import { ChevronRight, type LucideIcon } from "lucide-react";
import { Fragment, type ReactNode, useEffect, useMemo, useState } from "react";
import { Button } from "~/components/ui/button.tsx";
import { cn } from "~/lib/utils.ts";
import { groupRows, readCollapsed, toggleCollapsed, writeCollapsed } from "./data-table-groups.ts";
import { EmptyState, ErrorState, LoadingState } from "./empty-state.tsx";

export type DataColumn<T> = {
  /** 列 key(React key 用) */
  key: string;
  header: ReactNode;
  cell: (row: T) => ReactNode;
  /** 窄屏隐藏该列,避免横向溢出 */
  hideBelow?: "sm" | "md" | "lg";
  align?: "left" | "right";
  className?: string;
};

/** 分组:按键把行归组,组头可折叠并显示计数;给 storageKey 时在本浏览器记住折叠的组 */
export type DataGroupBy<T> = {
  key: (row: T) => string;
  /** 组头文字,缺省为 key */
  label?: (key: string, rows: T[]) => ReactNode;
  /** 组顺序,缺省按首次出现 */
  order?: (a: string, b: string) => number;
  storageKey?: string;
};

const HIDE: Record<NonNullable<DataColumn<unknown>["hideBelow"]>, string> = {
  sm: "hidden sm:table-cell",
  md: "hidden md:table-cell",
  lg: "hidden lg:table-cell",
};

/**
 * 数据表:内置 loading / error / empty 三态与"加载更多"游标翻页。
 * 外层自带 pg-slab 卡片(plain 时不带);表格在卡片内横向滚动,页面本身不溢出。
 *
 *   <DataTable columns={cols} rows={q.data?.items} rowKey={(r) => r.id}
 *     loading={q.isPending} error={q.error} onRetry={q.refetch}
 *     empty={{ title: "还没有记录" }} onRowClick={(r) => open(r.id)}
 *     hasMore={!!next} onLoadMore={...} loadingMore={...} />
 */
export function DataTable<T>({
  columns,
  rows,
  rowKey,
  loading = false,
  error,
  onRetry,
  empty,
  onRowClick,
  selectedKey,
  hasMore = false,
  onLoadMore,
  loadingMore = false,
  plain = false,
  groupBy,
  className,
}: {
  columns: DataColumn<T>[];
  rows: T[] | undefined;
  rowKey: (row: T) => string;
  loading?: boolean;
  error?: unknown;
  onRetry?: () => void;
  empty?: { title: string; description?: ReactNode; icon?: LucideIcon; action?: ReactNode };
  onRowClick?: (row: T) => void;
  selectedKey?: string | null;
  hasMore?: boolean;
  onLoadMore?: () => void;
  loadingMore?: boolean;
  plain?: boolean;
  groupBy?: DataGroupBy<T>;
  className?: string;
}) {
  const storageKey = groupBy?.storageKey;
  const [collapsed, setCollapsed] = useState<Set<string>>(() => new Set());
  // 折叠态在挂载后读(服务端渲染时没有 localStorage,首屏一律展开)
  useEffect(() => {
    const saved = readCollapsed(storageKey);
    if (saved) setCollapsed(saved);
  }, [storageKey]);
  const groupKey = groupBy?.key;
  const groupOrder = groupBy?.order;
  const groups = useMemo(
    () => (groupKey && rows ? groupRows(rows, groupKey, groupOrder) : null),
    [rows, groupKey, groupOrder],
  );
  const toggleGroup = (k: string) =>
    setCollapsed((prev) => {
      const next = toggleCollapsed(prev, k);
      writeCollapsed(storageKey, next);
      return next;
    });

  const renderRow = (row: T) => {
    const key = rowKey(row);
    return (
      <tr
        key={key}
        onClick={onRowClick ? () => onRowClick(row) : undefined}
        onKeyDown={
          onRowClick
            ? (e) => {
                if (e.key === "Enter" || e.key === " ") {
                  e.preventDefault();
                  onRowClick(row);
                }
              }
            : undefined
        }
        tabIndex={onRowClick ? 0 : undefined}
        aria-selected={selectedKey != null ? selectedKey === key : undefined}
        className={cn(
          "border-b border-border/60 transition-colors duration-micro last:border-b-0",
          onRowClick && "cursor-pointer outline-none hover:bg-foreground/[0.04] focus-visible:bg-foreground/[0.06]",
          selectedKey === key && "bg-foreground/[0.05]",
        )}
      >
        {columns.map((c) => (
          <td
            key={c.key}
            className={cn(
              "px-4 py-2.5 align-middle",
              c.align === "right" && "text-right",
              c.hideBelow && HIDE[c.hideBelow],
              c.className,
            )}
          >
            {c.cell(row)}
          </td>
        ))}
      </tr>
    );
  };

  let body: ReactNode;
  if (loading && !rows) {
    body = <LoadingState rows={5} className="p-4" />;
  } else if (error && !rows) {
    body = <ErrorState plain error={error} onRetry={onRetry} />;
  } else if (!rows || rows.length === 0) {
    body = (
      <EmptyState
        plain
        icon={empty?.icon}
        title={empty?.title ?? "暂无数据"}
        description={empty?.description}
        action={empty?.action}
        className="py-12"
      />
    );
  } else {
    body = (
      <div className="overflow-x-auto">
        <table className="w-full text-left text-sm">
          <thead>
            <tr className="border-b border-border">
              {columns.map((c) => (
                <th
                  key={c.key}
                  scope="col"
                  className={cn(
                    "px-4 py-2.5 text-meta font-medium whitespace-nowrap text-muted-foreground",
                    c.align === "right" && "text-right",
                    c.hideBelow && HIDE[c.hideBelow],
                    c.className,
                  )}
                >
                  {c.header}
                </th>
              ))}
            </tr>
          </thead>
          {groups ? (
            groups.map((g) => {
              const open = !collapsed.has(g.key);
              return (
                <Fragment key={`g:${g.key}`}>
                  <tbody>
                    <tr className="border-b border-border/60 bg-foreground/[0.02]">
                      <th scope="colgroup" colSpan={columns.length} className="p-0 text-left font-normal">
                        <button
                          type="button"
                          aria-expanded={open}
                          onClick={() => toggleGroup(g.key)}
                          className="flex w-full items-center gap-2 px-4 py-2 text-meta text-muted-foreground outline-none hover:text-foreground focus-visible:bg-foreground/[0.06]"
                        >
                          <ChevronRight
                            aria-hidden
                            className={cn(
                              "h-3.5 w-3.5 shrink-0 transition-transform duration-micro",
                              open && "rotate-90",
                            )}
                          />
                          <span className="min-w-0 truncate font-medium text-foreground">
                            {groupBy?.label ? groupBy.label(g.key, g.rows) : g.key}
                          </span>
                          <span className="tabular-nums">{g.rows.length}</span>
                        </button>
                      </th>
                    </tr>
                  </tbody>
                  {open ? <tbody>{g.rows.map(renderRow)}</tbody> : null}
                </Fragment>
              );
            })
          ) : (
            <tbody>{rows.map(renderRow)}</tbody>
          )}
        </table>
      </div>
    );
  }

  return (
    <div className={cn("min-w-0 overflow-hidden rounded-xl", !plain && "pg-slab", className)}>
      {body}
      {rows && rows.length > 0 && (hasMore || error) ? (
        <div className="flex items-center justify-center gap-3 border-t border-border/60 px-4 py-3">
          {error ? (
            <span className="text-meta text-destructive">{String((error as Error).message ?? error)}</span>
          ) : null}
          {hasMore && onLoadMore ? (
            <Button variant="outline" size="sm" onClick={onLoadMore} disabled={loadingMore}>
              {loadingMore ? "加载中…" : "加载更多"}
            </Button>
          ) : null}
        </div>
      ) : null}
    </div>
  );
}