import type {
  GameState, InfrastructureState, Cluster, Campus, DataCenter,
  DeploymentCohort, PipelineStage, RackSkuId,
  SwitchTier, DCNetworkSummary, CampusNetworkSummary, ClusterNetworkSummary,
  RepairBatch, CampusRetrofitQueue, DCTier, IntraNodeInterconnect, NetworkFabric, RackSkuConfig,
} from '@token-empire/shared';
import {
  LOCATION_CONFIGS,
  RACK_SKU_CONFIGS,
  DC_TIER_CONFIGS,
  BASE_ENERGY_COST_PER_FLOP,
  BASE_MAINTENANCE_PER_RACK,
  COOLING_FAILURE_REDUCTION,
  REDUNDANCY_FAILURE_REDUCTION,
  RACK_REPAIR_BASE_TICKS,
  COHORT_SCALE_FACTOR,
  PIPELINE_ORDER_BASE_TICKS,
  SWITCH_TIER_CONFIGS,
  T3_COUNT_PER_DC_TIER,
  SWITCH_REPAIR_COST_FRACTION,
  NETWORK_DEGRADATION,
  COOLING_TYPE_CONFIGS,
  NETWORK_FABRIC_CONFIGS,
  estimateNetworkSlots,
} from '@token-empire/shared';
import type { TickNotification } from '../tick';
import type { ResearchBonuses } from './researchBonuses';

export interface InfraTickResult {
  infrastructure: InfrastructureState;
  notifications: TickNotification[];
  repairCosts: number;
}

// --- Pipeline helpers ---

const PIPELINE_ADVANCE_ORDER: PipelineStage[] = [
  'ordered', 'manufacturing', 'receiving', 'installation', 'testing',
];

function nextStage(stage: PipelineStage): PipelineStage | 'production' {
  const idx = PIPELINE_ADVANCE_ORDER.indexOf(stage);
  if (idx === -1 || idx === PIPELINE_ADVANCE_ORDER.length - 1) return 'production';
  return PIPELINE_ADVANCE_ORDER[idx + 1];
}

function cohortStageTotal(stage: PipelineStage, skuId: string, count: number): number {
  const sku = RACK_SKU_CONFIGS[skuId as keyof typeof RACK_SKU_CONFIGS];
  const timings = sku.pipelineTimeTicks;
  let base: number;
  switch (stage) {
    case 'ordered': base = PIPELINE_ORDER_BASE_TICKS; break;
    case 'manufacturing': base = timings.manufacturing; break;
    case 'receiving': base = timings.receiving; break;
    case 'installation': base = timings.installation; break;
    case 'testing': base = timings.testing; break;
    case 'repair': base = RACK_REPAIR_BASE_TICKS; break;
    case 'decommission': base = timings.installation; break;
    case 'network-down': base = 0; break;
    default: base = 0;
  }
  return Math.ceil(base * (1 + COHORT_SCALE_FACTOR * count));
}

function stageSpeed(stage: PipelineStage, engEff: number, opsEff: number): number {
  switch (stage) {
    case 'manufacturing': return 1 + engEff * 0.1;
    case 'installation':
    case 'testing':
    case 'decommission': return 1 + opsEff * 0.1;
    case 'repair': return 1 + opsEff * 0.05;
    case 'network-down': return 0;
    default: return 1;
  }
}

function binomialSample(n: number, p: number): number {
  if (n <= 0 || p <= 0) return 0;
  if (p >= 1) return n;
  const expected = n * p;
  const base = Math.floor(expected);
  const frac = expected - base;
  return base + (Math.random() < frac ? 1 : 0);
}

// --- Aggregate Network Model ---

const DC_TIERS: SwitchTier[] = ['tor', 't1', 't2', 't3'];

export function emptyDCNetworkSummary(): DCNetworkSummary {
  return {
    totalByTier: {}, healthyByTier: {},
    repairBatches: [], networkRackCount: 0,
    racksDisconnected: 0, racksDegraded: 0,
    averageBandwidth: 1, effectiveFlopsFraction: 1,
  };
}

export function emptyCampusNetworkSummary(): CampusNetworkSummary {
  return { totalT4: 0, healthyT4: 0, crossDCBandwidth: 1 };
}

export function emptyClusterNetworkSummary(): ClusterNetworkSummary {
  return { totalT5: 0, healthyT5: 0, crossCampusBandwidth: 1 };
}

function computeTopologyCounts(
  computeRackCount: number,
  dcTier: DCTier,
): Partial<Record<SwitchTier, number>> {
  if (computeRackCount <= 0) return {};
  const t1Count = Math.ceil(computeRackCount / SWITCH_TIER_CONFIGS.t1.fanOut);
  const t2Count = Math.ceil(t1Count / SWITCH_TIER_CONFIGS.t2.fanOut);
  const t3Count = T3_COUNT_PER_DC_TIER[dcTier];
  return { tor: computeRackCount, t1: t1Count, t2: t2Count, t3: t3Count };
}

export function buildDCNetworkSummary(
  computeRackCount: number,
  dcTier: DCTier,
): DCNetworkSummary {
  if (computeRackCount <= 0) return emptyDCNetworkSummary();
  const totalByTier = computeTopologyCounts(computeRackCount, dcTier);
  const healthyByTier = { ...totalByTier };
  return {
    totalByTier, healthyByTier,
    repairBatches: [],
    networkRackCount: estimateNetworkSlots(computeRackCount, dcTier),
    racksDisconnected: 0, racksDegraded: 0,
    averageBandwidth: 1, effectiveFlopsFraction: 1,
  };
}

export function expandDCNetwork(
  existing: DCNetworkSummary,
  addedRacks: number,
  dcTier: DCTier,
): DCNetworkSummary {
  if (addedRacks <= 0) return existing;
  const oldTor = existing.totalByTier.tor ?? 0;
  const newTor = oldTor + addedRacks;
  const newTotal = computeTopologyCounts(newTor, dcTier);
  const healthyByTier: Partial<Record<SwitchTier, number>> = {};
  for (const tier of DC_TIERS) {
    const oldTotal = existing.totalByTier[tier] ?? 0;
    const oldHealthy = existing.healthyByTier[tier] ?? 0;
    const added = (newTotal[tier] ?? 0) - oldTotal;
    healthyByTier[tier] = oldHealthy + Math.max(0, added);
  }
  const summary: DCNetworkSummary = {
    ...existing,
    totalByTier: newTotal,
    healthyByTier,
    networkRackCount: estimateNetworkSlots(newTor, dcTier),
  };
  return recomputeBandwidth(summary);
}

export function shrinkDCNetwork(
  existing: DCNetworkSummary,
  removedRacks: number,
  dcTier: DCTier,
): DCNetworkSummary {
  if (removedRacks <= 0) return existing;
  const oldTor = existing.totalByTier.tor ?? 0;
  const newTor = Math.max(0, oldTor - removedRacks);
  if (newTor === 0) return emptyDCNetworkSummary();
  const newTotal = computeTopologyCounts(newTor, dcTier);
  const healthyByTier: Partial<Record<SwitchTier, number>> = {};
  for (const tier of DC_TIERS) {
    const nt = newTotal[tier] ?? 0;
    const oh = existing.healthyByTier[tier] ?? 0;
    healthyByTier[tier] = Math.min(oh, nt);
  }
  const repairBatches = existing.repairBatches.filter(b => {
    const nt = newTotal[b.tier] ?? 0;
    const nh = healthyByTier[b.tier] ?? 0;
    return nh < nt;
  });
  const summary: DCNetworkSummary = {
    ...existing,
    totalByTier: newTotal,
    healthyByTier,
    repairBatches,
    networkRackCount: estimateNetworkSlots(newTor, dcTier),
  };
  return recomputeBandwidth(summary);
}

function computeAggregateBandwidth(
  summary: DCNetworkSummary,
  redundancyBonus: number,
): number {
  let minBW = 1;
  for (const tier of DC_TIERS) {
    const total = summary.totalByTier[tier] ?? 0;
    if (total === 0) continue;
    const healthy = summary.healthyByTier[tier] ?? 0;
    const tierBW = Math.min(1, (healthy + redundancyBonus) / total);
    if (tierBW < minBW) minBW = tierBW;
  }
  return minBW;
}

function recomputeBandwidth(summary: DCNetworkSummary, redundancyBonus = 0): DCNetworkSummary {
  const avgBW = computeAggregateBandwidth(summary, redundancyBonus);
  const torTotal = summary.totalByTier.tor ?? 0;
  const torHealthy = summary.healthyByTier.tor ?? 0;
  const torFailed = torTotal - torHealthy;
  const disconnected = avgBW === 0 ? torTotal : torFailed;
  const degraded = avgBW > 0 && avgBW < 1 ? Math.ceil(torTotal * (1 - avgBW)) - disconnected : 0;
  return {
    ...summary,
    averageBandwidth: avgBW,
    effectiveFlopsFraction: avgBW,
    racksDisconnected: Math.max(0, disconnected),
    racksDegraded: Math.max(0, degraded),
  };
}

function processNetworkForDC(
  summary: DCNetworkSummary,
  networkResearchBonus: number,
  opsEff: number,
  repairSpeedBonus: number,
  hotStandbyTicks: number,
  redundancyBonus: number,
): { summary: DCNetworkSummary; costs: number; notifications: TickNotification[] } {
  const torTotal = summary.totalByTier.tor ?? 0;
  if (torTotal === 0) return { summary, costs: 0, notifications: [] };

  let costs = 0;
  const notifications: TickNotification[] = [];
  const healthyByTier = { ...summary.healthyByTier };
  let dirty = false;

  for (const tier of DC_TIERS) {
    const healthy = healthyByTier[tier] ?? 0;
    if (healthy <= 0) continue;
    const rate = SWITCH_TIER_CONFIGS[tier].failureRatePerTick * (1 - networkResearchBonus);
    const failed = binomialSample(healthy, rate);
    if (failed > 0) {
      healthyByTier[tier] = healthy - failed;
      const baseRepair = SWITCH_TIER_CONFIGS[tier].repairBaseTicks;
      const repairTime = hotStandbyTicks > 0
        ? hotStandbyTicks
        : baseRepair * (1 - repairSpeedBonus);
      summary.repairBatches.push({ tier, count: failed, ticksRemaining: repairTime });
      costs += SWITCH_TIER_CONFIGS[tier].baseCost * SWITCH_REPAIR_COST_FRACTION * failed;
      dirty = true;

      if (tier === 't3') {
        notifications.push({ title: 'Core Network Failure', message: `Tier-3 core switch failed — potential DC disconnect!`, type: 'danger' });
      } else if (tier === 't2') {
        notifications.push({ title: 'Network Switch Failure', message: `Tier-2 spine switch failed — racks may be degraded.`, type: 'warning' });
      }
    }
  }

  const remainingBatches: RepairBatch[] = [];
  for (const batch of summary.repairBatches) {
    const newTicks = batch.ticksRemaining - (1 + opsEff * 0.05);
    if (newTicks <= 0) {
      healthyByTier[batch.tier] = Math.min(
        summary.totalByTier[batch.tier] ?? 0,
        (healthyByTier[batch.tier] ?? 0) + batch.count,
      );
      dirty = true;
    } else {
      remainingBatches.push({ ...batch, ticksRemaining: newTicks });
    }
  }

  if (!dirty) return { summary: { ...summary, repairBatches: remainingBatches }, costs, notifications };

  const updated: DCNetworkSummary = {
    ...summary,
    healthyByTier,
    repairBatches: remainingBatches,
  };
  return { summary: recomputeBandwidth(updated, redundancyBonus), costs, notifications };
}

// --- Interconnect Training Multiplier ---

const INTRA_NODE_BONUS: Record<IntraNodeInterconnect, number> = {
  'pcie-gen4': 0.0,
  'pcie-gen5': 0.05,
  'nvlink-3': 0.15,
  'nvlink-4': 0.25,
  'nvlink-5': 0.35,
  'nvlink-domain': 0.50,
  'infinity-fabric': 0.10,
  'custom-mesh': 0.40,
};

function computeInterconnectMultiplier(
  sku: RackSkuConfig,
  rackCount: number,
  fabric: NetworkFabric,
): number {
  if (rackCount <= 1) return 1.0;
  const intra = INTRA_NODE_BONUS[sku.intraNodeInterconnect] ?? 0;
  const fabricBonus = NETWORK_FABRIC_CONFIGS[fabric].trainingScalingBonus;
  return Math.min(1.0, 0.6 + intra + fabricBonus);
}

// --- Main Infrastructure Tick ---

export function processInfrastructure(state: GameState, researchBonuses?: ResearchBonuses): InfraTickResult {
  const notifications: TickNotification[] = [];
  let repairCosts = 0;

  const engEff = state.talent.departments.engineering.effectiveness;
  const opsEff = state.talent.departments.operations.effectiveness;
  const qaResearchBonus = state.research.completedResearch.includes('quality-assurance') ? 0.25 : 0;
  const netResearch1 = state.research.completedResearch.includes('network-engineering-i') ? 0.4 : 0;
  const netResearch2 = state.research.completedResearch.includes('network-engineering-ii') ? 0.5 : 0;
  const networkResearchBonus = Math.min(0.8, netResearch1 + netResearch2);
  const repairSpeedBonus = state.research.completedResearch.includes('network-fast-repair') ? 0.4 : 0;
  const hotStandbyTicks = state.research.completedResearch.includes('network-hot-standby') ? 5 : 0;
  const redundancyBonus = state.research.completedResearch.includes('network-redundancy') ? 1 : 0;

  let totalFlops = 0;
  let totalTrainingFlops = 0;
  let totalInferenceFlops = 0;
  let totalVramGB = 0;
  let totalUptime = 0;
  let totalRackCount = 0;
  let totalComputeRackCount = 0;
  let totalDataCenterCount = 0;
  let dcWithRacks = 0;
  let globalLatencyPenalty = 0;
  let latencyDCCount = 0;

  const clusters: Cluster[] = state.infrastructure.clusters.map(cluster => {
    if (cluster.status === 'constructing') {
      const newProgress = cluster.constructionProgress + 1;
      if (newProgress >= cluster.constructionTotal) {
        notifications.push({
          title: 'Cluster Online',
          message: `${cluster.name} cluster in ${LOCATION_CONFIGS[cluster.locationId].name} is now operational!`,
          type: 'success',
        });
        return { ...cluster, constructionProgress: cluster.constructionTotal, status: 'operational' as const };
      }
      return { ...cluster, constructionProgress: newProgress };
    }

    const campuses: Campus[] = cluster.campuses.map(campus => {
      if (campus.status === 'constructing') {
        const newProgress = campus.constructionProgress + 1;
        if (newProgress >= campus.constructionTotal) {
          notifications.push({ title: 'Campus Ready', message: `Campus ${campus.name} is now operational!`, type: 'success' });
          return { ...campus, constructionProgress: campus.constructionTotal, status: 'operational' as const };
        }
        return { ...campus, constructionProgress: newProgress };
      }

      const dataCenters: DataCenter[] = campus.dataCenters.map(dc => {
        if (dc.status === 'constructing') {
          const newProgress = dc.constructionProgress + 1;
          if (newProgress >= dc.constructionTotal) {
            notifications.push({ title: 'Data Center Online', message: `${dc.name} is now operational!`, type: 'success' });
            return { ...dc, constructionProgress: dc.constructionTotal, status: 'operational' as const };
          }
          return { ...dc, constructionProgress: newProgress };
        }

        let computeRacksOnline = dc.computeRacksOnline;
        let dcRepairCosts = 0;

        // Process retrofit
        if (dc.status === 'retrofitting' && dc.retrofitState) {
          const rs = { ...dc.retrofitState };
          rs.progress += (1 + opsEff * 0.1);

          if (rs.progress >= rs.total) {
            if (rs.phase === 'decommissioning') {
              const installTotal = cohortStageTotal('installation', rs.toSkuId, rs.racksRemaining);
              return {
                ...dc,
                computeRacksOnline: 0,
                computeRacksFailed: 0,
                rackSkuId: rs.toSkuId,
                deploymentCohorts: [{
                  id: `retrofit-${dc.id}-${Date.now()}`,
                  count: rs.racksRemaining,
                  skuId: rs.toSkuId,
                  stage: 'installation' as PipelineStage,
                  stageProgress: 0,
                  stageTotal: installTotal,
                  repairCount: 0,
                }],
                retrofitState: { ...rs, phase: 'installing' as const, progress: 0, total: installTotal },
                networkSummary: emptyDCNetworkSummary(),
                effectiveComputeRacks: 0,
                usedSlots: 0, usedPowerKW: 0, currentUptime: 0,
                energyCostPerTick: DC_TIER_CONFIGS[dc.tier].baseEnergyCostPerTick * LOCATION_CONFIGS[cluster.locationId].energyCostMultiplier,
                maintenanceCostPerTick: 0,
              };
            } else {
              notifications.push({ title: 'Retrofit Complete', message: `${dc.name} retrofit to ${RACK_SKU_CONFIGS[rs.toSkuId].name} is complete!`, type: 'success' });
              return { ...dc, status: 'operational' as const, retrofitState: null };
            }
          }
          return { ...dc, retrofitState: rs };
        }

        // Process deployment cohorts
        const updatedCohorts: DeploymentCohort[] = [];
        let racksJustOnlined = 0;

        for (const cohort of dc.deploymentCohorts) {
          // network-down cohorts don't progress via speed — handled separately below
          if (cohort.stage === 'network-down') {
            updatedCohorts.push(cohort);
            continue;
          }

          const baseSpeed = stageSpeed(cohort.stage, engEff, opsEff);
          const pipelineBonus = cohort.stage !== 'repair' ? (researchBonuses?.pipelineSpeedBonus ?? 0) : 0;
          const speed = baseSpeed * (1 + pipelineBonus);
          const newProgress = cohort.stageProgress + speed;

          if (newProgress < cohort.stageTotal) {
            updatedCohorts.push({ ...cohort, stageProgress: newProgress });
            continue;
          }

          if (cohort.stage === 'decommission') continue;

          if (cohort.stage === 'repair') {
            const testTotal = cohortStageTotal('testing', cohort.skuId, cohort.count);
            updatedCohorts.push({ ...cohort, stage: 'testing', stageProgress: 0, stageTotal: testTotal });
            continue;
          }

          const next = nextStage(cohort.stage);

          if (next === 'production') {
            const sku = RACK_SKU_CONFIGS[cohort.skuId];
            const effectiveFailRate = sku.testFailureRate
              * (1 - dc.coolingLevel * COOLING_FAILURE_REDUCTION)
              * (1 - opsEff * 0.2)
              * (1 - qaResearchBonus);

            const failed = binomialSample(cohort.count, effectiveFailRate);
            const passed = cohort.count - failed;
            racksJustOnlined += passed;

            if (failed > 0) {
              const repairCost = sku.baseCost * sku.repairCostFraction * failed;
              dcRepairCosts += repairCost;
              updatedCohorts.push({
                id: `repair-${cohort.id}`,
                count: failed, skuId: cohort.skuId,
                stage: 'repair', stageProgress: 0,
                stageTotal: cohortStageTotal('repair', cohort.skuId, failed),
                repairCount: cohort.repairCount + 1,
              });
            }
          } else {
            const total = cohortStageTotal(next, cohort.skuId, cohort.count);
            updatedCohorts.push({ ...cohort, stage: next, stageProgress: 0, stageTotal: total });
          }
        }

        computeRacksOnline += racksJustOnlined;

        // Expand topology for newly onlined racks
        let networkSummary = dc.networkSummary;
        if (racksJustOnlined > 0) {
          const torTotal = networkSummary.totalByTier.tor ?? 0;
          if (torTotal === 0) {
            networkSummary = buildDCNetworkSummary(computeRacksOnline, dc.tier);
          } else {
            networkSummary = expandDCNetwork(networkSummary, racksJustOnlined, dc.tier);
          }
        }

        // Production failures
        if (computeRacksOnline > 0 && dc.rackSkuId) {
          const sku = RACK_SKU_CONFIGS[dc.rackSkuId];
          const effectiveRate = sku.productionFailureRate
            * (1 - dc.coolingLevel * COOLING_FAILURE_REDUCTION)
            * (1 - dc.redundancyLevel * REDUNDANCY_FAILURE_REDUCTION);
          const prodFailures = binomialSample(computeRacksOnline, effectiveRate);
          if (prodFailures > 0) {
            computeRacksOnline -= prodFailures;
            dcRepairCosts += sku.baseCost * sku.repairCostFraction * prodFailures;
            updatedCohorts.push({
              id: `prodfail-${dc.id}-${Date.now()}`,
              count: prodFailures, skuId: dc.rackSkuId,
              stage: 'repair', stageProgress: 0,
              stageTotal: cohortStageTotal('repair', dc.rackSkuId, prodFailures),
              repairCount: 0,
            });
            networkSummary = shrinkDCNetwork(networkSummary, prodFailures, dc.tier);
          }
        }

        repairCosts += dcRepairCosts;

        // Process per-DC network failures and repairs (aggregate model)
        const netResult = processNetworkForDC(
          networkSummary, networkResearchBonus, opsEff,
          repairSpeedBonus, hotStandbyTicks, redundancyBonus,
        );
        networkSummary = netResult.summary;
        repairCosts += netResult.costs;
        if (netResult.notifications.length > 0) notifications.push(...netResult.notifications);

        // Rackdown: detect recovery (previously disconnected racks now have connectivity)
        const prevDisconnected = dc.networkSummary.racksDisconnected;
        const currDisconnected = networkSummary.racksDisconnected;

        if (currDisconnected < prevDisconnected && dc.rackSkuId) {
          const recovered = prevDisconnected - currDisconnected;
          computeRacksOnline -= recovered;
          networkSummary = shrinkDCNetwork(networkSummary, recovered, dc.tier);
          updatedCohorts.push({
            id: `netrecovery-${dc.id}-${Date.now()}`,
            count: recovered, skuId: dc.rackSkuId,
            stage: 'testing', stageProgress: 0,
            stageTotal: cohortStageTotal('testing', dc.rackSkuId, recovered),
            repairCount: 0,
          });
        }

        // Compute DC aggregates
        const effectiveComputeRacks = Math.max(0,
          computeRacksOnline - networkSummary.racksDisconnected);
        const location = LOCATION_CONFIGS[cluster.locationId];
        const tierConfig = DC_TIER_CONFIGS[dc.tier];
        const pipelineRacks = updatedCohorts
          .filter(c => c.stage !== 'decommission')
          .reduce((sum, c) => sum + c.count, 0);
        const computeRacksFailed = updatedCohorts
          .filter(c => c.stage === 'repair')
          .reduce((sum, c) => sum + c.count, 0);
        const totalRacksInDc = computeRacksOnline + pipelineRacks;
        const netSlots = networkSummary.networkRackCount;
        const usedSlots = computeRacksOnline + pipelineRacks + netSlots;

        let usedPowerKW = 0;
        let dcFlops = 0;
        let dcTrainingFlops = 0;
        let dcInferenceFlops = 0;
        let dcTotalVramGB = 0;
        if (dc.rackSkuId && computeRacksOnline > 0) {
          const sku = RACK_SKU_CONFIGS[dc.rackSkuId];
          usedPowerKW = computeRacksOnline * sku.powerDrawKW;
          const bwFraction = networkSummary.effectiveFlopsFraction;
          const interconnectMult = computeInterconnectMultiplier(sku, effectiveComputeRacks, dc.networkFabric);
          dcTrainingFlops = effectiveComputeRacks * sku.trainingFlops * bwFraction * interconnectMult;
          dcInferenceFlops = effectiveComputeRacks * sku.inferenceFlops * bwFraction;
          dcTotalVramGB = computeRacksOnline * sku.totalVramGB;
          dcFlops = dcTrainingFlops + dcInferenceFlops;
        }

        const pue = COOLING_TYPE_CONFIGS[dc.coolingType].pueMultiplier;
        const energyReduction = researchBonuses?.energyCostReduction ?? 0;
        const energyCostPerTick = (tierConfig.baseEnergyCostPerTick + usedPowerKW * BASE_ENERGY_COST_PER_FLOP)
          * location.energyCostMultiplier * pue * (1 - energyReduction);
        const maintenanceCostPerTick = totalRacksInDc * BASE_MAINTENANCE_PER_RACK;
        const currentUptime = totalRacksInDc > 0 ? effectiveComputeRacks / totalRacksInDc : 1;

        // Latency penalty from bandwidth degradation
        if (networkSummary.averageBandwidth < 1 && computeRacksOnline > 0) {
          const penalty = (1 - networkSummary.averageBandwidth) * NETWORK_DEGRADATION.bandwidthToLatencyPenalty;
          globalLatencyPenalty += penalty;
          latencyDCCount++;
        }

        totalFlops += dcFlops;
        totalTrainingFlops += dcTrainingFlops;
        totalInferenceFlops += dcInferenceFlops;
        totalVramGB += dcTotalVramGB;
        totalRackCount += totalRacksInDc + netSlots;
        totalComputeRackCount += totalRacksInDc;
        totalDataCenterCount++;
        if (totalRacksInDc > 0) { totalUptime += currentUptime; dcWithRacks++; }

        return {
          ...dc,
          computeRacksOnline, computeRacksFailed,
          deploymentCohorts: updatedCohorts,
          networkSummary, effectiveComputeRacks,
          usedSlots, usedPowerKW, energyCostPerTick, maintenanceCostPerTick, currentUptime,
          dcTrainingFlops, dcInferenceFlops, dcTotalVramGB,
        };
      });

      // Process campus retrofit queue
      let finalDCs = dataCenters;
      let updatedQueue: CampusRetrofitQueue | null = campus.retrofitQueue ?? null;

      if (updatedQueue && updatedQueue.pendingDCIds.length + updatedQueue.activeDCIds.length > 0) {
        updatedQueue = { ...updatedQueue };

        const newlyCompleted = finalDCs.filter(
          dc => updatedQueue!.activeDCIds.includes(dc.id) && dc.status === 'operational',
        );
        if (newlyCompleted.length > 0) {
          updatedQueue.activeDCIds = updatedQueue.activeDCIds.filter(
            id => !newlyCompleted.some(dc => dc.id === id),
          );
          updatedQueue.completedDCIds = [...updatedQueue.completedDCIds, ...newlyCompleted.map(dc => dc.id)];
        }

        const slotsAvailable = updatedQueue.maxConcurrent - updatedQueue.activeDCIds.length;
        if (slotsAvailable > 0 && updatedQueue.pendingDCIds.length > 0) {
          const toStart = updatedQueue.pendingDCIds.slice(0, slotsAvailable);
          updatedQueue.pendingDCIds = updatedQueue.pendingDCIds.slice(toStart.length);
          updatedQueue.activeDCIds = [...updatedQueue.activeDCIds, ...toStart];

          finalDCs = finalDCs.map(dc => {
            if (!toStart.includes(dc.id)) return dc;
            if (dc.status !== 'operational' || !dc.rackSkuId) return dc;
            const pipelineCount = dc.deploymentCohorts.filter(c => c.stage !== 'decommission').reduce((sum, c) => sum + c.count, 0);
            const totalRacks = dc.computeRacksOnline + pipelineCount;
            if (totalRacks <= 0) return dc;
            const oldSku = RACK_SKU_CONFIGS[dc.rackSkuId as RackSkuId];
            const decommTicks = Math.ceil(oldSku.pipelineTimeTicks.installation * (1 + COHORT_SCALE_FACTOR * totalRacks));
            return {
              ...dc,
              status: 'retrofitting' as const,
              deploymentCohorts: [],
              networkSummary: emptyDCNetworkSummary(),
              retrofitState: {
                fromSkuId: dc.rackSkuId as RackSkuId,
                toSkuId: updatedQueue!.targetSkuId,
                phase: 'decommissioning' as const,
                progress: 0, total: decommTicks, racksRemaining: totalRacks,
              },
            };
          });
        }

        if (updatedQueue.pendingDCIds.length === 0 && updatedQueue.activeDCIds.length === 0) {
          notifications.push({
            title: 'Campus Retrofit Complete',
            message: `All DCs in ${campus.name} have been retrofitted to ${RACK_SKU_CONFIGS[updatedQueue.targetSkuId].name}!`,
            type: 'success',
          });
          updatedQueue = null;
        }
      }

      return { ...campus, dataCenters: finalDCs, retrofitQueue: updatedQueue };
    });

    return { ...cluster, campuses };
  });

  const avgLatencyPenalty = latencyDCCount > 0 ? globalLatencyPenalty / latencyDCCount : 0;

  return {
    infrastructure: {
      clusters,
      totalFlops,
      totalTrainingFlops,
      totalInferenceFlops,
      totalVramGB,
      totalUptime: dcWithRacks > 0 ? totalUptime / dcWithRacks : 1,
      totalRackCount,
      totalComputeRackCount,
      totalDataCenterCount,
      networkLatencyPenalty: avgLatencyPenalty,
    },
    notifications,
    repairCosts,
  };
}