"use client";

import { useCallback, useEffect, useMemo, useState } from "react";
import { Pencil, Plus, Trash2, Users } from "lucide-react";
import Avatar from "@/components/Avatar";
import BadgeChip from "@/components/BadgeChip";
import ConfirmDialog from "@/components/ConfirmDialog";
import Modal from "@/components/Modal";
import { BADGE_ICONS } from "@/lib/badgeIcons";
import { toast } from "@/lib/toast";
import {
  apiAdminBadgeHolders,
  apiAdminCreateBadge,
  apiAdminDeleteBadge,
  apiAdminGrantBadge,
  apiAdminListBadges,
  apiAdminListUsers,
  apiAdminRevokeBadge,
  apiAdminUpdateBadge,
  type BadgeHolder,
  type BadgeInput,
  type BadgeWithHolders,
} from "@/lib/api";

/** 与后端 model.BadgeColors 同步的色板（CSS token 名） */
const BADGE_COLORS = ["gold", "accent", "ok", "danger", "info", "purple", "teal"] as const;
const MAX_NAME_RUNES = 16;

const runeCount = (s: string) => [...s].length;

export default function BadgesClient() {
  const [badges, setBadges] = useState<BadgeWithHolders[]>([]);
  const [loading, setLoading] = useState(true);

  // 编辑/新建表单
  const [editing, setEditing] = useState<BadgeWithHolders | null>(null);
  const [creating, setCreating] = useState(false);
  const [form, setForm] = useState<BadgeInput>({ name: "", icon: "medal", color: "accent" });
  const [saving, setSaving] = useState(false);

  // 删除确认
  const [deleting, setDeleting] = useState<BadgeWithHolders | null>(null);
  const [deletingBusy, setDeletingBusy] = useState(false);

  // 持有者面板
  const [holdersFor, setHoldersFor] = useState<BadgeWithHolders | null>(null);
  const [holders, setHolders] = useState<BadgeHolder[]>([]);
  const [holdersLoading, setHoldersLoading] = useState(false);
  const [userQuery, setUserQuery] = useState("");
  const [searchResults, setSearchResults] = useState<{ id: number; nickname: string; username: string; avatar: string }[]>([]);
  const [searching, setSearching] = useState(false);
  const [grantingId, setGrantingId] = useState<number | null>(null);

  const reload = useCallback(async () => {
    try {
      const res = await apiAdminListBadges();
      setBadges(res.badges ?? []);
    } catch (e) {
      toast(e instanceof Error ? e.message : "获取徽章列表失败");
    } finally {
      setLoading(false);
    }
  }, []);

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

  const openCreate = () => {
    setForm({ name: "", icon: "medal", color: "accent" });
    setEditing(null);
    setCreating(true);
  };

  const openEdit = (b: BadgeWithHolders) => {
    setForm({ name: b.name, icon: b.icon || "medal", color: b.color || "accent" });
    setCreating(false);
    setEditing(b);
  };

  const closeForm = () => {
    setCreating(false);
    setEditing(null);
  };

  const saveForm = async () => {
    if (saving) return;
    if (runeCount(form.name.trim()) < 1 || runeCount(form.name.trim()) > MAX_NAME_RUNES) {
      toast(`名称需 1–${MAX_NAME_RUNES} 字`);
      return;
    }
    setSaving(true);
    try {
      if (editing) {
        await apiAdminUpdateBadge(editing.id, form);
        toast("徽章已更新", "ok");
      } else {
        await apiAdminCreateBadge(form);
        toast("徽章已创建", "ok");
      }
      closeForm();
      await reload();
    } catch (e) {
      toast(e instanceof Error ? e.message : "保存失败");
    } finally {
      setSaving(false);
    }
  };

  const doDelete = async () => {
    if (!deleting || deletingBusy) return;
    setDeletingBusy(true);
    try {
      await apiAdminDeleteBadge(deleting.id);
      toast("徽章已删除", "ok");
      setDeleting(null);
      if (holdersFor?.id === deleting.id) setHoldersFor(null);
      await reload();
    } catch (e) {
      toast(e instanceof Error ? e.message : "删除失败");
    } finally {
      setDeletingBusy(false);
    }
  };

  const openHolders = async (b: BadgeWithHolders) => {
    setHoldersFor(b);
    setUserQuery("");
    setSearchResults([]);
    setHoldersLoading(true);
    try {
      const res = await apiAdminBadgeHolders(b.id);
      setHolders(res.holders ?? []);
    } catch (e) {
      toast(e instanceof Error ? e.message : "获取持有者失败");
      setHolders([]);
    } finally {
      setHoldersLoading(false);
    }
  };

  const searchUsers = async () => {
    const q = userQuery.trim();
    if (!q || searching) return;
    setSearching(true);
    try {
      const res = await apiAdminListUsers({ q, size: 8 });
      setSearchResults(
        (res.users ?? []).map((u) => ({
          id: u.id,
          nickname: u.nickname,
          username: u.username,
          avatar: u.avatar,
        })),
      );
    } catch (e) {
      toast(e instanceof Error ? e.message : "搜索用户失败");
    } finally {
      setSearching(false);
    }
  };

  const grant = async (userId: number) => {
    if (!holdersFor || grantingId != null) return;
    setGrantingId(userId);
    try {
      await apiAdminGrantBadge(holdersFor.id, userId);
      toast("已授予", "ok");
      await openHolders(holdersFor);
      await reload();
    } catch (e) {
      toast(e instanceof Error ? e.message : "授予失败");
    } finally {
      setGrantingId(null);
    }
  };

  const revoke = async (userId: number) => {
    if (!holdersFor) return;
    try {
      await apiAdminRevokeBadge(holdersFor.id, userId);
      toast("已撤销", "ok");
      await openHolders(holdersFor);
      await reload();
    } catch (e) {
      toast(e instanceof Error ? e.message : "撤销失败");
    }
  };

  const holdersHeldIds = useMemo(() => new Set(holders.map((h) => h.user_id)), [holders]);

  return (
    <div className="admin-settings-stack">
      <div className="flex items-center justify-between flex-wrap gap-3">
        <div>
          <h2 className="text-lg font-bold" style={{ color: "var(--ink)" }}>
            徽章管理
          </h2>
          <p className="meta text-sm mt-1">
            管理员自定义徽章：全站作者处展示前 2 枚，个人主页展示徽章墙；授予后用户会收到站内通知。
          </p>
        </div>
        <button type="button" className="btn btn-solid btn-sm" onClick={openCreate}>
          <Plus size={14} /> 新建徽章
        </button>
      </div>

      {loading ? (
        <p className="meta px-1 py-6">加载徽章列表…</p>
      ) : badges.length === 0 ? (
        <div className="panel text-center py-12">
          <p className="meta">还没有徽章，点击右上角“新建徽章”开始。</p>
        </div>
      ) : (
        <div className="panel p-0 overflow-hidden">
          {badges.map((b, i) => (
            <div
              key={b.id}
              className="flex items-center gap-3 px-4 py-3 flex-wrap"
              style={{ borderTop: i === 0 ? "none" : "1px solid var(--line)" }}
            >
              <BadgeChip badge={b} />
              <span className="meta text-xs">
                {b.icon || "medal"} · {b.color || "accent"} · {b.holders} 人持有
              </span>
              <span className="flex-1" />
              <button
                type="button"
                className="btn btn-line btn-sm"
                onClick={() => void openHolders(b)}
              >
                <Users size={13} /> 持有者
              </button>
              <button type="button" className="btn btn-line btn-sm" onClick={() => openEdit(b)}>
                <Pencil size={13} /> 编辑
              </button>
              <button
                type="button"
                className="btn btn-line btn-sm"
                style={{ color: "var(--danger)" }}
                onClick={() => setDeleting(b)}
              >
                <Trash2 size={13} /> 删除
              </button>
            </div>
          ))}
        </div>
      )}

      {/* 持有者面板 */}
      <Modal
        open={holdersFor != null}
        title={`持有者 · ${holdersFor?.name ?? ""}`}
        onClose={() => setHoldersFor(null)}
        maxWidthClass="max-w-lg"
      >
        <div className="flex gap-2 mb-4">
          <input
            value={userQuery}
            onChange={(e) => setUserQuery(e.target.value)}
            onKeyDown={(e) => {
              if (e.key === "Enter") void searchUsers();
            }}
            placeholder="输入用户名或昵称搜索"
            className="flex-1 min-w-0"
          />
          <button
            type="button"
            className="btn btn-line btn-sm shrink-0"
            disabled={searching || !userQuery.trim()}
            onClick={() => void searchUsers()}
          >
            {searching ? "搜索中…" : "搜索"}
          </button>
        </div>
        {searchResults.length > 0 && (
          <div className="mb-4">
            <p className="meta text-xs mb-1.5">搜索结果</p>
            <div className="flex flex-col gap-1">
              {searchResults.map((u) => (
                <div key={u.id} className="flex items-center gap-2.5 px-2 py-1.5 rounded-lg" style={{ background: "var(--panel-2)" }}>
                  <Avatar name={u.nickname || u.username} src={u.avatar || undefined} size={26} />
                  <span className="text-sm truncate" style={{ color: "var(--ink)" }}>
                    {u.nickname || u.username}
                    <span className="meta ml-1">@{u.username}</span>
                  </span>
                  <span className="flex-1" />
                  {holdersHeldIds.has(u.id) ? (
                    <span className="meta text-xs">已持有</span>
                  ) : (
                    <button
                      type="button"
                      className="btn btn-solid btn-sm"
                      disabled={grantingId === u.id}
                      onClick={() => void grant(u.id)}
                    >
                      {grantingId === u.id ? "授予中…" : "授予"}
                    </button>
                  )}
                </div>
              ))}
            </div>
          </div>
        )}
        <p className="meta text-xs mb-1.5">当前持有者（{holders.length}）</p>
        {holdersLoading ? (
          <p className="meta text-sm py-3">加载持有者…</p>
        ) : holders.length === 0 ? (
          <p className="meta text-sm py-3">暂无人持有。</p>
        ) : (
          <div className="flex flex-col gap-1 max-h-64 overflow-y-auto">
            {holders.map((h) => (
              <div key={h.user_id} className="flex items-center gap-2.5 px-2 py-1.5 rounded-lg" style={{ background: "var(--panel-2)" }}>
                <span className="text-sm truncate" style={{ color: "var(--ink)" }}>
                  {h.nickname || h.username}
                  <span className="meta ml-1">@{h.username}</span>
                </span>
                <span className="meta text-xs">{new Date(h.awarded_at).toLocaleDateString("zh-CN")} 授予</span>
                <span className="flex-1" />
                <button
                  type="button"
                  className="btn btn-line btn-sm"
                  style={{ color: "var(--danger)" }}
                  onClick={() => void revoke(h.user_id)}
                >
                  撤销
                </button>
              </div>
            ))}
          </div>
        )}
      </Modal>

      {/* 新建/编辑表单 */}
      <Modal
        open={creating || editing != null}
        title={editing ? "编辑徽章" : "新建徽章"}
        onClose={closeForm}
        maxWidthClass="max-w-md"
      >
        <div className="flex flex-col gap-4">
          <div>
            <label className="text-sm font-medium block mb-1.5" style={{ color: "var(--ink)" }}>
              名称（1–{MAX_NAME_RUNES} 字）
            </label>
            <input
              value={form.name}
              onChange={(e) => setForm((f) => ({ ...f, name: e.target.value }))}
              maxLength={MAX_NAME_RUNES * 2}
              placeholder="如：元老、技术之星"
            />
          </div>
          <div>
            <label className="text-sm font-medium block mb-1.5" style={{ color: "var(--ink)" }}>
              图标
            </label>
            <div className="grid grid-cols-8 gap-1.5">
              {Object.keys(BADGE_ICONS).map((key) => {
                const Icon = BADGE_ICONS[key];
                const active = form.icon === key;
                return (
                  <button
                    key={key}
                    type="button"
                    aria-label={key}
                    title={key}
                    onClick={() => setForm((f) => ({ ...f, icon: key }))}
                    className="h-9 rounded-lg inline-flex items-center justify-center transition-colors"
                    style={{
                      background: active ? "var(--accent-soft)" : "var(--panel-2)",
                      color: active ? "var(--accent)" : "var(--ink-2)",
                      outline: active ? "1.5px solid var(--accent)" : "none",
                    }}
                  >
                    <Icon size={16} />
                  </button>
                );
              })}
            </div>
          </div>
          <div>
            <label className="text-sm font-medium block mb-1.5" style={{ color: "var(--ink)" }}>
              颜色
            </label>
            <div className="flex gap-2 flex-wrap">
              {BADGE_COLORS.map((c) => {
                const active = form.color === c;
                return (
                  <button
                    key={c}
                    type="button"
                    aria-label={c}
                    title={c}
                    onClick={() => setForm((f) => ({ ...f, color: c }))}
                    className="px-3 h-8 rounded-full text-xs font-medium transition-colors"
                    style={{
                      background: `var(--${c}-soft)`,
                      color: `var(--${c})`,
                      outline: active ? "1.5px solid var(--ink)" : "1.5px solid transparent",
                    }}
                  >
                    {c}
                  </button>
                );
              })}
            </div>
          </div>
          <div>
            <p className="meta text-xs mb-1.5">预览</p>
            <BadgeChip badge={{ name: form.name.trim() || "徽章名称", icon: form.icon, color: form.color }} />
          </div>
        </div>
        <div className="flex justify-end gap-2 mt-5">
          <button type="button" className="btn btn-line btn-sm" onClick={closeForm}>
            取消
          </button>
          <button
            type="button"
            className="btn btn-solid btn-sm"
            disabled={saving || runeCount(form.name.trim()) === 0}
            onClick={() => void saveForm()}
          >
            {saving ? "保存中…" : "保存"}
          </button>
        </div>
      </Modal>

      {/* 删除确认 */}
      <ConfirmDialog
        open={deleting != null}
        title="删除徽章"
        message={`确定删除徽章「${deleting?.name ?? ""}」？该徽章的全部授予记录（${deleting?.holders ?? 0} 人）会被一并删除，用户主页将不再显示。`}
        confirmLabel="删除"
        danger
        busy={deletingBusy}
        onCancel={() => setDeleting(null)}
        onConfirm={() => void doDelete()}
      />
    </div>
  );
}