/**
 * MarkItDown converter — spawns Microsoft's markitdown CLI to convert
 * office documents (PDF, DOCX, PPTX, XLSX) to Markdown.
 *
 * Follows the same Bun.spawn pattern as rpubs/typst-compile.ts.
 */

import { writeFile, readFile, mkdir, rm } from "node:fs/promises";
import { join } from "node:path";
import { randomUUID } from "node:crypto";

export const MARKITDOWN_EXTS = [".pdf", ".docx", ".pptx", ".xlsx"] as const;

/** Check if filename has an extension that markitdown can convert. */
export function isMarkitdownFormat(filename: string): boolean {
	const ext = filename.substring(filename.lastIndexOf(".")).toLowerCase();
	return (MARKITDOWN_EXTS as readonly string[]).includes(ext);
}

/** Convert an office file to Markdown via the markitdown CLI. */
export async function convertWithMarkitdown(
	filename: string,
	data: Uint8Array,
): Promise<string> {
	const jobId = randomUUID();
	const tmpDir = join("/tmp", `markitdown-${jobId}`);
	await mkdir(tmpDir, { recursive: true });

	const inputPath = join(tmpDir, filename);
	const outputPath = join(tmpDir, "output.md");

	try {
		await writeFile(inputPath, data);

		const proc = Bun.spawn(
			["markitdown", inputPath, "-o", outputPath],
			{
				stdout: "pipe",
				stderr: "pipe",
			},
		);

		const exitCode = await proc.exited;

		if (exitCode !== 0) {
			const stderr = await new Response(proc.stderr).text();
			throw new Error(`markitdown failed (exit ${exitCode}): ${stderr}`);
		}

		const markdown = await readFile(outputPath, "utf-8");
		return markdown;
	} finally {
		await rm(tmpDir, { recursive: true, force: true }).catch(() => {});
	}
}