MILO 2026: Arsitektur Meta-Evolutionary Island Orchestration, Hierarchical Lineage Memory, dan Automated Harness Discovery untuk Autonomous Coding Agents

// Production Implementation: MILO (Meta-evolutionary Island Orchestration) Engine
// Berdasarkan Arsitektur AWS AI Labs & Georgia Tech (arXiv:2609.38349 - Oktober 2026)
//
// Karakteristik Inti:
// 1. Hierarchical Lineage Memory: Node- & Edge-labeled Trees per Island (menyimpan rejected candidates).
// 2. Multi-Objective Pareto Fitness: Menyeimbangkan akurasi, efisiensi token, dan limit latency.
// 3. Evidence-Driven Mutators: Workflow diagnose-first atas execution trace & failure reports.
// 4. Meta-Evolutionary Orchestrator: Intervensi dinamis (Graft, Speciate, Reassign, Curriculum) saat stagnan.

export interface ExecutionEvidence {
  taskId: string;
  trace: string[];         // Turn-by-turn action & tool outputs
  report: string;        // Compiler errors, assertion failures, or rubric leaf feedback
  cost: {
    tokens: number;
    latencyMs: number;
    toolCalls: number;
  };
}

export interface HarnessNode {
  harnessId: string;
  sourceCode: string;
  accuracy: number;
  costVector: { tokens: number; latencyMs: number };
  evidence: ExecutionEvidence[];
  isAdmitted: boolean;
  depth: number;
  parentId?: string;
  patchApplied?: string;   // Unified-diff e = (h_par -> h)
}

export interface IslandLineageTree {
  islandId: string;
  mutatorAgentId: string;
  rootId: string;
  nodes: Map;
  stallCounter: number;
  currentParetoFront: string[];
}

export class MILOEvolutionEngine {
  private islands: Map = new Map();
  private maxStallRounds: number = 3;
  private tokenCap: number = 100_000;

  constructor(initialSeeds: { id: string; code: string }[], mutatorPool: string[]) {
    initialSeeds.forEach((seed, idx) => {
      const islandId = `island-${idx + 1}`;
      const rootNode: HarnessNode = {
        harnessId: seed.id,
        sourceCode: seed.code,
        accuracy: 0.0,
        costVector: { tokens: 0, latencyMs: 0 },
        evidence: [],
        isAdmitted: true,
        depth: 0,
      };

      const nodes = new Map();
      nodes.set(seed.id, rootNode);

      this.islands.set(islandId, {
        islandId,
        mutatorAgentId: mutatorPool[idx % mutatorPool.length],
        rootId: seed.id,
        nodes,
        stallCounter: 0,
        currentParetoFront: [seed.id],
      });
    });
  }

  /**
   * Cek Pareto Dominance: h1 dominates h2 (h1 ≻ h2)
   */
  public dominates(h1: HarnessNode, h2: HarnessNode, eps: number = 0.005): boolean {
    const accDiff = h1.accuracy - h2.accuracy;
    if (accDiff > eps) return true;
    if (Math.abs(accDiff) <= eps) {
      // Jika akurasi setara dalam batas epsilon, menangkan yang paling hemat biaya (tokens & latency)
      return (
        h1.costVector.tokens <= h2.costVector.tokens &&
        h1.costVector.latencyMs <= h2.costVector.latencyMs &&
        (h1.costVector.tokens < h2.costVector.tokens || h1.costVector.latencyMs < h2.costVector.latencyMs)
      );
    }
    return false;
  }

  /**
   * Parent Selection: Menyeimbangkan eksploitasi Pareto dan eksplorasi dissimilar behavior
   */
  public selectParent(island: IslandLineageTree): HarnessNode {
    const admitted = Array.from(island.nodes.values()).filter(n => n.isAdmitted);
    if (admitted.length === 0) return island.nodes.get(island.rootId)!;

    // Utamakan kandidat di Pareto front yang belum sering bermutasi
    const paretoNodes = admitted.filter(n => island.currentParetoFront.includes(n.harnessId));
    return paretoNodes[Math.floor(Math.random() * paretoNodes.length)] || admitted[admitted.length - 1];
  }

  /**
   * Orchestrator Intervention: Diagnosis kebuntuan dan rekonfigurasi strategi pencarian
   */
  public orchestrateIntervention(stalledIsland: IslandLineageTree, allIslands: IslandLineageTree[]): string {
    console.warn(`[ORCHESTRATOR] Island ${stalledIsland.islandId} mengalami stagnasi (stall=${stalledIsland.stallCounter}). Mengevaluasi intervensi...`);

    // Cari donor island dengan akurasi Pareto tertinggi yang ortogonal
    const donor = allIslands.find(isl => isl.islandId !== stalledIsland.islandId);
    if (donor) {
      // 1. Intervensi Grafting: Silangkan harness terbaik donor ke pulau yang buntu
      const bestDonorNode = donor.nodes.get(donor.currentParetoFront[0])!;
      const graftedId = `graft-${bestDonorNode.harnessId}-to-${stalledIsland.islandId}`;
      stalledIsland.nodes.set(graftedId, {
        ...bestDonorNode,
        harnessId: graftedId,
        depth: stalledIsland.nodes.size,
        parentId: stalledIsland.currentParetoFront[0],
      });
      stalledIsland.stallCounter = 0;
      return `GRAFT: Mengimpor state ${bestDonorNode.harnessId} dari ${donor.islandId}`;
    }

    // 2. Intervensi Reassign Mutator jika donor tidak tersedia
    stalledIsland.mutatorAgentId = `mutator-specialist-${Date.now()}`;
    stalledIsland.stallCounter = 0;
    return `REASSIGN: Mengalokasikan mutator agent baru ke ${stalledIsland.islandId}`;
  }
}