import {
  MAX_PHOTOS_PER_WORK_ORDER,
  MAX_VIDEOS_PER_WORK_ORDER,
  MAX_VIDEO_DURATION_SECONDS,
  resolveWorkOrderUploadKind,
  workOrderFileSizeRejection,
  type WorkOrderMediaKindCounts,
} from "@/domain/work-orders/utils/work-order-media-limits";
import { probeVideoDurationSeconds } from "@/lib/probe-video-duration";

export type WorkOrderUploadScreen = {
  /** Photos and videos already on the work order, across every surface. */
  existing: WorkOrderMediaKindCounts;
  isTypeAllowed: (file: File) => boolean;
  unsupportedTypeMessage: string;
};

export type WorkOrderUploadScreenResult = { accepted: File[]; rejections: string[] };

/**
 * SH-116 browser pre-check shared by every dispatcher upload surface: type, size,
 * per-work-order photo/video count (including earlier files in the same selection)
 * and video duration. The server enforces the same contract; a video whose duration
 * the browser cannot read is never blocked here.
 */
export async function screenWorkOrderUploads(
  files: readonly File[],
  { existing, isTypeAllowed, unsupportedTypeMessage }: WorkOrderUploadScreen,
): Promise<WorkOrderUploadScreenResult> {
  const counts = { ...existing };
  const accepted: File[] = [];
  const rejections: string[] = [];
  for (const file of files) {
    if (!isTypeAllowed(file)) {
      rejections.push(unsupportedTypeMessage);
      continue;
    }
    const sizeRejection = workOrderFileSizeRejection(file);
    if (sizeRejection) {
      rejections.push(sizeRejection);
      continue;
    }
    const kind = resolveWorkOrderUploadKind(file);
    if (kind === "photo" && counts.photos >= MAX_PHOTOS_PER_WORK_ORDER) {
      rejections.push(`A work order can have at most ${MAX_PHOTOS_PER_WORK_ORDER} photos.`);
      continue;
    }
    if (kind === "video" && counts.videos >= MAX_VIDEOS_PER_WORK_ORDER) {
      rejections.push(`A work order can have at most ${MAX_VIDEOS_PER_WORK_ORDER} videos.`);
      continue;
    }
    if (kind === "video") {
      const duration = await probeVideoDurationSeconds(file);
      if (duration != null && duration > MAX_VIDEO_DURATION_SECONDS) {
        rejections.push(`Videos must be ${MAX_VIDEO_DURATION_SECONDS} seconds or shorter.`);
        continue;
      }
    }
    if (kind === "photo") counts.photos += 1;
    if (kind === "video") counts.videos += 1;
    accepted.push(file);
  }
  return { accepted, rejections };
}