import { reactive, ref, type Ref } from 'vue';

const STORAGE_KEY = 'mes_ding_tpl_launch_pos';

export interface FloatPosition {
  left: number;
  top: number;
}

function readAllPositions(): Record<string, FloatPosition> {
  try {
    return JSON.parse(localStorage.getItem(STORAGE_KEY) || '{}') || {};
  } catch {
    return {};
  }
}

/** 查询条件区域（BasicTable 搜索表单）右侧的默认坐标 */
export function calcDefaultPosition(btnWidth: number, btnHeight: number): FloatPosition {
  const formEl =
    document.querySelector<HTMLElement>('.jeecg-basic-table-form-container .ant-form') ||
    document.querySelector<HTMLElement>('.jeecg-basic-table-form-container');
  if (!formEl) {
    return {
      left: Math.max(8, window.innerWidth - btnWidth - 24),
      top: 100,
    };
  }
  const rect = formEl.getBoundingClientRect();
  return {
    left: Math.max(8, rect.right - btnWidth - 12),
    top: Math.max(8, rect.top + (rect.height - btnHeight) / 2),
  };
}

/**
 * 可拖拽悬浮按钮位置：默认对齐查询区右侧，拖拽后按路由持久化。
 */
export function useDraggablePosition(routePath: Ref<string>) {
  const pos = reactive<FloatPosition>({ left: 0, top: 0 });
  const isDragging = ref(false);
  let moved = false;
  let pointerId: number | null = null;
  let startX = 0;
  let startY = 0;
  let startLeft = 0;
  let startTop = 0;
  let btnWidth = 120;
  let btnHeight = 36;

  function setButtonSize(width: number, height: number) {
    btnWidth = width;
    btnHeight = height;
  }

  function loadPosition(path: string): boolean {
    const saved = readAllPositions()[path];
    if (saved && typeof saved.left === 'number' && typeof saved.top === 'number') {
      pos.left = saved.left;
      pos.top = saved.top;
      return true;
    }
    return false;
  }

  function savePosition(path: string) {
    const all = readAllPositions();
    all[path] = { left: pos.left, top: pos.top };
    localStorage.setItem(STORAGE_KEY, JSON.stringify(all));
  }

  function applyDefaultPosition() {
    const p = calcDefaultPosition(btnWidth, btnHeight);
    pos.left = p.left;
    pos.top = p.top;
  }

  function initPosition(path: string, preferDefault = false) {
    if (!path) return;
    if (!preferDefault && loadPosition(path)) return;
    applyDefaultPosition();
  }

  function clampPosition() {
    const maxLeft = window.innerWidth - btnWidth - 8;
    const maxTop = window.innerHeight - btnHeight - 8;
    pos.left = Math.min(Math.max(8, pos.left), maxLeft);
    pos.top = Math.min(Math.max(8, pos.top), maxTop);
  }

  function onPointerMove(e: PointerEvent) {
    if (pointerId !== e.pointerId) return;
    const dx = e.clientX - startX;
    const dy = e.clientY - startY;
    if (!moved && (Math.abs(dx) > 4 || Math.abs(dy) > 4)) {
      moved = true;
      isDragging.value = true;
    }
    if (!moved) return;
    pos.left = startLeft + dx;
    pos.top = startTop + dy;
    clampPosition();
  }

  function endDrag(path: string) {
    document.removeEventListener('pointermove', onPointerMove);
    document.removeEventListener('pointerup', onPointerUp);
    document.removeEventListener('pointercancel', onPointerUp);
    if (moved && path) {
      savePosition(path);
    }
    pointerId = null;
    setTimeout(() => {
      isDragging.value = false;
      moved = false;
    }, 0);
  }

  function onPointerUp(e: PointerEvent) {
    if (pointerId !== e.pointerId) return;
    endDrag(routePath.value);
  }

  function onPointerDown(e: PointerEvent, el: HTMLElement | null) {
    if (e.button !== 0) return;
    if (el) {
      const rect = el.getBoundingClientRect();
      setButtonSize(rect.width, rect.height);
    }
    moved = false;
    isDragging.value = false;
    pointerId = e.pointerId;
    startX = e.clientX;
    startY = e.clientY;
    startLeft = pos.left;
    startTop = pos.top;
    (e.currentTarget as HTMLElement)?.setPointerCapture?.(e.pointerId);
    document.addEventListener('pointermove', onPointerMove);
    document.addEventListener('pointerup', onPointerUp);
    document.addEventListener('pointercancel', onPointerUp);
  }

  function wasDragged() {
    return moved;
  }

  return {
    pos,
    isDragging,
    setButtonSize,
    initPosition,
    applyDefaultPosition,
    onPointerDown,
    wasDragged,
    clampPosition,
  };
}