s level parameter: threaded through the recursion, never used.
  - radialReach's .slice(0, generations): widestPerLevel writes one entry per
    generation, so its length IS the depth. Confirmed over 20,000 random trees;
    removing it made RadialTree.depth dead too.
  - Two of three cycle guards in radialHierarchy: self-links are already skipped
    when the parent map is built, and that map holds one parent per node, so the
    structure is a forest and the visited-set filter cannot fire. The rootOf
    guard does fire and stays.
  - GraphOptions.layerGap/nodeGap/idPrefix: no caller, not in the tool schema.

Simplifications:
  - LayoutContext wrapped a single field; the link array now passes directly,
    which also removes the NO_CONTEXT default no call site ever took.
  - stretches() and the mirror-image check five lines below it expressed one rule
    two ways; unified, with the rationale stated once.
  - hasStencilFrame/isDirectional: one caller each, and isDirectional's name
    contradicted its body, which the guarded branch then re-discriminated anyway.
  - poolFrameStyle() took no arguments and had one caller.
  - poolCellOf clamped a value already clamped at the model boundary and
    unreachable-by-construction from the parser.
  - A comment on stampPoolDecoration described container behaviour the function
    does not implement.

Kept deliberately, with evidence:
  - The best-arrangement tracking in the crossing reducer. Two reviewers
    suspected it was dead weight. Measured: barycentre sweeping regressed below
    its own running best in 180 of 500 random graphs, so without it a third of
    flowcharts would keep a worse arrangement than one already found.
  - Vertical pools. Two reviewers recommended deleting the feature as
    undiscoverable. The bug was one line, and vertical swimlanes are a real
    convention — documented to the model instead, which is what was actually
    missing.
  - styleValue duplicating readMarker, isLeaf, findPageIndex: all genuinely
    redundant, all predating this branch. Left alone to keep the diff scoped.

525 unit tests and 11 diagram e2e tests pass.
2026-08-09 14:47:46 +09:00
dayuan.jiang
a3814f702d feat(diagram-engine): flowcharts, swimlanes, sequence diagrams and mind maps
Extends the declarative engine past cloud architecture. The tool routing was
divided by icon library — AWS through the engine, everything else hand-written
XML — which is the wrong axis. What matters is the LAYOUT SHAPE.

Measured first: a six-step approval flow declared in its natural order comes out
as one column, because the layout only arranges what nesting tells it to and
never looked at the arrows. That forces the arrow from the decision to its second
branch to jump over the first branch.

graph.ts computes what the layout should have looked at: layer assignment by
longest path, cycle breaking so a loop is drawn without setting the order, and
barycentre sweeping to cut edge crossings. It emits ordinary container
operations, so layout, routing and round-tripping are unchanged — reaching zero
arrows-through-boxes on a 14-node pipeline and zero crossings on a bipartite
graph whose declared order forces three.

Three new container kinds, each because one layout rule cannot serve them all:

  pool     — swimlanes. Lanes are real cells and each step is parented to its
             band, so dragging a step to another role records the change.
  sequence — participants across the top, one lifeline cell per participant so
             head and line stay together on a drag. Messages bypass the router:
             a message's height IS its order.
  radial   — mind maps and org charts. Children are a flat list and the
             hierarchy comes from the links, because a branch is a box and a box
             cannot hold children.

Flowchart box shapes (diamond, stadium, parallelogram, document) so a reader can
tell a branch from a step.

Two bugs the new tests caught: the duplicate-link guard blocked a sequence
diagram from having two messages between the same pair, and the fallback message
numbering was shared across containers, pushing a second diagram's messages off
its own lifelines.

523 unit tests and 17 diagram e2e tests pass. Every kind verified round-trip
stable to a fixed point, and rendered in a real browser — draw.io keeps the
lifeline shape and the lane markers.
2026-08-09 13:49:11 +09:00
dayuan.jiang
1e4c74d464 feat(diagram-engine): edge router — pinned ports, obstacle avoidance, cost search
Fixes the reported problem: arrows overlapped on top of icons and ran through shapes
they had nothing to do with.

The cause was a missing layer, not a bug. render.ts emitted only source and target, so
draw.io routed every edge itself — and its router sees the two terminals' bounds and
nothing else, not where the other icons are. It therefore ran lines straight through
whatever was in between and left several edges leaving one node at the same point.

Ported from drawio-ai-kit's router (MIT, see NOTICE):

  - Port de-collision. Edges leaving the same side of the same node spread along it,
    ordered by where their far end sits so they do not cross on the way out. An edge
    with a clean straight shot keeps the centre.
  - Obstacle avoidance. Candidate shapes in order of directness — straight, a Z through
    the gap, an L, a two-bend detour — each tested against every icon on the page.
  - Frame placement. A frame is passable (an edge into a VPC must cross its border) but
    not free: running alongside a border, or cutting through a frame that holds only one
    of the two endpoints, is penalised.
  - Port snapping. On a bent route, each port moves to the side its leg actually arrives
    from. Without this the terminal segment can pierce the icon to reach a far-side port.
  - Lane claiming. Each routed edge records the lanes it occupies so later edges avoid
    them, rather than colliding and being pulled apart afterwards.
  - Global nudge, three passes, reverting any move that makes a path worse.

Two things I got wrong on the way, both caught by looking at real geometry:

  - The Z corridor was computed as min/max of both nodes' edges, which spans the whole
    distance between them — including anything parked in between. So the lane sweep
    would place the detour's middle leg on top of the very icon it was avoiding. It has
    to be the gap: trailing edge of the first node to the leading edge of the other.
  - The router was fed layout's slot rectangles, but an icon's cell is the glyph square
    centred in a slot roughly twice as wide. Collision tests against slots both missed
    real overlaps and invented false ones. Extracted cellRect() so the router and the
    emitted XML cannot diverge.

Accept-or-reject was not enough on its own. When one endpoint is inside a VPC and the
other outside, EVERY path trespasses on that frame, so the strict rule always fails and
the relaxed pass took whatever it tried first — which is how a line ended up cutting
across a whole VPC. Candidates are now scored (frame offences 500, lane sharing 700,
bends 80, length 1) and the cheapest wins, so an edge that must trespass still gets the
least-bad route.

Waypoints are still written only when load-bearing — a labelled bend or a deliberate
detour — so an unobstructed edge stays drag-friendly.

455 unit tests (27 new, asserting produced geometry rather than algorithm shape).
Verified by rendering the reported diagram in the real editor: the two arrows that
overlapped on the EC2 icon now leave from different sides, and the load balancer's
fan-out leaves from three distinct points.
2026-08-09 13:49:11 +09:00
dayuan.jiang
cd1df1eb6a feat(diagram-engine): wire up restructure_diagram + stencil catalog
Closes the loop: the model can now build and edit AWS architecture diagrams by
declaring structure, and never writes an mxCell again.

catalog.ts — 983 AWS icon and 19 group stencils as a name→style map, generated from
drawio-ai-kit's catalog (itself generated from jgraph's draw.io shape index). Styles
are verbatim, so the official category colours, connection points and aspect=fixed
come along for free and nothing is hand-assembled. An invented name is rejected with
suggestions instead of rendering as a blank square, which is what draw.io does with
an unknown resIcon today.

operations.ts — what the model actually sends: add_icon / add_container / move /
link / set_dir and so on, applied in order against the tree. Guards the things that
break a diagram quietly: duplicate ids (draw.io drops one of the two cells), edges
left pointing at a removed node, and moving a container inside itself.

index.ts — the entry point. current XML → parse → apply ops → check names → layout →
render → new XML. The tree is not stored between calls; it is re-derived from the
canvas every time, so a user's manual edits are input to the next layout rather than
state to reconcile.

Token cost, measured with Claude's tokenizer rather than estimated:
  - build a VPC diagram:  515 tok as operations vs 3180 as XML   (6.2x)
  - add one icon:          27 tok as an operation vs 3823 re-emitting (142x)
  - read current state:   216 tok as an outline vs 3180 as XML   (14.7x)

The 142x is the one that matters day to day: "add a Redis" is one operation, not a
rewrite of the whole diagram.

Routing in the system prompt sends AWS architecture through this path and leaves
flowcharts, BPMN, sequence diagrams, mind maps and Azure/GCP on display_diagram —
the layout engine's primitives (nested rows, columns, grids) do not model a sequence
diagram's lifelines or a mind map's radial spread, and pretending otherwise would
make those worse rather than better.

Also: added a NOTICE recording the MIT port and the AWS Architecture Icons terms,
and a narrow .gitignore exception so the generated catalog is tracked while the
root data/ directory (admin settings, contains secrets) stays ignored.

403 unit tests + 3 new e2e. Verified in the real app: a structural tool call renders
with real stencils and container markers; a second call adds one node and keeps
everything from the first; an invented name is refused and nothing is drawn. The 13
existing diagram e2e tests still pass.
2026-08-09 13:49:11 +09:00
dayuan.jiang
a2f892ca82 feat(diagram-engine): layout + XML renderer, verified end to end in draw.io
Completes the tree → coordinates → XML direction, so the model can declare nesting
and never write a coordinate or an mxCell again.

layout.ts — measure bottom-up, place top-down, the same shape as flexbox. A
container sums its children along the flow axis and adds padding, so "child spills
out of its frame" and "siblings overlap" cannot happen by construction rather than
being caught afterwards. Slack from sibling equalisation is shared between children
instead of left as dead margin, capped at one gap so a stretched frame reads as
spaced rather than sparse.

render.ts — writes the mxCells, stamping container=1 and the dai_* markers so
parse.ts can read the structure back. Edges carry no waypoints: draw.io's own router
recomputes the route on every edit, so a user who moves a node never has to re-link
an arrow. Cells the parser could not interpret are re-emitted verbatim, so a
re-layout never deletes a user's annotations.

Phantoms are gone (task #5). The reference project's layout-only wrapper emits no
cell, which makes the round-trip lossy by construction — measured on its own
build_vpc.mjs, a phantom erased a container's "col" direction for good. An
unlabelled frame here emits a real cell with fillColor/strokeColor=none instead:
invisible, but present in the XML and therefore recoverable.

Two bugs the round-trip test caught, both real:

  - An icon's cell was being emitted at its measured slot size, which includes room
    for the label underneath. Parsing read that width back as the glyph size, so the
    icon grew on every round-trip. The cell is now the glyph square and the label
    renders outside it via verticalLabelPosition, as the reference does.
  - An Azure or GCP icon is an embedded base64 image whose style contains no name
    anywhere, so the catalog name was unrecoverable. Added a dai_name marker.

Verified in a real browser (3 Playwright tests, not mocks): engine output renders in
draw.io; dragging a shape into a frame makes draw.io rewrite its parent and the
engine reads the new structure back; re-laying out from that structure PRESERVES the
user's move instead of undoing it, and leaves untouched nodes alone; and the
re-laid-out XML still renders.

That last point is the whole design: there is no second copy of the state, so a
manual edit is an input to the next layout rather than a conflict to reconcile.

304 unit tests + 3 e2e.
2026-08-09 13:49:11 +09:00
dayuan.jiang
8765dfb96c feat(diagram-engine): style markers + XML→tree reverse parser
Groundwork for a declarative diagram engine where the model declares nesting and
the engine computes every coordinate, instead of the model emitting raw mxCell XML.

The design keeps the canvas as the SINGLE source of truth: the node tree is never
persisted, it is re-derived from the current canvas XML whenever needed. A user's
manual edits are therefore an input to the next re-layout, not a second copy of
the state that has to be reconciled.

Two behaviours this relies on, both verified against the real embedded editor with
a Playwright mouse drag (reading the editor's own autosave payload):

  1. An AWS group stencil WITHOUT container=1 does not get a dragged shape
     reparented — parent stays "1" and geometry stays absolute. WITH container=1
     it does: parent becomes the frame, geometry becomes parent-relative. So the
     engine must stamp container=1 on every container it emits.
  2. draw.io preserves style keys it does not understand, and resolves a duplicate
     key last-wins. So dai_* markers survive a user edit, and container=1 can be
     appended to a catalog style without first parsing out an existing value —
     which matters because the AWS catalog is inconsistent about it (group_vpc,
     group_region, group_subnet ship without it; group_account ships with it).

markers.ts  — dai_kind / dai_dir / dai_gap / dai_cols / dai_pin, and the container
              token normalisation.
types.ts    — the node tree contract, plus a `foreign` bucket so cells the engine
              does not understand (user annotations, imported shapes) round-trip
              verbatim rather than being destroyed by a re-layout.
parse.ts    — XML → tree. Handles all four icon encodings (resIcon=, bare shape=,
              shape=image data URI, grIcon=), resolves nesting from parent with a
              geometry fallback for frames that lack container=1, recovers layout
              direction from the marker or infers it from child positions, and
              survives cycles, compressed files and multi-page decks.

75 unit tests, including a round-trip against real output from the reference
project's build_vpc.mjs.

One finding worth recording: the reference project's "phantom" node (a wrapper that
participates in layout but emits no cell) makes the round-trip lossy by
construction. In build_vpc.mjs a phantom erased a container's col direction — its
children were reparented onto the grandparent, leaving a 2-D arrangement the parser
can only read as a grid. 26 of the reference project's 31 examples use phantoms, so
our engine needs an invisible-but-real container instead. Tracked separately.
2026-08-09 13:49:11 +09:00