import AssertionError from "../error/AssertionError";
import EtudeError from "../error/EtudeError";
import Direction from "./Direction";

export default class Mode {
  public static size: number = 0;
  private static _values: Mode[] = [];

  public static IONIAN = new Mode([2, 2, 1, 2, 2, 2, 1]);
  public static DORIAN = new Mode([2, 1, 2, 2, 2, 1, 2]);
  public static PHRYGIAN = new Mode([1, 2, 2, 2, 1, 2, 2]);
  public static LYDIAN = new Mode([2, 2, 2, 1, 2, 2, 1]);
  public static MIXOLYDIAN = new Mode([2, 2, 1, 2, 2, 1, 2]);
  public static AEOLIAN = new Mode([2, 1, 2, 2, 1, 2, 2]);
  public static LOCRIAN = new Mode([1, 2, 2, 1, 2, 2, 2]);

  private ascending: number[];
  private descending: number[];

  private constructor(private stepPattern: number[]) {
    ++Mode.size;
    Mode._values.push(this);

    this.ascending = stepPattern.slice();
    this.descending = stepPattern.slice().reverse().map(a => -a);
  }

  public static values(): Mode[] {
    return Mode._values.slice();
  }

  public ordinal(): number {
    return Mode._values.indexOf(this);
  }

  public static valueOf(modeString: string): Mode {
    const mode: Mode = Mode[modeString];
    if (mode instanceof Mode) {
      return mode;
    }
    throw EtudeError.forInvalid(Mode, modeString);
  }

  public toString(): string {
    return Object.keys(Direction).find(d => Direction[d] === this);
  }

  public getStepPattern(direction: Direction = Direction.DEFAULT): number[] {
    switch (direction) {
      case Direction.ASCENDING: return this.ascending.slice();
      case Direction.DESCENDING: return this.descending.slice();
      default: throw new AssertionError("Invalid direction");
    }
  }
}