"use client";

import { useCallback, useEffect, useState } from "react";

export async function readApiResponse<T>(
  response: Response,
  fallback: string,
) {
  const text = await response.text();
  const contentType = response.headers.get("content-type") ?? "";
  if (!contentType.includes("json")) {
    if (response.status === 403) {
      throw new Error("请求被安全网关拦截，请刷新页面后重试");
    }
    throw new Error(`${fallback}（服务返回异常，HTTP ${response.status}）`);
  }
  try {
    return JSON.parse(text) as T & { error?: string };
  } catch {
    throw new Error(`${fallback}（服务返回的数据无法解析）`);
  }
}

export type InternalWecomContact = {
  userid: string;
  name: string;
  departmentNames: string[];
};

let internalWecomContactsCache: {
  contacts: InternalWecomContact[];
  fetchedAt: number;
} | null = null;

const INTERNAL_WECOM_CONTACTS_TTL_MS = 5 * 60 * 1000;

export function WecomUserPickerModal({
  mode,
  selected,
  onClose,
  onConfirm,
}: {
  mode: "single" | "multi";
  selected: string[];
  onClose: () => void;
  onConfirm: (userids: string[]) => void;
}) {
  const [contacts, setContacts] = useState<InternalWecomContact[]>(
    internalWecomContactsCache?.contacts ?? [],
  );
  const [fetchedAt, setFetchedAt] = useState(0);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState("");
  const [search, setSearch] = useState("");
  const [checked, setChecked] = useState<string[]>(selected.filter(Boolean));

  const loadContacts = useCallback(async (force = false) => {
    const snapshot = internalWecomContactsCache;
    if (
      !force &&
      snapshot &&
      Date.now() - snapshot.fetchedAt <= INTERNAL_WECOM_CONTACTS_TTL_MS
    ) {
      setContacts(snapshot.contacts);
      setFetchedAt(snapshot.fetchedAt);
      setLoading(false);
      return;
    }
    setLoading(true);
    setError("");
    try {
      const response = await fetch("/api/action", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ action: "wecom_list_internal_contacts" }),
      });
      const parsed = await readApiResponse<{
        contacts?: InternalWecomContact[];
        error?: string;
      }>(response, "获取企业微信通讯录失败");
      if (!response.ok) {
        throw new Error(parsed.error || "获取企业微信通讯录失败");
      }
      const list = Array.isArray(parsed.contacts) ? parsed.contacts : [];
      internalWecomContactsCache = { contacts: list, fetchedAt: Date.now() };
      setContacts(list);
      setFetchedAt(internalWecomContactsCache.fetchedAt);
    } catch (reason) {
      setError(
        reason instanceof Error ? reason.message : "获取企业微信通讯录失败",
      );
    } finally {
      setLoading(false);
    }
  }, []);

  useEffect(() => {
    const timer = window.setTimeout(() => {
      void loadContacts();
    }, 0);
    return () => window.clearTimeout(timer);
  }, [loadContacts]);

  const keyword = search.trim().toLowerCase();
  const filteredContacts =
    keyword.length === 0
      ? contacts
      : contacts.filter((contact) =>
          `${contact.name} ${contact.userid}`.toLowerCase().includes(keyword),
        );

  const toggleChecked = (userid: string) => {
    setChecked((previous) =>
      previous.includes(userid)
        ? previous.filter((item) => item !== userid)
        : [...previous, userid],
    );
  };

  return (
    <div className="modal-backdrop" role="presentation" onMouseDown={onClose}>
      <div
        className="modal-card wecom-picker-modal"
        onMouseDown={(event) => event.stopPropagation()}
      >
        <div className="modal-heading">
          <div>
            <h2>选择企业微信成员</h2>
            <p>
              从企业微信通讯录（自建应用可见范围）中挑选，
              {mode === "multi" ? "勾选后点击确定" : "点击成员即填入"}。
            </p>
          </div>
          <button type="button" onClick={onClose} aria-label="关闭">×</button>
        </div>
        <div className="import-guide-strip">
          <input
            type="search"
            className="wecom-picker-search"
            placeholder="按姓名 / userid 搜索"
            value={search}
            onChange={(event) => setSearch(event.target.value)}
            disabled={loading}
          />
          <button
            type="button"
            className="ghost-button"
            onClick={() => void loadContacts(true)}
            disabled={loading}
          >
            {loading ? "拉取中…" : "刷新列表"}
          </button>
          {fetchedAt > 0 && !loading && (
            <span className="wecom-picker-cache-hint">
              缓存于 {new Date(fetchedAt).toLocaleTimeString()}（5 分钟内复用）
            </span>
          )}
        </div>
        {error && (
          <p className="form-error">
            {error} 可关闭此弹窗，直接在输入框手动填写 userid。
          </p>
        )}
        <div className="wecom-picker-list">
          {loading && contacts.length === 0 ? (
            <div className="wecom-picker-empty">正在拉取企业微信通讯录…</div>
          ) : contacts.length === 0 ? (
            <div className="wecom-picker-empty">
              {error
                ? "拉取失败，请检查应用配置（通讯录权限 / 可信 IP）后重试"
                : "未拉取到通讯录成员——仅显示自建应用可见范围内的成员，也可手动填写 userid"}
            </div>
          ) : filteredContacts.length === 0 ? (
            <div className="wecom-picker-empty">没有匹配的成员</div>
          ) : (
            filteredContacts.map((contact) => {
              const isSelected =
                mode === "multi"
                  ? checked.includes(contact.userid)
                  : selected.includes(contact.userid);
              const rowBody = (
                <>
                  <span className="wecom-picker-avatar placeholder" aria-hidden="true">
                    {(contact.name || contact.userid).slice(0, 1)}
                  </span>
                  <span className="wecom-picker-meta">
                    <span className="wecom-picker-name">
                      {contact.name || contact.userid}
                    </span>
                    <span className="wecom-picker-sub">
                      {contact.departmentNames.join(" / ") || "—"}
                    </span>
                    <code className="wecom-picker-id">{contact.userid}</code>
                  </span>
                </>
              );
              return mode === "multi" ? (
                <label key={contact.userid} className="wecom-picker-row">
                  {rowBody}
                  <input
                    type="checkbox"
                    checked={isSelected}
                    onChange={() => toggleChecked(contact.userid)}
                  />
                </label>
              ) : (
                <button
                  key={contact.userid}
                  type="button"
                  className="wecom-picker-row"
                  onClick={() => onConfirm([contact.userid])}
                >
                  {rowBody}
                  {isSelected ? (
                    <span className="wecom-picker-current">当前</span>
                  ) : null}
                </button>
              );
            })
          )}
        </div>
        {mode === "multi" && (
          <div className="modal-actions">
            <button type="button" className="ghost-button" onClick={onClose}>
              取消
            </button>
            <button
              type="button"
              className="primary-button"
              onClick={() => onConfirm(checked)}
            >
              {checked.length > 0 ? `确定（${checked.length} 人）` : "确定"}
            </button>
          </div>
        )}
      </div>
    </div>
  );
}