Attachment form and table, MusicXML renderer

packages/frontend/src/FileReducer.ts

@@ -0,0 +1,110 @@
+import { mapProp, Update } from "./store";
+
+export function FileReducer(prev: FileReducer.State, action: FileReducer.Action): FileReducer.State {
+	switch (action.type) {
+		case "reset":
+			return FileReducer.initial;
+		case "file":
+			if (prev.file !== null) {
+				if (action.file !== null) {
+					if (prev.file.name === prev.filename && prev.file.type === prev.mediaType) {
+						return Object.freeze<FileReducer.State>({
+							filename: action.file.name,
+							mediaType: action.file.type,
+							file: action.file,
+						});
+					} else {
+						return mapProp("file", action.file as File | null)(prev);
+					}
+				} else {
+					if (prev.file.name === prev.filename && prev.file.type === prev.mediaType) {
+						return FileReducer.initial;
+					} else {
+						return mapProp("file", action.file as File | null)(prev);
+					}
+				}
+			} else {
+				if (action.file !== null) {
+					if (prev.filename === "" && prev.mediaType === "") {
+						return Object.freeze<FileReducer.State>({
+							filename: action.file.name,
+							mediaType: action.file.type,
+							file: action.file,
+						});
+					} else {
+						return mapProp("file", action.file as File | null)(prev);
+					}
+				} else {
+					return prev;
+				}
+			}
+		case "filename":
+			return mapProp("filename", action.filename)(prev);
+		case "mediaType":
+			return mapProp("mediaType", action.mediaType)(prev);
+	}
+}
+
+export namespace FileReducer {
+
+	export interface ResetAction {
+		readonly type: "reset";
+	}
+
+	export const reset: ResetAction = Object.freeze<ResetAction>({
+		type: "reset",
+	});
+
+	export interface SetFileAction {
+		readonly type: "file";
+		readonly file: File | null;
+	}
+
+	export function setFile(file: File | null): SetFileAction {
+		return Object.freeze<SetFileAction>({
+			type: "file",
+			file,
+		});
+	}
+
+	export interface SetFilenameAction {
+		readonly type: "filename";
+		readonly filename: Update<string>;
+	}
+
+	export function setFilename(filename: Update<string>): SetFilenameAction {
+		return Object.freeze<SetFilenameAction>({
+			type: "filename",
+			filename,
+		});
+	}
+
+	export interface SetMediaTypeAction {
+		readonly type: "mediaType";
+		readonly mediaType: Update<string>;
+	}
+
+	export function setMediaType(mediaType: Update<string>): SetMediaTypeAction {
+		return Object.freeze<SetMediaTypeAction>({
+			type: "mediaType",
+			mediaType,
+		});
+	}
+
+	export type Action = ResetAction |
+		SetFileAction |
+		SetFilenameAction |
+		SetMediaTypeAction;
+
+	export interface State {
+		readonly filename: string;
+		readonly mediaType: string;
+		readonly file: File | null;
+	}
+
+	export const initial: State = Object.freeze<State>({
+		filename: "",
+		mediaType: "",
+		file: null,
+	});
+}