"use client";

import {
  useCallback,
  useEffect,
  useRef,
  useState,
  type CSSProperties,
  type ReactNode,
} from "react";
import { Loader2, MessageCircle, MessagesSquare, Undo2, Users } from "lucide-react";
import {
  apiAdminChatMessages,
  apiAdminRecallChatMessage,
  type AdminChatMessage,
  type AdminChatRoomType,
} from "@/lib/api";
import { formatRelative } from "@/lib/format";
import { toast } from "@/lib/toast";
import Avatar from "@/components/Avatar";
import AutolinkText from "@/components/AutolinkText";
import ConfirmDialog from "@/components/ConfirmDialog";
import {
  AdminEmpty,
  AdminPageHeader,
  AdminPager,
  AdminSearchField,
  AdminStatusChip,
} from "@/components/admin";

const PAGE_SIZE = 15;
const CLAMP_TOGGLE_CHARS = 90;
const pagerClass = "admin-content-col-pager px-3 sm:px-3.5";

type MsgKind = AdminChatRoomType;

function needsClampToggle(text: string): boolean {
  if (text.length > CLAMP_TOGGLE_CHARS) return true;
  return (text.match(/\n/g) || []).length >= 2;
}

function ClampText({
  text,
  className = "",
  style,
}: {
  text: string;
  className?: string;
  style?: CSSProperties;
}) {
  const [open, setOpen] = useState(false);
  const showToggle = needsClampToggle(text);
  const body = text || "（空）";
  return (
    <div className={className}>
      <p
        className={`text-[12.5px] leading-relaxed whitespace-pre-wrap break-words admin-content-clamp${open ? " is-open" : ""}`}
        style={style}
      >
        <AutolinkText text={body} forceNewTab />
      </p>
      {showToggle ? (
        <button
          type="button"
          className="meta text-[11.5px] mt-0.5 hover:underline"
          style={{ color: "var(--accent)" }}
          onClick={() => setOpen((v) => !v)}
        >
          {open ? "收起" : "展开"}
        </button>
      ) : null}
    </div>
  );
}

function ColumnShell({
  icon,
  title,
  count,
  toolbar,
  body,
  pager,
  className = "",
}: {
  icon: ReactNode;
  title: string;
  count?: number;
  toolbar?: ReactNode;
  body: ReactNode;
  pager?: ReactNode;
  className?: string;
}) {
  return (
    <section className={`panel admin-content-col ${className}`.trim()}>
      <header
        className="admin-content-col-head flex items-center gap-2 px-3.5 sm:px-4 py-3"
        style={{ borderBottom: "1px solid var(--line)", background: "var(--panel-2)" }}
      >
        <span className="shrink-0" style={{ color: "var(--accent)" }} aria-hidden>
          {icon}
        </span>
        <h2 className="text-[14px] font-semibold truncate" style={{ color: "var(--ink)" }}>
          {title}
        </h2>
        {typeof count === "number" ? (
          <span className="meta text-[12px] tabular-nums shrink-0">{count}</span>
        ) : null}
      </header>
      {toolbar}
      <div className="admin-content-col-body">{body}</div>
      {pager}
    </section>
  );
}

type DmPeer = { id: number; name: string; avatar: string };

/** 解析私聊：发送者在前、接收者在后 */
function resolveDmPair(m: AdminChatMessage): { sender: DmPeer; peer: DmPeer | null } {
  const sender: DmPeer = {
    id: m.sender_id,
    name: m.sender_name || "?",
    avatar: m.sender_avatar || "",
  };
  const fromParts = m.participants?.find((p) => p.id === m.sender_id);
  if (fromParts) {
    sender.name = fromParts.name || sender.name;
    sender.avatar = fromParts.avatar || sender.avatar;
  }
  const peer =
    m.participants?.find((p) => p.id !== m.sender_id) ||
    m.participants?.find((p) => p.name !== sender.name) ||
    null;
  return {
    sender,
    peer: peer
      ? { id: peer.id, name: peer.name || "?", avatar: peer.avatar || "" }
      : null,
  };
}

/** 私聊方向条：头像贴在各自名字左侧，发送者在前 */
function DmDirection({
  sender,
  peer,
}: {
  sender: DmPeer;
  peer: DmPeer | null;
}) {
  return (
    <span className="admin-dm-pair-names">
      <span className="admin-dm-person">
        <Avatar name={sender.name} src={sender.avatar || undefined} size={22} />
        <span className="admin-dm-person-name" style={{ color: "var(--ink)" }} data-tip={sender.name}>
          {sender.name}
        </span>
      </span>
      {peer ? (
        <>
          <span className="admin-dm-arrow" aria-hidden>
            →
          </span>
          <span className="admin-dm-person">
            <Avatar name={peer.name} src={peer.avatar || undefined} size={22} />
            <span className="admin-dm-person-name" style={{ color: "var(--ink-2)" }} data-tip={peer.name}>
              {peer.name}
            </span>
          </span>
        </>
      ) : null}
    </span>
  );
}

function RecallButton({
  busy,
  onClick,
}: {
  busy: boolean;
  onClick: () => void;
}) {
  return (
    <button type="button" className="admin-content-action is-danger" disabled={busy} onClick={onClick}>
      {busy ? <Loader2 size={13} className="animate-spin" /> : <Undo2 size={13} />}
      撤回
    </button>
  );
}

function useMessageColumn(roomType: MsgKind) {
  const [messages, setMessages] = useState<AdminChatMessage[]>([]);
  const [total, setTotal] = useState(0);
  const [page, setPage] = useState(1);
  const [keyword, setKeyword] = useState("");
  const [appliedQ, setAppliedQ] = useState("");
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState("");
  const seq = useRef(0);

  const load = useCallback(
    async (p: number, q: string) => {
      const s = ++seq.current;
      setLoading(true);
      try {
        const res = await apiAdminChatMessages(p, q, roomType);
        if (s !== seq.current) return;
        setMessages(Array.isArray(res.messages) ? res.messages : []);
        setTotal(typeof res.total === "number" ? res.total : 0);
        setPage(res.page || p);
        setAppliedQ(q);
        setError("");
      } catch (e) {
        if (s !== seq.current) return;
        setError(e instanceof Error ? e.message : "获取消息失败");
      } finally {
        if (s === seq.current) setLoading(false);
      }
    },
    [roomType]
  );

  useEffect(() => {
    void load(1, "");
    return () => {
      seq.current += 1;
    };
  }, [load]);

  const markRecalled = (id: number) => {
    setMessages((prev) =>
      prev.map((x) => (x.id === id ? { ...x, recalled_at: new Date().toISOString() } : x))
    );
  };

  return {
    messages,
    total,
    page,
    keyword,
    setKeyword,
    appliedQ,
    loading,
    error,
    load,
    markRecalled,
  };
}

/** 群聊（含大厅）| 私聊 双栏监管 */
export default function MessagesAdmin() {
  const [mobileKind, setMobileKind] = useState<MsgKind>("group");
  const group = useMessageColumn("group");
  const direct = useMessageColumn("direct");
  const [actingKey, setActingKey] = useState<string | null>(null);
  const [confirm, setConfirm] = useState<{
    title: string;
    message: string;
    run: () => Promise<void>;
  } | null>(null);
  const [confirmBusy, setConfirmBusy] = useState(false);

  const askRecall = (m: AdminChatMessage, markRecalled: (id: number) => void) => {
    const key = `m-${m.id}`;
    setConfirm({
      title: "撤回这条消息？",
      message: "撤回后会话中将显示为已撤回，此操作不可撤销。",
      run: async () => {
        setActingKey(key);
        try {
          await apiAdminRecallChatMessage(m.room_id, m.id);
          toast("消息已撤回", "ok");
          markRecalled(m.id);
        } finally {
          setActingKey(null);
        }
      },
    });
  };

  const groupToolbar = (
    <div className="admin-content-col-toolbar">
      <p className="meta text-[11.5px] leading-snug">含全站大厅与普通群聊</p>
      <AdminSearchField
        value={group.keyword}
        onChange={group.setKeyword}
        onSubmit={() => void group.load(1, group.keyword.trim())}
        onClear={() => {
          group.setKeyword("");
          void group.load(1, "");
        }}
        placeholder="搜索内容、群名或用户…"
        ariaLabel="搜索群聊消息"
      />
    </div>
  );

  const directToolbar = (
    <div className="admin-content-col-toolbar">
      <p className="meta text-[11.5px] leading-snug">一对一私信；按双方会话归档</p>
      <AdminSearchField
        value={direct.keyword}
        onChange={direct.setKeyword}
        onSubmit={() => void direct.load(1, direct.keyword.trim())}
        onClear={() => {
          direct.setKeyword("");
          void direct.load(1, "");
        }}
        placeholder="搜索内容或参与者…"
        ariaLabel="搜索私聊消息"
      />
    </div>
  );

  const groupBody = (
    <>
      {group.error ? <p className="alert-error m-3 text-[12.5px]">{group.error}</p> : null}
      {group.loading && group.messages.length === 0 ? (
        <div className="flex justify-center py-14">
          <Loader2 size={20} className="animate-spin" style={{ color: "var(--ink-3)" }} />
        </div>
      ) : group.messages.length === 0 ? (
        <AdminEmpty
          icon={<Users size={20} />}
          title="暂无群聊消息"
          description="大厅与群聊消息会按时间出现在这里"
        />
      ) : (
        group.messages.map((m, idx) => {
          const key = `m-${m.id}`;
          const busy = actingKey === key;
          const recalled = !!m.recalled_at;
          return (
            <div
              key={m.id}
              className="flex items-start gap-2.5 px-3 sm:px-3.5 py-3"
              style={idx === 0 ? undefined : { borderTop: "1px solid var(--line)" }}
            >
              <Avatar
                name={m.sender_name || "?"}
                src={m.sender_avatar || undefined}
                size={30}
              />
              <div className="min-w-0 flex-1">
                <div className="flex items-center gap-1.5 flex-wrap min-w-0">
                  <span
                    className="text-[12.5px] font-medium truncate max-w-[9rem]"
                    style={{ color: "var(--ink)" }}
                  >
                    {m.sender_name || "?"}
                  </span>
                  {recalled ? <AdminStatusChip tone="muted">已撤回</AdminStatusChip> : null}
                  {m.is_default ? (
                    <AdminStatusChip tone="muted">大厅</AdminStatusChip>
                  ) : (
                    <span className="meta text-[11px] truncate max-w-[10rem]" data-tip={m.room_name}>
                      {m.room_name}
                    </span>
                  )}
                  <span className="meta text-[11px] tabular-nums">
                    {formatRelative(m.created_at)}
                  </span>
                </div>
                <ClampText
                  text={m.content || "（空消息）"}
                  className="mt-1"
                  style={{
                    color: recalled ? "var(--ink-3)" : "var(--ink)",
                    textDecoration: recalled ? "line-through" : undefined,
                  }}
                />
                {!recalled ? (
                  <div className="mt-1.5">
                    <RecallButton busy={busy} onClick={() => askRecall(m, group.markRecalled)} />
                  </div>
                ) : null}
              </div>
            </div>
          );
        })
      )}
    </>
  );

  const directBody = (
    <>
      {direct.error ? <p className="alert-error m-3 text-[12.5px]">{direct.error}</p> : null}
      {direct.loading && direct.messages.length === 0 ? (
        <div className="flex justify-center py-14">
          <Loader2 size={20} className="animate-spin" style={{ color: "var(--ink-3)" }} />
        </div>
      ) : direct.messages.length === 0 ? (
        <AdminEmpty
          icon={<MessageCircle size={20} />}
          title="暂无私聊消息"
          description="用户一对一私信会出现在这里，可搜索参与者"
        />
      ) : (
        direct.messages.map((m, idx) => {
          const key = `m-${m.id}`;
          const busy = actingKey === key;
          const recalled = !!m.recalled_at;
          const { sender, peer } = resolveDmPair(m);
          return (
            <div
              key={m.id}
              className="admin-dm-row px-3 sm:px-3.5 py-3"
              style={idx === 0 ? undefined : { borderTop: "1px solid var(--line)" }}
            >
              <article className="admin-dm-card">
                <header className="admin-dm-card-head">
                  <div className="admin-dm-pair-meta min-w-0">
                    <DmDirection sender={sender} peer={peer} />
                    {recalled ? <AdminStatusChip tone="muted">已撤回</AdminStatusChip> : null}
                    <span className="meta text-[11px] tabular-nums shrink-0">
                      {formatRelative(m.created_at)}
                    </span>
                  </div>
                </header>
                <div className="admin-dm-card-body">
                  <ClampText
                    text={m.content || "（空消息）"}
                    style={{
                      color: recalled ? "var(--ink-3)" : "var(--ink)",
                      textDecoration: recalled ? "line-through" : undefined,
                    }}
                  />
                  {!recalled ? (
                    <div className="mt-1.5">
                      <RecallButton busy={busy} onClick={() => askRecall(m, direct.markRecalled)} />
                    </div>
                  ) : null}
                </div>
              </article>
            </div>
          );
        })
      )}
    </>
  );

  const groupCol = (
    <ColumnShell
      icon={<Users size={15} />}
      title="群聊"
      count={!group.loading || group.total > 0 ? group.total : undefined}
      toolbar={groupToolbar}
      body={groupBody}
      pager={
        <AdminPager
          page={group.page}
          total={group.total}
          pageSize={PAGE_SIZE}
          loading={group.loading}
          onChange={(p) => void group.load(p, group.appliedQ)}
          className={pagerClass}
        />
      }
      className={mobileKind === "group" ? "max-lg:flex" : "max-lg:hidden"}
    />
  );

  const directCol = (
    <ColumnShell
      icon={<MessageCircle size={15} />}
      title="私聊"
      count={!direct.loading || direct.total > 0 ? direct.total : undefined}
      toolbar={directToolbar}
      body={directBody}
      pager={
        <AdminPager
          page={direct.page}
          total={direct.total}
          pageSize={PAGE_SIZE}
          loading={direct.loading}
          onChange={(p) => void direct.load(p, direct.appliedQ)}
          className={pagerClass}
        />
      }
      className={mobileKind === "direct" ? "max-lg:flex" : "max-lg:hidden"}
    />
  );

  return (
    <div className="admin-content-page">
      <AdminPageHeader
        icon={MessagesSquare}
        title="消息管理"
        description="分栏监管群聊与私聊；可搜索并撤回违规内容"
      />

      <div className="admin-content-kind lg:hidden shrink-0" role="tablist" aria-label="消息类型">
        <button
          type="button"
          role="tab"
          aria-selected={mobileKind === "group"}
          className="admin-content-kind-btn"
          onClick={() => setMobileKind("group")}
        >
          <Users size={14} aria-hidden />
          群聊
          <span className="admin-content-kind-count">{group.total}</span>
        </button>
        <button
          type="button"
          role="tab"
          aria-selected={mobileKind === "direct"}
          className="admin-content-kind-btn"
          onClick={() => setMobileKind("direct")}
        >
          <MessageCircle size={14} aria-hidden />
          私聊
          <span className="admin-content-kind-count">{direct.total}</span>
        </button>
      </div>

      <div className="admin-content-triptych">
        {groupCol}
        {directCol}
      </div>

      <ConfirmDialog
        open={!!confirm}
        title={confirm?.title || ""}
        message={confirm?.message || ""}
        danger
        busy={confirmBusy}
        confirmLabel="确认撤回"
        onCancel={() => !confirmBusy && setConfirm(null)}
        onConfirm={() => {
          if (!confirm) return;
          setConfirmBusy(true);
          confirm
            .run()
            .catch((e) => toast(e instanceof Error ? e.message : "操作失败"))
            .finally(() => {
              setConfirmBusy(false);
              setConfirm(null);
            });
        }}
      />
    </div>
  );
}