import { isArray, isString } from 'lodash';

import { AdHocVariableFilter, UrlQueryValue } from '@grafana/data';

export const toUrl = (filters: AdHocVariableFilter[]): string[] => {
  return filters.map((filter) => toArray(filter).map(escapeDelimiter).join('|'));
};

export const toFilters = (value: UrlQueryValue): AdHocVariableFilter[] => {
  if (isArray(value)) {
    const values = value;
    return values.map(toFilter).filter(isFilter);
  }

  const filter = toFilter(value);
  return filter === null ? [] : [filter];
};

function escapeDelimiter(value: string | undefined): string {
  if (value === null || value === undefined) {
    return '';
  }

  return /\|/g[Symbol.replace](value, '__gfp__');
}

function unescapeDelimiter(value: string | undefined): string {
  if (value === null || value === undefined) {
    return '';
  }

  return /__gfp__/g[Symbol.replace](value, '|');
}

function toArray(filter: AdHocVariableFilter): string[] {
  return [filter.key, filter.operator, filter.value];
}

function toFilter(value: string | number | boolean | undefined | null): AdHocVariableFilter | null {
  if (!isString(value) || value.length === 0) {
    return null;
  }

  const parts = value.split('|').map(unescapeDelimiter);

  return {
    key: parts[0],
    operator: parts[1],
    value: parts[2],
  };
}

function isFilter(filter: AdHocVariableFilter | null): filter is AdHocVariableFilter {
  return filter !== null && isString(filter.value);
}