/**
 * POST /api/parse-docx
 *
 * Accepts a .docx file upload, parses it, and returns the paragraphs
 * with their text and formatting info. Stores the buffer for later use.
 */
import { NextResponse } from "next/server";
import { parseDocx } from "@/lib/docx-service";
import fileStore from "@/lib/file-store";
import { v4 as uuidv4 } from "uuid";

export async function POST(request) {
  try {
    const formData = await request.formData();
    const file = formData.get("file");

    if (!file) {
      return NextResponse.json(
        { error: "No file provided" },
        { status: 400 }
      );
    }

    if (
      !file.name.endsWith(".docx") &&
      file.type !==
        "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
    ) {
      return NextResponse.json(
        { error: "Only .docx files are supported" },
        { status: 400 }
      );
    }

    const arrayBuffer = await file.arrayBuffer();
    const buffer = Buffer.from(arrayBuffer);

    const { paragraphs } = parseDocx(buffer);

    // Generate a session ID and store the buffer
    const sessionId = uuidv4();
    fileStore.save(sessionId, {
      originalBuffer: buffer,
      fileName: file.name,
      paragraphs: paragraphs,
      enrichedBuffer: null,
      headingIndices: [],
    });

    return NextResponse.json({
      sessionId,
      fileName: file.name,
      paragraphs: paragraphs.map((p) => ({
        index: p.index,
        text: p.text,
        fontSizePt: p.fontSizePt,
        isBold: p.isBold,
        styleId: p.styleId,
      })),
      totalParagraphs: paragraphs.length,
    });
  } catch (err) {
    console.error("Parse error:", err);
    return NextResponse.json(
      { error: "Failed to parse document: " + err.message },
      { status: 500 }
    );
  }
}