import { useState, type HTMLAttributes, type MouseEvent, type ReactNode } from 'react';
import { ArrowUp, ArrowDown, ArrowUpDown } from 'lucide-react';
import { Pagination } from '../Pagination/Pagination';
import styles from './Table.module.css';

export type SortDirection = 'asc' | 'desc';

export interface TableColumn<T> {
  key: string;
  header: ReactNode;
  render: (row: T) => ReactNode;
  width?: string | number;
  align?: 'left' | 'center' | 'right';
  /** If true, a sort icon is shown and clicking the header triggers onSort */
  sortable?: boolean;
}

export interface TableProps<T> {
  columns: TableColumn<T>[];
  data: T[];
  rowKey: (row: T) => string | number;
  loading?: boolean;
  emptyMessage?: string;
  className?: string;
  /**
   * Client-side pagination: pass a default page size to enable.
   * For server-side pagination use `total` + `page` + `onPageChange` instead.
   */
  pageSize?: number;
  /** Offer a page-size selector when pagination is enabled */
  pageSizeOptions?: number[];
  /** Called when a row is clicked */
  onRowClick?: (row: T) => void;
  /** Optional per-row props, useful for drag-and-drop and row-level attributes */
  getRowProps?: (row: T) => HTMLAttributes<HTMLTableRowElement>;
  /** Currently sorted column key (controlled) */
  sortBy?: string;
  /** Current sort direction (controlled) */
  sortDir?: SortDirection;
  /** Called when the user clicks a sortable column header */
  onSort?: (key: string, dir: SortDirection) => void;
  // ── Server-side pagination (controlled) ──────────────────────────────────
  /** Total record count from server. Presence switches to server-side pagination mode. */
  total?: number;
  /** Controlled current page (1-based). Required when `total` is set. */
  page?: number;
  /** Called when the user navigates to a new page. Required when `total` is set. */
  onPageChange?: (page: number) => void;
  /** Called when the user changes page size. Optional for server-side pagination. */
  onPageSizeChange?: (size: number) => void;
}

export function Table<T>({
  columns,
  data,
  rowKey,
  loading = false,
  emptyMessage = 'No data.',
  className,
  pageSize: defaultPageSize,
  pageSizeOptions,
  onRowClick,
  getRowProps,
  sortBy,
  sortDir,
  onSort,
  total,
  page: controlledPage,
  onPageChange,
  onPageSizeChange,
}: TableProps<T>) {
  const [internalPage, setInternalPage] = useState(1);
  const [pageSize, setPageSize] = useState(defaultPageSize ?? 10);

  const serverMode = total !== undefined;

  const handleSortClick = (key: string) => {
    if (!onSort) return;
    const nextDir: SortDirection =
      sortBy === key && sortDir === 'asc' ? 'desc' : 'asc';
    onSort(key, nextDir);
  };

  // Client-side pagination
  const clientPaginated = !serverMode && defaultPageSize !== undefined && !loading;
  const visibleData = clientPaginated
    ? data.slice((internalPage - 1) * pageSize, internalPage * pageSize)
    : data;

  const lastClientPage = pageSize > 0 ? Math.ceil(data.length / pageSize) : 1;
  const safeInternalPage = Math.min(internalPage, Math.max(1, lastClientPage));

  // Server-side pagination display values
  const serverPage = controlledPage ?? 1;
  const serverTotal = total ?? 0;

  return (
    <div className={`${styles.wrapper} ${className ?? ''}`}>
      <table className={styles.table}>
        <thead>
          <tr>
            {columns.map((col) => {
              const isSorted = col.sortable && sortBy === col.key;
              const SortIcon = isSorted
                ? sortDir === 'asc'
                  ? ArrowUp
                  : ArrowDown
                : ArrowUpDown;

              return (
                <th
                  key={col.key}
                  className={[
                    styles.th,
                    col.sortable ? styles.thSortable : '',
                  ]
                    .filter(Boolean)
                    .join(' ')}
                  style={{
                    width: col.width,
                    textAlign: col.align ?? 'left',
                  }}
                  onClick={col.sortable ? () => handleSortClick(col.key) : undefined}
                >
                  <span className={styles.thContent}>
                    {col.header}
                    {col.sortable && (
                      <SortIcon
                        size={12}
                        className={[
                          styles.sortIcon,
                          isSorted ? styles.sortIconActive : '',
                        ]
                          .filter(Boolean)
                          .join(' ')}
                        aria-hidden="true"
                      />
                    )}
                  </span>
                </th>
              );
            })}
          </tr>
        </thead>
        <tbody>
          {loading ? (
            <tr>
              <td colSpan={columns.length} className={styles.empty}>
                Loading…
              </td>
            </tr>
          ) : visibleData.length === 0 ? (
            <tr>
              <td colSpan={columns.length} className={styles.empty}>
                {emptyMessage}
              </td>
            </tr>
          ) : (
            visibleData.map((row) => {
              const rowProps = getRowProps?.(row);
              const mergedClassName = [
                styles.tr,
                onRowClick ? styles.clickable : '',
                rowProps?.className ?? '',
              ]
                .filter(Boolean)
                .join(' ');

              const handleClick = (event: MouseEvent<HTMLTableRowElement>) => {
                rowProps?.onClick?.(event);
                if (!event.defaultPrevented) {
                  onRowClick?.(row);
                }
              };

              return (
                <tr
                  key={rowKey(row)}
                  {...rowProps}
                  className={mergedClassName}
                  onClick={onRowClick || rowProps?.onClick ? handleClick : undefined}
                >
                  {columns.map((col) => (
                    <td
                      key={col.key}
                      className={styles.td}
                      style={{ textAlign: col.align ?? 'left' }}
                      onClick={col.key === 'actions' ? (e) => e.stopPropagation() : undefined}
                    >
                      {col.render(row)}
                    </td>
                  ))}
                </tr>
              );
            })
          )}
        </tbody>
      </table>
      {serverMode && serverTotal > 0 && onPageChange && (
        <Pagination
          page={serverPage}
          pageSize={pageSize}
          total={serverTotal}
          onPageChange={onPageChange}
          onPageSizeChange={
            onPageSizeChange
              ? (size) => {
                  setPageSize(size);
                  onPageSizeChange(size);
                }
              : pageSizeOptions
                ? (size) => {
                    setPageSize(size);
                    onPageChange(1);
                  }
                : undefined
          }
          pageSizeOptions={pageSizeOptions}
        />
      )}
      {clientPaginated && data.length > 0 && (
        <Pagination
          page={safeInternalPage}
          pageSize={pageSize}
          total={data.length}
          onPageChange={setInternalPage}
          onPageSizeChange={
            pageSizeOptions
              ? (size) => {
                  setPageSize(size);
                  setInternalPage(1);
                }
              : undefined
          }
          pageSizeOptions={pageSizeOptions}
        />
      )}
    </div>
  );
}