import type { PropertyParser } from '../../types';

import { InvalidStringRecord } from './exception';

/** Парсит JSON в плоский объект, проверяя, что все значения — строки. */
export class StringRecordParser
  implements PropertyParser<Record<string, string>>
{
  type(): string {
    return 'json(Record<string, string>)';
  }

  description(): string {
    return 'Parses a JSON object whose values are all strings';
  }

  parse(value: unknown): Record<string, string> {
    const parsed = this.toJson(value);

    if (
      parsed === null ||
      typeof parsed !== 'object' ||
      Array.isArray(parsed)
    ) {
      throw new InvalidStringRecord('expected a JSON object', value);
    }

    const result: Record<string, string> = {};

    for (const [key, item] of Object.entries(parsed)) {
      if (typeof item !== 'string') {
        throw new InvalidStringRecord(
          `value of key <${key}> must be a string, got ${typeof item}`,
          value,
        );
      }

      result[key] = item;
    }

    return result;
  }

  private toJson(value: unknown): unknown {
    if (typeof value !== 'string') {
      return value;
    }

    try {
      return JSON.parse(value);
    } catch (error) {
      throw new InvalidStringRecord('value is not valid JSON', value, error);
    }
  }
}