Fix the TODO comment:

```
// file-versioning-plugin.ts
import {
  Notice,
  Plugin,
  PluginSettingTab,
  Setting,
  TFile,
  ItemView,
  WorkspaceLeaf,
  MarkdownView,
  ViewRegistry,
} from "obsidian";

interface FileVersioningSettings {
  maxVersions: number;
  versionsLocation: string;
  minDuration: number;
}

const DEFAULT_SETTINGS: FileVersioningSettings = {
  maxVersions: 5,
  versionsLocation: ".versions",
  minDuration: 1800, // 30 minutes
};

export default class FileVersioningPlugin extends Plugin {
  settings: FileVersioningSettings;

  async onload() {
    await this.loadSettings();

    this.addSettingTab(new FileVersioningSettingTab(this.app, this));

    this.registerEvent(
      this.app.vault.on("modify", async (file: TFile) => {
        const durationSinceLastSave = Date.now() - file.stat.mtime;

        if (durationSinceLastSave >= this.settings.minDuration) {
          await this.createVersion(file);
        }
      })
    );
		
    this.addCommand({
      id: "view-file-versions",
      name: "View File Versions",
      callback: async () => {
        const file = this.app.workspace.getActiveFile();
        if (!file) {
          new Notice("No active file to view versions for.");
          return;
        }
        await this.showVersions(file);
      },
    });

		this.registerView("file-versions-view", (leaf: WorkspaceLeaf) =>
      new FileVersionsView(leaf, this)
    );
		
  }
	
  async createVersion(file: TFile) {
    const data = await this.app.vault.read(file);
    const versionsFolder = this.app.vault.getAbstractFileByPath(this.settings.versionsLocation);
		
    if (!versionsFolder) {
      await this.app.vault.createFolder(this.settings.versionsLocation);
    }
		
    const uniqueTimestamp = Date.now().toString();

    await this.app.vault.create(
      this.settings.versionsLocation + '/' + file.basename + '-' + uniqueTimestamp + '.md',
      data
    );

    if (this.settings.maxVersions > 0) {
      await this.removeOldVersions(file, this.settings.maxVersions);
    }
  }

  async removeOldVersions(file: TFile, maxVersions: number) {
    const versions = await this.getVersions(file);
    const numVersions = versions.length;

    if (numVersions > maxVersions) {
      await this.app.vault.delete(versions[0]);
    }
  }

	//TODO: "file" undefined, getVersions fails to get versions
  async getVersions(file: TFile) {
		
    const folder = this.settings.versionsLocation
    const versions: TFile[] = [];

    if (folder) {
      this.app.vault.getFiles().forEach((version) => {
				if (version instanceof TFile && version.parent === folder && version.basename.startsWith(file.basename)) {
					versions.push(version);
        }
      });

      versions.sort((a: TFile, b: TFile) => {
        const timestampA = parseInt(
          a.basename.split("-").slice(-1).toString()
        );
        const timestampB = parseInt(
          b.basename.split("-").slice(-1).toString()
        );

        return timestampA - timestampB;
      });
    }

    return versions;
  }
	
  async showVersions(file: TFile) {
		const existingLeaf = this.app.workspace.getLeavesOfType(
			"file-versions-view"
		)?.[0];

		const leaf =
			existingLeaf ||
			this.app.workspace.splitActiveLeaf("horizontal");

		leaf
			.setViewState({ type: "file-versions-view", file: file.path })
			.then((fileVersionsView) => {
        // Check if the view has been created before
        if (!fileVersionsView) {
					this.app.workspace.setActiveLeaf(existingLeaf);
          return;
        }

        // Focus the leaf once it has been created.
				this.app.workspace.setActiveLeaf(leaf);
      })
  }

  async loadSettings() {
    this.settings = Object.assign({}, DEFAULT_SETTINGS, await this.loadData());
  }

  async saveSettings() {
    await this.saveData(this.settings);
  }
}

class FileVersionsView extends ItemView {
  plugin: FileVersioningPlugin;
  file: TFile;

  constructor(leaf: WorkspaceLeaf, plugin: FileVersioningPlugin) {
    super(leaf, plugin);
    this.plugin = plugin;
  }

  getViewType(): string {
    return "file-versions-view";
  }

  getDisplayText(): string {
    return "File Versions";
  }

  getIcon(): string {
    return "clock";
  }

	async onOpen() {
    const state = this.leaf.getViewState();
    this.file = this.app.vault.getAbstractFileByPath(state.file) as TFile;
    await this.reloadData();
  }

  async reloadData() {
    const container = createDiv({ cls: "file-versions-container" });
    const versions = await this.plugin.getVersions(this.file);
    versions.reverse();

    versions.forEach((version) => {
      const versionItem = container.createEl("div", {
        cls: "file-version-item",
      });
      versionItem.createEl("span", {
        cls: "file-version-label",
        text: version.basename.replace(this.file.basename, "").replace('.md', ''),
      });

      versionItem.createEl("a", {
        cls: "file-version-restore",
        text: "Restore",
        oncontextmenu: async (e: MouseEvent) => {
          e.preventDefault();
          await this.plugin.createVersion(this.file);
          await this.app.vault.modify(this.file, await this.app.vault.read(version));
          this.leaf.setEphemeralState({});
        },
      });
    });

    this.contentEl.empty();
    this.contentEl.appendChild(container);
  }
}

class FileVersioningSettingTab extends PluginSettingTab {
  plugin: FileVersioningPlugin;

  constructor(app: App, plugin: FileVersioningPlugin) {
    super(app, plugin);
    this.plugin = plugin;
  }

  display(): void {
    let { containerEl } = this;

    containerEl.empty();

    containerEl.createEl("h2", { text: "File Versioning Settings" });

    new Setting(containerEl)
      .setName("Maximum Versions")
      .setDesc("Maximum number of versions to keep. Set to 0 for no limit.")
      .addText((text) =>
        text
          .setPlaceholder("Enter maximum versions")
          .setValue(this.plugin.settings.maxVersions.toString())
          .onChange(async (value) => {
            this.plugin.settings.maxVersions = parseInt(value);
            await this.plugin.saveSettings();
          })
      );

    new Setting(containerEl)
      .setName("Versions Location")
      .setDesc("Specify the folder where versions should be stored.")
      .addText((text) =>
        text
          .setPlaceholder("Enter versions location")
          .setValue(this.plugin.settings.versionsLocation)
          .onChange(async (value) => {
            this.plugin.settings.versionsLocation = value;
            await this.plugin.saveSettings();
          })
      );

    new Setting(containerEl)
      .setName("Minimum Duration")
      .setDesc("Minimum time in seconds after which a new version may be created.")
      .addText((text) =>
        text
          .setPlaceholder("Enter minimum duration")
          .setValue(this.plugin.settings.minDuration.toString())
          .onChange(async (value) => {
            this.plugin.settings.minDuration = parseInt(value);
            await this.plugin.saveSettings();
          })
      );
  }
}
```