feat: add single player mode

packages/lib/client-only/hooks/use-field-page-coords.ts

@@ -0,0 +1,78 @@
+import { useCallback, useEffect, useState } from 'react';
+
+import { getBoundingClientRect } from '@documenso/lib/client-only/get-bounding-client-rect';
+import { PDF_VIEWER_PAGE_SELECTOR } from '@documenso/lib/constants/pdf-viewer';
+import { Field } from '@documenso/prisma/client';
+
+export const useFieldPageCoords = (field: Field) => {
+  const [coords, setCoords] = useState({
+    x: 0,
+    y: 0,
+    height: 0,
+    width: 0,
+  });
+
+  const calculateCoords = useCallback(() => {
+    const $page = document.querySelector<HTMLElement>(
+      `${PDF_VIEWER_PAGE_SELECTOR}[data-page-number="${field.page}"]`,
+    );
+
+    if (!$page) {
+      return;
+    }
+
+    const { top, left, height, width } = getBoundingClientRect($page);
+
+    // X and Y are percentages of the page's height and width
+    const fieldX = (Number(field.positionX) / 100) * width + left;
+    const fieldY = (Number(field.positionY) / 100) * height + top;
+
+    const fieldHeight = (Number(field.height) / 100) * height;
+    const fieldWidth = (Number(field.width) / 100) * width;
+
+    setCoords({
+      x: fieldX,
+      y: fieldY,
+      height: fieldHeight,
+      width: fieldWidth,
+    });
+  }, [field.height, field.page, field.positionX, field.positionY, field.width]);
+
+  useEffect(() => {
+    calculateCoords();
+  }, [calculateCoords]);
+
+  useEffect(() => {
+    const onResize = () => {
+      calculateCoords();
+    };
+
+    window.addEventListener('resize', onResize);
+
+    return () => {
+      window.removeEventListener('resize', onResize);
+    };
+  }, [calculateCoords]);
+
+  useEffect(() => {
+    const $page = document.querySelector<HTMLElement>(
+      `${PDF_VIEWER_PAGE_SELECTOR}[data-page-number="${field.page}"]`,
+    );
+
+    if (!$page) {
+      return;
+    }
+
+    const observer = new ResizeObserver(() => {
+      calculateCoords();
+    });
+
+    observer.observe($page);
+
+    return () => {
+      observer.disconnect();
+    };
+  }, [calculateCoords, field.page]);
+
+  return coords;
+};