// avatar/transcript.js
//
// DOM ONLY. Knows nothing about the facade, the transports or the host framework; builds
// children with createElement/textContent so glosses and learner text are never parsed as
// HTML. tests/test_transport_seam.py enforces it.
//
// The renderer behind #transcript-text (plan 02-07). host.js hands it the container and
// feeds it lines and the analyzer's token records; it turns each token's ruby spans into
// real <ruby><rt> elements, gates the readings by mode and level on the KANJI axis
// (D-02 / D-13), and publishes the numbers that prove the ruby rendered - the rt count,
// the rendered rt height and the line height - on debug.furigana, so a stylesheet that
// hides the annotation cannot pass a count (research Pitfall 4, the T-pose lesson).
//
// Every line's tokens are retained, so a mode or level change re-renders every line from
// data with no round trip (D-14), and a tap on a word (plan 02-08) reads its reading, its
// dictionary form, its level and its JMdict glosses straight out of the record the line
// already holds - the lookup issues no request of any kind (D-05 / D-07, research § Q3).
// Plan 02-09 adds the translation reveal under each line.
//
// The card is a positioned <div>, not the Popover API: iOS 16 Safari is still in the field
// without it and its top-layer behaviour inside the Hub's cross-origin frame is unverified
// (research § Q6). Anchoring is 40 lines of getBoundingClientRect + clamp that publish
// their numbers on debug.popover, so "it stayed inside the phone column" is an assertion
// rather than a screenshot. Press-and-hold is deliberately not a gesture here (D-04), and
// the card is read-only: no save, no tap history (D-08).
//
// The token record (plan 02-05, nlp/analyzer.TOKEN_KEYS): `surface`, `tappable`, `jlpt`,
// `kanji_levels` ({kanji: "N5".."N1" | null}) and `ruby` ([[text, rt | null], ...] - one
// span per kanji run with its reading, kana spans with null). Non-tappable units carry
// [[surface, null]] and never get an annotation.

/** Difficulty order for the gate; mirrors nlp/levels.LEVEL_RANK. */
export const LEVEL_RANK = { N5: 1, N4: 2, N3: 3, N2: 4, N1: 5 };
/** The three-way control (D-02). 'above' = "above my level". */
export const FURIGANA_MODES = ['always', 'above', 'never'];
/** The level picker's range (D-14). N1 is not offered: at N1 "above my level" is 'never'. */
export const LEVELS = ['N5', 'N4', 'N3', 'N2'];

const LABELS = { you: 'You: ', avatar: 'Avatar: ', slower: 'Avatar (slower): ' };

/**
 * The badge text for a token's WORD-level axis. N5..N1 read as themselves; the two values
 * the analyser uses for "not on a list" are spelled out on the card so the learner is never
 * told a level the data does not claim (D-10 / D-12).
 */
const LEVEL_LABELS = { 'N1+': 'N1+ / beyond lists', name: 'name' };

/** D-07: the card shows the first two or three senses, English glosses only. */
const MAX_SENSES = 3;

/** The gap between the tapped word and the card, and the inset from the column's edges. */
const ANCHOR_GAP_PX = 6;
const EDGE_INSET_PX = 8;
/** The card never grows past this, nor past the room beside the word (see position). */
const CARD_MAX_HEIGHT_PX = 240;
/** Below this a card is not worth showing at all, so it is allowed to overflow instead. */
const MIN_CARD_HEIGHT_PX = 48;

function clamp(value, low, high) {
  return Math.min(Math.max(value, low), high);
}

/**
 * D-02 / D-13: a run gets its rt when the mode says so; 'above' keys on the KANJI axis -
 * any kanji in the run above the learner's level, or unlisted (null, D-10), keeps the whole
 * run annotated. A run whose every kanji is at or below the level renders bare.
 *
 * @param {string} runText      the base text of one ruby span
 * @param {object} kanjiLevels  the token's {kanji: level | null}
 * @param {string} mode         one of FURIGANA_MODES
 * @param {string} level        one of LEVELS
 */
export function showRt(runText, kanjiLevels, mode, level) {
  if (mode === 'always') return true;
  if (mode === 'never') return false;
  const mine = LEVEL_RANK[level] ?? 1;
  const levels = kanjiLevels || {};
  for (const ch of runText) {
    if (!(ch in levels)) continue; // kana inside a run never happens; defensive
    const lv = levels[ch];
    if (lv == null || (LEVEL_RANK[lv] ?? 99) > mine) return true;
  }
  return false;
}

/**
 * @param {Element} container  the project-owned #transcript-text element
 * @param {object}  [opts]
 * @param {Document} [opts.doc]
 */
export function createTranscript(container, { doc = document } = {}) {
  if (!container) throw new Error('createTranscript: a container element is required');

  // Every key seeded here so the key set on getDebug() never depends on timing.
  const debug = {
    furigana: {
      mode: 'always',
      level: 'N5',
      storage: 'unknown', // host.js sets 'ok' | 'unavailable' after its browser-storage probe
      lines: 0,
      rtTotal: 0,
      lastLineId: null,
      lastLineRt: 0,
      lastLineKanjiRuns: 0,
      lastLineRtHeightPx: 0,
      lastLineHeightPx: 0,
    },
    // The lookup card's numbers (plan 02-08, research § Q6). insideTranscript is the phone
    // assertion: the card's rect within the column's rect. null until the first open, so
    // "never opened" and "opened outside" are different readings.
    popover: {
      open: false,
      lineId: null,
      tokenIndex: null,
      surface: null,
      reading: null,
      level: null,
      glossCount: 0,
      left: 0,
      top: 0,
      width: 0,
      insideTranscript: null,
      openCount: 0,
      closeCount: 0,
    },
  };

  /** lineId -> { el, said, who, text } in insertion order. */
  const lines = new Map();
  /** lineId -> the retained token records, so a re-render is pure. */
  const tokensByLine = new Map();
  let count = 0;
  let mode = 'always';
  let level = 'N5';

  /** The number of [text, rt] spans WITH a reading across a line's tokens: the potential. */
  function kanjiRuns(tokens) {
    let runs = 0;
    for (const token of tokens) {
      for (const span of token.ruby || []) if (span[1]) runs += 1;
    }
    return runs;
  }

  function renderTokens(said, tokens) {
    said.replaceChildren();
    tokens.forEach((token, index) => {
      const el = doc.createElement('span');
      if (token.tappable) {
        el.className = 'tok';
        el.dataset.token = String(index);
        el.setAttribute('role', 'button');
        el.tabIndex = 0;
        if (token.jlpt) el.dataset.level = token.jlpt;
      } else {
        el.className = 'plain';
      }
      const spans =
        Array.isArray(token.ruby) && token.ruby.length > 0
          ? token.ruby
          : [[String(token.surface ?? ''), null]];
      for (const [text, rt] of spans) {
        if (rt && showRt(text, token.kanji_levels, mode, level)) {
          const ruby = doc.createElement('ruby');
          ruby.append(doc.createTextNode(text));
          const rtEl = doc.createElement('rt');
          rtEl.textContent = rt;
          ruby.append(rtEl);
          el.append(ruby);
        } else {
          el.append(doc.createTextNode(text));
        }
      }
      said.append(el);
    });
  }

  /**
   * The published numbers, read from the rendered DOM after every (re)render. The line
   * height is the `.turn` block's: an inline `.said` box reports only its own font's
   * content area, which does not grow when an annotation sits above it, while the block
   * that contains the line boxes does - so the block is where "a ruby line is taller than
   * a bare one" is measurable.
   */
  function measure(lineId) {
    const line = lines.get(lineId);
    const f = debug.furigana;
    f.lines = lines.size;
    f.rtTotal = container.querySelectorAll('rt').length;
    if (!line) return;
    f.lastLineId = lineId;
    f.lastLineRt = line.said.querySelectorAll('rt').length;
    f.lastLineKanjiRuns = kanjiRuns(tokensByLine.get(lineId) || []);
    const rt = line.said.querySelector('rt');
    f.lastLineRtHeightPx = rt ? rt.getBoundingClientRect().height : 0;
    f.lastLineHeightPx = line.el.getBoundingClientRect().height;
  }

  function render(lineId) {
    const line = lines.get(lineId);
    if (!line) return;
    const tokens = tokensByLine.get(lineId);
    if (tokens && tokens.length > 0) renderTokens(line.said, tokens);
    else line.said.textContent = line.text; // no tokens (yet, or the analysis failed)
    measure(lineId);
  }

  function renderAll() {
    for (const lineId of lines.keys()) render(lineId);
  }

  /**
   * Append a line as plain text; tokens arrive through setTokens (immediately for the
   * avatar's lines, after the analyze round trip for the learner's).
   *
   * @param {{who: 'you'|'avatar'|'slower', text: string}} line
   * @returns {{lineId: string, el: Element}}
   */
  function addLine({ who, text }) {
    count += 1;
    const lineId = `L${count}`;
    const el = doc.createElement('div');
    el.className = `turn turn-${who}`;
    el.dataset.line = lineId;
    el.dataset.who = who;
    const label = doc.createElement('span');
    label.className = 'who';
    label.textContent = LABELS[who] ?? LABELS.avatar;
    const said = doc.createElement('span');
    said.className = 'said';
    said.textContent = String(text ?? '');
    el.append(label, said);
    container.append(el);
    container.scrollTop = container.scrollHeight;
    lines.set(lineId, { el, said, who, text: String(text ?? '') });
    measure(lineId);
    return { lineId, el };
  }

  /**
   * Attach (or replace) a line's tokens and rebuild its `.said` children from them.
   * @returns {boolean} whether the line exists
   */
  function setTokens(lineId, tokens) {
    if (!lines.has(lineId)) return false;
    closePopover(); // the line's spans are rebuilt below; the card's anchor would be stale
    tokensByLine.set(lineId, Array.isArray(tokens) ? tokens : []);
    render(lineId);
    return true;
  }

  // ------------------------------------------------------------- the lookup card (02-08)

  const popover = debug.popover;
  /** Built on the first open and reused; `card.el` is the one #lookup-popover element. */
  let card = null;
  let pointerBound = false;

  function buildCard() {
    const el = doc.createElement('div');
    el.id = 'lookup-popover';
    el.className = 'lookup-popover';
    el.setAttribute('role', 'dialog');
    el.setAttribute('aria-label', 'Word lookup');
    el.hidden = true;

    const head = doc.createElement('div');
    head.className = 'lk-head';
    const surface = doc.createElement('span');
    surface.className = 'lk-surface';
    const reading = doc.createElement('span');
    reading.className = 'lk-reading';
    const badge = doc.createElement('span');
    badge.className = 'lk-level';
    head.append(surface, reading, badge);

    const lemma = doc.createElement('div');
    lemma.className = 'lk-lemma';
    const gloss = doc.createElement('ol');
    gloss.className = 'lk-gloss';
    const none = doc.createElement('div');
    none.className = 'lk-none';
    none.textContent = 'no dictionary entry';
    none.hidden = true;

    el.append(head, lemma, gloss, none);
    container.append(el);
    card = { el, surface, reading, badge, lemma, gloss, none };
    return card;
  }

  /**
   * Anchor the card under (or above) the tapped word and publish where it landed.
   *
   * Offsets are in the container's PADDING-BOX coordinates - what `position: absolute`
   * inside `#transcript-text` resolves against - so `clientLeft` / `clientTop` (the border
   * widths) come off the viewport rects, and `scrollTop` converts the visible position into
   * the scrolled content's. The card is clamped horizontally into the column and placed on
   * whichever side of the word has more room, never growing past that room - it scrolls
   * internally instead. Those two rules together are what make the published numbers true
   * by construction rather than by luck: the card cannot leave the column
   * (insideTranscript) and cannot cover the word that was tapped, which is what would
   * otherwise make "tap the next word to re-anchor" impossible on a short phone column.
   */
  function position(el, tokEl) {
    el.style.left = '0px';
    el.style.top = '0px';
    el.style.maxHeight = `${CARD_MAX_HEIGHT_PX}px`;
    const contRect = container.getBoundingClientRect();
    const tokRect = tokEl.getBoundingClientRect();

    const viewTop = container.scrollTop;
    const viewBottom = viewTop + container.clientHeight;
    const tokTop = tokRect.top - contRect.top - container.clientTop + viewTop;
    const tokBottom = tokTop + tokRect.height;

    const roomBelow = viewBottom - (tokBottom + ANCHOR_GAP_PX) - 2;
    const roomAbove = tokTop - ANCHOR_GAP_PX - viewTop - 2;
    const below = roomBelow >= roomAbove;
    const room = Math.max(MIN_CARD_HEIGHT_PX, below ? roomBelow : roomAbove);
    el.style.maxHeight = `${Math.round(Math.min(CARD_MAX_HEIGHT_PX, room))}px`;

    const width = el.offsetWidth;
    const height = el.offsetHeight;

    const maxLeft = Math.max(EDGE_INSET_PX, container.clientWidth - width - EDGE_INSET_PX);
    const left = clamp(
      tokRect.left - contRect.left - container.clientLeft,
      EDGE_INSET_PX,
      maxLeft
    );
    const top = clamp(
      below ? tokBottom + ANCHOR_GAP_PX : tokTop - ANCHOR_GAP_PX - height,
      viewTop,
      Math.max(viewTop, viewBottom - height)
    );

    el.style.left = `${Math.round(left)}px`;
    el.style.top = `${Math.round(top)}px`;

    const rect = el.getBoundingClientRect();
    popover.left = Math.round(left);
    popover.top = Math.round(top);
    popover.width = rect.width;
    popover.insideTranscript =
      rect.left >= contRect.left - 0.5 &&
      rect.right <= contRect.right + 0.5 &&
      rect.top >= contRect.top - 0.5 &&
      rect.bottom <= contRect.bottom + 0.5;
  }

  /**
   * Show the card for one token of one line, filled from THAT token's own record.
   *
   * Every field is written with textContent: the glosses are dictionary data and the
   * surfaces can be anything the learner typed. Returns a copy of the published numbers.
   *
   * @param {string} lineId
   * @param {number} tokenIndex the index the `.tok` carries in data-token
   */
  function openPopover(lineId, tokenIndex) {
    const line = lines.get(lineId);
    const token = (tokensByLine.get(lineId) || [])[tokenIndex];
    if (!line || !token) return { ...popover };
    const tokEl = line.said.querySelector(`.tok[data-token="${tokenIndex}"]`);
    if (!tokEl) return { ...popover };
    const c = card || buildCard();

    const surface = String(token.surface ?? '');
    const badgeValue = token.jlpt == null ? '' : String(token.jlpt);
    c.surface.textContent = surface;
    c.reading.textContent = String(token.reading ?? '');
    c.badge.textContent = LEVEL_LABELS[badgeValue] ?? badgeValue;
    c.badge.hidden = badgeValue === '';
    if (badgeValue) c.badge.dataset.level = badgeValue;
    else delete c.badge.dataset.level;

    const lemma = String(token.lemma ?? '');
    const showLemma = lemma !== '' && lemma !== surface;
    c.lemma.textContent = showLemma ? `dictionary form: ${lemma}` : '';
    c.lemma.hidden = !showLemma;

    const senses = Array.isArray(token.gloss) ? token.gloss.slice(0, MAX_SENSES) : [];
    c.gloss.replaceChildren();
    for (const sense of senses) {
      const item = doc.createElement('li');
      item.textContent = Array.isArray(sense) ? sense.join('; ') : String(sense);
      c.gloss.append(item);
    }
    c.gloss.hidden = senses.length === 0;
    c.none.hidden = senses.length > 0;

    c.el.hidden = false;
    position(c.el, tokEl);

    popover.open = true;
    popover.lineId = lineId;
    popover.tokenIndex = tokenIndex;
    popover.surface = surface;
    popover.reading = c.reading.textContent;
    popover.level = badgeValue || null;
    popover.glossCount = senses.length;
    popover.openCount += 1;
    return { ...popover };
  }

  /** Hide the card. A no-op (and not counted) when it is already closed. */
  function closePopover() {
    if (!popover.open) return { ...popover };
    if (card) card.el.hidden = true;
    popover.open = false;
    popover.closeCount += 1;
    return { ...popover };
  }

  function openFromElement(tok) {
    const line = tok.closest('[data-line]');
    if (!line) return null;
    return openPopover(line.dataset.line, Number(tok.dataset.token));
  }

  /**
   * Install the tap wiring. Idempotent: the host calls it once at bind, the standalone
   * harness calls it too, so there is exactly one implementation of the gesture.
   *
   * `pointerup` on the column covers mouse, touch and pen alike, with no 300 ms delay
   * (the page has a viewport meta and `.tok` is touch-action: manipulation). The dismiss
   * listener is a CAPTURE-phase pointerdown on the document, so a tap on another word
   * falls through to the pointerup above and re-anchors WITHOUT passing through a closed
   * state. Scrolling the column moves the anchor, so it closes (research § Q6). No
   * press-and-hold gesture exists (D-04).
   */
  function bindPointer() {
    if (pointerBound) return false;
    pointerBound = true;

    container.addEventListener('pointerup', (event) => {
      const tok = event.target?.closest?.('.tok');
      if (!tok) return;
      openFromElement(tok);
    });

    doc.addEventListener(
      'pointerdown',
      (event) => {
        if (event.target?.closest?.('#lookup-popover, .tok')) return;
        closePopover();
      },
      true
    );

    doc.addEventListener('keydown', (event) => {
      if (event.key === 'Escape') {
        closePopover();
        return;
      }
      if (event.key !== 'Enter' && event.key !== ' ') return;
      const tok = event.target?.closest?.('.tok');
      if (!tok) return;
      event.preventDefault();
      openFromElement(tok);
    });

    container.addEventListener('scroll', () => closePopover());
    return true;
  }

  function setMode(value) {
    if (!FURIGANA_MODES.includes(value)) return mode;
    closePopover(); // Pitfall 10: a re-render replaces the .tok the card is anchored to
    mode = value;
    debug.furigana.mode = mode;
    renderAll();
    return mode;
  }

  function setLevel(value) {
    if (!LEVELS.includes(value)) return level;
    closePopover();
    level = value;
    debug.furigana.level = level;
    renderAll();
    return level;
  }

  return {
    addLine,
    setTokens,
    setMode,
    setLevel,
    getMode: () => mode,
    getLevel: () => level,
    getTokens: (lineId) => tokensByLine.get(lineId) || null,
    openPopover,
    closePopover,
    bindPointer,
    debug,
  };
}