/**
 * useTableResize.ts - 表格调整大小Hook
 * 
 * 实现高性能的表格列宽/行高拖拽调整功能
 * 参考Notion、飞书等主流编辑器的最佳实践
 */

import { useState, useEffect, useCallback } from 'react';
import type { RefObject } from 'react';
import { 
  getResizeBoundaries, 
  isNearBoundary, 
  pixelToPt,
  normalizePercents,
  percentToPtWidths,
  type ResizeBoundary 
} from '../utils/tableUtils';

// ══════════════════════════════════════════════════════════════════════════════
// Types
// ══════════════════════════════════════════════════════════════════════════════

/**
 * 拖拽状态
 */
export interface ResizeState {
  isResizing: boolean;           // 是否正在拖拽
  resizeType: 'column' | 'row';  // 拖拽类型
  targetIndex: number;           // 目标列/行索引
  startPos: { x: number; y: number }; // 拖拽起始坐标
  currentPos: { x: number; y: number }; // 当前鼠标坐标
  originalSize: number;          // 原始尺寸（百分比或pt）
  minSize: number;               // 最小约束（px）
  startLinePosition: number;     // 拖拽线起始位置（px）
  tableWidthPx: number;          // 拖拽开始时的表格宽度（px）
}

/**
 * Hover状态
 */
export interface HoverState {
  isHovering: boolean;
  boundary: ResizeBoundary | null;
}

/**
 * Hook参数
 */
export interface UseTableResizeOptions {
  /** 表格元素引用 */
  tableRef: RefObject<HTMLTableElement>;
  /** 列宽数组(百分比) */
  colWidths: number[];
  /** 行高数组(pt) */
  rowHeights: number[];
  /** 表格总宽度百分比 */
  tableWidth: number;
  /** 是否只读 */
  readOnly?: boolean;
  /** 列宽变更回调 */
  onColumnResize?: (colWidths: number[], colWidthsPt: number[]) => void;
  /** 行高变更回调 */
  onRowResize?: (rowIndex: number, heightPt: number) => void;
}

/**
 * Hook返回值
 */
export interface UseTableResizeReturn {
  /** 拖拽状态 */
  resizeState: ResizeState | null;
  /** Hover状态 */
  hoverState: HoverState;
  /** 虚拟拖拽线位置(px) */
  resizeLinePosition: number | null;
  /** 当前尺寸提示 */
  currentSizeTooltip: string | null;
}

// ══════════════════════════════════════════════════════════════════════════════
// Constants
// ══════════════════════════════════════════════════════════════════════════════

const MIN_CELL_SIZE = 40; // 最小单元格尺寸(px)
const HOVER_THRESHOLD = 5; // Hover检测阈值(px)

// ══════════════════════════════════════════════════════════════════════════════
// Hook Implementation
// ══════════════════════════════════════════════════════════════════════════════

/**
 * 表格调整大小Hook
 */
export function useTableResize(options: UseTableResizeOptions): UseTableResizeReturn {
  const {
    tableRef,
    colWidths,
    rowHeights,
    tableWidth,
    readOnly = false,
    onColumnResize,
    onRowResize,
  } = options;

  // ────────────────────────────────────────────────────────────────────────────
  // State
  // ────────────────────────────────────────────────────────────────────────────

  const [resizeState, setResizeState] = useState<ResizeState | null>(null);
  const [hoverState, setHoverState] = useState<HoverState>({
    isHovering: false,
    boundary: null,
  });
  const [resizeLinePosition, setResizeLinePosition] = useState<number | null>(null);

  // ────────────────────────────────────────────────────────────────────────────
  // Hover Detection
  // ────────────────────────────────────────────────────────────────────────────

  /**
   * 处理鼠标移动 - 检测边界Hover
   */
  const handleTableMouseMove = useCallback(
    (e: MouseEvent) => {
      if (readOnly || resizeState?.isResizing) return;

      const table = tableRef.current;
      if (!table) return;

      const rect = table.getBoundingClientRect();
      const mouseX = e.clientX - rect.left;
      const mouseY = e.clientY - rect.top;

      // 获取所有边界
      const boundaries = getResizeBoundaries(table);

      // 查找鼠标附近的边界
      const hoveredBoundary = boundaries.find((boundary: ResizeBoundary) =>
        isNearBoundary({ x: mouseX, y: mouseY }, boundary, HOVER_THRESHOLD)
      );

      if (hoveredBoundary) {
        setHoverState({
          isHovering: true,
          boundary: hoveredBoundary,
        });
        // 边界位置需要加上表格的偏移量（考虑padding等）
        setResizeLinePosition(hoveredBoundary.position);
        table.style.cursor = hoveredBoundary.type === 'column' ? 'col-resize' : 'row-resize';
      } else {
        setHoverState({
          isHovering: false,
          boundary: null,
        });
        setResizeLinePosition(null);
        table.style.cursor = 'default';
      }
    },
    [tableRef, readOnly, resizeState]
  );

  /**
   * 处理鼠标离开表格
   */
  const handleTableMouseLeave = useCallback(() => {
    if (!resizeState?.isResizing) {
      setHoverState({
        isHovering: false,
        boundary: null,
      });
      setResizeLinePosition(null);
      if (tableRef.current) {
        tableRef.current.style.cursor = 'default';
      }
    }
  }, [tableRef, resizeState]);

  // ────────────────────────────────────────────────────────────────────────────
  // Resize Start
  // ────────────────────────────────────────────────────────────────────────────

  /**
   * 开始拖拽
   */
  const handleResizeStart = useCallback(
    (e: MouseEvent) => {
      e.preventDefault();
      e.stopPropagation();

      if (readOnly || !hoverState.boundary) return;

      const table = tableRef.current;
      if (!table) return;

      const boundary = hoverState.boundary;
      const originalSize =
        boundary.type === 'column'
          ? colWidths[boundary.index]
          : rowHeights[boundary.index];

      setResizeState({
        isResizing: true,
        resizeType: boundary.type,
        targetIndex: boundary.index,
        startPos: { x: e.clientX, y: e.clientY },
        currentPos: { x: e.clientX, y: e.clientY },
        originalSize,
        minSize: MIN_CELL_SIZE,
        startLinePosition: boundary.position,
        tableWidthPx: table.offsetWidth,
      });

      // 更新拖拽线初始位置
      setResizeLinePosition(boundary.position);

      // 添加全局样式
      document.body.style.cursor = boundary.type === 'column' ? 'col-resize' : 'row-resize';
      document.body.style.userSelect = 'none';
    },
    [tableRef, hoverState, colWidths, rowHeights, readOnly]
  );

  // ────────────────────────────────────────────────────────────────────────────
  // Resize Move
  // ────────────────────────────────────────────────────────────────────────────

  const handleResizeMove = useCallback((e: MouseEvent) => {
    const currentPos = { x: e.clientX, y: e.clientY };
    setResizeState((currentState) =>
      currentState?.isResizing
        ? { ...currentState, currentPos }
        : currentState
    );
  }, []);

  // ────────────────────────────────────────────────────────────────────────────
  // Resize End
  // ────────────────────────────────────────────────────────────────────────────

  /**
   * 结束拖拽 - 计算最终尺寸并更新
   */
  const handleResizeEnd = useCallback(
    (e: MouseEvent) => {
      if (!resizeState?.isResizing) return;

      const table = tableRef.current;
      if (!table) return;

      // 计算最终偏移量
      const finalOffset =
        resizeState.resizeType === 'column'
          ? e.clientX - resizeState.startPos.x
          : e.clientY - resizeState.startPos.y;

      if (resizeState.resizeType === 'column') {
        // ──────────────────────────────────────────────────────────────────────
        // 列宽调整
        // ──────────────────────────────────────────────────────────────────────
        const tableWidthPx = table.offsetWidth;
        if (tableWidthPx <= 0) {
          setResizeState(null);
          setResizeLinePosition(null);
          document.body.style.cursor = '';
          document.body.style.userSelect = '';
          return;
        }
        const deltaPercent = (finalOffset / tableWidthPx) * 100;

        const newColWidths = [...colWidths];
        let newWidth = resizeState.originalSize + deltaPercent;

        // 调整相邻列以保持总宽度不变
        if (resizeState.targetIndex < newColWidths.length - 1) {
          const nextColWidth = newColWidths[resizeState.targetIndex + 1];
          const widthDiff = newWidth - resizeState.originalSize;
          const newNextWidth = nextColWidth - widthDiff;

          // 最小宽度约束（5%）
          if (newWidth < 5) {
            newWidth = 5;
          } else if (newNextWidth < 5) {
            newWidth = resizeState.originalSize + (nextColWidth - 5);
          }

          newColWidths[resizeState.targetIndex] = newWidth;
          newColWidths[resizeState.targetIndex + 1] = nextColWidth - (newWidth - resizeState.originalSize);
        } else {
          // 最后一列
          newColWidths[resizeState.targetIndex] = Math.max(5, newWidth);
        }

        // 归一化百分比
        const normalizedWidths = normalizePercents(newColWidths);

        // 计算pt单位的列宽
        const colWidthsPt = percentToPtWidths(normalizedWidths, tableWidth);

        // 触发回调
        onColumnResize?.(normalizedWidths, colWidthsPt);
      } else {
        // ──────────────────────────────────────────────────────────────────────
        // 行高调整
        // ──────────────────────────────────────────────────────────────────────
        const deltaPt = pixelToPt(finalOffset);
        const newHeight = Math.max(15, resizeState.originalSize + deltaPt); // 最小15pt
        const roundedHeight = Math.round(newHeight * 10) / 10;

        // 触发回调
        onRowResize?.(resizeState.targetIndex, roundedHeight);
      }

      // 清理状态
      setResizeState(null);
      setResizeLinePosition(null);
      document.body.style.cursor = '';
      document.body.style.userSelect = '';
    },
    [resizeState, tableRef, colWidths, tableWidth, onColumnResize, onRowResize]
  );

  // ────────────────────────────────────────────────────────────────────────────
  // Event Binding
  // ────────────────────────────────────────────────────────────────────────────

  /**
   * 绑定表格Hover事件
   */
  useEffect(() => {
    const table = tableRef.current;
    if (!table || readOnly) return;

    table.addEventListener('mousemove', handleTableMouseMove);
    table.addEventListener('mouseleave', handleTableMouseLeave);

    return () => {
      table.removeEventListener('mousemove', handleTableMouseMove);
      table.removeEventListener('mouseleave', handleTableMouseLeave);
    };
  }, [tableRef, readOnly, handleTableMouseMove, handleTableMouseLeave]);

  /**
   * 绑定全局拖拽事件
   */
  useEffect(() => {
    if (resizeState?.isResizing) {
      // 开始拖拽时添加mousedown监听
      const table = tableRef.current;
      if (table && hoverState.boundary) {
        table.addEventListener('mousedown', handleResizeStart);
      }

      window.addEventListener('mousemove', handleResizeMove);
      window.addEventListener('mouseup', handleResizeEnd);

      return () => {
        if (table) {
          table.removeEventListener('mousedown', handleResizeStart);
        }
        window.removeEventListener('mousemove', handleResizeMove);
        window.removeEventListener('mouseup', handleResizeEnd);
        document.body.style.cursor = '';
        document.body.style.userSelect = '';
      };
    }

    return undefined;
  }, [resizeState, tableRef, hoverState, handleResizeStart, handleResizeMove, handleResizeEnd]);

  /**
   * Hover状态变化时绑定mousedown
   */
  useEffect(() => {
    const table = tableRef.current;
    if (!table || readOnly || !hoverState.isHovering) return;

    table.addEventListener('mousedown', handleResizeStart);

    return () => {
      table.removeEventListener('mousedown', handleResizeStart);
    };
  }, [tableRef, readOnly, hoverState, handleResizeStart]);

  // ────────────────────────────────────────────────────────────────────────────
  // Return
  // ────────────────────────────────────────────────────────────────────────────

  // 计算尺寸提示
  const activeResizeLinePosition = resizeState?.isResizing
    ? resizeState.startLinePosition + (
        resizeState.resizeType === 'column'
          ? resizeState.currentPos.x - resizeState.startPos.x
          : resizeState.currentPos.y - resizeState.startPos.y
      )
    : resizeLinePosition;

  const currentSizeTooltip = resizeState?.isResizing
    ? (() => {
        if (resizeState.resizeType === 'column') {
          const offset = resizeState.currentPos.x - resizeState.startPos.x;
          const deltaPercent = (offset / resizeState.tableWidthPx) * 100;
          const newWidth = resizeState.originalSize + deltaPercent;
          
          // 计算pt值
          const widthPt = Math.round((tableWidth / 100) * newWidth * 478 / 100 * 10) / 10;
          return `宽度: ${widthPt}pt`;
        } else {
          const offset = resizeState.currentPos.y - resizeState.startPos.y;
          const deltaPt = pixelToPt(offset);
          const newHeight = Math.max(15, resizeState.originalSize + deltaPt);
          const roundedHeight = Math.round(newHeight * 10) / 10;
          return `高度: ${roundedHeight}pt`;
        }
      })()
    : null;

  return {
    resizeState,
    hoverState,
    resizeLinePosition: activeResizeLinePosition,
    currentSizeTooltip,
  };
}