import { ParsingError } from '../errors/parsing_error';
import { ParserTypings } from '../parser/types_parser';
import { Validation } from './validation_types';
import { ErrorBuilder } from './error_builder';
import { createDefaultValidators } from './default_validators';

/** @mutates */
const mergeOptions = (
  target: Required<Validation.ValidationOptions>,
  partial: Validation.ValidationOptions
) => {
  const keys = Object.keys(partial) as Array<
    keyof Validation.ValidationOptions
  >;
  keys.forEach(key => {
    if (key === 'getErrorText') {
      target[key] = partial[key]!;
    } else if (Array.isArray(target[key])) {
      target[key] = [...target[key], ...partial[key]!];
    }
  });
};

export class Validator {
  public errors: ParsingError[] = [];
  public options: Required<Validation.ValidationOptions> = createDefaultValidators();
  private errorBuilder = new ErrorBuilder();

  constructor(options: Validation.ValidationOptions = {}) {
    this.mergeOptions(options);
  }

  private mergeOptions(partial: Validation.ValidationOptions) {
    mergeOptions(this.options, partial);
    this.errorBuilder.getErrorText = this.options.getErrorText;
    return this;
  }

  public validate(parser: ParserTypings.Parser): this {
    this.options.preValidators.forEach(validator => {
      try {
        validator(parser, this.errorBuilder);
      } catch (beforeError) {
        this.errors.push(beforeError);
      }
    });

    for (const [parsingLineNumber, entry] of parser.parsingMeta) {
      this.errorBuilder.update(parsingLineNumber, entry);

      this.options.loopValidators.forEach(validator => {
        try {
          validator(parser, this.errorBuilder);
        } catch (loopError) {
          this.errors.push(loopError);
        }
      });
    }

    this.errorBuilder.update(0, {} as any);
    this.options.postValidators.forEach(validator => {
      try {
        validator(parser, this.errorBuilder);
      } catch (afterError) {
        this.errors.push(afterError);
      }
    });

    return this;
  }
}