Pylon PermissionOverwritesBuilder

export enum ModifyType {
  DENY = 'deny',
  ALLOW = 'allow'
}

export default class PermissionOverwritesBuilder {
  public overwrites: discord.Channel.IPermissionOverwrite[];

  constructor(overwrites?: discord.Channel.IPermissionOverwrite[]) {
    this.overwrites = overwrites || [];
  }

  private modify(
    modifyType: ModifyType,
    overwriteType: discord.Channel.PermissionOverwriteType,
    id: string,
    permissions: number
  ): PermissionOverwritesBuilder {
    const overwrite = this.overwrites.find(
      (v) => v.type === overwriteType && v.id === id
    );

    if (
      overwrite &&
      ((overwrite.deny & permissions) === permissions ||
        (overwrite.allow & permissions) === permissions)
    ) {
      throw new Error('Permission has already been denied or allowed');
    }

    if (overwrite && !overwrite.hasOwnProperty(modifyType)) {
      throw new Error("modifyType must be either 'deny' or 'allow'");
    }

    if (overwrite) {
      overwrite[modifyType] |= permissions;
    } else {
      const newOverwrite: discord.Channel.IPermissionOverwrite = {
        allow: 0,
        deny: 0,
        id,
        type: overwriteType
      };

      if (modifyType === ModifyType.ALLOW) {
        newOverwrite.allow = permissions;
      } else {
        newOverwrite.deny = permissions;
      }

      this.overwrites.push(newOverwrite);
    }

    return this;
  }

  public denyForRole(
    roleId: string,
    permissions: number
  ): PermissionOverwritesBuilder {
    return this.modify(
      ModifyType.DENY,
      discord.Channel.PermissionOverwriteType.ROLE,
      roleId,
      permissions
    );
  }

  public denyForMember(memberId: string, permissions: number) {
    return this.modify(
      ModifyType.DENY,
      discord.Channel.PermissionOverwriteType.MEMBER,
      memberId,
      permissions
    );
  }

  public allowForRole(
    roleId: string,
    permissions: number
  ): PermissionOverwritesBuilder {
    return this.modify(
      ModifyType.ALLOW,
      discord.Channel.PermissionOverwriteType.ROLE,
      roleId,
      permissions
    );
  }

  public allowForMember(memberId: string, permissions: number) {
    return this.modify(
      ModifyType.ALLOW,
      discord.Channel.PermissionOverwriteType.MEMBER,
      memberId,
      permissions
    );
  }

  public formatAsOverwrites(): discord.Channel.IPermissionOverwrite[] {
    return this.overwrites;
  }
}