class Whiteboard {
  constructor() {
    this.canvas = document.getElementById('whiteboard');
    this.ctx = this.canvas.getContext('2d');
    this.isDrawing = false;
    
    this.history = new History();
    this.tools = new DrawingTools(this.canvas, this.ctx);
    this.pages = new Pages();
    
    this.setupCanvas();
    this.setupEventListeners();
    this.setupBrushPreview();
    this.setupToolbarToggle();
  }

  setupCanvas() {
    const resize = () => {
      this.canvas.width = window.innerWidth;
      this.canvas.height = window.innerHeight;
      this.setupDrawingStyle();
      
      // Restore the current page
      const pageContent = this.pages.getPageContent();
      if (pageContent) {
        this.ctx.putImageData(pageContent, 0, 0); // Use the drawing content from the current page
      }
    };
  
    window.addEventListener('resize', resize);
    resize();
  }

  setupToolbarToggle() {
    const toolbar = document.querySelector('.bottom-toolbar');
    const toggleBtn = document.getElementById('toggleToolbar');
    
    toggleBtn.addEventListener('click', () => {
      toolbar.classList.toggle('hidden');
    });
  }

  setupBrushPreview() {
    this.brushPreview = document.getElementById('brushPreview');
    
    this.canvas.addEventListener('mousemove', (e) => {
      const { x, y } = getMousePos(this.canvas, e);
      this.updateBrushPreview(x, y);
    });

    this.canvas.addEventListener('mouseenter', () => {
      this.brushPreview.style.display = 'block';
    });

    this.canvas.addEventListener('mouseleave', () => {
      this.brushPreview.style.display = 'none';
    });
  }

  updateBrushPreview(x, y) {
    const size = this.tools.brushSize;
    this.brushPreview.style.width = size + 'px';
    this.brushPreview.style.height = size + 'px';
    this.brushPreview.style.left = (x - size/2) + 'px';
    this.brushPreview.style.top = (y - size/2) + 'px';
    this.brushPreview.style.borderColor = this.tools.isEraser ? '#000' : this.tools.color;
  }

  setupDrawingStyle() {
    this.ctx.lineCap = 'round';
    this.ctx.lineJoin = 'round';
    this.ctx.font = '24px Arial';
    this.tools.applyToolSettings();
  }

  setupEventListeners() {
    // Mouse events
    this.canvas.addEventListener('mousedown', this.startDrawing.bind(this));
    this.canvas.addEventListener('mousemove', this.draw.bind(this));
    this.canvas.addEventListener('mouseup', this.stopDrawing.bind(this));
    this.canvas.addEventListener('mouseout', this.stopDrawing.bind(this));

    // Touch events
    this.canvas.addEventListener('touchstart', this.handleTouch.bind(this));
    this.canvas.addEventListener('touchmove', this.handleTouch.bind(this));
    this.canvas.addEventListener('touchend', this.handleTouchEnd.bind(this));

    // Button events
    document.getElementById('aiBtn').addEventListener('click', this.processDrawing.bind(this));
    document.getElementById('submitBtn').addEventListener('click', this.generatePDF.bind(this));
    document.getElementById('clearBtn').addEventListener('click', this.clearCanvas.bind(this));
    document.getElementById('undoBtn').addEventListener('click', this.undo.bind(this));
    document.getElementById('redoBtn').addEventListener('click', this.redo.bind(this));

    // Keyboard shortcuts
    document.addEventListener('keydown', (e) => {
      if (e.ctrlKey || e.metaKey) {
        if (e.key === 'z') {
          e.preventDefault();
          this.undo();
        } else if (e.key === 'y') {
          e.preventDefault();
          this.redo();
        }
      }
    });
  }

  handleTouch(e) {
    e.preventDefault();
    const touch = e.touches[0];
    const eventType = e.type === 'touchstart' ? 'mousedown' : 'mousemove';
    const mouseEvent = new MouseEvent(eventType, {
      clientX: touch.clientX,
      clientY: touch.clientY
    });
    this.canvas.dispatchEvent(mouseEvent);
  }

  handleTouchEnd(e) {
    e.preventDefault();
    const mouseEvent = new MouseEvent('mouseup', {});
    this.canvas.dispatchEvent(mouseEvent);
  }

  startDrawing(e) {
    this.isDrawing = true;
    const { x, y } = getMousePos(this.canvas, e);
    this.tools.applyToolSettings();
    this.ctx.beginPath();
    this.ctx.moveTo(x, y);
  }

  draw(e) {
    if (!this.isDrawing) return;
    const { x, y } = getMousePos(this.canvas, e);
    this.ctx.lineTo(x, y);
    this.ctx.stroke();
  }

  stopDrawing() {
    if (this.isDrawing) {
      this.isDrawing = false;
      this.saveState();
    }
  }

  saveState() {
    const imageData = this.ctx.getImageData(0, 0, this.canvas.width, this.canvas.height);
    this.history.push(new DrawingState(imageData));
    this.pages.setPageContent(this.history.states);
  }

  undo() {
    const state = this.history.undo();
    if (state) {
      this.ctx.putImageData(state.imageData, 0, 0);
      this.pages.setPageContent(this.history.states);
    }
  }

  redo() {
    const state = this.history.redo();
    if (state) {
      this.ctx.putImageData(state.imageData, 0, 0);
      this.pages.setPageContent(this.history.states);
    }
  }

  clearCanvas() {
    this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
    this.saveState();
  }

  processDrawing() {
    const tempCanvas = document.createElement('canvas');
    const tempContext = tempCanvas.getContext('2d');
    tempCanvas.width = this.canvas.width;
    tempCanvas.height = this.canvas.height;
    tempContext.fillStyle = 'white';
    tempContext.fillRect(0, 0, tempCanvas.width, tempCanvas.height);
    tempContext.drawImage(this.canvas, 0, 0);
    const imageData = tempCanvas.toDataURL('image/png');
    console.log('Processing drawing with AI...');
    console.log(imageData.substring(0, 100) + '...');
    fetch('/whitebai', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify({
            image: imageData
        })
    })
    .then(response => response.json())
    .then(data => {

        if (data.status && Array.isArray(data.data)) {
          data.data.forEach(item => {
            const result = item.result;
            const x = item.location.x;
            const y = item.location.y;
            const size = item.size;
            const sizePx = `${size}px`;
            writeOnCanvasDynamic(whiteboard.pages, result, x, y, null, "Arial", sizePx, "black", false);
          });
        } else {
          console.error("Invalid data object or empty data array");
        }

        document.getElementById('result').innerText = data.text;
    })
    .catch(error => {
        console.error('Error:', error);
    });
  }

  async generatePDF() {
    const pages = this.pages.getAllPages();

    for (let i = 0; i < pages.length; i++) {
        const pageContent = pages[i];
        const tempCanvas = document.createElement('canvas');
        tempCanvas.width = this.canvas.width;
        tempCanvas.height = this.canvas.height;
        const tempCtx = tempCanvas.getContext('2d');
        tempCtx.fillStyle = 'white';
        tempCtx.fillRect(0, 0, tempCanvas.width, tempCanvas.height);

        if (pageContent && pageContent.drawing) {
            const imageData = pageContent.drawing;

            if (imageData) {
                try {
                    tempCtx.putImageData(imageData, 0, 0);
                    console.log("Image applied to canvas for page " + i);
                } catch (error) {
                    console.log("Error putting image data on page " + i, error);
                }
            } else {
                console.log("No image data for page " + i);
            }
        }

        const imgData = tempCanvas.toDataURL('image/png');
        console.log(`Base64 data for page ${i}:`, imgData);
    }
}

  writeText(text, x = 20, y = 40) {
    this.setupDrawingStyle();
    this.ctx.fillStyle = this.tools.color;
    this.ctx.fillText(text.toString(), x, y);
    this.saveState();
  }
}

const whiteboard = new Whiteboard();
const canvas = document.getElementById('whiteboard');

document.addEventListener('keydown', function(event) {
  if (event.ctrlKey && event.key === 's') {
      event.preventDefault();
      const tempCanvas = document.createElement('canvas');
      const tempContext = tempCanvas.getContext('2d');
      tempCanvas.width = canvas.width;
      tempCanvas.height = canvas.height;
      tempContext.fillStyle = 'white';
      tempContext.fillRect(0, 0, tempCanvas.width, tempCanvas.height);
      tempContext.drawImage(canvas, 0, 0);
      const imageData = tempCanvas.toDataURL("image/png");
      const link = document.createElement('a');
      link.href = imageData;
      link.download = 'canvas-image.png';
      link.click();
      console.log("Canvas saved as image with white background!");
  }
});

function writeOnCanvasDynamic(pagesInstance, text, x, y, fontUrl, fontFamily, fontSize = "16px", color = "black", clear = false) {
  const ctx = pagesInstance.ctx;
  if (!ctx) return;

  const applyFontAndWrite = () => {
    ctx.globalCompositeOperation = 'source-over'; 
    if (clear) {
        const textWidth = ctx.measureText(text).width;
        const lineHeight = parseInt(fontSize, 10) || 16;
        ctx.clearRect(x, y - lineHeight, textWidth, lineHeight);
        return;
    }
    ctx.font = `${fontSize} ${fontFamily}`;
    ctx.fillStyle = color;
    ctx.fillText(text, x, y);
  };
  if (fontUrl) {
      const fontFace = new FontFace(fontFamily, `url(${fontUrl})`);
      fontFace.load().then((loadedFont) => {
          document.fonts.add(loadedFont);
          applyFontAndWrite();
      }).catch((err) => {
          console.error("Font loading failed:", err);
      });
  } else {
      applyFontAndWrite();
  }
}