From 4cc442bdb03590591f8aa1a1bb34b44cd0954929 Mon Sep 17 00:00:00 2001
From: Nick De Villiers <nick.devilliers@canonical.com>
Date: Tue, 20 Feb 2024 14:12:32 +0000
Subject: [PATCH] feat: implement useReducer for FileUploadContainer state
 management (#105)

---
 .../FileUpload/FileUpload.stories.tsx         |  4 +-
 src/lib/components/FileUpload/FileUpload.tsx  | 41 +++------
 src/lib/components/FileUpload/hooks.ts        | 85 +++++++++++++++++++
 3 files changed, 101 insertions(+), 29 deletions(-)
 create mode 100644 src/lib/components/FileUpload/hooks.ts

diff --git a/src/lib/components/FileUpload/FileUpload.stories.tsx b/src/lib/components/FileUpload/FileUpload.stories.tsx
index 6397b9d..61ef1bb 100644
--- a/src/lib/components/FileUpload/FileUpload.stories.tsx
+++ b/src/lib/components/FileUpload/FileUpload.stories.tsx
@@ -14,9 +14,9 @@ export default meta;
 export const Example = {
   args: {
     error: "",
-    help: "Max file size is 2GB.",
+    help: "Max file size is 2MB.",
     label: "Upload files",
     maxFiles: 7,
-    maxSize: 2000000000,
+    maxSize: 2000000,
   },
 };
diff --git a/src/lib/components/FileUpload/FileUpload.tsx b/src/lib/components/FileUpload/FileUpload.tsx
index 6cdfaf5..02dcc1a 100644
--- a/src/lib/components/FileUpload/FileUpload.tsx
+++ b/src/lib/components/FileUpload/FileUpload.tsx
@@ -1,13 +1,15 @@
-import { ReactNode, useCallback, useId, useState } from "react";
+import { ReactNode, useId } from "react";
 
 import { Button, Icon, Label } from "@canonical/react-components";
 import classNames from "classnames";
 import { useDropzone, DropzoneOptions, FileRejection } from "react-dropzone";
 
 import "./FileUpload.scss";
+import { useFileUpload } from "./hooks";
+
 import { ProgressIndicator } from "@/lib/elements";
 
-type FileUploadFile = File & { percentUploaded?: number };
+export type FileUploadFile = File & { percentUploaded?: number };
 
 export interface FileUploadProps {
   accept?: DropzoneOptions["accept"];
@@ -19,7 +21,7 @@ export interface FileUploadProps {
   maxSize?: number;
   onFileUpload: NonNullable<DropzoneOptions["onDrop"]>;
   rejectedFiles: FileRejection[];
-  removeFile: (file: File) => void;
+  removeFile: (file: FileUploadFile) => void;
   removeRejectedFile: (fileRejection: FileRejection) => void;
 }
 
@@ -134,35 +136,20 @@ export const FileUploadContainer = ({
   FileUploadProps,
   "accept" | "error" | "help" | "label" | "maxFiles" | "maxSize"
 >) => {
-  const [files, setFiles] = useState<File[]>([]);
-  const [rejectedFiles, setRejectedFiles] = useState<FileRejection[]>([]);
-
-  const onFileUpload = useCallback(
-    (acceptedFiles: File[], fileRejections: FileRejection[]) => {
-      setFiles([...files, ...acceptedFiles]);
-      setRejectedFiles([...rejectedFiles, ...fileRejections]);
-    },
-    [files, rejectedFiles],
-  );
-
-  const removeFile = (file: File) => {
-    const newFiles = [...files];
-    newFiles.splice(newFiles.indexOf(file), 1);
-    setFiles(newFiles);
-  };
-
-  const removeRejectedFile = (fileRejection: FileRejection) => {
-    const newRejectedFiles = [...rejectedFiles];
-    newRejectedFiles.splice(newRejectedFiles.indexOf(fileRejection), 1);
-    setRejectedFiles(newRejectedFiles);
-  };
+  const {
+    acceptedFiles,
+    fileRejections,
+    onFileUpload,
+    removeFile,
+    removeRejectedFile,
+  } = useFileUpload();
 
   return (
     <FileUpload
       accept={accept}
       error={error}
-      files={files}
-      rejectedFiles={rejectedFiles}
+      files={acceptedFiles}
+      rejectedFiles={fileRejections}
       help={help}
       label={label}
       maxFiles={maxFiles}
diff --git a/src/lib/components/FileUpload/hooks.ts b/src/lib/components/FileUpload/hooks.ts
new file mode 100644
index 0000000..eac32e3
--- /dev/null
+++ b/src/lib/components/FileUpload/hooks.ts
@@ -0,0 +1,85 @@
+import { useCallback, useReducer } from "react";
+
+import { FileRejection } from "react-dropzone";
+
+import { FileUploadFile } from "./FileUpload";
+
+type FileUploadState = {
+  acceptedFiles: FileUploadFile[];
+  fileRejections: FileRejection[];
+};
+
+type AddFiles = {
+  type: "add-files";
+  payload: { acceptedFiles: FileUploadFile[]; fileRejections: FileRejection[] };
+};
+type RemoveAcceptedFile = { type: "remove-accepted"; payload: FileUploadFile };
+type RemoveRejectedFile = { type: "remove-rejected"; payload: FileRejection };
+
+type FileUploadActions =
+  | AddFiles
+  | RemoveAcceptedFile
+  | RemoveRejectedFile;
+
+export const useFileUpload = () => {
+  const fileUploadReducer = (
+    state: FileUploadState,
+    action: FileUploadActions,
+  ): FileUploadState => {
+    switch (action.type) {
+      case "add-files":
+        return {
+          acceptedFiles: [
+            ...state.acceptedFiles,
+            ...action.payload.acceptedFiles,
+          ],
+          fileRejections: [
+            ...state.fileRejections,
+            ...action.payload.fileRejections,
+          ],
+        };
+      case "remove-accepted": {
+        return {
+          ...state,
+          acceptedFiles: state.acceptedFiles.filter(
+            (file) => file !== action.payload,
+          ),
+        };
+      }
+      case "remove-rejected": {
+        return {
+          ...state,
+          fileRejections: state.fileRejections.filter(
+            (rejection) => rejection !== action.payload,
+          ),
+        };
+      }
+    }
+  };
+
+  const [{ acceptedFiles, fileRejections }, dispatch] = useReducer(
+    fileUploadReducer,
+    {
+      acceptedFiles: [],
+      fileRejections: [],
+    },
+  );
+
+  const onFileUpload = useCallback(
+    (acceptedFiles: FileUploadFile[], fileRejections: FileRejection[]) =>
+      dispatch({
+        type: "add-files",
+        payload: { acceptedFiles, fileRejections },
+      }),
+    [dispatch],
+  );
+
+  const removeFile = (file: FileUploadFile) =>
+    dispatch({ type: "remove-accepted", payload: file });
+
+  const removeRejectedFile = (fileRejection: FileRejection) =>
+    dispatch({ type: "remove-rejected", payload: fileRejection });
+  
+  return { acceptedFiles, fileRejections, onFileUpload, removeFile, removeRejectedFile };
+
+}