const MAX_TEXT_STORE = 120_000;
const MAX_PDF_BYTES = 5 * 1024 * 1024;

/** Payload sent from Build wizard client (`SeedDocumentUpload`). */
export type SeedDocumentRequestBody = {
  fileName: string;
  kind: "markdown" | "pdf";
  text?: string;
  base64?: string;
};

/** Persisted on project `kickoff.sourceData.seedDocument` (extracted text only). */
export type SeedDocumentPersisted = {
  fileName: string;
  kind: "markdown" | "pdf";
  textExtract: string;
};

export async function normalizeSeedDocument(
  raw: unknown,
): Promise<SeedDocumentPersisted | null> {
  if (!raw || typeof raw !== "object" || Array.isArray(raw)) return null;

  const o = raw as Record<string, unknown>;
  const fileNameRaw = typeof o.fileName === "string" ? o.fileName.trim() : "";
  const fileName = fileNameRaw.length > 0 ? fileNameRaw.slice(0, 240) : "document";

  const kind =
    o.kind === "pdf" ? "pdf" : o.kind === "markdown" ? "markdown" : null;
  if (!kind) return null;

  if (kind === "markdown") {
    const text = typeof o.text === "string" ? o.text : "";
    const trimmed = text.trim();
    if (!trimmed) return null;
    return {
      fileName,
      kind: "markdown",
      textExtract: trimmed.slice(0, MAX_TEXT_STORE),
    };
  }

  const b64 = typeof o.base64 === "string" ? o.base64.replace(/\s/g, "") : "";
  if (!b64) return null;

  let buf: Buffer;
  try {
    buf = Buffer.from(b64, "base64");
  } catch {
    return null;
  }

  if (buf.length > MAX_PDF_BYTES) {
    throw new Error("PDF exceeds 5MB limit");
  }

  const pdfParseMod = await import("pdf-parse");
  const pdfParse = pdfParseMod.default ?? pdfParseMod;
  const parsed = await pdfParse(buf);
  const extracted = typeof parsed?.text === "string" ? parsed.text.trim() : "";
  return {
    fileName,
    kind: "pdf",
    textExtract:
      extracted.length > 0
        ? extracted.slice(0, MAX_TEXT_STORE)
        : "[No extractable text in PDF]",
  };
}