import type { TaskOverviewPage } from '@dorfteich/shared';
import { useQuery, useQueryClient } from '@tanstack/react-query';
import { Node } from '@tiptap/core';
import { NodeViewWrapper, ReactNodeViewRenderer } from '@tiptap/react';
import type { NodeViewProps } from '@tiptap/react';
import { useState } from 'react';
import { useTranslation } from 'react-i18next';
import { Link, useParams } from 'react-router-dom';

import { apiGet, apiPost } from '../../lib/api';
import { attributesFromSpec, nodeSpec } from '../spec-utils';
import { useWikilinks } from '../wikilink-context';

/**
 * The task overview block (issue #154). Edit mode shows a placeholder card;
 * read mode fetches the permission-filtered collection of the current page +
 * subtree (`/read/:pond/:slug/tasks`) and renders the table. Checking a box
 * posts the toggle (#153) — applied asynchronously through the collab
 * server — so the UI flips optimistically and refetches shortly after.
 */
function TaskOverviewView({ editor }: NodeViewProps): React.JSX.Element {
  const { t, i18n } = useTranslation('tasks');
  const { pondSlug } = useWikilinks();
  const { pageSlug = '' } = useParams<{ pageSlug: string }>();
  const queryClient = useQueryClient();
  const [optimistic, setOptimistic] = useState<Record<string, boolean>>({});
  const editable = editor.isEditable;

  const overview = useQuery({
    queryKey: ['page-tasks', pondSlug, pageSlug],
    queryFn: () => apiGet<TaskOverviewPage[]>(`/read/${pondSlug}/${pageSlug}/tasks`),
    enabled: !editable && Boolean(pageSlug),
  });

  if (editable) {
    return (
      <NodeViewWrapper className="dt-transclusion-card" contentEditable={false}>
        <span className="dt-transclusion-card__icon" aria-hidden>
          ☑
        </span>
        <span className="dt-transclusion-card__label">{t('editorCard')}</span>
      </NodeViewWrapper>
    );
  }

  const formatDate = (iso: string | null): string =>
    iso
      ? new Intl.DateTimeFormat(i18n.language, { dateStyle: 'medium' }).format(
          new Date(`${iso}T00:00:00`),
        )
      : '';

  const toggle = async (pageId: string, taskId: string, checked: boolean): Promise<void> => {
    setOptimistic((prev) => ({ ...prev, [taskId]: checked }));
    await apiPost(`/pages/${pageId}/tasks/${taskId}`, { checked });
    // The collab server applies the edit and persists it debounced (~2 s) —
    // re-read a couple of times; the optimistic override stays until the
    // server agrees (cleared below when the data catches up).
    for (const delay of [2500, 6000]) {
      setTimeout(() => {
        void queryClient.invalidateQueries({ queryKey: ['page-tasks', pondSlug, pageSlug] });
      }, delay);
    }
  };

  const pages = overview.data ?? [];
  // Drop optimistic overrides the server data now agrees with.
  const agreed = pages
    .flatMap((page) => page.tasks)
    .filter((task) => task.id && task.id in optimistic && optimistic[task.id] === task.checked)
    .map((task) => task.id as string);
  if (agreed.length > 0) {
    setOptimistic((prev) => {
      const next = { ...prev };
      for (const id of agreed) delete next[id];
      return next;
    });
  }
  const total = pages.reduce((sum, page) => sum + page.tasks.length, 0);

  return (
    <NodeViewWrapper className="dt-task-overview-view" contentEditable={false}>
      {total === 0 ? (
        <div className="dt-task-overview-empty">{t('empty')}</div>
      ) : (
        <table className="dt-task-overview-table">
          <thead>
            <tr>
              <th>
                <span className="visually-hidden">{t('colDone')}</span>
              </th>
              <th>{t('colTask')}</th>
              <th>{t('colMentions')}</th>
              <th>{t('colStart')}</th>
              <th>{t('colDue')}</th>
              <th>{t('colPage')}</th>
            </tr>
          </thead>
          <tbody>
            {pages.flatMap((page) =>
              page.tasks.map((task, index) => {
                const key = task.id ?? `${page.pageId}:${index}`;
                const checked =
                  task.id && task.id in optimistic ? optimistic[task.id]! : task.checked;
                return (
                  <tr key={key}>
                    <td>
                      <input
                        type="checkbox"
                        checked={checked}
                        disabled={!task.id}
                        title={task.id ? undefined : t('unsavedHint')}
                        onChange={(event) =>
                          task.id && void toggle(page.pageId, task.id, event.target.checked)
                        }
                      />
                    </td>
                    <td>{task.text}</td>
                    <td>
                      {task.mentions.map((mention) => (
                        <span key={mention.id || mention.username} className="dt-mention">
                          @{mention.displayName}
                        </span>
                      ))}
                    </td>
                    <td>{formatDate(task.startDate)}</td>
                    <td>{formatDate(task.dueDate)}</td>
                    <td>
                      <Link className="wikilink" to={`/p/${pondSlug}/${page.slug}`}>
                        {page.title}
                      </Link>
                    </td>
                  </tr>
                );
              }),
            )}
          </tbody>
        </table>
      )}
    </NodeViewWrapper>
  );
}

const taskOverviewSpec = nodeSpec('task_overview');
export const TaskOverview = Node.create({
  name: 'task_overview',
  group: taskOverviewSpec.group,
  atom: taskOverviewSpec.atom,
  addAttributes() {
    return attributesFromSpec(taskOverviewSpec);
  },
  parseHTML: () => taskOverviewSpec.parseDOM,
  renderHTML: ({ node }) => taskOverviewSpec.toDOM!(node),
  addNodeView() {
    return ReactNodeViewRenderer(TaskOverviewView);
  },
});