import {
  documentExtensions,
  documentMimePatterns,
  spreadsheetExtensions,
  spreadsheetMimePatterns,
  videoExtensions,
} from "../constants";

export type FileCategory =
  | "document"
  | "spreadsheet"
  | "pdf"
  | "video"
  | "image"
  | "other";

interface GetFileCategoryParams {
  readonly fileName?: string;
  readonly fileType?: string;
}

function extensionOf(fileName: string): string {
  const dot = fileName.lastIndexOf(".");

  return dot < 0 ? "" : fileName.slice(dot + 1).toLowerCase();
}

function matchesAnyExtension(
  fileName: string | undefined,
  list: { type: string }[],
): boolean {
  if (!fileName) return false;
  const ext = extensionOf(fileName);
  if (!ext) return false;

  return list.some(({ type }) => type === ext);
}

function matchesAnyMimePattern(
  fileType: string | undefined,
  patterns: string[],
): boolean {
  if (!fileType) return false;
  const lower = fileType.toLowerCase();

  return patterns.some(pattern => lower.includes(pattern));
}

/**
 * Bucket a file into one of the generic categories the design system
 * recognises. Decoupled from icon names so that:
 *
 *   1. Consumers can use generic terminology in copy, accessibility
 *      labels, and filter UI ("Document", "Spreadsheet") without
 *      coupling to the brand-named icon assets (`word`, `excel`).
 *   2. When `@jobber/design` adds generic-document / generic-spreadsheet
 *      icons, the icon mapping can be updated without breaking
 *      consumers who already use this categorisation.
 *
 * Detection precedence: `fileType` (MIME) first, then `fileName`
 * extension. The extension lists cover OpenDocument Text / Spreadsheet,
 * RTF, Apple Pages / Numbers, CSV, and WordPerfect alongside the
 * Microsoft Office formats so callers do not have to enumerate them.
 *
 * `fileType` matching is case-insensitive and accepts both full MIME
 * strings (`"video/mp4"`, `"image/jpeg"`) and coarse type strings
 * (`"video"`, `"image"`) since `parseFile` collapses video MIMEs to
 * the bare token `"video"` for external files.
 */
export function getFileCategory({
  fileName,
  fileType,
}: GetFileCategoryParams): FileCategory {
  const normalizedType = fileType?.toLowerCase();

  if (normalizedType?.includes("pdf") || fileName?.match(/\.pdf$/i)) {
    return "pdf";
  }

  if (normalizedType?.includes("image")) {
    return "image";
  }

  if (
    normalizedType?.includes("video") ||
    matchesAnyExtension(fileName, videoExtensions)
  ) {
    return "video";
  }

  if (
    matchesAnyMimePattern(normalizedType, documentMimePatterns) ||
    matchesAnyExtension(fileName, documentExtensions)
  ) {
    return "document";
  }

  if (
    matchesAnyMimePattern(normalizedType, spreadsheetMimePatterns) ||
    matchesAnyExtension(fileName, spreadsheetExtensions)
  ) {
    return "spreadsheet";
  }

  return "other";
}