/** Campaign constellation force-graph helpers for Emberwake War Room. */

import type { WarRoomCampaign } from './warRoom';

export interface ConstellationNode {
  id: string;
  campaign: string;
  hits: number;
  online: number;
  conversionPct: number;
  pins: string[];
  radius: number;
  color: string;
  brightness: number;
  pulsing: boolean;
  x: number;
  y: number;
  vx: number;
  vy: number;
}

export interface ConstellationEdge {
  source: string;
  target: string;
  sharedPins: string[];
}

export interface ConstellationGraph {
  nodes: ConstellationNode[];
  edges: ConstellationEdge[];
}

const MIN_RADIUS = 10;
const MAX_RADIUS = 36;

/** Node radius scaled by hits (sqrt curve for readability). */
export function nodeRadius(hits: number, maxHits: number): number {
  if (hits <= 0) return MIN_RADIUS;
  if (maxHits <= 0) return MIN_RADIUS + 4;
  const t = Math.sqrt(hits / maxHits);
  return MIN_RADIUS + t * (MAX_RADIUS - MIN_RADIUS);
}

/** Brightness 0.35–1.0 from online agent count. */
export function nodeBrightness(online: number, maxOnline: number): number {
  if (online <= 0) return 0.35;
  if (maxOnline <= 0) return 1;
  return 0.35 + 0.65 * (online / maxOnline);
}

/** Aether palette: cool cyan (low) → gold (mid) → rose (high conversion). */
export function conversionColor(pct: number): string {
  const t = Math.max(0, Math.min(1, pct / 100));
  if (t < 0.5) {
    const u = t / 0.5;
    const r = Math.round(61 + u * (201 - 61));
    const g = Math.round(214 + u * (162 - 214));
    const b = Math.round(198 + u * (39 - 198));
    return `rgb(${r},${g},${b})`;
  }
  const u = (t - 0.5) / 0.5;
  const r = Math.round(201 + u * (244 - 201));
  const g = Math.round(162 + u * (63 - 162));
  const b = Math.round(39 + u * (94 - 39));
  return `rgb(${r},${g},${b})`;
}

/** Edges link campaigns that share at least one pin/build id. */
export function buildConstellationEdges(
  campaigns: Pick<WarRoomCampaign, 'campaign' | 'pins'>[],
): ConstellationEdge[] {
  const edges: ConstellationEdge[] = [];
  const seen = new Set<string>();

  for (let i = 0; i < campaigns.length; i++) {
    const pinsA = new Set((campaigns[i].pins ?? []).filter(Boolean));
    if (!pinsA.size) continue;

    for (let j = i + 1; j < campaigns.length; j++) {
      const shared = (campaigns[j].pins ?? []).filter((p) => pinsA.has(p));
      if (!shared.length) continue;

      const a = campaigns[i].campaign;
      const b = campaigns[j].campaign;
      const key = a < b ? `${a}|${b}` : `${b}|${a}`;
      if (seen.has(key)) continue;
      seen.add(key);

      edges.push({ source: a, target: b, sharedPins: [...new Set(shared)] });
    }
  }

  return edges;
}

/** Build graph nodes + pin-sharing edges from war-room campaigns. */
export function buildConstellationGraph(campaigns: WarRoomCampaign[]): ConstellationGraph {
  const maxHits = Math.max(1, ...campaigns.map((c) => c.hits ?? 0));
  const maxOnline = Math.max(1, ...campaigns.map((c) => c.online ?? 0));

  const nodes: ConstellationNode[] = campaigns.map((c) => {
    const hits = c.hits ?? 0;
    const online = c.online ?? 0;
    return {
      id: c.campaign,
      campaign: c.campaign,
      hits,
      online,
      conversionPct: c.conversion_pct ?? 0,
      pins: c.pins ?? [],
      radius: nodeRadius(hits, maxHits),
      color: conversionColor(c.conversion_pct ?? 0),
      brightness: nodeBrightness(online, maxOnline),
      pulsing: online > 0,
      x: 0,
      y: 0,
      vx: 0,
      vy: 0,
    };
  });

  return { nodes, edges: buildConstellationEdges(campaigns) };
}

/** Scatter nodes in a circle for force-sim cold start. */
export function initNodePositions(nodes: ConstellationNode[], width: number, height: number): void {
  const cx = width / 2;
  const cy = height / 2;
  const ring = Math.min(width, height) * 0.32;

  nodes.forEach((n, i) => {
    const angle = (i / Math.max(1, nodes.length)) * Math.PI * 2;
    n.x = cx + Math.cos(angle) * ring;
    n.y = cy + Math.sin(angle) * ring;
    n.vx = 0;
    n.vy = 0;
  });
}

const REPULSE = 4200;
const SPRING = 0.045;
const SPRING_LEN = 90;
const CENTER = 0.012;
const DAMPING = 0.82;
const PAD = 24;

/** One tick of lightweight force-directed layout (no D3). */
export function tickForceLayout(
  nodes: ConstellationNode[],
  edges: ConstellationEdge[],
  width: number,
  height: number,
  alpha = 1,
): void {
  const cx = width / 2;
  const cy = height / 2;
  const nodeById = new Map(nodes.map((n) => [n.id, n]));

  for (let i = 0; i < nodes.length; i++) {
    for (let j = i + 1; j < nodes.length; j++) {
      const a = nodes[i];
      const b = nodes[j];
      let dx = b.x - a.x;
      let dy = b.y - a.y;
      let dist = Math.hypot(dx, dy) || 0.01;
      const minDist = a.radius + b.radius + 12;
      const force = (REPULSE * alpha) / (dist * dist);
      if (dist < minDist) {
        const push = ((minDist - dist) / dist) * 0.5;
        dx *= push;
        dy *= push;
        dist = Math.hypot(dx, dy) || 0.01;
      }
      const fx = (dx / dist) * force;
      const fy = (dy / dist) * force;
      a.vx -= fx;
      a.vy -= fy;
      b.vx += fx;
      b.vy += fy;
    }
  }

  for (const e of edges) {
    const a = nodeById.get(e.source);
    const b = nodeById.get(e.target);
    if (!a || !b) continue;
    const dx = b.x - a.x;
    const dy = b.y - a.y;
    const dist = Math.hypot(dx, dy) || 0.01;
    const force = (dist - SPRING_LEN) * SPRING * alpha;
    const fx = (dx / dist) * force;
    const fy = (dy / dist) * force;
    a.vx += fx;
    a.vy += fy;
    b.vx -= fx;
    b.vy -= fy;
  }

  for (const n of nodes) {
    n.vx += (cx - n.x) * CENTER * alpha;
    n.vy += (cy - n.y) * CENTER * alpha;
    n.vx *= DAMPING;
    n.vy *= DAMPING;
    n.x += n.vx;
    n.y += n.vy;

    const r = n.radius + PAD;
    n.x = Math.max(r, Math.min(width - r, n.x));
    n.y = Math.max(r, Math.min(height - r, n.y));
  }
}

/** Run layout to near-equilibrium; returns same node references (mutated). */
export function settleForceLayout(
  nodes: ConstellationNode[],
  edges: ConstellationEdge[],
  width: number,
  height: number,
  ticks = 120,
): ConstellationNode[] {
  initNodePositions(nodes, width, height);
  for (let t = ticks; t > 0; t--) {
    tickForceLayout(nodes, edges, width, height, t / ticks);
  }
  return nodes;
}