const app = document.getElementById('app')
const SOURCES = { lc: 'LeerCapitulo (español)', md: 'MangaDex (multi-idioma)' }
// Filtros de imagen del lector (CSS filter); el brillo se suma aparte.
const FILTERS = {
  none: ['Sin filtro', ''],
  sepia: ['Sepia', 'sepia(.65) contrast(.95)'],
  paper: ['Papel cálido', 'sepia(.35) saturate(1.15) hue-rotate(-8deg) brightness(.95)'],
  vintage: ['Vintage', 'sepia(.45) contrast(1.1) saturate(.75)'],
  night: ['Noche (invertido)', 'invert(.88) hue-rotate(180deg) contrast(.95)'],
  gray: ['Blanco y negro', 'grayscale(1)'],
  contrast: ['Alto contraste', 'contrast(1.35) brightness(1.03)'],
  vivid: ['Colores vivos', 'saturate(1.45) contrast(1.05)'],
}
const DL_ACTIVE = ['queued', 'downloading']
const fmtSize = b => (b >= 1e9 ? `${(b / 1e9).toFixed(1)} GB` : b >= 1e6 ? `${Math.round(b / 1e6)} MB` : `${Math.round((b || 0) / 1e3)} KB`)
// Progreso global contando la fracción del capítulo en curso.
function downloadPct(d) {
  if (!d?.total) return 0
  const frac = d.current?.pagesTotal ? d.current.pages / d.current.pagesTotal : 0
  return Math.min(100, ((d.done + frac) / d.total) * 100)
}
function downloadDetail(d) {
  const c = d?.current
  if (!c) return d?.status === 'queued' ? 'Esperando turno…' : ''
  return c.pagesTotal ? `Cap. ${esc(c.chapter ?? '?')} · pág. ${c.pages}/${c.pagesTotal}` : `Cap. ${esc(c.chapter ?? '?')} · preparando…`
}
function downloadLabel(d) {
  if (!d) return ''
  const n = `${d.done}/${d.total || '?'}`
  return {
    queued: 'En cola…',
    downloading: `Descargando ${n}`,
    done: `Descargado (${d.done} caps.)`,
    error: `Descarga incompleta ${n}`,
    cancelled: `Descarga cancelada ${n}`,
  }[d.status] || d.status
}
const LANGS = { 'es-la': 'Español (Latam)', es: 'Español (España)', en: 'English', 'pt-br': 'Português (BR)', fr: 'Français', it: 'Italiano', ja: '日本語' }
let me = null
let cleanup = null

// ---------- Utilidades ----------
const esc = s => String(s ?? '').replace(/[&<>"']/g, c => ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[c]))
const $ = (sel, root = document) => root.querySelector(sel)
const store = {
  get(k, d) { try { return JSON.parse(localStorage.getItem(k)) ?? d } catch { return d } },
  set(k, v) { try { localStorage.setItem(k, JSON.stringify(v)) } catch {} },
}
function toast(msg) {
  const t = document.getElementById('toast')
  t.textContent = msg
  t.hidden = false
  clearTimeout(toast.t)
  toast.t = setTimeout(() => (t.hidden = true), 2500)
}
async function api(path, opts = {}) {
  const res = await fetch(path, {
    ...opts,
    headers: opts.body ? { 'Content-Type': 'application/json' } : undefined,
    body: opts.body ? JSON.stringify(opts.body) : undefined,
  })
  const data = await res.json().catch(() => ({}))
  if (res.status === 401 && !path.startsWith('/api/login')) { me = null; location.hash = '#/login'; throw new Error('No autenticado') }
  if (!res.ok) throw new Error(data.error || `Error ${res.status}`)
  return data
}
function timeAgo(ts) {
  const s = (Date.now() - ts) / 1000
  if (s < 60) return 'hace un momento'
  if (s < 3600) return `hace ${Math.floor(s / 60)} min`
  if (s < 86400) return `hace ${Math.floor(s / 3600)} h`
  return `hace ${Math.floor(s / 86400)} d`
}
const chapLabel = c => (c.num ? `Cap. ${c.num}` : 'Oneshot') + (c.title ? ` — ${c.title}` : '')
const readUrl = (mangaId, chapterId, page) => `#/read/${mangaId}/${chapterId}${page != null ? `?page=${page + 1}` : ''}`

// ---------- Router ----------
async function router() {
  if (cleanup) { cleanup(); cleanup = null }
  document.body.classList.remove('reading')
  const [pathPart, query] = location.hash.slice(1).split('?')
  const parts = (pathPart || '/').split('/').filter(Boolean)
  const params = new URLSearchParams(query || '')
  document.querySelectorAll('#topbar nav a').forEach(a => a.classList.toggle('active', a.getAttribute('href') === `#/${parts[0] ?? ''}`))

  if (!me) {
    const r = await api('/api/me').catch(() => ({}))
    me = r.user
    me && (me.signup = r.signup)
    if (!me) return viewAuth(r.signup)
  }
  try {
    if (parts[0] === 'login') return (location.hash = '#/')
    if (parts[0] === 'manga') return await viewManga(parts[1])
    if (parts[0] === 'read') return await viewReader(parts[1], parts[2], Number(params.get('page') || 0) - 1)
    if (parts[0] === 'history') return await viewHistory()
    if (parts[0] === 'downloads') return await viewDownloads()
    if (parts[0] === 'settings') return viewSettings()
    return await viewHome(params)
  } catch (e) {
    if (e.message !== 'No autenticado') app.innerHTML = `<p class="error">${esc(e.message)}</p>`
  }
}
window.addEventListener('hashchange', router)
router()

// ---------- Login / registro ----------
function viewAuth(signup) {
  app.innerHTML = `
  <div class="auth">
    <h1>Manga Reader</h1>
    <p class="muted">Inicia sesión para leer y guardar tu progreso.</p>
    <form>
      <input type="text" name="username" placeholder="Usuario" autocomplete="username" required>
      <input type="password" name="password" placeholder="Contraseña" autocomplete="current-password" required>
      <p class="error"></p>
      <button class="btn primary" value="login">Entrar</button>
      ${signup ? '<button class="btn" value="register">Crear cuenta</button>' : ''}
    </form>
  </div>`
  const form = $('form', app)
  form.addEventListener('submit', async ev => {
    ev.preventDefault()
    const mode = ev.submitter?.value === 'register' ? 'register' : 'login'
    const fd = new FormData(form)
    try {
      await api(`/api/${mode}`, { method: 'POST', body: { username: fd.get('username'), password: fd.get('password') } })
      me = null
      location.hash = '#/'
      router()
    } catch (e) { $('.error', form).textContent = e.message }
  })
}

// ---------- Inicio ----------
function mangaCard(m) {
  return `<a class="card" href="#/manga/${m.id}">
    <img class="cover" loading="lazy" src="${esc(m.cover || '/icon.svg')}" alt="">
    <div class="t">${esc(m.title)}</div>${m.sub ? `<div class="sub">${esc(m.sub)}</div>` : ''}</a>`
}
function continueCard(h) {
  const pct = h.total_pages ? Math.round(((h.page + 1) / h.total_pages) * 100) : 0
  return `<a class="cont" href="${readUrl(h.manga_id, h.chapter_id, h.page)}">
    <img src="${esc(h.cover || '/icon.svg')}" alt="" loading="lazy">
    <div class="info"><b>${esc(h.manga_title)}</b>
      <div class="muted">${h.chapter_num ? `Cap. ${esc(h.chapter_num)}` : 'Oneshot'} · pág. ${h.page + 1}/${h.total_pages || '?'}</div>
      <div class="muted" style="font-size:.8rem">${timeAgo(h.updated_at)}</div>
      <div class="bar"><i style="width:${pct}%"></i></div></div></a>`
}
const tagHref = (source, t) => `#/?source=${source}&tag=${encodeURIComponent(t.id)}&tagName=${encodeURIComponent(t.name)}`
async function viewHome(params) {
  const q = params.get('q') || ''
  const tag = params.get('tag') || ''
  const tagName = params.get('tagName') || tag
  const mode = tag ? 'cats' : params.get('mode') || 'popular'
  const anyLang = params.get('any') === '1'
  const source = SOURCES[params.get('source')] ? params.get('source') : store.get('source', 'lc')
  store.set('source', source)
  const showCats = mode === 'cats' && !tag
  app.innerHTML = `
    <section id="cont"></section>
    <div class="tabs" id="sources">${Object.entries(SOURCES).map(([k, v]) => `<button data-s="${k}" class="${k === source ? 'on' : ''}">${v}</button>`).join('')}</div>
    <form class="search"><input type="search" name="q" placeholder="Buscar ${tag ? `en «${esc(tagName)}»` : `en ${esc(SOURCES[source])}`}…" value="${esc(q)}"><button class="btn primary">Buscar</button></form>
    <label class="muted row" style="font-size:.88rem" ${source === 'md' ? '' : 'hidden'}><input type="checkbox" name="any" ${anyLang ? 'checked' : ''}> Incluir mangas sin traducción a ${esc(LANGS[me.lang] || me.lang)}</label>
    ${q && !tag ? `<h2>Resultados para “${esc(q)}”</h2>` : `<div class="tabs" id="modes">
      <button data-m="popular" class="${mode === 'popular' ? 'on' : ''}">Populares</button>
      <button data-m="latest" class="${mode === 'latest' ? 'on' : ''}">Actualizados recientemente</button>
      <button data-m="cats" class="${mode === 'cats' ? 'on' : ''}">Categorías</button></div>`}
    ${tag ? `<h2>Categoría: <a class="tag on" href="#/?source=${source}&mode=cats" title="Quitar filtro">${esc(tagName)} ✕</a>${q ? ` · “${esc(q)}”` : ''}</h2>` : ''}
    <div id="results" class="loading">Cargando…</div>
    <div class="row" style="justify-content:center;margin:16px 0"><button class="btn" id="more" hidden>Cargar más</button></div>`
  const form = $('form', app)
  const go = (extra = {}) => {
    const p = new URLSearchParams({ source, ...(form.q.value ? { q: form.q.value } : { mode }), ...(tag ? { tag, tagName } : {}), ...($('[name=any]').checked ? { any: '1' } : {}), ...extra })
    location.hash = `#/?${p}`
  }
  form.addEventListener('submit', e => { e.preventDefault(); go() })
  $('[name=any]').addEventListener('change', () => go())
  app.querySelectorAll('#modes button').forEach(b => b.addEventListener('click', () => { location.hash = `#/?source=${source}&mode=${b.dataset.m}${anyLang ? '&any=1' : ''}` }))
  app.querySelectorAll('#sources button').forEach(b => b.addEventListener('click', () => { location.hash = `#/?source=${b.dataset.s}&mode=${mode}${anyLang ? '&any=1' : ''}` }))

  api('/api/history').then(hist => {
    if (!hist.length || q || tag || showCats) return
    $('#cont').innerHTML = `<h2>Continuar leyendo</h2><div class="continue">${hist.slice(0, 12).map(continueCard).join('')}</div>`
  }).catch(() => {})

  const res = $('#results')
  if (showCats) {
    const cats = await api(`/api/categories?source=${source}`)
    const groups = cats.reduce((m, c) => m.set(c.group, [...(m.get(c.group) || []), c]), new Map())
    res.className = 'cats'
    res.innerHTML = [...groups].map(([g, list]) => `<h3>${esc(g)}</h3><div class="tags">${list.map(t => `<a class="tag big" href="${tagHref(source, t)}">${esc(t.name)}</a>`).join('')}</div>`).join('')
    return
  }

  // Paginación: MangaDex siempre; LeerCapitulo solo en categorías (sus otros listados no paginan).
  const pageable = source === 'md' || !!tag
  const seen = new Set()
  let page = 1
  const load = async () => {
    const qs = new URLSearchParams({ q, mode, source, page, ...(tag ? { tag } : {}), ...(anyLang ? { anyLang: '1' } : {}) })
    const list = (await api(`/api/search?${qs}`)).filter(m => !seen.has(m.id) && seen.add(m.id))
    if (page === 1) {
      res.className = list.length ? 'grid' : 'loading'
      res.innerHTML = list.length ? '' : 'Sin resultados.'
    }
    res.insertAdjacentHTML('beforeend', list.map(mangaCard).join(''))
    $('#more').hidden = !pageable || list.length < 20
  }
  $('#more').addEventListener('click', async e => {
    e.target.disabled = true
    page++
    try { await load() } catch (err) { toast(err.message) }
    e.target.disabled = false
  })
  await load()
}

// ---------- Ficha del manga ----------
async function viewManga(id, langOverride) {
  if (cleanup) { cleanup(); cleanup = null }
  app.innerHTML = '<div class="loading">Cargando…</div>'
  const lang = langOverride || store.get(`lang:${id}`, me.lang)
  const { manga, chapters, reads, progress, chapterLangs, offline, downloaded, download } = await api(`/api/manga/${id}?lang=${encodeURIComponent(lang)}`)
  const dlSet = new Set(downloaded)
  const readMap = new Map(reads.map(r => [r.chapter_id, r]))
  const isLc = manga.source === 'lc'
  const langOpts = [...new Set([lang, me.lang, ...chapterLangs, ...manga.languages])].filter(Boolean)
  const altSearch = `#/?source=lc&q=${encodeURIComponent(manga.title)}`
  const first = chapters[0]
  let mainBtn = ''
  if (progress && chapters.some(c => c.id === progress.chapter_id)) {
    mainBtn = `<a class="btn primary" href="${readUrl(id, progress.chapter_id, progress.page)}">Continuar · ${progress.chapter_num ? `Cap. ${esc(progress.chapter_num)}` : 'Oneshot'}, pág. ${progress.page + 1}</a>`
  } else if (progress) {
    mainBtn = `<a class="btn primary" href="${readUrl(id, progress.chapter_id, progress.page)}">Continuar · Cap. ${esc(progress.chapter_num ?? '?')} (${esc(LANGS[progress.lang] || progress.lang || '')}), pág. ${progress.page + 1}</a>`
  }
  if (first && !mainBtn) mainBtn = `<a class="btn primary" href="${readUrl(id, first.id)}">Empezar a leer</a>`

  app.innerHTML = `
  <div class="detail">
    <img class="cover" src="${esc(manga.cover || '/icon.svg')}" alt="">
    <div>
      <h1>${esc(manga.title)}</h1>
      <div class="muted">${esc(manga.authors.join(', '))}${manga.year ? ` · ${manga.year}` : ''}${manga.status ? ` · ${esc(manga.status)}` : ''}</div>
      <div class="tags">${manga.tags.map(t => (t.id ? `<a class="tag" href="${tagHref(manga.source, t)}">${esc(t.name)}</a>` : `<span class="tag">${esc(t.name ?? t)}</span>`)).join('')}</div>
      <p class="desc">${esc(manga.description)}</p>
      <div class="row">${mainBtn}
        ${progress || reads.length ? '<button class="btn danger" id="drop">Dejar de leer</button>' : ''}
        ${isLc ? '' : `<select id="lang">${langOpts.map(l => `<option value="${esc(l)}" ${l === lang ? 'selected' : ''}>${esc(LANGS[l] || l)}</option>`).join('')}</select>
        <a class="btn" href="${altSearch}">Buscar en LeerCapitulo</a>`}
      </div>
      <div class="muted" style="font-size:.85rem;margin-top:6px">Fuente: ${esc(SOURCES[manga.source])}${download ? ` · Carpeta: mangas/${esc(download.folder)}` : ''}</div>
      ${offline ? '<p class="error">Sin conexión con la fuente: mostrando solo los capítulos descargados.</p>' : ''}
      <div id="dl" class="dlbox"></div>
      <p class="error" id="dlerr" style="font-size:.85rem"></p>
    </div>
  </div>
  <h2>Capítulos <span class="muted">(${chapters.length})</span>
    ${chapters.length > 1 ? '<button class="btn small" id="order" style="float:right">Invertir orden</button>' : ''}</h2>
  ${chapters.length ? '<ul class="chapters"></ul>' : isLc ? '<p class="muted">Este manga no tiene capítulos.</p>' : `<p class="muted">No hay capítulos legibles en ${esc(LANGS[lang] || lang)} (MangaDex retira algunos por licencia).
    Prueba a <a class="tag" href="${altSearch}">buscarlo en LeerCapitulo</a>.
    ${chapterLangs.length ? `Disponibles en: ${chapterLangs.map(l => `<a class="tag" href="#" data-lang="${esc(l)}">${esc(LANGS[l] || l)}</a>`).join(' ')}` : 'No hay capítulos en ningún idioma.'}</p>`}`
  // Botón de descarga con sondeo del progreso mientras está activa.
  let dlTimer = null
  const renderDl = d => {
    const box = $('#dl')
    if (!box) return
    const active = d && DL_ACTIVE.includes(d.status)
    const delBtn = d ? `<button class="btn small danger" id="dldel">Eliminar copia local${d.size ? ` (${fmtSize(d.size)})` : ''}</button>` : ''
    const bar = d && (active || d.done < d.total) ? `<div class="bar dlbar"><i style="width:${downloadPct(d).toFixed(1)}%"></i></div>` : ''
    let html
    if (!d || d.status === 'cancelled') html = `<div class="row"><button class="btn" id="dlgo">⬇ Descargar${d ? ` (llevas ${d.done}/${d.total})` : ''}</button>${delBtn}</div>${bar}`
    else if (active) html = `<div class="row"><span>${downloadLabel(d)} · ${Math.floor(downloadPct(d))}%</span><button class="btn small" id="dlcancel">Cancelar</button>${delBtn}</div>${bar}<div class="muted" style="font-size:.8rem">${downloadDetail(d)}</div>`
    else html = `<div class="row"><span class="muted">✓ ${downloadLabel(d)}</span><button class="btn small" id="dlgo" title="Descarga los capítulos que falten">${d.status === 'error' ? 'Reintentar' : 'Buscar nuevos'}</button>${delBtn}</div>${bar}`
    box.innerHTML = offline ? (d ? `<span class="muted">${downloadLabel(d)}</span>` : '') : html
    $('#dlerr').textContent = d?.status === 'error' ? d.error || '' : ''
    $('#dlgo')?.addEventListener('click', async () => {
      renderDl(await api(`/api/download/${id}`, { method: 'POST', body: { lang, title: manga.title } }))
      toast(`Descargando en mangas/${manga.title}`)
    })
    $('#dlcancel')?.addEventListener('click', async () => renderDl(await api(`/api/download/${id}/cancel`, { method: 'POST' })))
    $('#dldel')?.addEventListener('click', async () => {
      if (!confirm(`¿Eliminar la copia local de «${manga.title}»?\nSe borrará la carpeta mangas/${d.folder}${d.size ? ` (${fmtSize(d.size)})` : ''}.\nTu historial de lectura no se toca.`)) return
      await api(`/api/download/${id}`, { method: 'DELETE' })
      toast('Copia local eliminada')
      viewManga(id, langOverride)
    })
    clearTimeout(dlTimer)
    if (active) dlTimer = setTimeout(async () => {
      const next = await api(`/api/download/${id}`).catch(() => d)
      if (!$('#dl')) return
      if (next && next.done !== d.done) { const fresh = await api(`/api/manga/${id}?lang=${encodeURIComponent(lang)}`).catch(() => null); fresh?.downloaded.forEach(x => dlSet.add(x)); renderList(); if (fresh?.download) next.size = fresh.download.size }
      renderDl(next)
    }, 2000)
  }
  renderDl(download)
  cleanup = () => clearTimeout(dlTimer)
  $('#drop')?.addEventListener('click', async () => {
    if (!confirm(`¿Dejar de leer «${manga.title}»?\nSe quitará del historial y se borrará el progreso de sus capítulos.`)) return
    await api(`/api/history/${id}`, { method: 'DELETE' })
    toast('Quitado del historial')
    viewManga(id, langOverride)
  })
  app.querySelectorAll('[data-lang]').forEach(a => a.addEventListener('click', e => { e.preventDefault(); store.set(`lang:${id}`, a.dataset.lang); viewManga(id, a.dataset.lang) }))

  const ul = $('.chapters', app)
  let desc = store.get('chapterOrderDesc', true)
  const renderList = () => {
    if (!ul) return
    const list = desc ? [...chapters].reverse() : chapters
    ul.innerHTML = list.map(c => {
      const r = readMap.get(c.id)
      const done = r && r.total_pages && r.page >= r.total_pages - 1
      const cls = progress?.chapter_id === c.id ? 'current' : done ? 'read' : ''
      const meta = (dlSet.has(c.id) ? '<span title="Descargado">⬇</span> ' : '') + (r ? (done ? 'Leído' : `pág. ${r.page + 1}/${r.total_pages}`) : esc(c.group))
      return `<li><a class="${cls}" href="${readUrl(id, c.id, r && !done ? r.page : (done ? 0 : null))}"><span>${esc(chapLabel(c))}</span><span class="meta">${meta}</span></a></li>`
    }).join('')
  }
  renderList()
  $('#order')?.addEventListener('click', () => { desc = !desc; store.set('chapterOrderDesc', desc); renderList() })
  $('#lang')?.addEventListener('change', e => { store.set(`lang:${id}`, e.target.value); viewManga(id, e.target.value) })
}

// ---------- Lector ----------
async function viewReader(mangaId, chapterId, startPage) {
  document.body.classList.add('reading')
  app.innerHTML = '<div class="reader"><div class="loading">Cargando capítulo…</div></div>'
  const lang = store.get(`lang:${mangaId}`, me.lang)
  const settings = { mode: 'paged', fit: 'height', dir: 'ltr', saver: false, filter: 'none', brightness: 100, ...store.get('readerSettings', {}) }
  const [info, chap] = await Promise.all([
    api(`/api/manga/${mangaId}?lang=${encodeURIComponent(lang)}`),
    api(`/api/chapter/${chapterId}?saver=${settings.saver ? 1 : 0}`),
  ])
  const { manga, chapters } = info
  const idx = chapters.findIndex(c => c.id === chapterId)
  const chapter = chapters[idx] || { id: chapterId, num: info.progress?.chapter_num, title: '' }
  const prev = idx > 0 ? chapters[idx - 1] : null
  const next = idx >= 0 && idx < chapters.length - 1 ? chapters[idx + 1] : null
  const pages = chap.pages
  const total = pages.length
  let page = Math.min(Math.max(startPage >= 0 ? startPage : chap.savedPage || 0, 0), total - 1)

  // Guardado del progreso (con debounce y al salir de la página).
  let saveTimer = null
  const payload = () => ({
    mangaId, chapterId, mangaTitle: manga.title, cover: manga.cover, chapterNum: chapter.num ?? null,
    chapterTitle: chapter.title, lang: manga.source === 'lc' ? 'es' : chapter.lang || lang, page, totalPages: total,
  })
  const saveNow = () => { clearTimeout(saveTimer); saveTimer = null; api('/api/progress', { method: 'POST', body: payload() }).catch(() => {}) }
  const scheduleSave = () => { clearTimeout(saveTimer); saveTimer = setTimeout(saveNow, 700) }
  const beacon = () => { if (saveTimer) { clearTimeout(saveTimer); saveTimer = null; navigator.sendBeacon('/api/progress', JSON.stringify(payload())) } }
  const onVis = () => document.visibilityState === 'hidden' && beacon()
  document.addEventListener('visibilitychange', onVis)
  window.addEventListener('pagehide', beacon)
  saveNow()

  const chapOpts = chapters.map(c => `<option value="${c.id}" ${c.id === chapterId ? 'selected' : ''}>${esc(chapLabel(c))}</option>`).join('')
  app.innerHTML = `
  <div class="reader">
    <div class="rbar top">
      <a class="btn small" href="#/manga/${mangaId}">←</a>
      <div class="ttl"><b>${esc(manga.title)}</b></div>
      <select id="chap" style="max-width:40vw">${chapOpts}</select>
      <select id="mode"><option value="paged">Por página</option><option value="vertical">Vertical</option></select>
      <select id="fit"><option value="height">Ajustar alto</option><option value="width">Ajustar ancho</option></select>
      <select id="dir"><option value="ltr">Izq → Der</option><option value="rtl">Der → Izq</option></select>
      <select id="filter" title="Filtro">${Object.entries(FILTERS).map(([k, [label]]) => `<option value="${k}">${label}</option>`).join('')}</select>
      <label class="row muted" style="font-size:.85rem" title="Brillo">☀ <input type="range" id="bright" min="40" max="120" step="5" style="width:90px"></label>
      ${manga.source === 'lc' ? '' : '<label class="row muted" style="font-size:.85rem"><input type="checkbox" id="saver"> Ahorro datos</label>'}
    </div>
    <div id="pages"></div>
    <div class="rbar bottom">
      ${prev ? `<a class="btn small" href="${readUrl(mangaId, prev.id)}">« Cap. ant.</a>` : ''}
      <span id="pnum" class="muted"></span>
      <input type="range" id="slider" min="1" max="${total}" value="${page + 1}">
      ${next ? `<a class="btn small" href="${readUrl(mangaId, next.id)}">Cap. sig. »</a>` : ''}
    </div>
  </div>`
  const reader = $('.reader', app)
  const box = $('#pages', app)
  const slider = $('#slider', app)
  $('#mode').value = settings.mode
  $('#fit').value = settings.fit
  $('#dir').value = settings.dir
  $('#filter').value = FILTERS[settings.filter] ? settings.filter : 'none'
  $('#bright').value = settings.brightness
  const applyFilter = () => {
    const f = [FILTERS[settings.filter]?.[1] || '', settings.brightness != 100 ? `brightness(${settings.brightness / 100})` : ''].join(' ').trim()
    box.style.setProperty('--page-filter', f || 'none')
  }
  applyFilter()
  if ($('#saver')) $('#saver').checked = settings.saver
  const endBlock = `<div class="chapter-end"><p class="muted">Fin del capítulo ${esc(chapter.num ?? '')}</p>
    ${next ? `<a class="btn primary" href="${readUrl(mangaId, next.id)}">Siguiente: ${esc(chapLabel(next))}</a>` : '<p>No hay más capítulos disponibles.</p>'}
    <a class="btn" href="#/manga/${mangaId}">Volver a la ficha</a></div>`

  const setPageLabel = () => { $('#pnum').textContent = `${page + 1} / ${total}`; slider.value = page + 1 }
  let observer = null
  let atEnd = false

  function goTo(n, fromScroll = false) {
    if (n >= total && settings.mode === 'paged') { atEnd = true; box.innerHTML = endBlock; reader.classList.remove('hide-ui'); return }
    n = Math.min(Math.max(n, 0), total - 1)
    const changed = n !== page || atEnd
    atEnd = false
    page = n
    setPageLabel()
    if (settings.mode === 'paged') {
      const img = $('img', box) || Object.assign(document.createElement('img'), { alt: '' })
      if (!img.isConnected) { box.innerHTML = ''; box.append(img) }
      img.src = pages[page]
      window.scrollTo(0, 0)
      for (let k = 1; k <= 3; k++) if (pages[page + k]) new Image().src = pages[page + k]
    } else if (!fromScroll) {
      box.querySelectorAll('img')[page]?.scrollIntoView()
    }
    if (changed) scheduleSave()
  }

  function render() {
    observer?.disconnect()
    box.className = settings.mode === 'paged' ? `paged ${settings.fit === 'width' ? 'fit-width' : ''}` : 'vertical'
    $('#fit').hidden = settings.mode !== 'paged'
    $('#dir').hidden = settings.mode !== 'paged'
    if (settings.mode === 'paged') {
      box.innerHTML = ''
      goTo(page)
      return
    }
    box.innerHTML = pages.map((src, i) => `<img data-i="${i}" ${i < page + 3 ? `src="${src}"` : `data-src="${src}"`} alt="">`).join('') + endBlock
    box.querySelectorAll('img').forEach(img => img.addEventListener('load', () => img.setAttribute('data-loaded', ''), { once: true }))
    const lazy = new IntersectionObserver(entries => entries.forEach(e => {
      if (e.isIntersecting && e.target.dataset.src) { e.target.src = e.target.dataset.src; delete e.target.dataset.src }
    }), { rootMargin: '2000px 0px' })
    // No seguir el scroll hasta haber saltado a la página guardada, para no pisarla con la 0.
    let ready = false
    observer = new IntersectionObserver(entries => {
      if (!ready) return
      for (const e of entries) if (e.isIntersecting) goTo(Number(e.target.dataset.i), true)
    }, { rootMargin: '-45% 0px -45% 0px' })
    const imgs = [...box.querySelectorAll('img')]
    imgs.forEach(img => { lazy.observe(img); observer.observe(img) })
    const lazyDisconnect = observer.disconnect.bind(observer)
    observer.disconnect = () => { lazyDisconnect(); lazy.disconnect() }
    const before = imgs.slice(0, page + 1).map(img => img.complete ? null : new Promise(r => { img.addEventListener('load', r, { once: true }); img.addEventListener('error', r, { once: true }) }))
    Promise.race([Promise.all(before), new Promise(r => setTimeout(r, 8000))]).then(() => {
      imgs[page]?.scrollIntoView()
      lastY = window.scrollY
      setTimeout(() => (ready = true), 300)
    })
    setPageLabel()
  }

  const saveSettings = () => store.set('readerSettings', settings)
  $('#mode').addEventListener('change', e => { settings.mode = e.target.value; saveSettings(); render() })
  $('#fit').addEventListener('change', e => { settings.fit = e.target.value; saveSettings(); render() })
  $('#dir').addEventListener('change', e => { settings.dir = e.target.value; saveSettings() })
  $('#filter').addEventListener('change', e => { settings.filter = e.target.value; saveSettings(); applyFilter() })
  $('#bright').addEventListener('input', e => { settings.brightness = Number(e.target.value); saveSettings(); applyFilter() })
  $('#bright').addEventListener('dblclick', e => { e.target.value = settings.brightness = 100; saveSettings(); applyFilter() })
  $('#saver')?.addEventListener('change', e => { settings.saver = e.target.checked; saveSettings(); history.replaceState(null, '', readUrl(mangaId, chapterId, page)); router() })
  $('#chap').addEventListener('change', e => { location.hash = readUrl(mangaId, e.target.value) })
  slider.addEventListener('input', () => goTo(Number(slider.value) - 1))

  // Toques: izquierda/derecha cambian de página (según dirección), centro muestra/oculta barras.
  box.addEventListener('click', e => {
    if (e.target.closest('a,button')) return
    if (settings.mode !== 'paged') { reader.classList.toggle('hide-ui'); return }
    const x = e.clientX / window.innerWidth
    if (x > 0.35 && x < 0.65) { reader.classList.toggle('hide-ui'); return }
    const forward = (x >= 0.65) === (settings.dir === 'ltr')
    if (atEnd && !forward) { atEnd = false; box.innerHTML = ''; goTo(total - 1); return }
    if (!atEnd) goTo(page + (forward ? 1 : -1))
  })
  const onKey = e => {
    if (settings.mode !== 'paged' || e.target.matches('input,select')) return
    const fwdKey = settings.dir === 'ltr' ? 'ArrowRight' : 'ArrowLeft'
    const backKey = settings.dir === 'ltr' ? 'ArrowLeft' : 'ArrowRight'
    if (e.key === fwdKey || e.key === ' ') { e.preventDefault(); if (!atEnd) goTo(page + 1) }
    else if (e.key === backKey) { if (atEnd) { atEnd = false; box.innerHTML = ''; goTo(total - 1) } else goTo(page - 1) }
  }
  document.addEventListener('keydown', onKey)
  let lastY = 0
  const onScroll = () => {
    if (settings.mode !== 'vertical') return
    const y = window.scrollY
    if (Math.abs(y - lastY) > 30) { reader.classList.toggle('hide-ui', y > lastY); lastY = y }
  }
  window.addEventListener('scroll', onScroll, { passive: true })

  render()
  cleanup = () => {
    if (saveTimer) saveNow()
    observer?.disconnect()
    document.removeEventListener('visibilitychange', onVis)
    window.removeEventListener('pagehide', beacon)
    document.removeEventListener('keydown', onKey)
    window.removeEventListener('scroll', onScroll)
  }
}

// ---------- Historial ----------
async function viewHistory() {
  app.innerHTML = '<div class="loading">Cargando…</div>'
  const hist = await api('/api/history')
  app.innerHTML = `<h1>Historial de lectura</h1>
    ${hist.length ? '' : '<p class="muted">Aún no has leído nada.</p>'}
    <div class="history">${hist.map(h => `
      <div class="cont">
        ${continueCard(h).replace('class="cont"', 'style="display:flex;gap:12px;flex:1;min-width:0;align-items:center"')}
        <div class="row" style="flex:none">
          <a class="btn small" href="#/manga/${h.manga_id}">Ficha</a>
          <button class="btn small danger" data-del="${h.manga_id}">Borrar</button>
        </div>
      </div>`).join('')}</div>`
  app.querySelectorAll('[data-del]').forEach(b => b.addEventListener('click', async () => {
    if (!confirm('¿Borrar el historial de este manga?')) return
    await api(`/api/history/${b.dataset.del}`, { method: 'DELETE' })
    viewHistory()
  }))
}

// ---------- Descargas ----------
async function viewDownloads() {
  if (cleanup) { cleanup(); cleanup = null }
  const list = await api('/api/downloads')
  if (location.hash !== '#/downloads') return
  const total = list.reduce((n, d) => n + (d.size || 0), 0)
  app.innerHTML = `<h1>Descargas</h1>
    <p class="muted">Se guardan en <code>/zdata/media/mangas</code> como CBZ (compatibles con Kavita, Komga, Mihon…). Los capítulos descargados se leen desde el disco.${list.length ? ` Total: <b>${fmtSize(total)}</b>.` : ''}</p>
    ${list.length ? '' : '<p class="muted">Aún no has descargado nada. Usa “⬇ Descargar” en la ficha de un manga.</p>'}
    <div class="history">${list.map(d => {
      const active = DL_ACTIVE.includes(d.status)
      return `<div class="cont">
        <a class="info" href="#/manga/${d.manga_id}"><b>${esc(d.title)}</b>
          <div class="muted">${esc(downloadLabel(d))}${active ? ` · ${Math.floor(downloadPct(d))}%` : ''} · ${fmtSize(d.size)} · mangas/${esc(d.folder)}</div>
          ${active ? `<div class="muted" style="font-size:.8rem">${downloadDetail(d)}</div>` : ''}
          ${d.status === 'error' ? `<div class="error" style="font-size:.8rem">${esc(d.error || '')}</div>` : ''}
          <div class="bar dlbar"><i style="width:${downloadPct(d).toFixed(1)}%"></i></div></a>
        <div class="row" style="flex:none">
          ${active ? `<button class="btn small" data-cancel="${esc(d.manga_id)}">Cancelar</button>` : ''}
          <button class="btn small danger" data-del="${esc(d.manga_id)}" data-title="${esc(d.title)}" data-size="${d.size || 0}">Eliminar</button>
        </div></div>`
    }).join('')}</div>`
  app.querySelectorAll('[data-cancel]').forEach(b => b.addEventListener('click', async () => { await api(`/api/download/${b.dataset.cancel}/cancel`, { method: 'POST' }); viewDownloads() }))
  app.querySelectorAll('[data-del]').forEach(b => b.addEventListener('click', async () => {
    if (!confirm(`¿Eliminar la copia local de «${b.dataset.title}» (${fmtSize(Number(b.dataset.size))})?\nTu historial de lectura no se toca.`)) return
    await api(`/api/download/${b.dataset.del}`, { method: 'DELETE' })
    toast('Copia local eliminada')
    viewDownloads()
  }))
  if (list.some(d => DL_ACTIVE.includes(d.status))) {
    const t = setTimeout(() => location.hash === '#/downloads' && viewDownloads(), 2000)
    cleanup = () => clearTimeout(t)
  }
}

// ---------- Ajustes ----------
function viewSettings() {
  app.innerHTML = `<h1>Ajustes</h1>
  <div class="settings">
    <section><b>Cuenta</b><div class="muted">Sesión iniciada como <b>${esc(me.username)}</b></div>
      <button class="btn" id="logout">Cerrar sesión</button></section>
    <section><b>Idioma preferido de los capítulos</b>
      <select id="lang">${Object.entries(LANGS).map(([k, v]) => `<option value="${k}" ${k === me.lang ? 'selected' : ''}>${v}</option>`).join('')}</select></section>
    <section><b>Cambiar contraseña</b>
      <form id="pw" style="display:grid;gap:8px">
        <input type="password" name="old" placeholder="Contraseña actual" autocomplete="current-password" required>
        <input type="password" name="new" placeholder="Nueva contraseña" autocomplete="new-password" required minlength="6">
        <button class="btn primary">Guardar</button></form></section>
  </div>`
  $('#logout').addEventListener('click', async () => { await api('/api/logout', { method: 'POST' }); me = null; location.hash = '#/login'; router() })
  $('#lang').addEventListener('change', async e => { await api('/api/settings', { method: 'POST', body: { lang: e.target.value } }); me.lang = e.target.value; toast('Idioma guardado') })
  $('#pw').addEventListener('submit', async e => {
    e.preventDefault()
    try {
      await api('/api/settings', { method: 'POST', body: { oldPassword: e.target.old.value, newPassword: e.target.new.value } })
      e.target.reset(); toast('Contraseña cambiada')
    } catch (err) { toast(err.message) }
  })
}