Generic muse

src/muse-file.ts

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+import type { BunFile } from "bun";
+import { normalize, basename, extname, dirname } from "node:path";
+import YAML from "yaml";
+import TOML from "smol-toml";
+import { FileError } from "./errors";
+
+export type MuseFileType = "md" | "yaml" | "json" | "toml";
+export interface MuseFileContent {
+  type: MuseFileType;
+  text: string;
+  data: Record<string, unknown>;
+}
+
+function extensionToFiletype(ext: string): MuseFileType {
+  switch (ext) {
+    case "md":
+      return "md";
+    case "yaml":
+      return "yaml";
+    case "json":
+      return "json";
+    case "toml":
+      return "toml";
+    default:
+      throw new Error(`Unsupported file format: ${ext}`);
+  }
+}
+
+const FRONTMATTER_REGEX = /^---[\s\S]*?---/gm;
+/**
+ * Attempt to parse YAML frontmatter from a mixed yaml/md doc
+ * @param content The raw markdown content
+ * @returns Any successfully parsed frontmatter
+ */
+function extractFrontmatter(content: string) {
+  // If it does not start with `---`, it is invalid for frontmatter
+  if (content.trim().indexOf("---") !== 0) {
+    return {};
+  }
+
+  if (FRONTMATTER_REGEX.test(content)) {
+    const frontmatterString = content.match(FRONTMATTER_REGEX)?.[0] ?? "";
+    const cleanFrontmatter = frontmatterString.replaceAll("---", "").trim();
+    return YAML.parse(cleanFrontmatter);
+  }
+
+  return {};
+}
+
+/**
+ * Given a string of a markdown document, extract the markdown content
+ * @param content The raw markdown content
+ * @returns The markdown content without frontmatter
+ */
+function extractMarkdown(content: string): string {
+  if (content.trim().indexOf("---") !== 0) {
+    return content;
+  }
+  return content.replace(FRONTMATTER_REGEX, "").trim();
+}
+
+export class MuseFile {
+  protected _path: string;
+  protected _file: BunFile;
+  protected _fileType: MuseFileType;
+
+  constructor(filePath: string) {
+    this._path = normalize(filePath);
+    this._file = Bun.file(this._path);
+    this._fileType = extensionToFiletype(this.extension.slice(1));
+  }
+
+  get dirname(): string {
+    return dirname(this._path);
+  }
+
+  get extension(): string {
+    return extname(this._path);
+  }
+
+  get basename(): string {
+    return basename(this._path);
+  }
+
+  get filename(): string {
+    return basename(this._path, this.extension);
+  }
+
+  get path(): string {
+    return this._path;
+  }
+
+  public async readJSON(): Promise<MuseFileContent> {
+    try {
+      const text = await this._file.text();
+
+      return {
+        type: "json",
+        text: text,
+        data: JSON.parse(text),
+      };
+    } catch (error) {
+      throw new FileError(`Failed to read JSON file: ${error}`, this._path);
+    }
+  }
+
+  public async readYAML(): Promise<MuseFileContent> {
+    try {
+      const text = await this._file.text();
+      return {
+        type: "yaml",
+        text,
+        data: YAML.parse(text),
+      };
+    } catch (error) {
+      throw new FileError(`Failed to read YAML file: ${error}`, this._path);
+    }
+  }
+
+  public async readTOML(): Promise<MuseFileContent> {
+    try {
+      const text = await this._file.text();
+      return {
+        type: "toml",
+        text,
+        data: TOML.parse(text),
+      };
+    } catch (error) {
+      throw new FileError(`Failed to read TOML file: ${error}`, this._path);
+    }
+  }
+
+  public async readMarkdown(): Promise<MuseFileContent> {
+    try {
+      const text = await this._file.text();
+      const frontmatter = extractFrontmatter(text);
+      const markdown = extractMarkdown(text);
+
+      return {
+        type: "md",
+        text: markdown,
+        data: {
+          ...frontmatter,
+        },
+      };
+    } catch (error) {
+      throw new FileError(`Failed to read Markdown file: ${error}`, this._path);
+    }
+  }
+
+  public async read(): Promise<MuseFileContent> {
+    switch (this._fileType) {
+      case "json":
+        return this.readJSON();
+      case "yaml":
+        return this.readYAML();
+      case "toml":
+        return this.readTOML();
+      case "md":
+        return this.readMarkdown();
+      default:
+        throw new FileError(
+          `No reader for file type ${this._fileType}`,
+          this._path,
+        );
+    }
+  }
+}