import { useEffect, useState } from 'react';
import { ApiError, deletePost, getPost, savePost } from '../../../../lib/api';
import { confirmDialog, notify } from '../../../../lib/confirm';
import { clientSlugify } from './codemirror';

interface Opts {
  editSlug?: string;
  getContent: () => string;
  setContent: (s: string) => void;
}

/** Post metadata form + slug derivation + load/save/delete. */
export function usePostMeta({ editSlug, getContent, setContent }: Opts) {
  const today = new Date().toISOString().slice(0, 10);
  const [title, setTitle] = useState('');
  const [slug, setSlug] = useState(editSlug || '');
  const [slugTouched, setSlugTouched] = useState(!!editSlug);
  const [date, setDate] = useState(today);
  const [summary, setSummary] = useState('');
  const [tagsInput, setTagsInput] = useState('');
  const [draft, setDraft] = useState(false);
  const [originalSlug, setOriginalSlug] = useState(editSlug || '');

  // Load existing post for editing.
  useEffect(() => {
    if (!editSlug) return;
    getPost(editSlug)
      .then(post => {
        if (post.title) setTitle(post.title);
        if (post.summary) setSummary(post.summary);
        if (post.date) setDate(post.date);
        if (post.tags?.length) setTagsInput(post.tags.join(', '));
        setDraft(!!post.draft);
        if (post.content) setContent(post.content);
      })
      .catch(() => notify('Failed to load post.', 'error'));
  }, [editSlug, setContent]);

  // Auto-derive slug from title until the user edits the slug field.
  useEffect(() => {
    if (slugTouched) return;
    setSlug(clientSlugify(title));
  }, [title, slugTouched]);

  async function handleSave() {
    const content = getContent();
    if (!title.trim() || !slug || !content) {
      notify('Title, slug, and body are required.', 'error');
      return;
    }
    if (!/!\[[^\]]*\]\([^)]+\)/.test(content)) {
      notify(
        'Add at least one image before saving — drag, paste, or use the Add image button.',
        'error',
      );
      return;
    }
    const tags = tagsInput
      .split(',')
      .map(t => t.trim())
      .filter(Boolean);
    try {
      const saved = await savePost({
        slug,
        old_slug: originalSlug || null,
        title: title.trim(),
        date,
        summary: summary || null,
        tags,
        draft,
        content,
      });
      notify('Post saved!', 'success');
      if (saved?.slug && saved.slug !== slug) {
        setSlug(saved.slug);
        setSlugTouched(true);
      }
      setOriginalSlug(saved?.slug ?? slug);
    } catch (e) {
      notify(
        e instanceof ApiError ? `Error: ${e.message}` : 'Failed to connect to server.',
        'error',
      );
    }
  }

  async function handleDelete() {
    const target = originalSlug || slug;
    const ok = await confirmDialog({
      title: 'Remove from catalogue?',
      message: `“${target}” will be permanently removed. This cannot be undone.`,
      confirmLabel: 'Remove',
    });
    if (!ok) return;
    try {
      await deletePost(target);
      window.location.href = '/admin';
    } catch {
      notify('Error deleting post.', 'error');
    }
  }

  return {
    title,
    setTitle,
    slug,
    setSlug,
    setSlugTouched,
    date,
    setDate,
    summary,
    setSummary,
    tagsInput,
    setTagsInput,
    draft,
    setDraft,
    originalSlug,
    handleSave,
    handleDelete,
  };
}