feat: excel import (#527)

* refactor: simplify excel import

* chore: add external deepmerge utility

* chore: create import map utilities

* chore: increase size limits on uploads

* style: small presentation tweaks

* feat: resolve times on excel import, refs #508

apps/client/src/features/modals/upload-modal/UploadFile.tsx

@@ -0,0 +1,66 @@
+import { ChangeEvent, useRef, useState } from 'react';
+import { Input } from '@chakra-ui/react';
+
+import UploadEntry from './upload-entry/UploadEntry';
+import { useUploadModalContextStore } from './uploadModalContext';
+import { validateFile } from './uploadUtils';
+
+import style from './UploadModal.module.scss';
+
+export default function UploadFile() {
+  const fileInputRef = useRef<HTMLInputElement>(null);
+
+  const { file, setFile, progress } = useUploadModalContextStore();
+
+  const [errors, setErrors] = useState<string>('');
+
+  const clearFile = () => {
+    setFile(null);
+    setErrors('');
+  };
+
+  const handleFile = (event: ChangeEvent<HTMLInputElement>) => {
+    setErrors('');
+
+    const selectedFile = event?.target?.files?.[0];
+    if (!selectedFile) {
+      setFile(null);
+      return;
+    }
+
+    try {
+      validateFile(selectedFile);
+      setFile(selectedFile);
+    } catch (error) {
+      if (error instanceof Error) {
+        setErrors(error.message);
+      } else {
+        setErrors('An unexpected error occurred while validating the file.');
+      }
+      setFile(null);
+    }
+  };
+
+  const handleClick = () => {
+    fileInputRef.current?.click();
+  };
+
+  return (
+    <>
+      <Input
+        ref={fileInputRef}
+        style={{ display: 'none' }}
+        type='file'
+        onChange={handleFile}
+        accept='.json, .xlsx'
+        data-testid='file-input'
+      />
+      {!file && (
+        <div className={style.uploadArea} onClick={handleClick} role='button'>
+          Click to select Ontime project or xlsx rundown
+        </div>
+      )}
+      {(file || errors) && <UploadEntry file={file} errors={errors} progress={progress} handleClear={clearFile} />}
+    </>
+  );
+}