"use client";

import { useCallback, useEffect, useRef, useState } from "react";
import Link from "next/link";
import { ChevronDown, ChevronUp, ChevronsUpDown, History, SlidersHorizontal, Users as UsersIcon } from "lucide-react";
import {
  apiAdminAdjustUserPoints,
  apiAdminListUsers,
  apiAdminUserPointLedger,
  type AdminUser,
  type PointLedgerItem,
} from "@/lib/api";
import Avatar from "@/components/Avatar";
import LevelBadge from "@/components/LevelBadge";
import Modal from "@/components/Modal";
import { AdminPageHeader, AdminPager, AdminSearchField, AdminStepper } from "@/components/admin";
import { pointReasonLabel } from "@/lib/points";
import { formatRelative } from "@/lib/format";
import { toast } from "@/lib/toast";

const PAGE_SIZE = 20;
const MAX_DELTA = 100000; // 与后端 adminAdjustMaxDelta 一致
const fmt = (n?: number) => (Number(n) || 0).toLocaleString("zh-CN");

type PointsSortKey = "id" | "points" | "total_points";

/** 表头排序按钮：未激活显示双向箭头，激活显示单向箭头并高亮 */
function SortHeader({
  label,
  active,
  dir,
  onClick,
}: {
  label: string;
  active: boolean;
  dir: "asc" | "desc";
  onClick: () => void;
}) {
  return (
    <button
      type="button"
      className="inline-flex items-center gap-1 transition-colors hover:text-[var(--accent)]"
      style={{ color: active ? "var(--accent)" : "inherit" }}
      onClick={onClick}
      aria-label={`按${label}排序`}
    >
      {label}
      {active ? (
        dir === "asc" ? (
          <ChevronUp size={13} />
        ) : (
          <ChevronDown size={13} />
        )
      ) : (
        <ChevronsUpDown size={13} className="opacity-50" />
      )}
    </button>
  );
}

/**
 * 用户积分标签：搜索用户 → 余额/累计/等级一览；行内「调整」弹窗（加分计累计可升级，
 * 扣分仅扣余额不降级，理由必填）与「流水」弹窗（分页查看该用户积分流水）。
 */
export default function UserPointsTab() {
  const [keyword, setKeyword] = useState("");
  const [appliedQ, setAppliedQ] = useState("");
  const [page, setPage] = useState(1);
  const [users, setUsers] = useState<AdminUser[]>([]);
  const [total, setTotal] = useState(0);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState("");
  const [loaded, setLoaded] = useState(false);
  const [sort, setSort] = useState<PointsSortKey>("id");
  const [dir, setDir] = useState<"asc" | "desc">("desc");

  const [adjustTarget, setAdjustTarget] = useState<AdminUser | null>(null);
  const [ledgerTarget, setLedgerTarget] = useState<AdminUser | null>(null);

  const seqRef = useRef(0);
  const debounceRef = useRef<ReturnType<typeof setTimeout> | null>(null);
  // 排序走 ref：load 身份保持稳定，防抖搜索与切页自动沿用当前排序
  const sortRef = useRef<{ sort: PointsSortKey; dir: "asc" | "desc" }>({ sort: "id", dir: "desc" });

  const load = useCallback(async (opts: { page: number; q: string }) => {
    const seq = ++seqRef.current;
    setLoading(true);
    try {
      const res = await apiAdminListUsers({
        page: opts.page,
        size: PAGE_SIZE,
        q: opts.q || undefined,
        sort: sortRef.current.sort,
        order: sortRef.current.dir,
      });
      if (seq !== seqRef.current) return;
      setUsers(res.users);
      setTotal(res.total);
      setPage(opts.page);
      setAppliedQ(opts.q);
      setError("");
      setLoaded(true);
    } catch (e) {
      if (seq !== seqRef.current) return;
      setError(e instanceof Error ? e.message : "获取用户列表失败");
    } finally {
      if (seq === seqRef.current) setLoading(false);
    }
  }, []);

  useEffect(() => {
    void load({ page: 1, q: "" });
  }, [load]);

  // 搜索 400ms 防抖（对齐 UsersAdmin）
  const onKeywordChange = useCallback(
    (v: string) => {
      setKeyword(v);
      if (debounceRef.current) clearTimeout(debounceRef.current);
      debounceRef.current = setTimeout(() => {
        void load({ page: 1, q: v.trim() });
      }, 400);
    },
    [load]
  );

  const patchUser = useCallback((id: number, patch: Partial<AdminUser>) => {
    setUsers((prev) => prev.map((u) => (u.id === id ? { ...u, ...patch } : u)));
  }, []);

  // 切换排序：点未激活列 → 该列降序；点已激活列 → 升降切换；始终回到第 1 页
  const toggleSort = useCallback(
    (key: PointsSortKey) => {
      const cur = sortRef.current;
      const next = cur.sort === key ? { sort: key, dir: cur.dir === "desc" ? ("asc" as const) : ("desc" as const) } : { sort: key, dir: "desc" as const };
      sortRef.current = next;
      setSort(next.sort);
      setDir(next.dir);
      void load({ page: 1, q: appliedQ });
    },
    [load, appliedQ]
  );

  return (
    <div>
      <AdminPageHeader
        icon={UsersIcon}
        title="用户积分"
        description="查看与管理用户积分：加分计入累计获得（可升级），扣分仅扣余额不降级"
      />

      <div className="mb-4 max-w-xs">
        <AdminSearchField
          value={keyword}
          onChange={onKeywordChange}
          placeholder="搜索用户名 / 昵称 / 邮箱"
          ariaLabel="搜索用户"
        />
      </div>

      <div className="panel p-0 overflow-hidden">
        <div className="overflow-x-auto">
          <table className="w-full text-[13px]" style={{ borderCollapse: "collapse" }}>
            <thead>
              <tr style={{ borderBottom: "1px solid var(--line)" }}>
                <th className="px-4 py-2.5 text-left font-medium" style={{ color: "var(--ink-3)" }}>
                  用户
                </th>
                <th className="px-4 py-2.5 text-right font-medium" style={{ color: "var(--ink-3)" }}>
                  <SortHeader label="余额" active={sort === "points"} dir={dir} onClick={() => toggleSort("points")} />
                </th>
                <th className="px-4 py-2.5 text-right font-medium" style={{ color: "var(--ink-3)" }}>
                  <SortHeader label="累计获得" active={sort === "total_points"} dir={dir} onClick={() => toggleSort("total_points")} />
                </th>
                <th className="px-4 py-2.5 text-left font-medium" style={{ color: "var(--ink-3)" }}>
                  等级
                </th>
                <th className="px-4 py-2.5 text-right font-medium" style={{ color: "var(--ink-3)" }}>
                  操作
                </th>
              </tr>
            </thead>
            <tbody>
              {users.map((u) => (
                <tr key={u.id} style={{ borderBottom: "1px solid var(--line)" }}>
                  <td className="px-4 py-2.5">
                    <Link href={`/u/${u.id}`} className="flex items-center gap-2.5 min-w-0 group">
                      <Avatar name={u.nickname || u.username} src={u.avatar || undefined} size={30} />
                      <span className="min-w-0">
                        <span
                          className="block truncate text-[13.5px] font-medium group-hover:text-[var(--accent)] transition-colors"
                          style={{ color: "var(--ink)" }}
                        >
                          {u.nickname || u.username}
                        </span>
                        <span className="block meta text-[11.5px] truncate">@{u.username}</span>
                      </span>
                    </Link>
                  </td>
                  <td className="px-4 py-2.5 text-right tabular-nums" style={{ color: "var(--ink)" }}>
                    {fmt(u.points)}
                  </td>
                  <td className="px-4 py-2.5 text-right tabular-nums" style={{ color: "var(--ink-2)" }}>
                    {fmt(u.total_points)}
                  </td>
                  <td className="px-4 py-2.5">
                    <LevelBadge level={u.level} />
                  </td>
                  <td className="px-4 py-2.5">
                    <div className="flex items-center justify-end gap-2">
                      <button
                        type="button"
                        className="btn btn-line btn-sm"
                        onClick={() => setLedgerTarget(u)}
                      >
                        <History size={13} /> 流水
                      </button>
                      <button
                        type="button"
                        className="btn btn-line btn-sm"
                        onClick={() => setAdjustTarget(u)}
                      >
                        <SlidersHorizontal size={13} /> 调整
                      </button>
                    </div>
                  </td>
                </tr>
              ))}
            </tbody>
          </table>
        </div>
        {loading ? <p className="meta text-center py-4">加载中…</p> : null}
        {!loading && error ? <p className="text-center py-6 text-[13px]" style={{ color: "var(--danger)" }}>{error}</p> : null}
        {!loading && !error && loaded && users.length === 0 ? (
          <p className="meta text-center py-10">没有匹配的用户</p>
        ) : null}
      </div>

      {!error && users.length > 0 ? (
        <div className="mt-4">
          <AdminPager page={page} total={total} pageSize={PAGE_SIZE} loading={loading} onChange={(p) => void load({ page: p, q: appliedQ })} />
        </div>
      ) : null}

      {adjustTarget ? (
        <AdjustModal
          user={adjustTarget}
          onClose={() => setAdjustTarget(null)}
          onAdjusted={(balance, totalPoints, level) => {
            patchUser(adjustTarget.id, { points: balance, total_points: totalPoints, level });
          }}
        />
      ) : null}
      {ledgerTarget ? (
        <LedgerModal user={ledgerTarget} onClose={() => setLedgerTarget(null)} />
      ) : null}
    </div>
  );
}

/** 调整弹窗：方向（加/减）+ 数量 + 理由；成功后回填余额/累计/等级 */
function AdjustModal({
  user,
  onClose,
  onAdjusted,
}: {
  user: AdminUser;
  onClose: () => void;
  onAdjusted: (balance: number, totalPoints: number, level: number) => void;
}) {
  const [dir, setDir] = useState<"add" | "sub">("add");
  const [amount, setAmount] = useState(10);
  const [note, setNote] = useState("");
  const [saving, setSaving] = useState(false);

  const submit = async () => {
    if (saving) return;
    if (!Number.isInteger(amount) || amount < 1 || amount > MAX_DELTA) {
      toast(`积分数量须为 1–${MAX_DELTA} 的整数`);
      return;
    }
    const trimmed = note.trim();
    if (!trimmed) {
      toast("请填写调整理由");
      return;
    }
    setSaving(true);
    try {
      const delta = dir === "add" ? amount : -amount;
      const res = await apiAdminAdjustUserPoints(user.id, delta, trimmed);
      onAdjusted(res.balance, res.total_points, res.level);
      toast(
        `已${dir === "add" ? "增加" : "扣减"} ${fmt(amount)} 积分：余额 ${fmt(res.balance)}，当前 Lv.${res.level}`,
        "ok"
      );
      onClose();
    } catch (e) {
      toast(e instanceof Error ? e.message : "积分调整失败");
    } finally {
      setSaving(false);
    }
  };

  return (
    <Modal
      open
      title={`调整积分 - ${user.nickname || user.username}`}
      description={`当前余额 ${fmt(user.points)} · 累计获得 ${fmt(user.total_points)} · Lv.${user.level ?? 1}`}
      onClose={onClose}
      busy={saving}
      footer={
        <>
          <button type="button" className="btn btn-line btn-sm" onClick={onClose} disabled={saving}>
            取消
          </button>
          <button type="button" className="btn btn-primary btn-sm" onClick={() => void submit()} disabled={saving}>
            {saving ? "提交中…" : "确认调整"}
          </button>
        </>
      }
    >
      <div className="flex flex-col gap-4">
        <div>
          <p className="text-xs mb-1.5" style={{ color: "var(--ink-2)" }}>
            方向
          </p>
          <div className="flex gap-2">
            <button
              type="button"
              onClick={() => setDir("add")}
              className={`btn btn-sm flex-1 ${dir === "add" ? "btn-primary" : "btn-line"}`}
            >
              增加
            </button>
            <button
              type="button"
              onClick={() => setDir("sub")}
              className={`btn btn-sm flex-1 ${dir === "sub" ? "btn-danger" : "btn-line"}`}
            >
              扣减
            </button>
          </div>
          <p className="meta text-[11.5px] mt-1.5">
            {dir === "add"
              ? "加分同时计入累计获得，可能触发升级"
              : "扣分仅扣减余额，不改变累计获得与等级"}
          </p>
        </div>

        <div>
          <p className="text-xs mb-1.5" style={{ color: "var(--ink-2)" }}>
            数量（1–{MAX_DELTA}）
          </p>
          <AdminStepper
            value={amount}
            onChange={setAmount}
            min={1}
            max={MAX_DELTA}
            unit="分"
            ariaLabel="调整数量"
            disabled={saving}
          />
        </div>

        <div>
          <p className="text-xs mb-1.5" style={{ color: "var(--ink-2)" }}>
            调整理由（必填，写入积分流水）
          </p>
          <textarea
            value={note}
            onChange={(e) => setNote(e.target.value)}
            maxLength={200}
            rows={3}
            className="w-full px-3 py-2 text-[13px] rounded-[var(--r-sm)] outline-none focus:border-[var(--accent)] transition-colors"
            style={{ background: "var(--panel-2)", border: "1px solid var(--line-2)", color: "var(--ink)" }}
            placeholder="例如：活动奖励补偿 / 违规扣减"
          />
        </div>
      </div>
    </Modal>
  );
}

/** 流水弹窗：懒加载分页查询该用户积分流水 */
function LedgerModal({ user, onClose }: { user: AdminUser; onClose: () => void }) {
  const [items, setItems] = useState<PointLedgerItem[]>([]);
  const [total, setTotal] = useState(0);
  const [page, setPage] = useState(1);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState("");

  const load = useCallback(async (p: number) => {
    setLoading(true);
    try {
      const res = await apiAdminUserPointLedger(user.id, p);
      setItems(res.items);
      setTotal(res.total);
      setPage(p);
      setError("");
    } catch (e) {
      setError(e instanceof Error ? e.message : "获取积分流水失败");
    } finally {
      setLoading(false);
    }
  }, [user.id]);

  useEffect(() => {
    void load(1);
  }, [load]);

  return (
    <Modal
      open
      title={`积分流水 - ${user.nickname || user.username}`}
      description={`余额 ${fmt(user.points)} · 累计获得 ${fmt(user.total_points)} · 共 ${fmt(total)} 条`}
      onClose={onClose}
      maxWidthClass="max-w-2xl"
    >
      {loading && items.length === 0 ? (
        <p className="meta text-center py-8">加载中…</p>
      ) : error ? (
        <p className="text-center py-8 text-[13px]" style={{ color: "var(--danger)" }}>
          {error}
        </p>
      ) : items.length === 0 ? (
        <p className="meta text-center py-8">暂无积分流水</p>
      ) : (
        <>
          <ul className="flex flex-col max-h-[50vh] overflow-y-auto">
            {items.map((it) => {
              const delta = Number(it.delta) || 0;
              return (
                <li
                  key={it.id}
                  className="flex items-center gap-3 py-2.5"
                  style={{ borderBottom: "1px solid var(--line)" }}
                >
                  <span
                    className="shrink-0 inline-flex items-center rounded-full px-2 py-0.5 text-[11px] font-medium select-none"
                    style={{
                      background: delta > 0 ? "var(--ok-soft)" : "var(--danger-soft)",
                      color: delta > 0 ? "var(--ok)" : "var(--danger)",
                    }}
                  >
                    {delta > 0 ? `+${fmt(delta)}` : fmt(delta)}
                  </span>
                  <span className="min-w-0 flex-1">
                    <span className="block text-[13px] truncate" style={{ color: "var(--ink)" }}>
                      {pointReasonLabel(it.reason)}
                      {it.note ? (
                        <span className="ml-1.5 text-[12px]" style={{ color: "var(--ink-3)" }}>
                          {it.note}
                        </span>
                      ) : null}
                    </span>
                    <span className="block meta text-[11.5px] mt-0.5">
                      变动后余额 {fmt(it.balance)} · {formatRelative(it.created_at)}
                    </span>
                  </span>
                </li>
              );
            })}
          </ul>
          <div className="mt-4">
            <AdminPager
              page={page}
              total={total}
              pageSize={20}
              loading={loading}
              onChange={(p) => void load(p)}
            />
          </div>
        </>
      )}
    </Modal>
  );
}