/**
 * Dashboard Chart Animator
 * Gently animates SVG bar charts, line graph, and pie chart.
 * Pauses off-screen via IntersectionObserver for performance.
 */
(function () {
  'use strict';

  var SPEED    = 0.002;    // phase increment per frame
  var BAR_H    = 120;      // max bar height (SVG units)
  var BAR_MIN  = 0.15;     // min bar ratio
  var LINE_PTS = 8;

  var DARK  = { text: '#E0E0E0', muted: '#9E9E9E', border: '#333', center: '#222' };
  var LIGHT = { text: '#333333', muted: '#666666', border: '#E0E0E0', center: '#fff' };

  function isDark() { return document.documentElement.getAttribute('data-theme') === 'dark'; }
  function pal()    { return isDark() ? DARK : LIGHT; }

  function wave(t, off) {
    return Math.max(0, Math.min(1,
      0.55 +
      Math.sin(t + off) * 0.25 +
      Math.sin(t * 1.8 + off * 1.3) * 0.15
    ));
  }

  function makeState(svg) {
    return {
      svg: svg,
      bars1: svg.querySelectorAll('#bars-group-1 .bar'),
      bars2: svg.querySelectorAll('#bars-group-2 .bar'),
      vals1: svg.querySelectorAll('#values-group-1 text'),
      vals2: svg.querySelectorAll('#values-group-2 text'),
      linePath: svg.querySelector('#line-path'),
      lineFill: svg.querySelector('#line-fill'),
      pieSegs:  svg.querySelectorAll('.pie-segment'),
      phase: Math.random() * Math.PI * 2,
      paused: false,
      themeN: 0
    };
  }

  function updateBars(bars, vals, st, pct) {
    for (var i = 0; i < bars.length; i++) {
      var v = Math.max(BAR_MIN, wave(st.phase, i * 1.1));
      var h = v * BAR_H;
      bars[i].setAttribute('height', h);
      bars[i].setAttribute('y', BAR_H - h);
    }
    for (var j = 0; j < Math.min(bars.length, vals.length); j++) {
      var val = Math.max(BAR_MIN, wave(st.phase, j * 1.1));
      vals[j].textContent = pct ? Math.round(val * 100) + '%' : Math.round(val * 5000);
    }
  }

  function updateLine(st) {
    if (!st.linePath) return;
    var d = 'M';
    for (var i = 0; i < LINE_PTS; i++) {
      var x = (i / (LINE_PTS - 1)) * 200;
      var y = 25 + (1 - wave(st.phase * 0.8, i * 0.9)) * 110;
      d += (i ? ' L' : '') + x.toFixed(1) + ',' + y.toFixed(1);
    }
    st.linePath.setAttribute('d', d);
    if (st.lineFill) st.lineFill.setAttribute('d', d + ' L200,145 L0,145 Z');
  }

  /* Pie: each segment gently shifts its slice size, no spinning */
  function updatePie(st) {
    if (!st.pieSegs.length) return;
    var n = st.pieSegs.length;
    // Generate proportional weights that shift over time
    var weights = [], total = 0;
    for (var i = 0; i < n; i++) {
      var w = 0.5 + wave(st.phase * 0.4, i * 2.0) * 0.5;
      weights.push(w);
      total += w;
    }
    // Convert to cumulative angles
    var angle = 0;
    for (var j = 0; j < n; j++) {
      var sweep = (weights[j] / total) * 360;
      var startA = angle * Math.PI / 180;
      var endA   = (angle + sweep) * Math.PI / 180;
      // Large-arc flag needed when sweep > 180
      var large = sweep > 180 ? 1 : 0;
      var r = 45;
      var x1 = Math.sin(startA) * r, y1 = -Math.cos(startA) * r;
      var x2 = Math.sin(endA)   * r, y2 = -Math.cos(endA)   * r;
      var path = st.pieSegs[j].querySelector('path');
      if (path) {
        path.setAttribute('d',
          'M0,0 L' + x1.toFixed(2) + ',' + y1.toFixed(2) +
          ' A' + r + ',' + r + ' 0 ' + large + ',1 ' +
          x2.toFixed(2) + ',' + y2.toFixed(2) + ' Z'
        );
      }
      // Remove any rotation transform — segments are positioned by path geometry
      st.pieSegs[j].removeAttribute('transform');
      angle += sweep;
    }
  }

  function applyTheme(st) {
    var c = pal(), q = st.svg.querySelectorAll.bind(st.svg), all, k;
    all = q('.ct'); for (k = 0; k < all.length; k++) all[k].setAttribute('fill', c.text);
    all = q('.cl'); for (k = 0; k < all.length; k++) all[k].setAttribute('fill', c.muted);
    all = q('.cv'); for (k = 0; k < all.length; k++) all[k].setAttribute('fill', c.text);
    all = q('.grid-line'); for (k = 0; k < all.length; k++) all[k].setAttribute('stroke', c.border);
    var cc = st.svg.querySelector('#pie-center');
    if (cc) { cc.setAttribute('fill', c.center); cc.setAttribute('stroke', c.border); }
    var pt = st.svg.querySelector('#pie-center-text');
    if (pt) pt.setAttribute('fill', c.text);
  }

  function tick(st) {
    if (!st.paused) {
      st.phase += SPEED * 16;
      updateBars(st.bars1, st.vals1, st, true);
      updateBars(st.bars2, st.vals2, st, false);
      updateLine(st);
      updatePie(st);
      if (++st.themeN > 30) { st.themeN = 0; applyTheme(st); }
    }
    requestAnimationFrame(function () { tick(st); });
  }

  function observe(st) {
    if (!('IntersectionObserver' in window)) return;
    new IntersectionObserver(function (entries) {
      for (var i = 0; i < entries.length; i++) st.paused = !entries[i].isIntersecting;
    }, { rootMargin: '200px', threshold: 0.05 }).observe(st.svg);
  }

  function boot() {
    var svgs = document.querySelectorAll('.dashboard-chart');
    if (!svgs.length) return;
    if (window.matchMedia('(prefers-reduced-motion: reduce)').matches) return;
    for (var i = 0; i < svgs.length; i++) {
      if (svgs[i]._dbAnim) continue;
      var st = makeState(svgs[i]);
      svgs[i]._dbAnim = st;
      applyTheme(st);
      tick(st);
      observe(st);
    }
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', boot);
  } else {
    boot();
  }
})();