// One-off analyzer: scan every .bbmodel in a directory and report UV-layout
// statistics that characterize the project's sorting/packing conventions.
//
// Usage:
//   node analyze_uvs.mjs <path/to/bbmodel/directory>
//   MODELS_DIR=path/to/dir node analyze_uvs.mjs

import fs from 'node:fs';
import path from 'node:path';

const MODELS_DIR = path.resolve(
  process.argv[2] || process.env.MODELS_DIR || 'bbmodel'
);
if (!fs.existsSync(MODELS_DIR)) {
  console.error(`Models dir not found: ${MODELS_DIR}`);
  console.error('Pass it as an argument or set MODELS_DIR.');
  process.exit(1);
}

const FACE_NAMES = ['north', 'east', 'south', 'west', 'up', 'down'];

function rectOf(uv) {
  const [x1, y1, x2, y2] = uv;
  return {
    x: Math.min(x1, x2),
    y: Math.min(y1, y2),
    w: Math.abs(x2 - x1),
    h: Math.abs(y2 - y1),
    flipX: x2 < x1,
    flipY: y2 < y1,
  };
}

function rectArea(r) {
  return r.w * r.h;
}

function bboxOf(rects) {
  if (!rects.length) return { x: 0, y: 0, w: 0, h: 0 };
  let x0 = Infinity, y0 = Infinity, x1 = -Infinity, y1 = -Infinity;
  for (const r of rects) {
    if (r.x < x0) x0 = r.x;
    if (r.y < y0) y0 = r.y;
    if (r.x + r.w > x1) x1 = r.x + r.w;
    if (r.y + r.h > y1) y1 = r.y + r.h;
  }
  return { x: x0, y: y0, w: x1 - x0, h: y1 - y0 };
}

// Walk outliner tree to record group-membership for each cube uuid
function buildCubeGroupMap(outlinerNodes, parentName, out, depth = 0) {
  for (const node of outlinerNodes) {
    if (typeof node === 'string') {
      // leaf: cube uuid
      out.set(node, parentName || '__root__');
    } else if (node && Array.isArray(node.children)) {
      const groupName = node.name || `group@${depth}`;
      buildCubeGroupMap(node.children, groupName, out, depth + 1);
    }
  }
}

function rectsOverlap(a, b) {
  return !(a.x + a.w <= b.x || b.x + b.w <= a.x || a.y + a.h <= b.y || b.y + b.h <= a.y);
}

function rectsIdentical(a, b) {
  return a.x === b.x && a.y === b.y && a.w === b.w && a.h === b.h;
}

function analyzeModel(filePath) {
  const data = JSON.parse(fs.readFileSync(filePath, 'utf8'));
  if (data.meta?.box_uv === true) return { skipped: 'box_uv' };

  const uvW = data.resolution?.width ?? 16;
  const uvH = data.resolution?.height ?? 16;
  const elements = data.elements || [];
  const cubeGroup = new Map();
  buildCubeGroupMap(data.outliner || [], null, cubeGroup);

  // Per-cube faces
  const allRects = [];
  const groupRects = new Map(); // groupName -> [rects]

  for (const el of elements) {
    if (el.type && el.type !== 'cube') continue;
    if (!el.faces) continue;
    const groupName = cubeGroup.get(el.uuid) || '__root__';
    if (!groupRects.has(groupName)) groupRects.set(groupName, []);
    for (const fname of FACE_NAMES) {
      const face = el.faces[fname];
      if (!face || !face.uv) continue;
      const r = rectOf(face.uv);
      if (r.w === 0 || r.h === 0) continue;
      allRects.push({ ...r, cube: el.name, group: groupName, face: fname });
      groupRects.get(groupName).push({ ...r, cube: el.name, face: fname });
    }
  }

  if (!allRects.length) return { skipped: 'no_faces' };

  // Global bbox
  const globalBbox = bboxOf(allRects);
  const usedArea = allRects.reduce((s, r) => s + rectArea(r), 0);
  const bboxArea = globalBbox.w * globalBbox.h;
  const canvasArea = uvW * uvH;

  // Identical-rect dedupe — count how many distinct rect positions+sizes
  const uniqRects = new Set(allRects.map(r => `${r.x},${r.y},${r.w},${r.h}`));
  const sharedRectFraction = 1 - uniqRects.size / allRects.length;

  // Flip usage
  const flippedFraction =
    allRects.filter(r => r.flipX || r.flipY).length / allRects.length;

  // Group clustering: for each group, how tight is its bbox vs. group total area?
  const groupStats = [];
  for (const [name, rects] of groupRects.entries()) {
    if (!rects.length) continue;
    const bb = bboxOf(rects);
    const a = rects.reduce((s, r) => s + rectArea(r), 0);
    const bbA = bb.w * bb.h;
    groupStats.push({
      name,
      faces: rects.length,
      totalArea: a,
      bboxW: bb.w,
      bboxH: bb.h,
      bboxArea: bbA,
      density: bbA > 0 ? a / bbA : 0,
    });
  }

  // Group separation score: do groups overlap each other's bboxes?
  let groupBboxOverlapPairs = 0;
  for (let i = 0; i < groupStats.length; i++) {
    for (let j = i + 1; j < groupStats.length; j++) {
      const a = { x: 0, y: 0, w: 0, h: 0 }; // recompute
    }
  }
  // Better: actually compute group bboxes once and check overlap
  const gBboxes = [];
  for (const [name, rects] of groupRects.entries()) {
    if (!rects.length) continue;
    gBboxes.push({ name, ...bboxOf(rects) });
  }
  for (let i = 0; i < gBboxes.length; i++) {
    for (let j = i + 1; j < gBboxes.length; j++) {
      if (rectsOverlap(gBboxes[i], gBboxes[j])) groupBboxOverlapPairs++;
    }
  }
  const totalGroupPairs = (gBboxes.length * (gBboxes.length - 1)) / 2;
  const groupOverlapRatio = totalGroupPairs ? groupBboxOverlapPairs / totalGroupPairs : 0;

  // Sort within groups: do faces appear biggest-first in the outliner / file order?
  // Approximate: take group rects in file order, see how often successor area <= prev area.
  let monotoneDecreaseHits = 0, monotoneDecreaseTotal = 0;
  for (const rects of groupRects.values()) {
    for (let i = 1; i < rects.length; i++) {
      monotoneDecreaseTotal++;
      if (rectArea(rects[i]) <= rectArea(rects[i - 1])) monotoneDecreaseHits++;
    }
  }
  const biggestFirstScore = monotoneDecreaseTotal
    ? monotoneDecreaseHits / monotoneDecreaseTotal
    : 0;

  // Padding: nearest-neighbor gap between non-overlapping rects
  // For each rect, look at its right and bottom neighbors and measure gap
  // Approximate by sampling: spend min gap across all neighbors
  const sortedByX = [...allRects].sort((a, b) => a.y - b.y || a.x - b.x);
  let zeroGapCount = 0, smallGapCount = 0, totalGapsMeasured = 0;
  for (let i = 0; i < sortedByX.length; i++) {
    for (let j = i + 1; j < sortedByX.length; j++) {
      const a = sortedByX[i], b = sortedByX[j];
      if (b.y > a.y + a.h + 4) break;
      // Right-edge to left-edge gap when y-overlap exists
      const yOverlap = Math.min(a.y + a.h, b.y + b.h) - Math.max(a.y, b.y);
      if (yOverlap > 0) {
        const gap = b.x - (a.x + a.w);
        if (gap >= 0 && gap <= 4) {
          totalGapsMeasured++;
          if (gap === 0) zeroGapCount++;
          else if (gap <= 1) smallGapCount++;
        }
      }
    }
  }
  const zeroPaddingFraction = totalGapsMeasured ? zeroGapCount / totalGapsMeasured : 0;

  return {
    name: path.basename(filePath, '.bbmodel'),
    canvas: { uvW, uvH },
    cubes: elements.length,
    groups: gBboxes.length,
    faces: allRects.length,
    uniqueRects: uniqRects.size,
    sharedRectFraction: round(sharedRectFraction, 3),
    flippedFraction: round(flippedFraction, 3),
    globalBbox,
    bboxFillOfCanvas: round(bboxArea / canvasArea, 3),
    densityInBbox: round(usedArea / Math.max(bboxArea, 1), 3),
    groupStats: groupStats.map(g => ({ ...g, density: round(g.density, 3) })),
    groupOverlapRatio: round(groupOverlapRatio, 3),
    biggestFirstScore: round(biggestFirstScore, 3),
    zeroPaddingFraction: round(zeroPaddingFraction, 3),
    paddedSamples: totalGapsMeasured,
  };
}

function round(n, d) {
  return Math.round(n * 10 ** d) / 10 ** d;
}

const files = fs
  .readdirSync(MODELS_DIR)
  .filter(f => f.endsWith('.bbmodel'))
  .map(f => path.join(MODELS_DIR, f));

const results = [];
const skipped = { box_uv: 0, no_faces: 0, error: 0 };
for (const f of files) {
  try {
    const r = analyzeModel(f);
    if (r.skipped) {
      skipped[r.skipped]++;
      continue;
    }
    results.push(r);
  } catch (e) {
    skipped.error++;
  }
}

// Aggregate
function avg(xs) {
  return xs.length ? xs.reduce((a, b) => a + b, 0) / xs.length : 0;
}
function median(xs) {
  if (!xs.length) return 0;
  const s = [...xs].sort((a, b) => a - b);
  return s[Math.floor(s.length / 2)];
}
function pctile(xs, p) {
  if (!xs.length) return 0;
  const s = [...xs].sort((a, b) => a - b);
  return s[Math.floor((s.length - 1) * p)];
}

const summary = {
  totalAnalyzed: results.length,
  skipped,
  avgCubes: round(avg(results.map(r => r.cubes)), 1),
  avgGroups: round(avg(results.map(r => r.groups)), 1),
  avgFaces: round(avg(results.map(r => r.faces)), 1),
  medianBboxFillOfCanvas: round(median(results.map(r => r.bboxFillOfCanvas)), 3),
  medianDensityInBbox: round(median(results.map(r => r.densityInBbox)), 3),
  medianSharedRectFraction: round(median(results.map(r => r.sharedRectFraction)), 3),
  medianFlippedFraction: round(median(results.map(r => r.flippedFraction)), 3),
  medianGroupOverlapRatio: round(median(results.map(r => r.groupOverlapRatio)), 3),
  medianBiggestFirstScore: round(median(results.map(r => r.biggestFirstScore)), 3),
  medianZeroPadFraction: round(median(results.map(r => r.zeroPaddingFraction)), 3),
  // Distribution-of-density
  densityP10: round(pctile(results.map(r => r.densityInBbox), 0.1), 3),
  densityP50: round(pctile(results.map(r => r.densityInBbox), 0.5), 3),
  densityP90: round(pctile(results.map(r => r.densityInBbox), 0.9), 3),
  groupOverlapP10: round(pctile(results.map(r => r.groupOverlapRatio), 0.1), 3),
  groupOverlapP50: round(pctile(results.map(r => r.groupOverlapRatio), 0.5), 3),
  groupOverlapP90: round(pctile(results.map(r => r.groupOverlapRatio), 0.9), 3),
  biggestFirstP10: round(pctile(results.map(r => r.biggestFirstScore), 0.1), 3),
  biggestFirstP50: round(pctile(results.map(r => r.biggestFirstScore), 0.5), 3),
  biggestFirstP90: round(pctile(results.map(r => r.biggestFirstScore), 0.9), 3),
};

console.log('=== AGGREGATE ===');
console.log(JSON.stringify(summary, null, 2));

// Show 10 sample model breakdowns of varying complexity
const samples = [...results].sort((a, b) => a.faces - b.faces);
const picks = [
  samples[Math.floor(samples.length * 0.1)],
  samples[Math.floor(samples.length * 0.3)],
  samples[Math.floor(samples.length * 0.5)],
  samples[Math.floor(samples.length * 0.7)],
  samples[Math.floor(samples.length * 0.9)],
].filter(Boolean);

console.log('\n=== SAMPLE BREAKDOWNS (low → high complexity) ===');
for (const r of picks) {
  console.log(`\n--- ${r.name} ---`);
  console.log(`  canvas: ${r.canvas.uvW}x${r.canvas.uvH}, cubes: ${r.cubes}, groups: ${r.groups}, faces: ${r.faces}`);
  console.log(`  global UV bbox: ${r.globalBbox.w}x${r.globalBbox.h} @ (${r.globalBbox.x},${r.globalBbox.y})  fill=${r.bboxFillOfCanvas}  density=${r.densityInBbox}`);
  console.log(`  shared-rect fraction: ${r.sharedRectFraction}, flipped: ${r.flippedFraction}, zero-padding gaps: ${r.zeroPaddingFraction} (n=${r.paddedSamples})`);
  console.log(`  group-bbox overlap ratio: ${r.groupOverlapRatio}  biggest-first score: ${r.biggestFirstScore}`);
  if (r.groupStats.length <= 8) {
    for (const g of r.groupStats) {
      console.log(`    group "${g.name}": ${g.faces} faces, area=${g.totalArea}, bbox=${g.bboxW}x${g.bboxH}, density=${g.density}`);
    }
  }
}