// Place a crisp pose into the canonical 409x370 frame.
// usage: yarn node - <crispDir> <outDir> < normalise-pose.cjs
//
// The frame and the floor line are measured from the first twenty: content is centred on
// x=204.5 and its baseline sits at y=341. Matching them is what lets a new pose drop into
// Companion.tsx beside the existing set without its own viewBox.
//
// The floor is the bottom of the content, which is the shadow. Note the companion FLOATS, so
// the shadow is its own connected component, not part of the body — anchoring on the largest
// component instead puts the body's bottom on the floor and sinks the whole pose by the
// shadow's height.
//
// A prop floating clear of the head (27-reach-sparkle's sparkle) can make the content taller
// than the floor allows. Rescaling would break the uniform character size across the set and a
// taller canvas would break the shared viewBox, so the prop is nudged down just far enough to
// fit instead. The character never moves.
const sharp = require('sharp');
const fs = require('node:fs');
const SRC = process.argv[2] + '/', OUT = process.argv[3] + '/';
const W = 409, H = 370, FLOOR = 341, TOP_PAD = 2;
// A prop is small. Anything larger overflowing the top is the character itself, which means
// the pose does not fit the canonical frame — that is a problem to look at, not to nudge away.
// 18-flag trips this: its flag reaches ~400px, so a blind nudge would shunt the whole pose
// down by 56px and silently break it.
const MAX_PROP_PX = 8000;
fs.mkdirSync(OUT, { recursive: true });

(async () => {
  for (const f of fs.readdirSync(SRC).filter(f => f.endsWith('.png')).sort()) {
    const { data, info } = await sharp(SRC + f).ensureAlpha().raw().toBuffer({ resolveWithObject: true });
    const { width: w, height: h, channels: C } = info;
    const A = p => data[p * C + 3];

    const seen = new Uint8Array(w * h);
    const comps = [];
    for (let p0 = 0; p0 < w * h; p0++) {
      if (seen[p0] || A(p0) <= 8) continue;
      const st = [p0]; seen[p0] = 1; const comp = [];
      while (st.length) {
        const p = st.pop(); comp.push(p);
        const x = p % w, y = (p / w) | 0;
        for (const [dx, dy] of [[1,0],[-1,0],[0,1],[0,-1],[1,1],[1,-1],[-1,1],[-1,-1]]) {
          const nx = x + dx, ny = y + dy;
          if (nx < 0 || ny < 0 || nx >= w || ny >= h) continue;
          const np = ny * w + nx;
          if (A(np) > 8 && !seen[np]) { seen[np] = 1; st.push(np); }
        }
      }
      comps.push(comp);
    }
    if (!comps.length) continue;
    comps.sort((a, b) => b.length - a.length);
    const box = (comp) => {
      let x0 = w, x1 = -1, y0 = h, y1 = -1;
      for (const p of comp) {
        const x = p % w, y = (p / w) | 0;
        if (x < x0) x0 = x; if (x > x1) x1 = x; if (y < y0) y0 = y; if (y > y1) y1 = y;
      }
      return { x0, x1, y0, y1 };
    };
    const all = box(comps.flat());

    const dy = FLOOR - all.y1;                      // baseline of the whole pose on the floor
    const dx = Math.round((W - (all.x1 - all.x0 + 1)) / 2) - all.x0;
    const out = Buffer.alloc(W * H * 4, 0);
    const place = (comp, extraDy) => {
      for (const p of comp) {
        const x = (p % w) + dx, y = ((p / w) | 0) + dy + extraDy;
        if (x < 0 || y < 0 || x >= W || y >= H) continue;
        const d = (y * W + x) * 4, s = p * C;
        out[d] = data[s]; out[d+1] = data[s+1]; out[d+2] = data[s+2]; out[d+3] = data[s+3];
      }
    };
    const nudged = []; let warn = '';
    for (const comp of comps) {
      const b = box(comp);
      const over = TOP_PAD - (b.y0 + dy);
      let extra = over > 0 ? over : 0;
      if (extra && comp.length > MAX_PROP_PX) {
        warn = `OVERFLOWS TOP by ${extra}px and is too big (${comp.length}px) to be a prop — left in place, will clip`;
        extra = 0;
      } else if (extra) nudged.push(`${comp.length}px by ${extra}`);
      place(comp, extra);
    }
    await sharp(out, { raw: { width: W, height: H, channels: 4 } }).png().toFile(OUT + f);
    console.log(`  ${f.padEnd(20)} floor ${all.y1}->${FLOOR}${nudged.length ? '  nudged prop ' + nudged.join(', ') : ''}${warn ? '  ** ' + warn : ''}`);
  }
})();