/* Hex Bridgecraft. Adapted from PlayHex; AGPL-3.0. See LICENSE.txt.
   PlayHex Board.ts supplies adjacency, connection detection and winning paths.
   This offline shell and shortest-path opponent are additions. */
import Board from './Board.ts';
const $=(s)=>document.querySelector(s);
let board,turn=0,winner=null,history=[],last=null,busy=false,version=0;
const mode=()=>$('#mode').value;
function resize(){const n=board.getSize();const w=Math.min(840,window.innerWidth-42);$('#board').style.setProperty('--cell',Math.min(56,(w-12)/(n*1.5-.5))+'px');}
function reset(){version++;board=new Board(Number($('#size').value));turn=0;winner=null;history=[];last=null;busy=false;render();resize();$('#message').textContent='Select any empty hex to place your first stone.';}
function render(){const n=board.getSize(),grid=board.getCells(),path=board.getShortestWinningPath()||[],wins=new Set(path.map(c=>c.row+','+c.col));const root=$('#board');root.style.setProperty('--n',n);root.replaceChildren();for(let r=0;r<n;r++){const row=document.createElement('div');row.className='row';row.style.setProperty('--r',r);for(let c=0;c<n;c++){const b=document.createElement('button');const p=grid[r][c],name=String.fromCharCode(65+c)+(r+1);b.className='hex '+(p===null?'empty':'p'+p)+(last&&last.row===r&&last.col===c?' last':'')+(wins.has(r+','+c)?' win':'');b.dataset.row=r;b.dataset.col=c;b.setAttribute('aria-label',name+', '+(p===null?'empty':p===0?'red':'blue'));b.innerHTML='<span>'+name+'</span>';b.disabled=p!==null||busy||winner!==null;b.addEventListener('click',()=>play(r,c));row.appendChild(b);}root.appendChild(row);}$('#turn').textContent=winner!==null?(winner===0?'Red':'Blue')+' connected the shores!':busy?'Blue is planning a bridge…':(turn===0?'Red · connect top to bottom':'Blue · connect left to right');$('#turn').style.color=winner===1||turn===1?'#8ccafa':'#ff9690';$('#moves').textContent=history.length+' stones played';$('#undo').disabled=history.length===0||busy;}
function place(r,c){history.push({grid:board.getCellsClone(),turn,last});board.setCell({row:r,col:c},turn);last={row:r,col:c};winner=board.calculateWinner();turn=1-turn;}
function play(r,c){if(busy||winner!==null||!board.isEmpty({row:r,col:c}))return;place(r,c);$('#message').textContent=winner!==null?'A complete bridge! Start a new game or Undo to explore another line.':'Stone placed at '+String.fromCharCode(65+c)+(r+1)+'.';if(mode()==='ai'&&turn===1&&winner===null){busy=true;render();const v=version;setTimeout(()=>{if(v!==version)return;const m=chooseMove();place(m.row,m.col);busy=false;render();$('#message').textContent=winner!==null?'Blue completed a bridge. Try again, or Undo to find a defense.':'Blue played '+String.fromCharCode(65+m.col)+(m.row+1)+'. Your move.';},250);}else render();}
function distance(p){const n=board.getSize(),dist=Array(n*n).fill(Infinity),seen=new Set(),grid=board.getCells();const cost=(r,c)=>grid[r][c]===p?0:grid[r][c]===null?1:Infinity;for(const x of board.getSideCells(p,0))dist[x.row*n+x.col]=cost(x.row,x.col);for(let t=0;t<n*n;t++){let u=-1;for(let i=0;i<n*n;i++)if(!seen.has(i)&&(u<0||dist[i]<dist[u]))u=i;if(u<0||!Number.isFinite(dist[u]))return n*n;const r=Math.floor(u/n),c=u%n;if(board.isCellOnSide({row:r,col:c},p,1))return dist[u];seen.add(u);for(const a of board.getNeighboors({row:r,col:c})){const j=a.row*n+a.col;dist[j]=Math.min(dist[j],dist[u]+cost(a.row,a.col));}}return n*n;}
function chooseMove(){const n=board.getSize(),empty=[];for(let r=0;r<n;r++)for(let c=0;c<n;c++)if(board.isEmpty({row:r,col:c}))empty.push({row:r,col:c});for(const p of [1,0])for(const a of empty){board.setCell(a,p);const win=board.hasPlayerConnection(p);board.setCell(a,null);if(win)return a;}
let best=empty[0],value=-Infinity;for(const a of empty){board.setCell(a,1);const attack=distance(1),defense=distance(0);const neighbors=board.getNeighboors(a,1).length;board.setCell(a,null);const center=Math.abs(a.row-(n-1)/2)+Math.abs(a.col-(n-1)/2);const v=defense*2.1-attack*2.7+neighbors*.18-center*.035+Math.random()*.08;if(v>value){value=v;best=a;}}return best;}
$('#new').addEventListener('click',reset);$('#size').addEventListener('change',reset);$('#mode').addEventListener('change',reset);$('#undo').addEventListener('click',()=>{if(busy||!history.length)return;version++;let prev=history.pop();if(mode()==='ai'&&prev.turn===1&&history.length)prev=history.pop();board=Board.createFromGrid(prev.grid);turn=prev.turn;last=prev.last;winner=null;render();$('#message').textContent='Move taken back. Try a different bridge.';});window.addEventListener('resize',resize);reset();