import { useState } from 'react';

import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
import { useNavigate } from 'react-router-dom';

import { Icon } from '@/app/Icon';
import { Toast } from '@/app/Toast';
import { fetchAllPages } from '@/lib/api/client';
import { getBlocks } from '@/lib/api/friends';
import { getMyPrivacy, updateMyPrivacy, type AddMeMethods } from '@/lib/api/profile';

const ADD_ME_LABELS: { key: keyof AddMeMethods; label: string }[] = [
  { key: 'account', label: '通过用户 ID' },
  { key: 'phone', label: '通过手机号' },
  { key: 'qr', label: '通过二维码' },
  { key: 'group', label: '通过群聊' },
];
const VISIBILITY_OPTIONS = [
  { value: 'everyone', label: '所有人' },
  { value: 'friends', label: '仅好友' },
  { value: 'nobody', label: '不展示' },
];

function Toggle({ checked, onChange, disabled }: { checked: boolean; onChange: () => void; disabled?: boolean }) {
  return (
    <button
      type="button"
      role="switch"
      aria-checked={checked}
      disabled={disabled}
      onClick={onChange}
      className={`relative h-[22px] w-10 flex-none rounded-full transition-colors disabled:opacity-50 ${checked ? 'bg-accent' : 'bg-[#d5d9df]'}`}
    >
      <span className={`absolute left-0.5 top-0.5 h-[18px] w-[18px] rounded-full bg-white transition-transform ${checked ? 'translate-x-[18px]' : ''}`} />
    </button>
  );
}

/**
 * screens/07-profile-settings.dc.html#1c: 添加我的方式 (4 toggles, ungrouped -- no dividers between
 * them, just the section label above) sits in its own card; 黑名单 sits in a second card alone
 * (that mockup also puts "加我为好友时需要验证" there, but that toggle has NO backing field anywhere
 * in this response shape or the group-invite backend logic -- confirmed absent, not built). The
 * visibility/read-receipts rows below have no mockup at all (added once the real backend fields were
 * found during research) -- given their own third card rather than folding them into either of the
 * above, so a real capability the design never anticipated doesn't look like it was crammed in.
 */
export function PrivacySettingsPage() {
  const navigate = useNavigate();
  const queryClient = useQueryClient();
  const [error, setError] = useState('');
  const query = useQuery({ queryKey: ['my-privacy'], queryFn: getMyPrivacy });
  const blocksQuery = useQuery({ queryKey: ['blocks'], queryFn: () => fetchAllPages((cursor) => getBlocks(cursor)) });

  const mutation = useMutation({
    mutationFn: (patch: Parameters<typeof updateMyPrivacy>[0]) => updateMyPrivacy(patch),
    // Merge, don't replace -- the doc's own worked example for this exact endpoint (line 2494)
    // returns a PARTIAL object (`{add_me_methods,read_receipts,version,updated_at}`, missing
    // `profile_visibility`/`last_seen_visibility`/`editable`). A blind replace would erase those
    // from the cache after every single save, most importantly `editable`: once it silently
    // disappeared, `const editable = query.data.editable || {}` re-derives an EMPTY object, which
    // re-enables every field a tenant policy had actually locked, until an unrelated refetch happens
    // to restore it.
    onSuccess: (data) => queryClient.setQueryData(['my-privacy'], (prev: typeof query.data) => (prev ? { ...prev, ...data } : data)),
    // Same reasoning as ProfileSettingsPage's own saveMutation: a version conflict shouldn't leave
    // the cached `version` stale, or every retry just resends the same rejected value forever.
    onError: (err) => {
      setError(err instanceof Error ? err.message : '设置失败');
      queryClient.invalidateQueries({ queryKey: ['my-privacy'] });
    },
  });
  const patch = (partial: Partial<Omit<Parameters<typeof updateMyPrivacy>[0], 'version'>>) => {
    if (!query.data) return;
    mutation.mutate({ ...partial, version: query.data.version });
  };

  if (query.isLoading) return <div className="p-10 text-sm text-text-tertiary-4">加载中…</div>;
  // `isLoading` alone used to gate this: it turns false once the fetch SETTLES, including into an
  // error, but `query.data` stays undefined either way -- the page was falling through to the same
  // "加载中…" text forever on a genuine failure (a slow/dropped connection, not just "still loading"),
  // with no retry affordance at all. Same fix already applied to SystemMessagesView's own query.
  if (query.isError || !query.data) {
    return (
      <div className="flex flex-col items-center gap-2 p-10 text-sm text-danger-text">
        <span>加载失败，请重试</span>
        <button type="button" onClick={() => query.refetch()} className="text-accent">
          重试
        </button>
      </div>
    );
  }
  const editable = query.data.editable || {};

  return (
    <div className="mx-auto w-full max-w-[720px] px-5 py-8 md:px-10">
      <h2 className="mb-5 text-xl font-semibold text-text-heading">隐私</h2>
      <div className="flex flex-col gap-5">
        <div className="rounded-xl bg-white text-sm">
          <div className="px-7 pb-1.5 pt-4 text-[13px] text-text-tertiary-2">添加我的方式</div>
          {ADD_ME_LABELS.map((item, i) => (
            <div key={item.key} className={`flex items-center justify-between px-7 py-3 ${i === ADD_ME_LABELS.length - 1 ? 'pb-4.5' : ''}`}>
              <span className="text-text-body">{item.label}</span>
              <Toggle
                checked={query.data.add_me_methods[item.key]}
                disabled={editable.add_me_methods === false || mutation.isPending}
                onChange={() => patch({ add_me_methods: { [item.key]: !query.data.add_me_methods[item.key] } })}
              />
            </div>
          ))}
        </div>

        <button type="button" onClick={() => navigate('/contacts/blocklist')} className="flex w-full items-center justify-between rounded-xl bg-white px-7 py-4 text-left text-sm">
          <span className="text-text-body">黑名单</span>
          <span className="flex items-center gap-1 text-text-tertiary-2">
            {blocksQuery.data?.length ?? 0} 人
            <Icon name="chevron_right" className="text-[20px] text-icon-arrow" />
          </span>
        </button>

        <div className="rounded-xl bg-white text-sm">
          <div className="flex items-center justify-between border-b border-border-row px-7 py-4">
            <span className="text-text-body">资料可见范围</span>
            <div className="flex overflow-hidden rounded-md border border-[#d5d9df] text-xs">
              {VISIBILITY_OPTIONS.map((opt) => (
                <button
                  key={opt.value}
                  type="button"
                  disabled={editable.profile_visibility === false || mutation.isPending}
                  onClick={() => patch({ profile_visibility: opt.value })}
                  className={`px-3 py-1.5 ${query.data.profile_visibility === opt.value ? 'bg-accent text-white' : 'text-text-secondary'}`}
                >
                  {opt.label}
                </button>
              ))}
            </div>
          </div>
          <div className="flex items-center justify-between border-b border-border-row px-7 py-4">
            <span className="text-text-body">最近在线可见范围</span>
            <div className="flex overflow-hidden rounded-md border border-[#d5d9df] text-xs">
              {VISIBILITY_OPTIONS.map((opt) => (
                <button
                  key={opt.value}
                  type="button"
                  disabled={editable.last_seen_visibility === false || mutation.isPending}
                  onClick={() => patch({ last_seen_visibility: opt.value })}
                  className={`px-3 py-1.5 ${query.data.last_seen_visibility === opt.value ? 'bg-accent text-white' : 'text-text-secondary'}`}
                >
                  {opt.label}
                </button>
              ))}
            </div>
          </div>
          <div className="flex items-center justify-between px-7 py-4">
            <span className="text-text-body">已读回执</span>
            <Toggle
              checked={query.data.read_receipts}
              disabled={editable.read_receipts === false || mutation.isPending}
              onChange={() => patch({ read_receipts: !query.data.read_receipts })}
            />
          </div>
        </div>
      </div>
      <Toast message={error} variant="error" onDone={() => setError('')} />
    </div>
  );
}