// imageEditor.js
export function openImageEditor(initialSrc) {
    return new Promise((resolve, reject) => {
      const dialog   = document.getElementById('editorDialog');
      const canvasEl = document.getElementById('c');
      const applyBtn = document.getElementById('applyBtn');
      const closeBtn = document.getElementById('closeEditorBtn');
  
      // 1회성 초기화
      if (!openImageEditor._initialized) {
        const canvas = new fabric.Canvas(canvasEl, { selection: false });
        openImageEditor._canvas = canvas;
  
        // 상태 변수
        let mode = 'polyline';
        let selectMode = false;
        let isLine = false;
        let lineObj = null;
        let polyPoints = [];
        let previewLine = null;
        let isPreview = true;
        let isRight = true;
        let currentColor = '#000000';
  
        // 브러시 설정
        const freeBrush = canvas.freeDrawingBrush;
        freeBrush.width = 2;
        freeBrush.color = currentColor;
  
        const eraserBrush = new fabric.PencilBrush(canvas);
        eraserBrush.width = +document.getElementById('eraserRange').value;
        eraserBrush.color = '#ffffff';
  
        function updateEraserCursor(r) {
          const svg = `<svg xmlns="http://www.w3.org/2000/svg" width="${r}" height="${r}"><circle cx="${r/2}" cy="${r/2}" r="${r/2}" stroke="black" fill="none"/></svg>`;
          canvas.freeDrawingCursor = `url("data:image/svg+xml,${encodeURIComponent(svg)}") ${r/2} ${r/2}, auto`;
        }
        updateEraserCursor(eraserBrush.width);
  
        // 버튼 강조
        function highlight() {
          document.querySelectorAll('.toolbar-btn').forEach(btn => btn.classList.remove('active'));
          switch (mode) {
            case 'polyline': document.getElementById('polyBtn').classList.add('active'); break;
            case 'free':     document.getElementById('freeBtn').classList.add('active');     break;
            case 'line':     document.getElementById('lineBtn').classList.add('active');     break;
            case 'text':     document.getElementById('textBtn').classList.add('active');     break;
            case 'eraser':   document.getElementById('eraserBtn').classList.add('active');   break;
            case 'select':   document.getElementById('selectBtn').classList.add('active');   break;
          }
        }
  
        // 모드 전환
        function setMode(m) {
          if (mode === 'polyline' && m !== 'polyline') {
            if (previewLine) { canvas.remove(previewLine); previewLine = null; }
            polyPoints = [];
          }
          mode = m;
          canvas.isDrawingMode = false;
          if (m === 'free') {
            canvas.isDrawingMode = true;
            canvas.freeDrawingBrush = freeBrush;
          }
          if (m === 'eraser') {
            canvas.isDrawingMode = true;
            canvas.freeDrawingBrush = eraserBrush;
          }
          selectMode = (m === 'select');
          canvas.selection = selectMode;
          canvas.upperCanvasEl.style.cursor = (m === 'eraser') ? canvas.freeDrawingCursor : 'crosshair';
          canvas.getObjects().forEach(o => {
            if (o === canvas.backgroundImage) return;
            o.selectable = selectMode;
            o.evented = selectMode;
          });
          highlight();
        }
        setMode('polyline');
  
        // 툴바 버튼 이벤트
        document.getElementById('polyBtn').addEventListener('click', () => setMode('polyline'));
        document.getElementById('freeBtn').addEventListener('click', () => setMode('free'));
        document.getElementById('lineBtn').addEventListener('click', () => setMode('line'));
        document.getElementById('textBtn').addEventListener('click', () => setMode('text'));
        document.getElementById('eraserBtn').addEventListener('click', () => setMode('eraser'));
        document.getElementById('selectBtn').addEventListener('click', () =>
          setMode(document.getElementById('selectBtn').classList.contains('active') ? 'free' : 'select')
        );
        document.getElementById('clearBtn').addEventListener('click', () => {
          canvas.clear();
          fabric.Image.fromURL(openImageEditor._lastSrc, img => {
            img.selectable = false;
            canvas.setBackgroundImage(img, canvas.renderAll.bind(canvas));
          });
          polyPoints = [];
          if (previewLine) { canvas.remove(previewLine); previewLine = null; }
          canvas.upperCanvasEl.style.cursor = 'crosshair';
          setMode('polyline');
        });
  
        // 색상 선택
        document.querySelectorAll('#colorPicker .color-btn').forEach(btn => {
          btn.addEventListener('click', () => {
            document.querySelectorAll('#colorPicker .color-btn').forEach(b => b.classList.remove('active'));
            btn.classList.add('active');
            currentColor = btn.getAttribute('data-color');
            freeBrush.color = currentColor;
          });
        });
  
        // 지우개 크기
        document.getElementById('eraserRange').addEventListener('input', e => {
          const r = +e.target.value;
          document.getElementById('eraserSizeLabel').innerText = r;
          eraserBrush.width = r;
          updateEraserCursor(r);
          if (mode === 'eraser') canvas.upperCanvasEl.style.cursor = canvas.freeDrawingCursor;
        });
  
        // 직각 고정
        document.getElementById('rightAngle').addEventListener('change', e => {
          isRight = e.target.checked;
        });
  
        // 키보드 단축키
        document.addEventListener('keydown', e => {
          if (e.key.toLowerCase() === 'l') setMode('line');
          if (e.key === 'Escape' && mode === 'polyline') {
            isPreview = false;
            if (previewLine) { canvas.remove(previewLine); previewLine = null; canvas.requestRenderAll(); }
          }
          if (e.key === 'Escape' && mode === 'text') {
            document.querySelectorAll('.canvas-text-input').forEach(el => el.remove());
          }
          if (e.key === 'Delete' && selectMode) {
            canvas.getActiveObjects().forEach(o => canvas.remove(o));
            canvas.discardActiveObject();
            canvas.requestRenderAll();
          }
        });
  
        // 마우스 이벤트
        canvas.on('mouse:down', opt => {
          const p = canvas.getPointer(opt.e);
          if (mode === 'line') {
            isLine = true;
            lineObj = new fabric.Line([p.x, p.y, p.x, p.y], {
              stroke: currentColor,
              strokeWidth: 2,
              originX: 'center', originY: 'center',
              selectable: selectMode
            });
            canvas.add(lineObj);
          } else if (mode === 'polyline') {
            isPreview = true;
            let x = p.x, y = p.y;
            if (isRight && polyPoints.length) {
              const prev = polyPoints[polyPoints.length - 1];
              const dx = Math.abs(x - prev.x), dy = Math.abs(y - prev.y);
              if (dx > dy) y = prev.y; else x = prev.x;
            }
            if (polyPoints.length) {
              const prev = polyPoints[polyPoints.length - 1];
              const seg = new fabric.Line([prev.x, prev.y, x, y], {
                stroke: currentColor,
                strokeWidth: 2,
                originX: 'center', originY: 'center',
                selectable: selectMode
              });
              canvas.add(seg);
            }
            polyPoints.push({ x, y });
            if (previewLine) { canvas.remove(previewLine); previewLine = null; }
          } else if (mode === 'text') {
            document.querySelectorAll('.canvas-text-input').forEach(el => el.remove());
            const ta = document.createElement('textarea');
            ta.className = 'canvas-text-input';
            ta.style.left = `${p.x}px`; ta.style.top = `${p.y}px`;
            ta.rows = 1; ta.cols = 20; ta.style.fontSize = '14px';
            document.getElementById('editorBody').appendChild(ta);
            setTimeout(() => ta.focus(), 0);
            ta.addEventListener('keydown', ev => {
              if (ev.key === 'Enter') {
                ev.preventDefault();
                const txt = ta.value.trim();
                if (txt) {
                  const t = new fabric.Text(txt, { left: p.x, top: p.y, fontSize: 14, fill: currentColor });
                  canvas.add(t);
                }
                ta.remove();
              } else if (ev.key === 'Escape') ta.remove();
            });
          }
        });
        
        canvas.on('mouse:move', opt => {
          const p = canvas.getPointer(opt.e);
          if (mode === 'line' && isLine) {
            let x2 = p.x, y2 = p.y;
            if (isRight) {
              const dx = Math.abs(x2 - lineObj.x1), dy = Math.abs(y2 - lineObj.y1);
              if (dx > dy) y2 = lineObj.y1; else x2 = lineObj.x1;
            }
            lineObj.set({ x2, y2 }); 
            canvas.requestRenderAll();
          } else if (mode === 'polyline' && polyPoints.length && isPreview) {
            const L = polyPoints[polyPoints.length - 1];
            let x2 = p.x, y2 = p.y;
            if (isRight) {
              const dx = Math.abs(x2 - L.x), dy = Math.abs(y2 - L.y);
              if (dx > dy) y2 = L.y; else x2 = L.x;
            }
            if (previewLine) {
              previewLine.set({ x1: L.x, y1: L.y, x2, y2 });
            } else {
              previewLine = new fabric.Line([L.x, L.y, x2, y2], {
                stroke: 'gray', strokeWidth: 1, strokeDashArray: [5,5], selectable: false
              });
              canvas.add(previewLine);
            }
            canvas.requestRenderAll();
          }
        });
        
        canvas.on('mouse:up', () => {
          if (mode === 'line') { 
            isLine = false; 
            lineObj = null; 
          }
        });
  
        // path 생성 시 스타일
        canvas.on('path:created', e => {
          e.path.selectable = selectMode;
          e.path.stroke = (mode === 'eraser') ? '#ffffff' : currentColor;
        });
  
        openImageEditor._initialized = true;
      }
  
      // 이미지 로드 및 dialog 표시
      openImageEditor._lastSrc = initialSrc;
      fabric.Image.fromURL(initialSrc, img => {
        img.selectable = false;
        openImageEditor._canvas.setBackgroundImage(img, openImageEditor._canvas.renderAll.bind(openImageEditor._canvas));
        dialog.showModal();
      });
  
      // 적용 버튼
      applyBtn.addEventListener('click', () => {
        const dataURL = openImageEditor._canvas.toDataURL({ format: 'png' });
        resolve(dataURL);
        dialog.close();
      });
  
      // 닫기 버튼
      closeBtn.addEventListener('click', () => {
        reject(new Error('User cancelled'));
        dialog.close();
      });
  
      // ESC로 닫기 방지
      dialog.addEventListener('cancel', e => e.preventDefault());
    });
  }