import * as fabric from 'fabric';
import { v4 as uuidv4 } from 'uuid';
import { useEditorStore } from '../store';
import type { ToolHandler } from '../../../lib/annotations/registry';
import type { Annotation, SignatureAnnotation, SignatureDrawProps, SignatureTypeProps } from '../../../lib/annotations/types';
import { screenRectToPdf, pdfRectToScreen } from '../../../lib/coords';
import type { ViewportParams } from '../../../lib/coords';

let previewObj: fabric.FabricObject | null = null;
let currentPreviewCanvas: fabric.Canvas | null = null;
let isCreatingPreview = false;

const createPreview = async (canvas: fabric.Canvas, vp: ViewportParams, props: any) => {
  isCreatingPreview = true;
  const storeState = useEditorStore.getState();
  if (props.mode === 'draw') {
    const url = `/api/v1/documents/${storeState.documentId}/assets/${props.ref}`;
    try {
      const img = await fabric.Image.fromURL(url);
      const maxWidth = 200 * vp.scale;
      if (img.width! > maxWidth) {
        img.scaleToWidth(maxWidth);
      }
      img.set({ originX: 'center', originY: 'center', opacity: 0.5, evented: false });
      previewObj = img;
    } catch (e) {}
  } else {
    previewObj = new fabric.Text(props.text, {
      fontFamily: props.fontFamily,
      fontSize: 48 * vp.scale * (vp.dpr || 1),
      fill: props.color,
      originX: 'center',
      originY: 'center',
      opacity: 0.5,
      evented: false
    });
  }
  isCreatingPreview = false;
  if (previewObj && currentPreviewCanvas === canvas) {
    canvas.add(previewObj);
    canvas.requestRenderAll();
  }
};

export const SignatureTool: ToolHandler = {
  name: 'signature',

  onActivate: (canvas: fabric.Canvas) => {
    canvas.defaultCursor = 'none';
    canvas.selection = false;
  },

  onDeactivate: (canvas: fabric.Canvas) => {
    canvas.defaultCursor = 'default';
    if (previewObj && currentPreviewCanvas === canvas) {
      currentPreviewCanvas.remove(previewObj);
      currentPreviewCanvas.requestRenderAll();
    }
    previewObj = null;
    currentPreviewCanvas = null;
    isCreatingPreview = false;
  },

  onPointerMove: (e: any, canvas: fabric.Canvas, vp: ViewportParams, _pageNumber: number) => {
    const props = useEditorStore.getState().pendingSignatureProps;
    if (!props) return;
    
    // Switch canvas if we moved to a new page
    if (currentPreviewCanvas !== canvas) {
      if (previewObj && currentPreviewCanvas) {
        currentPreviewCanvas.remove(previewObj);
        currentPreviewCanvas.requestRenderAll();
      }
      currentPreviewCanvas = canvas;
      previewObj = null;
    }
    
    if (!previewObj && !isCreatingPreview) {
      createPreview(canvas, vp, props);
    }
    
    if (previewObj) {
      const pointer = e.scenePoint || canvas.getScenePoint(e.e);
      previewObj.set({ left: pointer.x, top: pointer.y });
      canvas.requestRenderAll();
    }
  },

  onPointerDown: async (e: any, canvas: fabric.Canvas, vp: ViewportParams, pageNumber: number) => {
    if (e.target && e.target !== previewObj) return;

    const storeState = useEditorStore.getState();
    const props = storeState.pendingSignatureProps;
    if (!props) return;

    if (previewObj && currentPreviewCanvas === canvas) {
      currentPreviewCanvas.remove(previewObj);
      previewObj = null;
      currentPreviewCanvas = null;
    }

    const pointer = e.scenePoint || canvas.getScenePoint(e.e);
    
    let fabricObj: fabric.FabricObject;
    
    if (props.mode === 'draw') {
      const drawProps = props as SignatureDrawProps;
      const url = `/api/v1/documents/${storeState.documentId}/assets/${drawProps.ref}`;
      try {
        const img = await fabric.Image.fromURL(url);
        // By default, scale it down to a reasonable size if it's too big
        const maxWidth = 200 * vp.scale;
        if (img.width! > maxWidth) {
          img.scaleToWidth(maxWidth);
        }
        img.set({
          left: pointer.x,
          top: pointer.y,
          originX: 'center',
          originY: 'center',
        });
        // We set id on the object so it can be identified
        (img as any).id = uuidv4();
        fabricObj = img;
      } catch (err) {
        console.error("Failed to load signature image", err);
        return;
      }
    } else {
      const typeProps = props as SignatureTypeProps;
      const textObj = new fabric.Text(typeProps.text, {
        left: pointer.x,
        top: pointer.y,
        fontFamily: typeProps.fontFamily,
        fontSize: 48 * vp.scale * (vp.dpr || 1),
        fill: typeProps.color,
        originX: 'center',
        originY: 'center',
      });
      (textObj as any).id = uuidv4();
      fabricObj = textObj;
    }

    fabricObj.set({
      transparentCorners: false,
      cornerColor: '#3b82f6',
      cornerStrokeColor: '#3b82f6',
      borderColor: '#3b82f6',
      cornerSize: 8,
      padding: 5,
    });

    (fabricObj as any).annotationType = 'signature';
    (fabricObj as any).annotationProps = props;

    canvas.add(fabricObj);
    canvas.setActiveObject(fabricObj);
    canvas.requestRenderAll();

    // Convert to canonical space
    const bounds = fabricObj.getBoundingRect();
    const pdfRect = screenRectToPdf({
      x: bounds.left,
      y: bounds.top,
      width: bounds.width,
      height: bounds.height
    }, vp);

    const annotation: SignatureAnnotation = {
      id: (fabricObj as any).id,
      page: pageNumber,
      type: 'signature',
      rect: pdfRect,
      rotation: 0,
      z: 0,
      props: props,
      createdAt: new Date().toISOString(),
      updatedAt: new Date().toISOString()
    };

    useEditorStore.getState().addAnnotation(annotation);
    
    // Switch back to select tool and clear pending
    useEditorStore.getState().setPendingSignatureProps(null);
    useEditorStore.getState().setActiveTool('select');
  },

  renderToFabric: async (annotation: Annotation, canvas: fabric.Canvas, vp: ViewportParams) => {
    if (annotation.type !== 'signature') return null;
    const sigAnn = annotation as SignatureAnnotation;
    const screenRect = pdfRectToScreen(sigAnn.rect, vp);
    
    let fabricObj: fabric.FabricObject;
    
    if (sigAnn.props.mode === 'draw') {
      const url = `/api/v1/documents/${useEditorStore.getState().documentId}/assets/${sigAnn.props.ref}`;
      try {
        const img = await fabric.Image.fromURL(url);
        img.set({
          left: screenRect.x,
          top: screenRect.y,
          scaleX: screenRect.width / img.width!,
          scaleY: screenRect.height / img.height!,
        });
        fabricObj = img;
      } catch (e) {
        console.error("Failed to load signature asset", e);
        return null;
      }
    } else {
      const typeProps = sigAnn.props as SignatureTypeProps;
      fabricObj = new fabric.Text(typeProps.text, {
        left: screenRect.x,
        top: screenRect.y,
        fontFamily: typeProps.fontFamily,
        fill: typeProps.color,
      });
      // Set scale manually to match the saved rect
      fabricObj.set({
        scaleX: screenRect.width / fabricObj.width!,
        scaleY: screenRect.height / fabricObj.height!,
      });
    }

    fabricObj.set({
      id: sigAnn.id,
      annotationType: 'signature',
      annotationProps: sigAnn.props,
      transparentCorners: false,
      cornerColor: '#3b82f6',
      cornerStrokeColor: '#3b82f6',
      borderColor: '#3b82f6',
      cornerSize: 8,
      padding: 5,
    } as any);

    canvas.add(fabricObj);
  }
};