/**
 * @author Martin Karkowski
 * @email m.karkowski@zema.de
 * @create date 2020-12-29 17:06:25
 * @modify date 2020-12-30 11:34:20
 * @desc [description]
 */

import {
  IWaMOBaseModuleDescription,
  IWaMOConverterModuleDescription,
  IWaMOLineDescription
} from "../types/interfaces";

/**
 * Helper Function to get the order of elements.
 * Returns a dictionary containing information
 * of neigbors for each station in the line.
 *
 * @export
 * @param {IWaMOLineDescription} line The Line-Configuration
 * @return {*} Dict, using the Stations-ID as key, as Value Object with the next-station-id and prev-station-id is provided
 */
export function getOrder(line: IWaMOLineDescription) {
  const ret: {
    [index: string]: {
      prev: string | false;
      next: string | false;
    };
  } = {};

  for (const id in line.elements) {
    const element = line.elements[id];

    if (ret[id] === undefined) {
      ret[id] = {
        prev: false,
        next: false
      };
    }

    if (element.leftNeighbor) {
      if (ret[element.leftNeighbor] === undefined) {
        ret[element.leftNeighbor] = {
          prev: false,
          next: id
        };
      } else {
        ret[element.leftNeighbor].next = id;
      }
      ret[id].prev = element.leftNeighbor;
    }
  }

  return ret;
}

/**
 * Returns the Elements in the Order, as array.
 * Throws errors if items arent connected correctly
 * or there are multiple starts.
 *
 * @export
 * @param {IWaMOLineDescription} line The Line-Configuration
 */
export function getOrderAsArray(line: IWaMOLineDescription) {
  // First, determine the Elements without a left neigbor
  const firstElements = Object.getOwnPropertyNames(line.elements)
    .filter((key) => !line.elements[key].leftNeighbor)
    .map((key) => line.elements[key]);

  if (firstElements.length == 1) {
    // Extract the most Left item
    const firstItem = firstElements[0];
    const itemsToCheck = Object.getOwnPropertyNames(line.elements);

    let currentItem = firstItem;
    const ret: Array<
      IWaMOBaseModuleDescription | IWaMOConverterModuleDescription
    > = [];

    do {
      // Add the Element to the Return Item.
      ret.push(currentItem);

      // Remove the Element for the Items to Check.
      itemsToCheck.splice(itemsToCheck.indexOf(currentItem.id), 1);

      let found = false;

      // Iterate over the Items and determine the next item.
      for (const id in line.elements) {
        // Get the Item
        const item = line.elements[id];
        if (item.leftNeighbor == currentItem.id) {
          // Mark the Element as Found and assign
          // the new current item
          found = true;
          currentItem = item;

          break;
        }
      }

      if (!found) {
        // That should not happen
        throw Error("Element isnt connected :'" + currentItem.name + "'");
      }
    } while (itemsToCheck.length > 1);

    // Add the Last Element
    ret.push(line.elements[itemsToCheck[0]]);

    return ret;
  } else {
    throw Error("Unconnected Elements");
  }
}