import { runCommand } from "./process";
import { readdir } from "fs/promises";
import { join } from "path";

/**
 * Extract a .rm file (which is a zip archive) to a temporary directory.
 * Returns the path to the extraction directory.
 */
export async function extractRmFile(rmPath: string, outputDir: string): Promise<string> {
  // .rm files are zip archives
  const { code, stderr } = await runCommand("unzip", ["-o", rmPath, "-d", outputDir]);
  if (code !== 0) {
    throw new Error(`Failed to extract .rm file: ${stderr}`);
  }
  return outputDir;
}

/**
 * List the contents of the extracted .rm archive.
 */
export async function listRmContents(extractedDir: string): Promise<string[]> {
  const files: string[] = [];

  async function walk(dir: string): Promise<void> {
    const entries = await readdir(dir, { withFileTypes: true });
    for (const entry of entries) {
      const entryPath = join(dir, entry.name);
      if (entry.isDirectory()) {
        await walk(entryPath);
      } else if (entry.isFile()) {
        files.push(entryPath);
      }
    }
  }

  await walk(extractedDir);
  return files;
}

/**
 * Check if a document is a notebook (handwritten) or a PDF/ebook.
 * On reMarkable v3.x, notebooks have .rm page files and no content.pdf.
 * Falls back to rendering a test page if ambiguous.
 */
export async function isNotebook(extractedDir: string): Promise<boolean> {
  const contents = await listRmContents(extractedDir);
  const hasRmPages = contents.some((f) => f.endsWith(".rm") && !f.endsWith(".zip"));
  const hasContentPdf = contents.some((f) => f.endsWith("content.pdf") || f.endsWith(".pdf"));
  // PDF-with-annotations documents have both; treat them as non-notebooks since the PDF is the source
  return hasRmPages && !hasContentPdf;
}

/**
 * Get the list of page .rm files from an extracted notebook.
 * Returns basenames only.
 * Recursively searches for .rm files (not just root).
 */
export async function getPageFiles(extractedDir: string): Promise<string[]> {
  const contents = await listRmContents(extractedDir);
  return contents.filter((f) => f.endsWith(".rm") && !f.endsWith(".zip")).sort();
}