"use client";

import { useCallback, useEffect, useMemo, useRef, useState } from "react";
import { Award, ChevronRight, Plus, Trash2, Users } from "lucide-react";
import Avatar from "@/components/Avatar";
import BadgeChip from "@/components/BadgeChip";
import ConfirmDialog from "@/components/ConfirmDialog";
import AdminEmpty from "@/components/admin/AdminEmpty";
import AdminPageHeader from "@/components/admin/AdminPageHeader";
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);

  // 主从布局：左侧列表选中项 / 右侧详情（编辑表单 + 持有者）
  const [selectedId, setSelectedId] = useState<number | 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 [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 detailRef = useRef<HTMLDivElement>(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 selected = useMemo(
    () => badges.find((b) => b.id === selectedId) ?? null,
    [badges, selectedId],
  );

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

  const selectBadge = (b: BadgeWithHolders, scroll = true) => {
    setCreating(false);
    setSelectedId(b.id);
    // 窄屏单列时，点选后滚动到右侧详情
    if (scroll && window.matchMedia("(max-width: 1023px)").matches) {
      detailRef.current?.scrollIntoView({ behavior: "smooth", block: "start" });
    }
  };

  // 首次加载完成后自动选中第一个徽章（删除刷新期间跳过，避免选中已删除项）
  useEffect(() => {
    if (loading || creating || deletingBusy || selectedId != null) return;
    if (badges.length > 0) selectBadge(badges[0], false);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [loading, badges, creating, deletingBusy, selectedId]);

  // 选中项被删除时回落到第一个（或清空）
  useEffect(() => {
    if (creating || loading || selectedId == null) return;
    if (!badges.some((b) => b.id === selectedId)) {
      setSelectedId(badges.length > 0 ? badges[0].id : null);
    }
  }, [badges, selectedId, creating, loading]);

  // 选中变化：同步表单草稿并重置搜索（badges 刻意不作为依赖，避免授予/撤销刷新时清掉搜索结果与未保存草稿）
  useEffect(() => {
    if (creating || selectedId == null) return;
    const sel = badges.find((b) => b.id === selectedId);
    if (!sel) return;
    setForm({ name: sel.name, icon: sel.icon || "medal", color: sel.color || "accent" });
    setUserQuery("");
    setSearchResults([]);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [selectedId, creating]);

  // 持有者加载：选中变化或徽章列表刷新（授予/撤销后）重新拉取
  useEffect(() => {
    if (creating || selectedId == null) {
      setHolders([]);
      setHoldersLoading(false);
      return;
    }
    let alive = true;
    setHoldersLoading(true);
    apiAdminBadgeHolders(selectedId)
      .then((res) => {
        if (alive) setHolders(res.holders ?? []);
      })
      .catch((e) => {
        if (alive) {
          toast(e instanceof Error ? e.message : "获取持有者失败");
          setHolders([]);
        }
      })
      .finally(() => {
        if (alive) setHoldersLoading(false);
      });
    return () => {
      alive = false;
    };
  }, [selectedId, creating, badges]);

  const formDirty =
    creating ||
    (selected != null &&
      (form.name !== selected.name ||
        form.icon !== (selected.icon || "medal") ||
        form.color !== (selected.color || "accent")));

  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 (creating) {
        const created = await apiAdminCreateBadge(form);
        toast("徽章已创建", "ok");
        setCreating(false);
        setSelectedId(created.id);
      } else if (selected) {
        await apiAdminUpdateBadge(selected.id, form);
        toast("徽章已更新", "ok");
      }
      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 (selectedId === deleting.id) setSelectedId(null);
      await reload();
    } catch (e) {
      toast(e instanceof Error ? e.message : "删除失败");
    } finally {
      setDeletingBusy(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 (!selected || grantingId != null) return;
    setGrantingId(userId);
    try {
      await apiAdminGrantBadge(selected.id, userId);
      toast("已授予", "ok");
      await reload();
    } catch (e) {
      toast(e instanceof Error ? e.message : "授予失败");
    } finally {
      setGrantingId(null);
    }
  };

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

  // 授予/撤销后 reload 刷新持有数；这里再同步持有者列表
  useEffect(() => {
    if (selectedId == null || creating) return;
    setHoldersLoading(true);
    apiAdminBadgeHolders(selectedId)
      .then((res) => setHolders(res.holders ?? []))
      .catch(() => setHolders([]))
      .finally(() => setHoldersLoading(false));
  }, [badges, selectedId, creating]);

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

  const nameOk = runeCount(form.name.trim()) >= 1 && runeCount(form.name.trim()) <= MAX_NAME_RUNES;

  return (
    <div className="admin-settings-stack">
      <AdminPageHeader
        icon={Award}
        title="徽章管理"
        description="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。"
        actions={
          <button type="button" className="btn btn-primary btn-sm" onClick={openCreate}>
            <Plus size={14} /> 新建徽章
          </button>
        }
      />

      <div className="grid gap-5 items-start lg:grid-cols-2">
        {/* 左半屏：徽章列表 */}
        <section className="panel p-0 overflow-hidden" aria-label="徽章列表">
          <div
            className="flex items-center justify-between gap-2 px-4 py-3"
            style={{ borderBottom: "1px solid var(--line)" }}
          >
            <p className="text-[13.5px] font-semibold" style={{ color: "var(--ink)" }}>
              全部徽章
            </p>
            {!loading && badges.length > 0 && (
              <span className="meta text-xs tabular-nums">{badges.length} 枚</span>
            )}
          </div>

          {loading ? (
            <p className="meta px-4 py-6">加载徽章列表…</p>
          ) : badges.length === 0 ? (
            <div className="px-4 py-12 text-center">
              <p className="meta">还没有徽章，点击右上角“新建徽章”开始。</p>
            </div>
          ) : (
            <ul>
              {badges.map((b, i) => {
                const active = !creating && b.id === selectedId;
                return (
                  <li key={b.id}>
                    <button
                      type="button"
                      onClick={() => selectBadge(b)}
                      aria-current={active ? "true" : undefined}
                      className="w-full flex items-center gap-3 px-4 py-3 text-left transition-colors hover:bg-[var(--panel-2)] focus-visible:bg-[var(--panel-2)]"
                      style={{
                        borderTop: i === 0 ? "none" : "1px solid var(--line)",
                        background: active ? "var(--accent-soft)" : undefined,
                      }}
                    >
                      <BadgeChip badge={b} />
                      <span className="meta text-xs">{b.holders} 人持有</span>
                      <span className="flex-1" />
                      <ChevronRight
                        size={14}
                        className="shrink-0 transition-transform duration-200"
                        style={{
                          color: active ? "var(--accent)" : "var(--ink-3)",
                          transform: active ? "translateX(2px)" : "none",
                        }}
                        aria-hidden
                      />
                    </button>
                  </li>
                );
              })}
            </ul>
          )}
        </section>

        {/* 右半屏：编辑表单 + 持有者 */}
        <div ref={detailRef} className="flex flex-col gap-5 min-w-0">
          {creating || selected ? (
            <>
              {/* 编辑/新建表单 */}
              <section className="panel overflow-hidden">
                <div
                  className="flex items-center justify-between gap-3 px-4 py-3.5 sm:px-5"
                  style={{ borderBottom: "1px solid var(--line)" }}
                >
                  <p className="text-[15px] font-semibold" style={{ color: "var(--ink)" }}>
                    {creating ? "新建徽章" : "编辑徽章"}
                  </p>
                  {!creating && selected && (
                    <button
                      type="button"
                      className="btn btn-line btn-sm"
                      style={{ color: "var(--danger)" }}
                      onClick={() => setDeleting(selected)}
                    >
                      <Trash2 size={13} /> 删除
                    </button>
                  )}
                </div>
                <div className="flex flex-col gap-4 px-4 py-4 sm:px-5">
                  <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 px-4 py-3 sm:px-5"
                  style={{ borderTop: "1px solid var(--line)" }}
                >
                  {creating ? (
                    <button type="button" className="btn btn-line btn-sm" onClick={() => setCreating(false)}>
                      取消
                    </button>
                  ) : (
                    <button
                      type="button"
                      className="btn btn-line btn-sm"
                      disabled={!formDirty || saving}
                      onClick={() => selected && setForm({ name: selected.name, icon: selected.icon || "medal", color: selected.color || "accent" })}
                    >
                      重置
                    </button>
                  )}
                  <button
                    type="button"
                    className="btn btn-primary btn-sm"
                    disabled={saving || !nameOk || (!creating && !formDirty)}
                    onClick={() => void saveForm()}
                  >
                    {saving ? "保存中…" : creating ? "创建" : "保存修改"}
                  </button>
                </div>
              </section>

              {/* 持有者管理 */}
              {!creating && selected && (
                <section className="panel overflow-hidden">
                  <div
                    className="flex items-center gap-2.5 px-4 py-3.5 sm:px-5"
                    style={{ borderBottom: "1px solid var(--line)" }}
                  >
                    <span
                      className="w-8 h-8 rounded-lg flex items-center justify-center shrink-0"
                      style={{ background: "var(--accent-soft)", color: "var(--accent)" }}
                      aria-hidden
                    >
                      <Users size={16} />
                    </span>
                    <p className="text-[15px] font-semibold" style={{ color: "var(--ink)" }}>
                      持有者
                      <span className="meta ml-2 text-[12px] font-normal tabular-nums">{holders.length} 人</span>
                    </p>
                  </div>
                  <div className="px-4 py-4 sm:px-5">
                    <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-primary 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-72 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>
                    )}
                  </div>
                </section>
              )}
            </>
          ) : (
            <section className="panel">
              <AdminEmpty
                icon={<Award size={22} />}
                title={loading ? "加载中…" : "从左侧选择一个徽章"}
                description={loading ? undefined : "选中后可在此编辑名称、图标与颜色，管理持有者"}
              />
            </section>
          )}
        </div>
      </div>

      {/* 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>
  );
}