import { probeVideoDurationSeconds } from "@/lib/probe-video-duration";

/**
 * SH-116 client-confirmed media contract on the vendor portal: photos up to
 * 10 MB (JPEG/PNG/HEIC), videos up to 100 MB and 90 seconds (MP4/MOV).
 * PDF documents keep the previous 10 MB document cap.
 */
const MAX_DOCUMENT_BYTES = 10 * 1024 * 1024;
const MAX_PHOTO_BYTES = 10_000_000;
const MAX_VIDEO_BYTES = 100_000_000;
const MAX_VIDEO_DURATION_SECONDS = 90;

const UNSUPPORTED_TYPE_MESSAGE = "Only PDF, JPG, PNG, HEIC, MP4, and MOV files are allowed.";

type VendorUploadKind = "document" | "photo" | "video";

function resolveKind(file: File): VendorUploadKind | null {
  const extension = file.name.toLowerCase().split(".").pop() ?? "";
  const mime = file.type.toLowerCase();
  if (mime.startsWith("video/") || extension === "mp4" || extension === "mov") return "video";
  if (mime.startsWith("image/") || ["jpg", "jpeg", "png", "heic"].includes(extension)) {
    return "photo";
  }
  if (mime === "application/pdf" || extension === "pdf") return "document";
  return null;
}

export async function validateVendorDocument(file: File): Promise<string | undefined> {
  const kind = resolveKind(file);
  if (!kind) {
    return UNSUPPORTED_TYPE_MESSAGE;
  }

  if (kind === "photo" && file.size > MAX_PHOTO_BYTES) {
    return "Photos must be 10 MB or smaller.";
  }

  if (kind === "video") {
    if (file.size > MAX_VIDEO_BYTES) {
      return "Videos must be 100 MB or smaller.";
    }
    // Duration is checked client-side only; unreadable metadata never blocks.
    const duration = await probeVideoDurationSeconds(file);
    if (duration != null && duration > MAX_VIDEO_DURATION_SECONDS) {
      return `Videos must be ${MAX_VIDEO_DURATION_SECONDS} seconds or shorter.`;
    }
  }

  if (kind === "document" && file.size > MAX_DOCUMENT_BYTES) {
    return "Files must be 10 MB or smaller.";
  }

  return undefined;
}