data/src/FileSystem/FileUtils2.ts

// To avoid circular dependencies, need to put some functions here instead of
// Utils.ts.

import { getFileNameParts } from "./FilenameManipulation";
import { getFormatInfoGivenType } from "./LoadSaveMolModels/Types/MolFormats";
import { IFileInfo } from "./Types";
import memoize from "lodash.memoize";
type FileInfo = IFileInfo; // To avoid circular dependencies.

/**
 * Given FileInfo object, returns a string representing the file type,
 * uppercase.
 *
 * @param  {FileInfo | string} fileInfo  The file to get the type of. Can be of
 *                                       type FileInfo, or just the filename.
 * @returns {string | undefined}  The type of the file, uppercase.
 */
export const getFileType = memoize(
    function (fileInfo: FileInfo | string): string | undefined {
        // If string provided, turn it into an FileInfo object.
        if (typeof fileInfo === "string") {
            fileInfo = {
                name: fileInfo,
                contents: "",
            };
        }
        const prts = getFileNameParts(fileInfo.name);
        // TODO: Could also examine contents, but for now just proceed based on
        // extension.
        let ext = prts.ext.toUpperCase();
        // If extension ends in "TXT", get next extension. Because Windows often
        // appends .txt to ends of files.
        if (ext.endsWith(".TXT")) {
            ext = prts.ext.slice(0, -4);
        }
        const possibleTypes = [ext];
        if (prts.ext.indexOf(".") != -1) {
            // Yes, so consider first and last parts of extension. For example, for
            // tmp.pdb, consider both tmp and pdb. But consider last one first (so
            // pdb before tmp).
            const extParts = prts.ext.split(".");
            possibleTypes.push(extParts[extParts.length - 1].toUpperCase());
            possibleTypes.push(extParts[0].toUpperCase());
        }
        for (const typ of possibleTypes) {
            const formatInfo = getFormatInfoGivenType(typ);
            if (formatInfo === undefined) {
                // Not found
                continue;
            }
            // It was found.
            return formatInfo.primaryExt.toUpperCase();
        }
        // If it's JSON, that's from molmoda.
        if (ext === "JSON") {
            return ext;
        }
        // This happens when extension hasn't been added yet (for example, filename
        // user gives from plugin).
        if (ext === "") {
            return ext;
        }
        // It's not a molecular filetype. TODO: Will need to implement something
        // separate for other foramts (CSV, etc.).
        return;
        // throw new Error("Could not determine filetype for " + fileInfo.name);
    },
    (fileInfo) => (typeof fileInfo === "string" ? fileInfo : fileInfo.name)
);