type ProjectDragStateLike = {
  isDragging: boolean;
  projectId: string | null;
  projectName: string | null;
  allocationId: string | null;
  originalStartDate: Date | null;
  originalEndDate: Date | null;
  currentStartDate: Date | null;
  currentEndDate: Date | null;
  startMouseX: number;
  pointerDeltaX: number;
  originalLeft: number;
  blockWidth: number;
  daysDelta: number;
};

type CreateProjectDragStateInput = {
  projectId: string;
  projectName: string;
  allocationId?: string | null;
  startDate: Date;
  endDate: Date;
  startMouseX: number;
  originalLeft?: number;
  blockWidth?: number;
};

export function createProjectDragState<TState extends ProjectDragStateLike>(
  input: CreateProjectDragStateInput,
): TState {
  return {
    isDragging: true,
    projectId: input.projectId,
    projectName: input.projectName,
    allocationId: input.allocationId ?? null,
    originalStartDate: input.startDate,
    originalEndDate: input.endDate,
    currentStartDate: input.startDate,
    currentEndDate: input.endDate,
    startMouseX: input.startMouseX,
    pointerDeltaX: 0,
    originalLeft: input.originalLeft ?? 0,
    blockWidth: input.blockWidth ?? 0,
    daysDelta: 0,
  } as TState;
}

export function buildProjectShiftMutationInput(
  drag: Pick<ProjectDragStateLike, "daysDelta" | "projectId" | "currentStartDate" | "currentEndDate">,
): { projectId: string; newStartDate: Date; newEndDate: Date } | null {
  if (drag.daysDelta === 0 || !drag.projectId || !drag.currentStartDate || !drag.currentEndDate) {
    return null;
  }

  return {
    projectId: drag.projectId,
    newStartDate: drag.currentStartDate,
    newEndDate: drag.currentEndDate,
  };
}