import { ono } from '@jsdevtools/ono';

import type { $RefParserOptions } from './options';
import type { FileInfo } from './types';
import { ParserError } from './util/errors';
import type { PluginResult } from './util/plugins';
import * as plugins from './util/plugins';
import { getExtension } from './util/url';

/**
 * Prepares the file object so we can populate it with data and other values
 * when it's read and parsed. This "file object" will be passed to all
 * resolvers and parsers.
 */
export function newFile(path: string): FileInfo {
  let url = path;
  // Remove the URL fragment, if any
  const hashIndex = url.indexOf('#');
  let hash = '';
  if (hashIndex > -1) {
    hash = url.substring(hashIndex);
    url = url.substring(0, hashIndex);
  }
  return {
    extension: getExtension(url),
    hash,
    url,
  } as FileInfo;
}

/**
 * Parses the given file's contents, using the configured parser plugins.
 */
export async function parseFile(
  file: FileInfo,
  options: $RefParserOptions['parse'],
): Promise<PluginResult> {
  try {
    // If none of the parsers are a match for this file, try all of them. This
    // handles situations where the file is a supported type, just with an
    // unknown extension.
    const parsers = [options.json, options.yaml, options.text, options.binary];
    const filtered = parsers.filter((plugin) => plugin.canHandle(file));
    return await plugins.run(filtered.length ? filtered : parsers, file);
  } catch (error: any) {
    if (error && error.message && error.message.startsWith('Error parsing')) {
      throw error;
    }

    if (!error || !('error' in error)) {
      throw ono.syntax(`Unable to parse ${file.url}`);
    }

    if (error.error instanceof ParserError) {
      throw error.error;
    }

    throw new ParserError(error.error.message, file.url);
  }
}