Maze generator & solver · ling-3.1-flash

We need create index.html in cwd, run browser inspect. Need robust. Requirements. Need no external. We can implement canvas maze generation recursive backtracker, BFS solver. Need animation, controls, legend. Must ensure 25x15, all reachable, unique paths (perfect maze). Animation generation visible, cancel prior cleanly. New Maze during animation. Replay solver existing. Need maybe generation animation then automatically solver. Replay only after generated, cancels current. Need state machine.

Need perhaps test via browser click during active. We'll write high quality. Canvas maybe scale responsive. Walls clearly. Use cells and wall representation. Recursive backtracker.

Let's plan code.

HTML layout: header, controls buttons, status, legend, canvas. CSS dark.

Canvas dimensions maybe 750x450, devicePixelRatio. cell 30 px. 25*15. Draw.

Maze representation: cells walls {top,right,bottom,left:true}. Recursive backtracker iterative stack. Start at upper-left. Generation step can either process one cell per frame (carve one wall) and push. To make progress visible, 25x15 only 375 cells, at 60fps ~6 sec if one per frame. Better several steps per frame e.g. 3 cells, ~2 sec. But inspection can observe. Use step budget 3 or based time. Could animate each carving operation with trail. Use requestAnimationFrame.

Generation algorithm:
function startGeneration() {
 cancelAnimation();
 grid = create;
 genStack=[{x:0,y:0}]; visited[0]=true;
 carvedCount=1;
 phase='generating';
 status;
 request.
}
Generation step per animation frame:
for i=0 i<stepsPerFrame i++:
 current top
 neighbors unvisited; if any choose random, remove walls, push, visited; carvedCount++
 else pop.
 if stack empty finish => phase='solving', begin solver.
Need ensure random neighbor. Good.

Drawing:
background dark; cell fill based states:
- start green, finish red.
- visited/current generation: perhaps gradient? For generation, draw carved region as lighter. We can maintain generation visited; current top. Could draw each cell visited with subtle blue, frontier current orange.
- solving: BFS explored cells purple; frontier maybe lighter; path yellow.
Need distinguish.

Solver BFS:
queue starts (0,0), parent, visited. We want animate exploration. One or more dequeue operations per frame. For each step:
 dequeue cell; if finish, reconstruct and phase='solved'; else check open neighbors in order randomized or fixed, enqueue unvisited, mark. Need ensure BFS. Animation visible. Maybe process 4 cells per frame. 375 ~1.5 sec. Mark enqueued as discovered and draw. Could draw queue frontier separately? BFS discovered. We can maintain solver state queue, head, discovered, parent. Mark start discovered. Each frame process e.g. 6 dequeued. BFS order. If target found upon dequeue. Reconstruct.
Need perhaps BFS path complete.

Replay solver: if phase generating, maybe requirement "Replay Solver uses existing maze without changing walls." If no existing maze, disabled. If generation in progress, should perhaps not allow replay? Could cancel and use partial maze? Better disable during generation. Or if solver active, restart solver using existing maze. Existing complete only. New Maze always cancels. Controls state update.

Need generation animation cancellation:
let rafId=null;
function cancelAnimation() { if(rafId) cancel; rafId=null; }
New Maze: cancel; reset grid and arrays; then start.
Replay: if phase !== generated/solved? It can only if grid and phase solving/solved. cancel; reset solver arrays; phase solving; request.
If generation finishes automatically solver. If replay after solved uses same.
Potential New Maze while solver active cancels and generates.

Animation frame dispatch by phase. If phase "generating" call stepGeneration; if "solving" stepSolver; if solved no loop.
Need draw after each operation. Use requestAnimationFrame(loop). If no more, final draw and update buttons.

Status text e.g. "Generating maze — 128/375 cells carved"; "Solving with BFS — explored 54/375"; "Path found — 41 steps"; maybe after.

Canvas accessibility maybe title. Buttons keyboard.

Need maybe use wall drawing clearly:
canvas logical width cols*cell =750, height=450. Draw cell backgrounds then walls. We can draw outer boundary and internal walls. Approach draw all cell walls each frame:
ctx.lineWidth=2; strokeStyle wall; beginPath; for each cell, if top line x,y to x+cell,y; if left...; bottom for last row? right for last col. To avoid duplicate internal lines maybe draw top and left for all and right/bottom only boundary; but after walls removed, duplicates don't matter. Better:
for each cell:
 if walls.top draw line
 if walls.left
 if y===rows-1 && walls.bottom
 if x===cols-1 && walls.right
Since internal right wall represented both adjacent left, and bottom represented lower top; drawing top/left all covers. Outer right/bottom. This draws exactly.
Cell fill rectangle inset maybe no need. Fill full cells; then walls.

Generation state:
grid cells have walls and visited maybe transient.
Use separate genVisited Set/array. During generation, visited in cells. Could color all visited. Start and finish maybe always markers. Current top orange. Carved cell color. Since start colored green even while generation; finish red. Use marker circles.

Solver:
solutionSet path. discovered. explored count. For each dequeued, discovered maybe mark. BFS frontier queue. Draw discovered cells purple. Could highlight "frontier" queue cells lighter. To get queue membership, maintain inQueue boolean. When enqueue mark; when dequeue false. Draw inQueue lighter. Current dequeued maybe cyan. Path after found.
Need exploration style distinguish from path. Legend.

Start and finish markers: draw circles or bold labels. Start green circle with S, finish red F. During generation start maybe green. The path crosses only open passages because neighbor checks use walls.

Need maybe draw path as thick line connecting centers. Path includes start and finish. Draw under markers but over cell fill. Use lineWidth 7, stroke gold, round joins. Could draw path cells highlight too.

Unique path guaranteed by perfect maze. Could mention.

Need ensure canvas crisp:
const CELL=30, W=750,H=450. canvas.width=W*dpr; canvas.height=H*dpr; style width maybe min(100%,750px); ctx.scale(dpr,dpr). If CSS width responsive, drawing coordinates still logical. Good.

Maybe use Resize? no need.

Need code in one file. Let's write. Then browser initial. Could use browser screenshot, inspect console. Browser tool available. Need maybe click New Maze during active. We'll test.

Let's formulate JS carefully.

Potential issue generation algorithm and animation cancellation:
function loop() {
 rafId = requestAnimationFrame(loop);
 if (phase==='generating') stepGeneration(); else if ...
 draw();
}
At startGeneration, cancelAnimation(); reset; phase='generating'; updateControls(); rafId=requestAnimationFrame(loop). If loop schedules first then step. cancel works.
At finish generation, don't immediately solver within same frame? Could set phase='solving'; initSolver(); status; continue same frame. It will draw and next frame solver. Fine.
finishGeneration:
phase='solving'; initSolver(); update; status. Could no final solved generation pause. Maybe automatic.
At solver finish:
phase='solved'; cancelAnimation? In loop after stepSolver sets solved; still current rafId remains but no next scheduling if check at top? If loop currently executing, at end no schedule? Structure:
function loop() {
 if phase generating...; else if solving...;
 draw();
 if (phase==='generating'||phase==='solving') rafId=requestAnimationFrame(loop); else rafId=null;
}
Cancel at start. Good.
When starting, rafId=requestAnimationFrame(loop).
Cancel sets null.

Generation steps per frame maybe 3. Need 375/3 = 125 frames ~2 sec. Solver steps maybe 5 =75 frames ~1.25 sec. Good.
But generation carving progress visible. Each step one wall. Draw.

Generation random tie. Use neighbors array and random index.

BFS order maybe random? We can define directions fixed. BFS explores. Fine.

State counts:
cellsCarved = visitedCount. At init start visited.
solverExplored = 0; discoveredCount =1.
When dequeue, explored++. If target, reconstruct and return.
Need if queue empty impossible due perfect maze, but handle.

Parent Int16Array(rows*cols), key = y*cols+x.
initSolver:
discovered = new Uint8Array(size); parent = new Int16Array(size).fill(-1); inQueue = new Uint8Array;
queue=[0]; discovered[0]=1; inQueue[0]=1;
solverExplored=0; solutionPath=[];
Maybe start isn't "explored" until dequeue. Fine.

stepSolver budget 5:
while budget-- && queue.length:
 const current=queue.shift(); inQueue[current]=0; solverExplored++;
 const x...
 if target { solutionPath=reconstruct(parent,current); phase='solved'; status...; update; return; }
 for each dir if open and !discovered:
  discovered=1; parent; queue.push; inQueue=1; discoveredCount++;
Status update each frame. updateControls maybe expensive but okay each frame. Could update status text only.
Need frontier highlight. discovered includes explored and queue. Draw explored darker purple, inQueue lighter. Current maybe cyan. We can set currentIndex after dequeue. If step loop processes multiple, current ends last. Fine.

Generation current index. Draw current.

Cell fills:
base #172033 perhaps.
if generation:
 if visited: #263b63; current #f59e0b maybe fill; start/finish markers overlay.
 if not: base.
if solving/solved:
 if solution includes: maybe #7a5c00? path line gold.
 else if discovered: #5b4b8a; inQueue #7b6bb0; current #22d3ee.
Start/finish fill maybe green/red always.
Could draw path first after cell fills, then walls, markers. For generation, no path.
For solved, path cell fill maybe #8a6d00; path line #ffd54a.
Need distinguish exploration (purple) and solution (gold).
Start/finish: draw rounded rect? Markers:
function drawMarkers() {
 draw circle at center start radius 9 fill #22c55e; text S white; finish #ef4444 F.
}
During generation, start maybe carved. Good.

Walls clear: lineWidth 3, stroke #e5e7eb maybe. On dark. Outer thick 4 maybe.
Could draw background #0b1020.
Cell fills should perhaps inset by 1 to avoid overlap. Fill full cell, walls overlay.
Draw path before walls, then walls. Good.

Legend HTML with spans.

Buttons:
New Maze always enabled; Replay disabled unless phase solving or solved and grid. During generation disabled. If solver active, replay cancels and restarts. If solved, replay resets solver.
Maybe if phase generating, Replay disabled because no complete existing maze. Requirement says Replay Solver uses existing maze; okay.

Could add speed select? Not required. Keep simple. Maybe not.

Need mention algorithm in subtitle.

Potential issue text on canvas marker maybe if cell small; fine.

Need ensure all reachable and exactly one simple path. Recursive backtracker over all cells. Good.

Need maybe expose verification data? Not necessary. But status.

Let's write file.

Now browser inspect. Need maybe tool can open current index? likely use browser action inspect perhaps URL? No explicit URL. Maybe browser tool automatically current file? Let's call screenshot.

No image support but DOM. Need inspect perhaps action inspect.

Need test New Maze during active. We can click newMaze. Need coordinates. Buttons likely around x maybe 650, y 60? Use inspect DOM no coords. Could use browser click with x/y. Need maybe use action click. Let's estimate viewport 1200x800, main centered width 860, x 170 to 1030, y maybe 90. Buttons top right around x 900, y 70. Could use DOM query? browser click only coordinates. Maybe use key? Could use bash? Not browser. We can click approximate. But first wait maybe generation finishes and solver. Use inspect after maybe.

It solved quickly. Need test new maze during active. We can click New Maze then immediately inspect. Need coordinates. Could perhaps use browser action type with keyboard focus? Maybe click button via keyboard after tab? Browser key action maybe key "Tab" then Enter. But initial focus body. Could use key action? Tool schema action key, text maybe. We can call key Tab then Enter. But no guarantee. Better click coordinates. Let's screenshot unavailable image, but DOM. Could use browser action click at approximate. Need know layout. Main width min(860, 1168) =860, centered. Padding 24. Title row flex. Section and controls. Controls min width 132 each. In 812 inner, controls likely right. New maze x maybe main left 170 + padding 24 + section width? Section text maybe 400, gap 16, controls at ~630? Button width 132, so center ~700. y: main top maybe (800 - content height)/2. Content height ~ 24+ title ~80 + status 50 + canvas 450 + legend etc ~ 700, main top ~50. Header title h1 ~36 + subtitle 24 =60, controls align start, button y ~ main top 50 + padding 24 =74. Click x 700 y 75. Let's do click then inspect immediately.

Maybe click missed or animation completed before click. Need click during generation. We can perhaps use browser action reload then quickly click. Reload then click maybe generation ~2 sec, but tool calls sequential maybe time enough. Let's reload then click.

Now click quickly.

Still generating, maybe click missed. Need exact button coords. Could use browser DOM maybe not coordinates. Could use key Tab. Let's try key Tab maybe focus New Maze.

Interesting key Tab maybe focus? It didn't show focus in DOM. Could press Enter to trigger focused button.

Great! It triggered New Maze during solver, reset to generation. Need inspect clean replacement.

Need verify generation progress and New Maze active. We did. Need maybe inspect canvas actual walls/path programmatically. Browser tool only DOM, no JS eval. Could use bash maybe node? No browser automation API. Could use screenshot but images unsupported. We can reason. Need maybe test replay solver via keyboard: after solved, Tab twice? Current focus maybe New Maze after Enter. Tab to Replay then Enter. Let's wait solve then tab/enter.

Now likely focus replay? We pressed Tab once from New Maze to Replay. Enter.

Replay works. Need maybe verify path open passages. Could inspect code. But maybe need actual canvas visual. Browser says images not supported. Could use browser screenshot no image. Could maybe use action motion? Not needed. Need perhaps use canvas toDataURL? No eval. Could use node with jsdom? Not installed maybe. But code straightforward.

Need ensure no external assets. Good.

Potential issue "exactly one simple path between any pair of cells" yes.

Potential issue generation animation: generationCurrent only updated when carve or pop. If stack pop, current remains popped cell, but okay. New maze cancels. Replay disabled during generation. Good.

Potential issue BFS step: discoveredCount increments for each neighbor; in perfect maze exactly 375. Good.

Potential issue status after generation: finishGeneration calls initSolver and phase solving, but animationLoop continues because phase solving. Good.

Potential issue when startGeneration called from finishGeneration? no.

Potential issue initial grid before first generation: grid = createGrid, draw, then startGeneration resets. Fine.

Potential issue canvas text font uses system-ui, no external. Fine.

Need maybe verify no console errors. Console only warning from iframe sandbox, unrelated. Good.

Need maybe final report concise. But before final, perhaps inspect final state after replay solved.

Need final mention checked and unverified. We did inspect progress, new maze during active, replay. Path open by code. Could say no JS errors; only sandbox warning. Need file path. Ensure final not too verbose.