// --- browser-bundle/40-overlay.js ---
// The overlay UI: outlines + labels per flagged element, the page-level
// banner, the hover spotlight, visibility toggling. Pure presentation over a
// findings list — no rules, no thresholds, no snippet strings; the rule
// names and categories come from the registry it is handed. Ported from
// cli/engine/browser/injected/index.mjs Section 7.
//
// createImpeccableOverlay({ extensionMode, antipatterns }) ->
//   { highlight(el, findings), showPageBanner(findings), clearOverlays(),
//     remove(), toggleOverlays() -> visible, spotlight(target),
//     unspotlight(), highlightSelector(selector), setFirstScanDone(),
//     overlays }
// Used by the in-page bundle (50-scan.js) and, as `overlay.js`, by the
// extension's content script.

function createImpeccableOverlay({ extensionMode = false, antipatterns = [] } = {}) {
  // Kinpaku gold — pinned to the site's brand token (see
  // site/styles/kinpaku-tokens.css --ks-kinpaku). Keep this in sync with
  // the picker's C.brand in skill/scripts/live-browser.js and the kit's
  // picker section in site/styles/kinpaku-kit.css.
  //
  // One color across both light and dark host pages. The outline is a
  // 2px gesture pointing at an element + a labeled tag — it's a marker,
  // not body text, so it doesn't need WCAG AA against the page. The
  // label text inside the gold tag is dark (LABEL_INK) which has ~16:1
  // against the leaf gold, so reading the rule name is solid in both
  // modes. Hover deepens the gold (preserves chroma — never drops it,
  // dropping chroma washes the gold into a sand/olive tone).
  const BRAND_COLOR = 'oklch(84% 0.19 80.46)';
  const BRAND_COLOR_HOVER = 'oklch(74% 0.18 80)';
  const LABEL_INK = 'oklch(4% 0.004 95)';
  const LABEL_BG = BRAND_COLOR;
  const OUTLINE_COLOR = BRAND_COLOR;

  // Inject hover styles via CSS (more reliable than JS event listeners)
  const styleEl = document.createElement('style');
  styleEl.textContent = `
    @keyframes impeccable-reveal {
      from { opacity: 0; }
      to { opacity: 1; }
    }
    .impeccable-overlay:not(.impeccable-banner) {
      pointer-events: none;
      outline: 2px solid ${OUTLINE_COLOR};
      border-radius: 4px;
      transition: outline-color 0.15s ease;
      animation: impeccable-reveal 0.4s cubic-bezier(0.16, 1, 0.3, 1) both;
      animation-play-state: paused;
      border-top-left-radius: 0;
    }
    .impeccable-overlay.impeccable-visible {
      animation-play-state: running;
    }
    .impeccable-overlay.impeccable-hover {
      outline-color: ${BRAND_COLOR_HOVER};
      z-index: 100001 !important;
    }
    .impeccable-overlay.impeccable-hover .impeccable-label {
      background: ${BRAND_COLOR_HOVER};
    }
    .impeccable-overlay.impeccable-spotlight {
      z-index: 100002 !important;
    }
    .impeccable-overlay.impeccable-spotlight-dimmed {
      opacity: 0.15 !important;
      animation: none !important;
      filter: blur(3px);
    }
    .impeccable-spotlight-backdrop {
      position: fixed;
      top: 0; left: 0; right: 0; bottom: 0;
      backdrop-filter: blur(3px) brightness(0.6);
      -webkit-backdrop-filter: blur(3px) brightness(0.6);
      pointer-events: none;
      z-index: 99998;
      opacity: 0;
      outline: none !important;
      animation: none !important;
    }
    .impeccable-spotlight-backdrop.impeccable-visible {
      opacity: 1;
    }
    .impeccable-hidden .impeccable-overlay${extensionMode ? '' : ':not(.impeccable-banner)'} {
      display: none !important;
    }
  `;
  (document.head || document.documentElement).appendChild(styleEl);

  let firstScanDone = false;

  // Spotlight backdrop element (created lazily on first use)
  let spotlightBackdrop = null;
  let spotlightTarget = null;

  function getSpotlightBackdrop() {
    if (!spotlightBackdrop) {
      spotlightBackdrop = document.createElement('div');
      spotlightBackdrop.className = 'impeccable-spotlight-backdrop';
      document.body.appendChild(spotlightBackdrop);
    }
    return spotlightBackdrop;
  }

  function updateSpotlightClipPath() {
    if (!spotlightBackdrop || !spotlightTarget) return;
    const r = spotlightTarget.getBoundingClientRect();
    // Match the overlay's outer edge: element rect + 4px (2px overlay offset + 2px outline width)
    const inset = 4;
    const radius = 6; // outline border-radius (4) + outline width (2)
    const x1 = r.left - inset;
    const y1 = r.top - inset;
    const x2 = r.right + inset;
    const y2 = r.bottom + inset;
    const vw = window.innerWidth;
    const vh = window.innerHeight;
    // Outer rect + rounded inner rect (evenodd creates a hole)
    const path = `M0 0H${vw}V${vh}H0Z M${x1 + radius} ${y1}H${x2 - radius}A${radius} ${radius} 0 0 1 ${x2} ${y1 + radius}V${y2 - radius}A${radius} ${radius} 0 0 1 ${x2 - radius} ${y2}H${x1 + radius}A${radius} ${radius} 0 0 1 ${x1} ${y2 - radius}V${y1 + radius}A${radius} ${radius} 0 0 1 ${x1 + radius} ${y1}Z`;
    spotlightBackdrop.style.clipPath = `path(evenodd, "${path}")`;
  }

  function showSpotlight(target) {
    if (!target || !target.getBoundingClientRect) return;
    // Respect the spotlightBlur setting: if disabled, don't show the backdrop
    if (window.__IMPECCABLE_CONFIG__?.spotlightBlur === false) {
      spotlightTarget = target;
      return;
    }
    spotlightTarget = target;
    const bd = getSpotlightBackdrop();
    updateSpotlightClipPath();
    bd.classList.add('impeccable-visible');
  }

  function hideSpotlight() {
    spotlightTarget = null;
    if (spotlightBackdrop) spotlightBackdrop.classList.remove('impeccable-visible');
  }

  function isInViewport(el) {
    const r = el.getBoundingClientRect();
    return r.top >= 0 && r.left >= 0 && r.bottom <= window.innerHeight && r.right <= window.innerWidth;
  }

  // Reposition spotlight on scroll/resize
  window.addEventListener('scroll', () => {
    if (spotlightTarget) updateSpotlightClipPath();
  }, { passive: true });
  window.addEventListener('resize', () => {
    if (spotlightTarget) updateSpotlightClipPath();
  });

  const overlays = [];
  const ANTIPATTERNS = antipatterns || [];
  const TYPE_LABELS = {};
  const RULE_CATEGORY = {};
  for (const ap of ANTIPATTERNS) {
    TYPE_LABELS[ap.id] = ap.name.toLowerCase();
    RULE_CATEGORY[ap.id] = ap.category || 'quality';
  }

  function isInFixedContext(el) {
    let p = el;
    while (p && p !== document.body) {
      if (getComputedStyle(p).position === 'fixed') return true;
      p = p.parentElement;
    }
    return false;
  }

  function positionOverlay(overlay) {
    const el = overlay._targetEl;
    if (!el) return;
    const rect = el.getBoundingClientRect();
    if (overlay._isFixed) {
      // Viewport-relative coords for fixed targets
      overlay.style.top = `${rect.top - 2}px`;
      overlay.style.left = `${rect.left - 2}px`;
    } else {
      // Document-relative coords for normal targets
      overlay.style.top = `${rect.top + scrollY - 2}px`;
      overlay.style.left = `${rect.left + scrollX - 2}px`;
    }
    overlay.style.width = `${rect.width + 4}px`;
    overlay.style.height = `${rect.height + 4}px`;
  }

  function repositionOverlays() {
    for (const o of overlays) {
      if (!o._targetEl || o.classList.contains('impeccable-banner')) continue;
      // Skip overlays whose target is currently hidden (display: none on the overlay)
      if (o.style.display === 'none') continue;
      positionOverlay(o);
    }
  }

  let resizeRAF;
  const onResize = () => {
    cancelAnimationFrame(resizeRAF);
    resizeRAF = requestAnimationFrame(repositionOverlays);
  };
  window.addEventListener('resize', onResize);
  // Reposition on scroll too -- catches sticky/parallax shifts
  window.addEventListener('scroll', onResize, { passive: true });
  // Reposition when body resizes (lazy-loaded images, dynamic content, fonts loading)
  if (typeof ResizeObserver !== 'undefined') {
    const bodyResizeObserver = new ResizeObserver(onResize);
    bodyResizeObserver.observe(document.body);
  }

  // Track target element visibility via IntersectionObserver.
  // Uses a huge rootMargin so all *rendered* elements count as intersecting,
  // while display:none / closed <details> / hidden modals etc. do not.
  // This is event-driven -- no polling needed.
  let overlayIndex = 0;
  const visibilityObserver = new IntersectionObserver((entries) => {
    for (const entry of entries) {
      const overlay = entry.target._impeccableOverlay;
      if (!overlay) continue;
      if (entry.isIntersecting) {
        overlay.style.display = '';
        positionOverlay(overlay);
        if (!overlay._revealed) {
          overlay._revealed = true;
          if (firstScanDone) {
            // Subsequent reveals (re-scans, scroll-into-view): instant, no animation
            overlay.style.animation = 'none';
          } else {
            // Initial scan: staggered cascade reveal
            overlay.style.animationDelay = `${Math.min((overlay._staggerIndex || 0) * 60, 600)}ms`;
          }
          requestAnimationFrame(() => {
            overlay.classList.add('impeccable-visible');
            if (overlay._checkLabel) overlay._checkLabel();
          });
        }
      } else {
        overlay.style.display = 'none';
      }
    }
  }, { rootMargin: '99999px' });

  function detachOverlay(overlay) {
    if (!overlay) return;
    if (typeof overlay._cleanup === 'function') {
      try { overlay._cleanup(); } catch { /* best effort overlay teardown */ }
    }
    if (overlay._targetEl && overlay._targetEl._impeccableOverlay === overlay) {
      visibilityObserver.unobserve(overlay._targetEl);
      delete overlay._targetEl._impeccableOverlay;
    }
    const idx = overlays.indexOf(overlay);
    if (idx >= 0) overlays.splice(idx, 1);
    overlay.remove();
  }

  // Reposition overlays after CSS transitions end (e.g. reveal animations).
  // Listens at document level so it catches transitions on ancestor elements
  // (the transform may be on a parent, not the flagged element itself).
  document.addEventListener('transitionend', (e) => {
    if (e.propertyName !== 'transform') return;
    for (const o of overlays) {
      if (!o._targetEl || o.classList.contains('impeccable-banner') || o.style.display === 'none') continue;
      if (e.target === o._targetEl || e.target.contains(o._targetEl)) {
        positionOverlay(o);
      }
    }
  });

  const highlight = function(el, findings) {
    if (el._impeccableOverlay) detachOverlay(el._impeccableOverlay);
    const hasSlop = findings.some(f => RULE_CATEGORY[f.type || f.id] === 'slop');

    const fixed = isInFixedContext(el);
    const rect = el.getBoundingClientRect();
    const outline = document.createElement('div');
    outline.className = 'impeccable-overlay';
    outline._targetEl = el;
    outline._isFixed = fixed;
    Object.assign(outline.style, {
      position: fixed ? 'fixed' : 'absolute',
      top: fixed ? `${rect.top - 2}px` : `${rect.top + scrollY - 2}px`,
      left: fixed ? `${rect.left - 2}px` : `${rect.left + scrollX - 2}px`,
      width: `${rect.width + 4}px`, height: `${rect.height + 4}px`,
      zIndex: '99999', boxSizing: 'border-box',
    });

    // Build per-finding label entries: ✦ prefix for slop
    const entries = findings.map(f => {
      const name = TYPE_LABELS[f.type || f.id] || f.type || f.id;
      const prefix = RULE_CATEGORY[f.type || f.id] === 'slop' ? '\u2726 ' : '';
      return { name: prefix + name, detail: f.detail || f.snippet };
    });
    const allText = entries.map(e => e.name).join(', ');

    const label = document.createElement('div');
    label.className = 'impeccable-label';
    Object.assign(label.style, {
      position: 'absolute', bottom: '100%', left: '-2px',
      display: 'flex', alignItems: 'center',
      whiteSpace: 'nowrap',
      fontSize: '11px', fontWeight: '600', letterSpacing: '0.02em',
      color: LABEL_INK, lineHeight: '14px',
      background: LABEL_BG,
      fontFamily: 'system-ui, sans-serif',
      borderRadius: '4px 4px 0 0',
    });

    const textSpan = document.createElement('span');
    textSpan.style.padding = '3px 8px';
    textSpan.textContent = allText;
    label.appendChild(textSpan);

    // State for cycling mode
    let cycleMode = false;
    let cycleIndex = 0;
    let isHovered = false;
    let prevBtn, nextBtn;

    function updateCycleText() {
      const e = entries[cycleIndex];
      textSpan.textContent = isHovered ? e.detail : e.name;
    }

    function enableCycleMode() {
      if (cycleMode || entries.length < 2) return;
      cycleMode = true;

      const btnStyle = {
        background: 'none', border: 'none', color: 'rgba(255,255,255,0.7)',
        fontSize: '11px', cursor: 'pointer', padding: '3px 4px',
        fontFamily: 'system-ui, sans-serif', lineHeight: '14px',
        pointerEvents: 'auto',
      };

      const navGroup = document.createElement('span');
      Object.assign(navGroup.style, {
        display: 'inline-flex', alignItems: 'center', flexShrink: '0',
      });

      prevBtn = document.createElement('button');
      prevBtn.textContent = '\u2039';
      Object.assign(prevBtn.style, btnStyle);
      prevBtn.style.paddingLeft = '6px';
      prevBtn.addEventListener('click', (e) => {
        e.stopPropagation();
        cycleIndex = (cycleIndex - 1 + entries.length) % entries.length;
        updateCycleText();
      });

      nextBtn = document.createElement('button');
      nextBtn.textContent = '\u203A';
      Object.assign(nextBtn.style, btnStyle);
      nextBtn.style.paddingRight = '2px';
      nextBtn.addEventListener('click', (e) => {
        e.stopPropagation();
        cycleIndex = (cycleIndex + 1) % entries.length;
        updateCycleText();
      });

      navGroup.appendChild(prevBtn);
      navGroup.appendChild(nextBtn);
      label.insertBefore(navGroup, textSpan);
      textSpan.style.padding = '3px 8px 3px 4px';
      updateCycleText();
    }

    outline.appendChild(label);

    // Start hidden; the IntersectionObserver will show it once the target is rendered
    outline.style.display = 'none';
    outline._staggerIndex = overlayIndex++;
    el._impeccableOverlay = outline;
    visibilityObserver.observe(el);

    // After first paint, check label width vs outline
    outline._checkLabel = () => {
      if (entries.length > 1 && label.offsetWidth > outline.offsetWidth) {
        enableCycleMode();
      }
    };

    // Hover: show detail text, darken
    const onMouseEnter = () => {
      isHovered = true;
      outline.classList.add('impeccable-hover');
      outline.style.outlineColor = BRAND_COLOR_HOVER;
      label.style.background = BRAND_COLOR_HOVER;
      if (cycleMode) {
        updateCycleText();
      } else {
        textSpan.textContent = entries.map(e => e.detail).join(' | ');
      }
    };
    const onMouseLeave = () => {
      isHovered = false;
      outline.classList.remove('impeccable-hover');
      outline.style.outlineColor = '';
      label.style.background = LABEL_BG;
      if (cycleMode) {
        updateCycleText();
      } else {
        textSpan.textContent = allText;
      }
    };
    el.addEventListener('mouseenter', onMouseEnter);
    el.addEventListener('mouseleave', onMouseLeave);
    outline._cleanup = () => {
      el.removeEventListener('mouseenter', onMouseEnter);
      el.removeEventListener('mouseleave', onMouseLeave);
    };

    document.body.appendChild(outline);
    overlays.push(outline);
  };

  const showPageBanner = function(findings) {
    if (!findings.length) return;
    const banner = document.createElement('div');
    banner.className = 'impeccable-overlay impeccable-banner';
    Object.assign(banner.style, {
      position: 'fixed', top: '0', left: '0', right: '0', zIndex: '100000',
      background: LABEL_BG, color: LABEL_INK,
      fontFamily: 'system-ui, sans-serif', fontSize: '13px',
      display: 'flex', alignItems: 'center', pointerEvents: 'auto',
      height: '36px', overflow: 'hidden', maxWidth: '100vw',
      transform: 'translateY(-100%)',
      transition: 'transform 0.4s cubic-bezier(0.16, 1, 0.3, 1)',
    });
    requestAnimationFrame(() => requestAnimationFrame(() => {
      banner.style.transform = 'translateY(0)';
    }));

    // Scrollable findings area
    const scrollArea = document.createElement('div');
    Object.assign(scrollArea.style, {
      flex: '1', minWidth: '0', overflowX: 'auto', overflowY: 'hidden',
      display: 'flex', gap: '8px', alignItems: 'center',
      padding: '0 12px', scrollSnapType: 'x mandatory',
      scrollbarWidth: 'none',
    });
    for (const f of findings) {
      const prefix = RULE_CATEGORY[f.type] === 'slop' ? '\u2726 ' : '';
      const tag = document.createElement('span');
      tag.textContent = `${prefix}${TYPE_LABELS[f.type] || f.type}: ${f.detail}`;
      Object.assign(tag.style, {
        background: 'rgba(255,255,255,0.15)', padding: '2px 8px',
        borderRadius: '3px', fontSize: '12px', fontFamily: 'ui-monospace, monospace',
        whiteSpace: 'nowrap', flexShrink: '0', scrollSnapAlign: 'start',
      });
      scrollArea.appendChild(tag);
    }
    banner.appendChild(scrollArea);

    // Controls area (only in standalone mode, not extension)
    if (!extensionMode) {
      const controls = document.createElement('div');
      Object.assign(controls.style, {
        display: 'flex', alignItems: 'center', gap: '2px',
        padding: '0 8px', flexShrink: '0',
      });

      // Toggle visibility button
      const toggle = document.createElement('button');
      toggle.textContent = '\u25C9'; // circle with dot (visible state)
      toggle.title = 'Toggle overlay visibility';
      Object.assign(toggle.style, {
        background: 'none', border: 'none',
        color: 'white', fontSize: '16px', cursor: 'pointer', padding: '0 4px',
        opacity: '0.85', transition: 'opacity 0.15s',
      });
      let overlaysVisible = true;
      toggle.addEventListener('click', () => {
        overlaysVisible = !overlaysVisible;
        document.body.classList.toggle('impeccable-hidden', !overlaysVisible);
        toggle.textContent = overlaysVisible ? '\u25C9' : '\u25CB'; // filled vs empty circle
        toggle.style.opacity = overlaysVisible ? '0.85' : '0.5';
      });
      controls.appendChild(toggle);

      // Close button
      const close = document.createElement('button');
      close.textContent = '\u00d7';
      close.title = 'Dismiss banner';
      Object.assign(close.style, {
        background: 'none', border: 'none',
        color: 'white', fontSize: '18px', cursor: 'pointer', padding: '0 4px',
      });
      close.addEventListener('click', () => banner.remove());
      controls.appendChild(close);

      banner.appendChild(controls);
    }
    document.body.appendChild(banner);
    overlays.push(banner);
  };

  function clearOverlays() {
    for (const o of [...overlays]) detachOverlay(o);
    overlays.length = 0;
    visibilityObserver.disconnect();
    overlayIndex = 0;
  }

  // Tear the UI down entirely (the extension's `remove` command).
  function remove() {
    clearOverlays();
    styleEl.remove();
    if (spotlightBackdrop) { spotlightBackdrop.remove(); spotlightBackdrop = null; }
    document.body.classList.remove('impeccable-hidden');
  }

  // Toggle every overlay; returns the new visibility.
  function toggleOverlays() {
    const visible = !document.body.classList.contains('impeccable-hidden');
    document.body.classList.toggle('impeccable-hidden', visible);
    return !visible;
  }

  // Spotlight the overlay of the element `selector` names (scrolling it into
  // view first so positionOverlay reads the post-scroll rect).
  function highlightSelector(selector) {
    try {
      const target = selector ? document.querySelector(selector) : null;
      if (!target) return;
      if (!isInViewport(target) && target.scrollIntoView) {
        target.scrollIntoView({ behavior: 'instant', block: 'center' });
      }
      for (const o of overlays) {
        if (o.classList.contains('impeccable-banner')) continue;
        const isMatch = o._targetEl === target;
        o.classList.toggle('impeccable-spotlight', isMatch);
        o.classList.toggle('impeccable-spotlight-dimmed', !isMatch);
        if (isMatch) {
          // Force the matching overlay visible immediately, don't wait for IntersectionObserver
          o.style.display = '';
          o.style.animation = 'none';
          o.classList.add('impeccable-visible');
          o._revealed = true;
          positionOverlay(o);
        }
      }
      showSpotlight(target);
    } catch { /* invalid selector */ }
  }

  function unspotlight() {
    hideSpotlight();
    for (const o of overlays) {
      o.classList.remove('impeccable-spotlight');
      o.classList.remove('impeccable-spotlight-dimmed');
    }
  }

  return {
    highlight,
    showPageBanner,
    clearOverlays,
    remove,
    toggleOverlays,
    spotlight: showSpotlight,
    unspotlight,
    highlightSelector,
    setFirstScanDone() { firstScanDone = true; },
    overlays,
    TYPE_LABELS,
    RULE_CATEGORY,
  };
}