import { HashCodec } from './HashCodec';
import { Route } from './Interfaces';

export function getWindowLocation() {
  if (typeof window === 'undefined') {
    return undefined;
  }

  return (window || {}).location;
}

export function getPath(state: { route: Route }) {
  let path: string | undefined;

  if (
    state != null &&
    state.route != null &&
    String.isNullOrEmpty(state.route.path) === false
  ) {
    path = state.route.path;

    delete state.route;
  }

  return path;
}

export function trimPath(path: string, removeLeadingSlash = false) {
  return path
    .replace(/^\/+/, removeLeadingSlash ? '' : '/')
    .replace(/\/+$/, '');
}

export function joinPath(path: string, base?: string) {
  if (String.isNullOrEmpty(base)) {
    return trimPath(path);
  }

  return `${trimPath(base)}/${trimPath(path, true)}`;
}

export function normalizePath(
  path: string,
  currentPath?: string,
  hashCodec?: HashCodec,
) {
  if (String.isNullOrEmpty(path) === false) {
    if (path[0] !== '/') {
      if (String.isNullOrEmpty(currentPath)) {
        const windowLocation = getWindowLocation();
        const currentHash =
          windowLocation == null ? undefined : windowLocation.hash;
        currentPath = (hashCodec || HashCodec.Default).decode(
          currentHash,
          x => x,
        );
      }

      // relative path
      path = `${currentPath!
        .split('/')
        .slice(0, -1)
        .join('/')}/${path}`;
    }

    // manage relative path elements (..)
    const pathElems = path.split('/');

    for (let i = 0; i < pathElems.length; ++i) {
      if (pathElems[i] === '..') {
        if (i === 0) {
          pathElems.shift();
          --i;
        } else {
          pathElems.splice(i - 1, 2);
          i -= 2;
        }
      } else if (pathElems[i] === '.') {
        pathElems.splice(i--, 1);
      } else if (pathElems[i] === '') {
        // trim out empty path elements (except for the beginning and end)
        if (i > 0 && i < pathElems.length - 1) {
          pathElems.splice(i--, 1);
        }
      }
    }

    path = pathElems.join('/');
  }

  return path;
}