/**
 * @author Timo Lehnertz
 */
import { Heading } from "./Heading";
import { TileType } from "./PathTile";

/**
 * Immutable OpenSides class representing the open sides of a tile
 */
export class OpenSides {
  public readonly northOpen: boolean;
  public readonly eastOpen: boolean;
  public readonly southOpen: boolean;
  public readonly westOpen: boolean;

  public constructor(tileType: TileType, rotation: number) {
    switch (tileType) {
      case TileType.STREIGHT:
        this.northOpen = false;
        this.eastOpen = true;
        this.southOpen = false;
        this.westOpen = true;
        break;
      case TileType.L:
        this.northOpen = false;
        this.eastOpen = true;
        this.southOpen = true;
        this.westOpen = false;
        break;
      case TileType.T:
        this.northOpen = true;
        this.eastOpen = true;
        this.southOpen = false;
        this.westOpen = true;
        break;
    }
    while (rotation < 0) {
      rotation += 4;
    }
    for (let i = 0; i < rotation; i++) {
      const newNorthOpen: boolean = this.northOpen;
      const newEastOpen: boolean = this.eastOpen;
      const newSouthOpen: boolean = this.southOpen;
      const newWestOpen: boolean = this.westOpen;
      this.northOpen = newWestOpen;
      this.eastOpen = newNorthOpen;
      this.southOpen = newEastOpen;
      this.westOpen = newSouthOpen;
    }
  }

  public isOpposingOpen(heading: Heading): boolean {
    switch (heading) {
      case Heading.NORTH:
        return this.southOpen;
      case Heading.EAST:
        return this.westOpen;
      case Heading.SOUTH:
        return this.northOpen;
      case Heading.WEST:
        return this.eastOpen;
    }
  }

  public get headings(): Heading[] {
    const headings: Heading[] = [];
    if (this.northOpen) {
      headings.push(Heading.NORTH);
    }
    if (this.eastOpen) {
      headings.push(Heading.EAST);
    }
    if (this.southOpen) {
      headings.push(Heading.SOUTH);
    }
    if (this.westOpen) {
      headings.push(Heading.WEST);
    }
    return headings;
  }
}