// Press ⌘K (Ctrl+K) anywhere: type a passage ("john 3:16") to go straight to it, or a few letters to
// find a study, a note you wrote, a bookmark or highlight, a page, or to search the Bible's text.
import { useEffect, useMemo, useRef, useState } from 'react';
import { useApp } from '../context/AppContext.js';
import { themeVars } from './reader/readerThemes.js';
import { SearchIcon } from './reader/icons.jsx';
import { formatPassage, parsePassageRef } from '../utils/passageRef.js';
import { searchMarks, searchNotes, searchProjects } from '../utils/personalSearch.js';
import { loadProjectIndex } from '../utils/bibleUtils.jsx';
import { loadProjectById } from '../utils/projectStorage.js';

export default function CommandPalette({ onClose }) {
  const {
    readerTheme, authUser, authServerDown, projectIndex, readerBookmarks, readerTextHighlights, readerColorLabels,
    jumpToReaderVerse, setCurrentPage, setProject, resumeProject, openNewProject, goStudies, openReadingPlans,
    openBibleReader, requestReaderSearch, openBackup,
  } = useApp();
  const [query, setQuery] = useState('');
  const [active, setActive] = useState(0);
  const listRef = useRef(null);
  const inputRef = useRef(null);
  const opener = useRef(document.activeElement);

  useEffect(() => {
    inputRef.current?.focus();
    const from = opener.current;
    return () => { if (from instanceof HTMLElement && document.contains(from)) from.focus({ preventScroll: true }); };
  }, []);

  const items = useMemo(() => {
    const out = [];
    const q = query.trim();
    const go = (fn) => () => { onClose(); fn(); };

    // 1. A passage typed in
    for (const r of parsePassageRef(q)) {
      out.push({ group: 'Go to', label: formatPassage(r), hint: 'Open in the Bible', run: go(() => { jumpToReaderVerse(r.book, r.chapter, r.verse ?? 1); openBibleReader(); }) });
    }

    // 2. Pages and actions
    const pages = [
      ['Studies', 'My Studies', goStudies], ['Read Bible', 'The Bible reader', openBibleReader], ['Reading Plans', 'Plans and today’s reading', openReadingPlans],
      ['New project', 'Start a Bible study', openNewProject], ['Settings', 'Account and preferences', () => setCurrentPage('settings')],
      ['Back up my data', 'Download everything as a file', openBackup],
    ];
    const lower = q.toLowerCase();
    for (const [label, hint, fn] of pages) {
      if (!lower || label.toLowerCase().includes(lower)) out.push({ group: lower ? 'Pages' : 'Go to', label, hint, run: go(fn) });
    }

    if (q.length >= 2) {
      // 3. Studies
      for (const e of searchProjects(projectIndex, q)) {
        out.push({ group: 'Studies', label: e.title, hint: e.chapterSummary, run: go(() => resumeProject(e.id)) });
      }
      // 4. Notes you wrote
      const projects = loadProjectIndex().map((e) => loadProjectById(e.id)).filter(Boolean);
      for (const h of searchNotes(projects, q)) {
        out.push({
          group: 'Your notes', label: `${h.ref} — ${h.projectTitle}`, hint: h.snippet,
          run: go(() => {
            const full = loadProjectById(h.projectId);
            if (!full) return;
            setProject({ ...full, selectedChunkId: h.chunkId });
            setCurrentPage('study');
          }),
        });
      }
      // 5. Bookmarks and highlights
      for (const m of searchMarks({ bookmarks: readerBookmarks, highlights: readerTextHighlights, labels: readerColorLabels ?? {} }, q)) {
        out.push({
          group: 'Bookmarks & highlights', label: `${m.bookName} ${m.chapter}:${m.verse}`, color: m.color,
          hint: m.kind === 'highlight' ? `${m.label ? `${m.label}: ` : ''}${m.text ?? 'Highlight'}` : 'Bookmark',
          run: go(() => { jumpToReaderVerse(m.book, m.chapter, m.verse); openBibleReader(); }),
        });
      }
      // 6. The Bible's own text
      out.push({ group: 'Search', label: `Search the Bible for “${q}”`, hint: 'Whole-Bible search in the reader', run: go(() => { requestReaderSearch(q); openBibleReader(); }) });
    }
    return out;
  }, [query]); // eslint-disable-line react-hooks/exhaustive-deps

  useEffect(() => { setActive(0); }, [query]);
  useEffect(() => { listRef.current?.querySelector('[aria-selected="true"]')?.scrollIntoView?.({ block: 'nearest' }); }, [active]);

  const onKeyDown = (e) => {
    if (e.key === 'ArrowDown') { e.preventDefault(); setActive((a) => Math.min(a + 1, items.length - 1)); }
    else if (e.key === 'ArrowUp') { e.preventDefault(); setActive((a) => Math.max(a - 1, 0)); }
    else if (e.key === 'Enter') { e.preventDefault(); items[active]?.run(); }
    else if (e.key === 'Escape') { e.preventDefault(); e.stopPropagation(); onClose(); }
    else if (e.key === 'Tab') { e.preventDefault(); } // the box and the list are one control
  };

  if (authUser === null && !authServerDown) return null; // the sign-in screen has nothing to search
  let lastGroup = null;
  return (
    <div style={themeVars(readerTheme)} className="fixed inset-0 z-[90] flex items-start justify-center bg-black/40 px-3 pt-[12vh] font-sans" onMouseDown={(e) => { if (e.target === e.currentTarget) onClose(); }}>
      <div role="dialog" aria-modal="true" aria-label="Search and go to" className="w-full max-w-xl overflow-hidden rounded-2xl border border-[var(--r-line)] bg-[var(--r-bar)] text-[var(--r-text)] shadow-2xl">
        <div className="flex items-center gap-2 border-b border-[var(--r-line)] px-4 py-3">
          <span className="text-[var(--r-sub)]"><SearchIcon /></span>
          <input
            ref={inputRef} value={query} onChange={(e) => setQuery(e.target.value)} onKeyDown={onKeyDown}
            role="combobox" aria-expanded="true" aria-controls="palette-list" aria-autocomplete="list"
            aria-activedescendant={items[active] ? `palette-item-${active}` : undefined}
            placeholder="Go to a passage, or search your studies and notes…"
            className="min-w-0 flex-1 bg-transparent text-base outline-none placeholder:text-[var(--r-sub)]"
          />
          <kbd className="hidden rounded border border-[var(--r-line)] px-1.5 py-0.5 text-[10px] text-[var(--r-sub)] sm:block">esc</kbd>
        </div>
        <ul id="palette-list" role="listbox" ref={listRef} className="max-h-[50vh] overflow-y-auto p-2">
          {items.length === 0 && <li className="px-3 py-6 text-center text-sm text-[var(--r-sub)]">Nothing found. Try a book and chapter, like “romans 8”.</li>}
          {items.map((item, i) => {
            const header = item.group !== lastGroup ? item.group : null;
            lastGroup = item.group;
            return (
              <li key={i} role="presentation">
                {header && <p className="px-3 pb-1 pt-2 text-[11px] uppercase tracking-wide text-[var(--r-sub)]">{header}</p>}
                <div id={`palette-item-${i}`} role="option" aria-selected={i === active} onMouseMove={() => setActive(i)} onClick={item.run}
                  className={`flex cursor-pointer items-baseline gap-2 rounded-lg px-3 py-2 text-sm ${i === active ? 'bg-[var(--r-text)] text-[var(--r-bg)]' : ''}`}>
                  {item.color && <span className="h-2.5 w-2.5 shrink-0 translate-y-px rounded-full border border-black/10" style={{ backgroundColor: item.color }} />}
                  <span className="shrink-0 font-medium">{item.label}</span>
                  {item.hint && <span className={`min-w-0 truncate text-xs ${i === active ? 'opacity-80' : 'text-[var(--r-sub)]'}`}>{item.hint}</span>}
                </div>
              </li>
            );
          })}
        </ul>
        <p className="border-t border-[var(--r-line)] px-4 py-2 text-[11px] text-[var(--r-sub)]">↑↓ to move · Enter to open · Esc to close</p>
      </div>
    </div>
  );
}