/* ============================================================
   qft/scene.js — assemble a QFT plate from params.
   Per-field origins (each lattice movable), multi-E8 clusters
   scattered around the canvas, and explicit cross-field LINKS
   (Feynman propagator symbols connecting a vertex in one field
   to a vertex in another — the "interactions" between fields).

   Returns:
     { grids: [...], links: [...], hash, plate, exposure, lab }
   Each grid: { id, propagator, vertices:[{x,y}], edges:[{a,b}] }
   Each link: { a:{x,y}, b:{x,y}, propagator: 'photon'|'scalar'|'gluon' }
   ============================================================ */
import { makeRng, cyrb53, pick } from '../rng.js';
import { buildCubic, buildSchlegel, buildE8, buildNautilus, buildRipples } from './topology.js';
import { distortVertices, applyWavepackets, applyVortices, applyStandingWaves } from './distortion.js';

const LABS = [
  'LATTICE QFT · LANL',
  'BNL · ALGEBRAIC GEOMETRY GROUP',
  'IHES · BURES-SUR-YVETTE',
  'PERIMETER INSTITUTE · WATERLOO',
  'INST. THEORETICAL PHYSICS · COPENHAGEN',
];

function rotateScale(verts, angle, scale) {
  const c = Math.cos(angle), s = Math.sin(angle);
  for (const v of verts) {
    const x = v.x * c - v.y * s;
    const y = v.x * s + v.y * c;
    v.x = x * scale; v.y = y * scale;
  }
}
function translateVerts(verts, dx, dy) {
  for (const v of verts) { v.x += dx; v.y += dy; }
}

export function generateQFTScene(params) {
  // ---- cubic ---- (cubicN controls density: 1=27v, 2=125v, 3=343v)
  const cubic = buildCubic(Math.max(1, params.cubicN | 0));
  rotateScale(cubic.vertices, params.cubicRot, params.cubicScale);
  translateVerts(cubic.vertices, params.cubicOriginX, params.cubicOriginY);
  cubic.id = 'cubic'; cubic.propagator = 'photon';

  // ---- schlegel ---- (outer/inner radius and 3D rotation now parameterised)
  const schl = buildSchlegel(
    params.schlegelOuterR ?? 0.78,
    params.schlegelInnerR ?? 0.32,
    params.schlegelRot3D ?? 0.42,
  );
  rotateScale(schl.vertices, params.schlegelRot, params.schlegelScale);
  translateVerts(schl.vertices, params.schlegelOriginX, params.schlegelOriginY);
  schl.id = 'schlegel'; schl.propagator = 'scalar';

  // ---- E8 clusters ----
  // If params.e8Origins (array of {x,y}) is provided, place clusters exactly
  // at those positions (count comes from the array length). Otherwise auto-
  // distribute on a ring of radius e8OriginRadius.
  const e8Rng = makeRng(params.seed, 'qft-e8');
  const e8Instances = [];
  let e8Origins;
  if (Array.isArray(params.e8Origins) && params.e8Origins.length) {
    e8Origins = params.e8Origins;
  } else {
    const N = Math.max(1, params.e8Count | 0);
    e8Origins = [];
    const angleJitter = 0.35;
    for (let i = 0; i < N; i++) {
      const baseAng = (i / N) * Math.PI * 2;
      const ang = baseAng + (e8Rng() - 0.5) * angleJitter;
      const radius = N === 1 ? 0 : params.e8OriginRadius;
      e8Origins.push({ x: Math.cos(ang) * radius, y: Math.sin(ang) * radius });
    }
  }
  for (let i = 0; i < e8Origins.length; i++) {
    const o = e8Origins[i];
    // per-cluster scale override: e8Origins[i] may include {x, y, scale}
    const clusterScale = (typeof o.scale === 'number') ? o.scale : params.e8Scale;
    // pick rosette geometry: open NAUTILUS spiral (default for chaotic-growth feel)
    // or closed concentric RINGS (the older E8-Coxeter-style mandala).
    const style = params.e8Style ?? 'nautilus';
    const e = style === 'rings'
      ? buildE8(4, 18)
      : buildNautilus(params.nautilusTurns ?? 2.6,
                      params.nautilusPerTurn ?? 14,
                      params.nautilusGrowth ?? 0.21);
    rotateScale(e.vertices, params.e8Rot + (e8Rng() - 0.5) * 0.6, clusterScale);
    translateVerts(e.vertices, o.x, o.y);
    e.id = 'e8';
    e.instance = i;
    e.propagator = 'gluon';
    e8Instances.push(e);
  }

  // ---- RIPPLES — concentric wavefronts from source points ----
  // params.ripples: [{ x, y, count?, r0?, dR?, propagator? }]
  const rippleInstances = [];
  if (Array.isArray(params.ripples)) {
    for (let i = 0; i < params.ripples.length; i++) {
      const rs = params.ripples[i];
      const r = buildRipples(
        { x: rs.x, y: rs.y },
        rs.count ?? 6,
        rs.r0 ?? 0.06,
        rs.dR ?? 0.09,
        rs.segments ?? 40,
      );
      r.id = 'ripple';
      r.instance = i;
      r.propagator = rs.propagator ?? 'photon';
      rippleInstances.push(r);
    }
  }

  const allFields = [cubic, schl, ...e8Instances, ...rippleInstances];

  // ---- FIELD PERTURBATIONS — applied to cubic + schlegel after scale/rotate ----
  // wavepackets: Gaussian bulge/dimple (Schrödinger particle as field feature)
  if (Array.isArray(params.wavepackets) && params.wavepackets.length) {
    applyWavepackets(cubic.vertices, params.wavepackets);
    applyWavepackets(schl.vertices, params.wavepackets);
  }
  // vortices: swirling Gaussian rotation (angular momentum / spin)
  if (Array.isArray(params.vortices) && params.vortices.length) {
    applyVortices(cubic.vertices, params.vortices);
    applyVortices(schl.vertices, params.vortices);
  }
  // standing waves: global plane-wave sinusoidal modulation (Chladni / nodal lines)
  if (Array.isArray(params.standingWaves) && params.standingWaves.length) {
    applyStandingWaves(cubic.vertices, params.standingWaves);
    applyStandingWaves(schl.vertices, params.standingWaves);
  }

  // distortion (per-field salt so neighbouring lattices warp differently)
  for (const g of allFields) {
    const salt = 'dist:' + g.id + (g.instance != null ? ':' + g.instance : '');
    distortVertices(g.vertices, params.distRCalm, params.distRMax, params.distStrength,
                    params.seed, salt);
  }

  // composition offset — translate the whole scene on the paper
  if (params.compositionOffsetX || params.compositionOffsetY) {
    for (const g of allFields) translateVerts(g.vertices, params.compositionOffsetX, params.compositionOffsetY);
  }

  // ---- cross-field links ----
  const linkRng = makeRng(params.seed, 'qft-links');
  const propChoices = ['photon', 'scalar', 'gluon'];
  const linkCount = Math.max(0, params.linkCount | 0);
  const links = [];
  // pair fields by their INDEX in allFields so multi-E8 clusters can interact
  // with cubic/schlegel and with each other
  for (let i = 0; i < linkCount && allFields.length >= 2; i++) {
    let f1Idx, f2Idx, attempts = 0;
    do {
      f1Idx = Math.floor(linkRng() * allFields.length);
      f2Idx = Math.floor(linkRng() * allFields.length);
      attempts++;
    } while ((f1Idx === f2Idx || allFields[f1Idx].id === allFields[f2Idx].id) && attempts < 20);
    const f1 = allFields[f1Idx], f2 = allFields[f2Idx];
    const v1 = f1.vertices[Math.floor(linkRng() * f1.vertices.length)];
    const v2 = f2.vertices[Math.floor(linkRng() * f2.vertices.length)];
    const prop = params.linkPropagator === 'mixed'
      ? propChoices[Math.floor(linkRng() * propChoices.length)]
      : (params.linkPropagator || 'photon');
    // per-link curvature: random sign × random magnitude up to params.linkCurvature.
    // a fraction of links stay straight (curvature=0) so the result is mixed-tangle.
    let curvature = 0;
    const lc = params.linkCurvature ?? 0;
    if (lc > 1e-3) {
      // 30% straight, 70% curved; signed
      if (linkRng() > 0.30) {
        const sign = linkRng() < 0.5 ? -1 : 1;
        curvature = sign * lc * (0.45 + linkRng() * 0.55);
      }
    }
    links.push({ a: { x: v1.x, y: v1.y }, b: { x: v2.x, y: v2.y }, propagator: prop, curvature });
  }

  // archival metadata
  const hash = cyrb53(params.seed);
  const ds = parseInt(hash.slice(0, 8), 16);
  const plate = (parseInt(hash.slice(-3), 16) % 999).toString().padStart(3, '0');
  const year = 1985 + (ds % 30);
  const month = 1 + ((ds >> 4) % 12);
  const day = 1 + ((ds >> 8) % 28);
  const exposure = `${year}.${String(month).padStart(2, '0')}.${String(day).padStart(2, '0')}`;
  const lab = pick(makeRng(params.seed, 'qft-lab'), LABS);

  return { grids: allFields, links, hash, plate, exposure, lab };
}