// Observe / Interpret / Apply as an accordion (one open at a time), plus a "More"
// area for background notes and tags so the page stays quiet.
import { useEffect, useState } from 'react';

const SECTIONS = [
  { field: 'observation', label: 'Observe', hint: 'What does the text say?',
    placeholder: "What does the text actually say?\n• Who is speaking, and to whom?\n• What key words or phrases repeat?\n• What's the tone, structure, or literary style?" },
  { field: 'interpretation', label: 'Interpret', hint: 'What does it mean?',
    placeholder: "What did this mean to its original audience?\n• What's the historical/cultural context?\n• How does it fit the surrounding argument?\n• What does it reveal about God's character?" },
  { field: 'application', label: 'Apply', hint: 'What do I do with it?',
    placeholder: 'How should this shape your life today?\n• What attitude or action does this call for?\n• Is there a promise to trust or a warning to heed?\n• Who could you share this with?' },
];

const areaCls = 'w-full resize-y rounded-xl border border-[var(--r-line)] bg-[var(--r-bg)] px-3.5 py-3 font-serif text-[15px] leading-7 text-[var(--r-text)] placeholder:font-sans placeholder:text-[13px] placeholder:leading-5 placeholder:text-[var(--r-sub)] focus:outline-none focus:ring-2 focus:ring-[var(--r-line)]';
const words = (s) => (s ?? '').trim().split(/\s+/).filter(Boolean).length;

export default function NotesPane({ chunk, updateChunk, allTags }) {
  const [open, setOpen] = useState(() => {
    try { return localStorage.getItem('studyNotesOpen') || 'observation'; } catch { return 'observation'; }
  });
  const [more, setMore] = useState(false);
  const [tagInput, setTagInput] = useState('');
  useEffect(() => { setTagInput(''); }, [chunk.id]);
  useEffect(() => { try { localStorage.setItem('studyNotesOpen', open || ''); } catch { /* storage unavailable */ } }, [open]);

  const tags = chunk.tags ?? [];
  const addTag = (tag) => {
    const t = tag.trim();
    if (!t || tags.some((x) => x.toLowerCase() === t.toLowerCase())) { setTagInput(''); return; }
    updateChunk(chunk.id, { tags: [...tags, t] });
    setTagInput('');
  };
  const suggestions = allTags.filter((t) => !tags.some((x) => x.toLowerCase() === t.toLowerCase()));

  return (
    <section aria-label="Study notes" className="space-y-2">
      {SECTIONS.map(({ field, label, hint, placeholder }) => {
        const isOpen = open === field;
        const n = words(chunk[field]);
        return (
          <div key={field} className={`overflow-hidden rounded-2xl border ${isOpen ? 'border-[var(--r-accent)]' : 'border-[var(--r-line)]'}`}>
            <button type="button" onClick={() => setOpen(isOpen ? null : field)} aria-expanded={isOpen}
              className="flex w-full items-center justify-between gap-3 px-4 py-3 text-left">
              <span className="flex items-center gap-2.5">
                <span aria-hidden="true" className={`h-2.5 w-2.5 rounded-full border ${n ? 'border-[var(--r-accent)] bg-[var(--r-accent)]' : 'border-[var(--r-sub)]'}`} />
                <span className="text-sm font-medium">{label}</span>
                <span className="text-xs text-[var(--r-sub)]">{hint}</span>
              </span>
              <span className="text-xs text-[var(--r-sub)]">{n ? `${n} word${n === 1 ? '' : 's'}` : ''}</span>
            </button>
            {isOpen && (
              <div className="px-4 pb-4">
                <textarea aria-label={label} value={chunk[field] ?? ''} rows={7} placeholder={placeholder}
                  onChange={(e) => updateChunk(chunk.id, { [field]: e.target.value })} className={areaCls} />
              </div>
            )}
          </div>
        );
      })}

      <div className="rounded-2xl border border-[var(--r-line)]">
        <button type="button" onClick={() => setMore((m) => !m)} aria-expanded={more}
          className="flex w-full items-center justify-between px-4 py-3 text-left text-sm">
          <span><span className="font-medium">More</span> <span className="text-xs text-[var(--r-sub)]">background{tags.length ? ` · ${tags.length} tag${tags.length === 1 ? '' : 's'}` : ' and tags'}</span></span>
          <span className="text-xs text-[var(--r-sub)]">{more ? '▾' : '▸'}</span>
        </button>
        {more && (
          <div className="space-y-4 px-4 pb-4">
            <label className="block text-xs text-[var(--r-sub)]">
              Background / general notes
              <textarea value={chunk.generalNotes ?? ''} rows={5} onChange={(e) => updateChunk(chunk.id, { generalNotes: e.target.value })}
                placeholder="e.g. author, date, audience, historical context, key themes…" className={`mt-1 ${areaCls}`} />
            </label>
            <div>
              <p className="mb-1.5 text-xs text-[var(--r-sub)]">Tags</p>
              <div className="flex flex-wrap items-center gap-1.5">
                {tags.map((tag) => (
                  <span key={tag} className="inline-flex items-center gap-1 rounded-full bg-[var(--r-bar)] px-2.5 py-1 text-xs">
                    {tag}
                    <button type="button" aria-label={`Remove tag ${tag}`} onClick={() => updateChunk(chunk.id, { tags: tags.filter((t) => t !== tag) })} className="text-[var(--r-sub)] hover:text-[var(--r-danger,#b42318)]">×</button>
                  </span>
                ))}
                <input value={tagInput} onChange={(e) => setTagInput(e.target.value)} list="study-tag-suggestions"
                  onKeyDown={(e) => { if (e.key === 'Enter') { e.preventDefault(); addTag(tagInput); } }}
                  placeholder="Add a tag and press Enter"
                  className="min-w-[10rem] flex-1 rounded-lg border border-[var(--r-line)] bg-[var(--r-bg)] px-2.5 py-1 text-xs text-[var(--r-text)] focus:outline-none" />
              </div>
              {suggestions.length > 0 && (
                <div className="mt-2 flex flex-wrap items-center gap-1.5 text-xs">
                  <span className="text-[var(--r-sub)]">Suggestions:</span>
                  {suggestions.slice(0, 12).map((t) => (
                    <button key={t} type="button" onClick={() => addTag(t)} className="rounded-full border border-[var(--r-line)] px-2.5 py-0.5 text-[var(--r-sub)] hover:bg-black/5">+ {t}</button>
                  ))}
                </div>
              )}
              <datalist id="study-tag-suggestions">{allTags.map((t) => <option key={t} value={t} />)}</datalist>
            </div>
          </div>
        )}
      </div>
    </section>
  );
}