// The Outline stage: choose a chapter, then cut it into chunks by clicking between
// verses (or let the section headings suggest them). Each chunk becomes one unit of
// study in the next stage.
import { STUDY_TEMPLATES, getTemplate } from '../utils/studyTemplates.js';
import { useApp } from '../context/AppContext.js';
import { useChunkBuilder } from '../hooks/useChunkBuilder.js';
import StudioShell from '../components/study/StudioShell.jsx';
import { bookOptions, formatChunkReference } from '../utils/bibleUtils.jsx';

const inputCls = 'mt-1 block w-full rounded-xl border border-[var(--r-line)] bg-[var(--r-bg)] px-3 py-2 text-sm text-[var(--r-text)] focus:outline-none focus:ring-2 focus:ring-[var(--r-line)]';
const smallBtn = 'rounded-lg border border-[var(--r-line)] px-2.5 py-1.5 text-xs hover:bg-black/5 disabled:opacity-40';
const primaryBtn = 'rounded-xl bg-[var(--r-accent)] px-5 py-2.5 text-sm font-medium text-[var(--r-on)] hover:opacity-90 disabled:cursor-not-allowed disabled:opacity-40';

// Band tints that alternate from chunk to chunk so neighbouring chunks are easy to tell apart.
const BANDS = ['color-mix(in srgb, var(--r-accent) 13%, transparent)', 'color-mix(in srgb, var(--r-sub) 17%, transparent)'];

function PassageForm({ setup, onField, onTitleChange, onLoad, loading, error, withTitle, userTemplates = [], onDeleteTemplate }) {
  return (
    <div className="space-y-4">
      <div className="grid gap-4 sm:grid-cols-2">
        <label className="block text-sm">Book
          <select value={setup.bookAbbrev} onChange={(e) => onField('book', e.target.value)} className={inputCls}>
            {bookOptions.map((b) => <option key={b.abbrev} value={b.abbrev}>{b.name}</option>)}
          </select>
        </label>
        <label className="block text-sm">Chapter
          <input type="number" min="1" value={setup.chapter} onChange={(e) => onField('chapter', e.target.value)} className={inputCls} />
        </label>
        {withTitle && (
          <label className="block text-sm sm:col-span-2">Study title
            <input type="text" value={setup.title} onChange={(e) => onTitleChange(e.target.value)} className={inputCls} />
          </label>
        )}
        {withTitle && (
          <label className="block text-sm sm:col-span-2">Start from
            <select value={setup.template ?? 'blank'} onChange={(e) => onField('template', e.target.value)} className={inputCls}>
              {STUDY_TEMPLATES.map((t) => <option key={t.id} value={t.id}>{t.name}</option>)}
              {userTemplates.length > 0 && <optgroup label="Your templates">{userTemplates.map((t) => <option key={t.id} value={t.id}>{t.name}</option>)}</optgroup>}
            </select>
            <span className="mt-1 block text-xs text-[var(--r-sub)]">{getTemplate(setup.template, userTemplates).description}</span>
            {setup.template?.startsWith('user-') && onDeleteTemplate && (
              <button type="button" onClick={() => { onDeleteTemplate(setup.template); onField('template', 'blank'); }} className="mt-1 text-xs text-[var(--r-danger,#b42318)] hover:underline">Delete this template</button>
            )}
          </label>
        )}
      </div>
      <div className="flex items-center justify-between gap-3">
        <p className="text-xs text-[var(--r-sub)]">{error ? <span className="text-[var(--r-danger,#b42318)]">{error}</span> : 'Text: Berean Standard Bible (BSB).'}</p>
        <button type="button" onClick={onLoad} disabled={loading} className={primaryBtn}>{loading ? 'Loading…' : 'Load chapter'}</button>
      </div>
    </div>
  );
}

export default function SetupPage() {
  const { project, setProject, allChunks, updateProject, setCurrentPage, userTemplates, deleteUserTemplate } = useApp();
  const b = useChunkBuilder({ project, setProject, updateProject, allChunks, setCurrentPage, userTemplates });
  const { activeChapter, activeChapterIndex } = b;
  const chapters = project?.chapters ?? [];

  const onTitleChange = (val) => { b.setTitleEdited(true); b.handleSetupField('title', val); };
  const select = (id) => updateProject((current) => ({ ...current, selectedChunkId: id }));

  // Which chunk (if any) each verse of the active chapter belongs to
  const chunkOf = (n) => activeChapter?.chunks.findIndex((c) => n >= c.startVerse && n <= c.endVerse) ?? -1;
  const prevChapter = chapters[activeChapterIndex - 1];
  const spilledFromPrev = (n) => !!prevChapter && prevChapter.bookAbbrev === activeChapter.bookAbbrev
    && prevChapter.chunks.some((c) => Number.isInteger(c.spilloverEndVerse) && n <= c.spilloverEndVerse);
  const lastVerse = activeChapter?.verses.at(-1)?.number ?? 0;
  const uncovered = activeChapter ? activeChapter.verses.some((v) => chunkOf(v.number) < 0 && !spilledFromPrev(v.number)) : false;

  return (
    <StudioShell stage="setup" loading={b.loadingChapter}>
      <main className="mx-auto max-w-6xl px-4 py-6">
        {!project && (
          <section className="mx-auto max-w-xl rounded-2xl border border-[var(--r-line)] bg-[var(--r-bar)] p-6">
            <h1 className="mb-1 text-xl font-medium">New study</h1>
            <p className="mb-5 text-sm text-[var(--r-sub)]">Pick a chapter, then cut it into chunks. You’ll study one chunk at a time.</p>
            <PassageForm setup={b.setup} onField={b.handleSetupField} onTitleChange={onTitleChange} onLoad={b.handleLoadChapter}
              loading={b.loadingChapter} error={b.errorMessage} withTitle userTemplates={userTemplates} onDeleteTemplate={deleteUserTemplate} />
          </section>
        )}

        {project && (
          <div className="grid gap-6 lg:grid-cols-[minmax(0,1fr)_22rem]">
            <section className="min-w-0 space-y-4">
              <div className="flex flex-wrap items-center gap-2">
                {chapters.map((ch, idx) => (
                  <button key={`${ch.bookAbbrev}-${ch.chapter}`} type="button" aria-current={b.activeChapterIndex === idx ? 'true' : undefined}
                    onClick={() => { b.setActiveChapterIndex(idx); b.setRangeStart(null); b.setRangeEnd(null); }}
                    className={`rounded-full border px-4 py-1.5 text-sm ${b.activeChapterIndex === idx ? 'border-[var(--r-text)] bg-[var(--r-text)] text-[var(--r-bg)]' : 'border-[var(--r-line)] hover:bg-black/5'}`}>
                    {ch.book} {ch.chapter}
                  </button>
                ))}
                <button type="button" onClick={() => b.setShowAddChapterForm((v) => !v)}
                  className="rounded-full border border-dashed border-[var(--r-sub)] px-4 py-1.5 text-sm text-[var(--r-sub)] hover:bg-black/5">+ Add chapter</button>
              </div>

              {b.showAddChapterForm && (
                <div className="rounded-2xl border border-[var(--r-line)] bg-[var(--r-bar)] p-5">
                  <h2 className="mb-3 text-sm font-medium">Add another chapter</h2>
                  <PassageForm setup={b.setup} onField={b.handleSetupField} onTitleChange={onTitleChange} onLoad={b.handleLoadChapter}
                    loading={b.loadingChapter} error={b.errorMessage} />
                </div>
              )}

              {activeChapter && (
                <div className="rounded-2xl border border-[var(--r-line)] bg-[var(--r-bar)] p-5">
                  <div className="mb-3">
                    <p className="text-xs text-[var(--r-sub)]">Scripture &amp; Chunks</p>
                    <h1 className="text-xl font-medium">{activeChapter.book} {activeChapter.chapter} <span className="text-sm font-normal text-[var(--r-sub)]">({project.translation})</span></h1>
                    <p className="mt-1 text-xs text-[var(--r-sub)]">Click the line between two verses to split or join chunks. Or click a verse, then shift-click another, to make a chunk from that range.</p>
                  </div>
                  <input type="text" value={b.verseSearch} onChange={(e) => b.setVerseSearch(e.target.value)} placeholder="Search verses in this chapter…"
                    className="mb-3 w-full rounded-xl border border-[var(--r-line)] bg-[var(--r-bg)] px-3 py-2 text-sm text-[var(--r-text)] focus:outline-none focus:ring-2 focus:ring-[var(--r-line)]" />
                  <div data-testid="verse-list" className="max-h-[68dvh] overflow-y-auto rounded-xl bg-[var(--r-bg)] px-3 py-3 font-serif text-[1.02rem] leading-[1.8]">
                    {activeChapter.verses
                      .filter((v) => v.text.toLowerCase().includes(b.verseSearch.trim().toLowerCase()))
                      .map((verse) => {
                        const n = verse.number;
                        const ci = chunkOf(n);
                        const chunk = ci >= 0 ? activeChapter.chunks[ci] : null;
                        const inRange = b.rangeStart !== null && n >= Math.min(b.rangeStart, b.rangeEnd) && n <= Math.max(b.rangeStart, b.rangeEnd);
                        const isFirst = chunk && chunk.startVerse === n;
                        const next = activeChapter.chunks.find((c) => c.startVerse === n + 1);
                        const insideChunk = chunk && n < chunk.endVerse && !chunk.spilloverEndVerse;
                        const endsChunk = chunk && chunk.endVerse === n && next && chunk.id;
                        const showGutter = n < lastVerse && !b.verseSearch.trim();
                        return (
                          <div key={n}>
                            {isFirst && (
                              <button type="button" onClick={() => select(chunk.id)}
                                className={`mt-2 block font-sans text-[11px] ${project.selectedChunkId === chunk.id ? 'text-[var(--r-accent)]' : 'text-[var(--r-sub)]'} hover:underline`}>
                                Chunk {ci + 1} · {formatChunkReference(project, activeChapterIndex, chunk, '–')}
                              </button>
                            )}
                            <button type="button" onClick={(event) => b.handleVerseClick(n, event)}
                              className={`block w-full rounded-lg px-3 py-1.5 text-left transition hover:brightness-95 ${inRange ? 'ring-2 ring-[var(--r-accent)]' : ''}`}
                              style={{ background: chunk ? BANDS[ci % 2] : spilledFromPrev(n) ? BANDS[1] : 'transparent' }}>
                              <span className="mr-2 font-sans text-[11px] font-medium text-[var(--r-accent)]">{n}</span>{verse.text}
                            </button>
                            {showGutter && (insideChunk ? (
                              <button type="button" onClick={() => b.splitAfterVerse(n)} aria-label={`Split after verse ${n}`}
                                className="group relative block h-3 w-full" title="Split the chunk here">
                                <span className="absolute inset-x-2 top-1/2 h-px bg-[var(--r-line)] group-hover:h-0.5 group-hover:bg-[var(--r-accent)]" />
                                <span className="absolute left-1/2 top-1/2 hidden -translate-x-1/2 -translate-y-1/2 rounded-full bg-[var(--r-bg)] px-2 font-sans text-[10px] text-[var(--r-accent)] group-hover:block group-focus:block">split here</span>
                              </button>
                            ) : endsChunk ? (
                              <button type="button" onClick={() => b.joinWithNext(chunk.id)} aria-label={`Join chunks at verse ${n}`}
                                className="group relative block h-4 w-full" title="Join these two chunks (their notes are combined)">
                                <span className="absolute inset-x-2 top-1/2 h-0.5 bg-[var(--r-accent)] opacity-60" />
                                <span className="absolute left-1/2 top-1/2 hidden -translate-x-1/2 -translate-y-1/2 rounded-full bg-[var(--r-bg)] px-2 font-sans text-[10px] text-[var(--r-accent)] group-hover:block group-focus:block">join</span>
                              </button>
                            ) : !chunk && !spilledFromPrev(n) ? (
                              <button type="button" onClick={() => b.splitAfterVerse(n)} aria-label={`End a chunk after verse ${n}`}
                                className="group relative block h-3 w-full" title="End a chunk after this verse">
                                <span className="absolute inset-x-2 top-1/2 h-px border-t border-dashed border-[var(--r-sub)] group-hover:border-[var(--r-accent)]" />
                                <span className="absolute left-1/2 top-1/2 hidden -translate-x-1/2 -translate-y-1/2 rounded-full bg-[var(--r-bg)] px-2 font-sans text-[10px] text-[var(--r-accent)] group-hover:block group-focus:block">end chunk here</span>
                              </button>
                            ) : <div className="h-3" />)}
                          </div>
                        );
                      })}
                  </div>
                </div>
              )}
            </section>

            {activeChapter && (
              <aside className="min-w-0 lg:sticky lg:top-4 lg:self-start">
                <div className="rounded-2xl border border-[var(--r-line)] bg-[var(--r-bar)] p-4">
                  <div className="mb-3 flex items-baseline justify-between">
                    <h2 className="text-sm font-medium">Chunks</h2>
                    <span className="text-xs text-[var(--r-sub)]">{activeChapter.chunks.length} created</span>
                  </div>
                  {b.statusMessage && <p role="status" className="mb-3 rounded-lg bg-[var(--r-bg)] px-3 py-2 text-xs text-[var(--r-accent)]">{b.statusMessage}</p>}
                  <div className="mb-3 flex flex-wrap gap-2">
                    <button type="button" onClick={b.suggestChunks} disabled={b.suggesting} className={smallBtn}
                      title="Make a chunk for each section heading in the text (only verses not yet in a chunk)">{b.suggesting ? 'Suggesting…' : 'Suggest from headings'}</button>
                    {uncovered && activeChapter.chunks.length > 0 && (
                      <button type="button" onClick={() => b.splitAfterVerse(lastVerse)} className={smallBtn} title="Make one chunk from the last chunk to the end of the chapter">Chunk the rest</button>
                    )}
                  </div>
                  <div className="max-h-[42dvh] space-y-2 overflow-y-auto">
                    {activeChapter.chunks.length === 0 ? (
                      <p className="rounded-xl border border-dashed border-[var(--r-line)] p-3 text-sm text-[var(--r-sub)]">No chunks yet. Click between verses, or suggest them from the headings.</p>
                    ) : activeChapter.chunks.map((chunk, index) => (
                      <div key={chunk.id} className={`rounded-xl border p-3 ${project.selectedChunkId === chunk.id ? 'border-[var(--r-accent)]' : 'border-[var(--r-line)]'}`}>
                        <button type="button" onClick={() => select(chunk.id)} className="block w-full text-left">
                          <span className="text-sm font-medium">{formatChunkReference(project, activeChapterIndex, chunk, '–')}</span>
                          <span className="mt-0.5 block truncate font-serif text-xs text-[var(--r-sub)]">{activeChapter.verses.find((v) => v.number === chunk.startVerse)?.text || ''}</span>
                        </button>
                        <div className="mt-2 flex items-center gap-1.5">
                          <button type="button" onClick={() => b.moveChunk(chunk.id, -1)} disabled={index === 0} aria-label="Move chunk up" className={smallBtn}>↑</button>
                          <button type="button" onClick={() => b.moveChunk(chunk.id, 1)} disabled={index === activeChapter.chunks.length - 1} aria-label="Move chunk down" className={smallBtn}>↓</button>
                          <button type="button" onClick={() => b.deleteChunk(chunk.id)} className={`${smallBtn} ml-auto text-[var(--r-danger,#b42318)]`}>× Delete</button>
                        </div>
                      </div>
                    ))}
                  </div>

                  <details className="mt-4 rounded-xl border border-[var(--r-line)] p-3 text-xs">
                    <summary className="cursor-pointer font-medium">Type ranges instead</summary>
                    <div className="mt-3 space-y-3">
                      <div className="flex flex-wrap items-end gap-2">
                        <label className="min-w-0 flex-1 text-[var(--r-sub)]">Start
                          <input type="number" min="1" max={lastVerse} value={b.typedChunkStart} onChange={(e) => b.setTypedChunkStart(e.target.value)} className={inputCls} /></label>
                        <label className="min-w-0 flex-1 text-[var(--r-sub)]">End
                          <input type="number" min="1" max={lastVerse} value={b.typedChunkEnd} onChange={(e) => b.setTypedChunkEnd(e.target.value)}
                            onKeyDown={(e) => { if (e.key === 'Enter') { e.preventDefault(); b.addTypedChunk(); } }} className={inputCls} /></label>
                        <label className="min-w-0 flex-1 text-[var(--r-sub)]">Next ch end
                          <input type="number" min="1" value={b.typedChunkNextEnd} onChange={(e) => b.setTypedChunkNextEnd(e.target.value)} placeholder="optional" className={inputCls} /></label>
                        <button type="button" onClick={b.addTypedChunk} className={smallBtn}>Add</button>
                      </div>
                      <label className="block text-[var(--r-sub)]">Bulk ranges (comma or new line; <code>start-end:nextEnd</code> spans into the next chapter)
                        <textarea rows={2} value={b.typedChunkBulk} onChange={(e) => b.setTypedChunkBulk(e.target.value)} placeholder="1-6, 7-31:5, 6" className={`${inputCls} resize-y`} />
                      </label>
                      <button type="button" onClick={b.addBulkTypedChunks} className={smallBtn}>Add all ranges</button>
                      <div className="border-t border-[var(--r-line)] pt-3">
                        <p className="mb-1 text-[var(--r-sub)]">Span into the next chapter: click a start verse, then choose where to end there.</p>
                        <div className="flex items-end gap-2">
                          <div className="flex-1 text-[var(--r-sub)]">Start<div className={`${inputCls} text-[var(--r-text)]`}>{b.rangeStart ?? 'Not selected'}</div></div>
                          <label className="flex-1 text-[var(--r-sub)]">Next ch end
                            <input type="number" min="1" value={b.clickedSpanNextEnd} onChange={(e) => b.setClickedSpanNextEnd(e.target.value)} placeholder="e.g. 5" className={inputCls} /></label>
                          <button type="button" onClick={b.addClickSpanChunk} className={smallBtn}>Span into next</button>
                        </div>
                      </div>
                    </div>
                  </details>

                  <button type="button" onClick={b.beginStudying} disabled={allChunks.length === 0} className={`${primaryBtn} mt-4 w-full`}>Begin studying →</button>
                </div>
              </aside>
            )}
          </div>
        )}
      </main>
    </StudioShell>
  );
}