import type { ApiTierState, ApiTierId, DeveloperEcosystem, TierServingMetrics } from '@ai-tycoon/shared';
import {
  API_TIER_ORDER,
  API_CONVERSION_RATES,
  API_TIER_CHURN_RATES,
  API_TOKENS_PER_DEVELOPER_PER_TICK,
  REJECTION_CHURN_MULTIPLIER,
} from '@ai-tycoon/shared';

export interface ApiTickResult {
  apiTiers: ApiTierState;
  apiRevenue: number;
  totalApiTokenDemand: number;
}

export function processApiTiers(
  tiers: ApiTierState,
  playerDevCustomers: number,
  modelQuality: number,
  seasonalApiMultiplier: number,
  ecosystem: DeveloperEcosystem,
  apiPaidMetrics: TierServingMetrics,
  apiFreeMetrics: TierServingMetrics,
): ApiTickResult {
  const updated: ApiTierState = {
    tiers: { ...tiers.tiers },
    totalDevelopers: 0,
    totalTokensPerTick: 0,
  };

  for (const id of API_TIER_ORDER) {
    updated.tiers[id] = { ...tiers.tiers[id], config: { ...tiers.tiers[id].config } };
  }

  if (modelQuality <= 0) {
    return { apiTiers: updated, apiRevenue: 0, totalApiTokenDemand: 0 };
  }

  const targetFreeDevelopers = playerDevCustomers * 0.1 * seasonalApiMultiplier;
  const freeGrowth = (targetFreeDevelopers - updated.tiers.free.developerCount) * 0.03;
  updated.tiers.free.developerCount = Math.max(0, updated.tiers.free.developerCount + freeGrowth);
  const freeChurn = updated.tiers.free.developerCount * API_TIER_CHURN_RATES.free;
  updated.tiers.free.developerCount = Math.max(0, updated.tiers.free.developerCount - freeChurn);
  updated.tiers.free.churnRate = API_TIER_CHURN_RATES.free;

  const prevTierMap: Record<ApiTierId, ApiTierId | null> = {
    free: null,
    payg: 'free',
    scale: 'payg',
    'enterprise-api': 'scale',
  };

  for (const id of API_TIER_ORDER) {
    if (id === 'free') continue;
    const tier = updated.tiers[id];
    if (!tier.config.isActive) continue;

    const prevId = prevTierMap[id];
    if (!prevId) continue;
    const prevTier = updated.tiers[prevId];

    const convKey = `${prevId}->${id}`;
    const baseRate = API_CONVERSION_RATES[convKey] ?? 0;
    const ecosystemBoost = 1 + ecosystem.ecosystemScore / 200;
    const convRate = baseRate * Math.max(0.1, modelQuality) * ecosystemBoost * seasonalApiMultiplier;

    const converting = prevTier.developerCount * convRate;
    prevTier.developerCount = Math.max(0, prevTier.developerCount - converting);
    tier.developerCount += converting;

    tier.churnRate = API_TIER_CHURN_RATES[id];
    const churned = tier.developerCount * tier.churnRate;
    tier.developerCount = Math.max(0, tier.developerCount - churned);
  }

  let totalDevelopers = 0;
  let totalTokens = 0;
  let apiRevenue = 0;

  for (const id of API_TIER_ORDER) {
    const tier = updated.tiers[id];
    totalDevelopers += tier.developerCount;

    const tokensPerDev = API_TOKENS_PER_DEVELOPER_PER_TICK[id];
    tier.tokensPerTick = tier.developerCount * tokensPerDev;
    totalTokens += tier.tokensPerTick;

    apiRevenue += tier.developerCount * (tier.config.monthlyFee / 86400);
    apiRevenue += (tier.tokensPerTick / 1_000_000) * tier.config.outputTokenPrice;
  }

  updated.totalDevelopers = totalDevelopers;
  updated.totalTokensPerTick = totalTokens;

  const freeRejectRate = apiFreeMetrics.demandTokens > 0
    ? apiFreeMetrics.rejectedTokens / apiFreeMetrics.demandTokens : 0;
  if (freeRejectRate > 0) {
    const extraChurn = updated.tiers.free.developerCount * freeRejectRate * 0.01 * REJECTION_CHURN_MULTIPLIER;
    updated.tiers.free.developerCount = Math.max(0, updated.tiers.free.developerCount - extraChurn);
  }

  const paidRejectRate = apiPaidMetrics.demandTokens > 0
    ? apiPaidMetrics.rejectedTokens / apiPaidMetrics.demandTokens : 0;
  if (paidRejectRate > 0) {
    for (const id of API_TIER_ORDER) {
      if (id === 'free') continue;
      const extraChurn = updated.tiers[id].developerCount * paidRejectRate * 0.005 * REJECTION_CHURN_MULTIPLIER;
      updated.tiers[id].developerCount = Math.max(0, updated.tiers[id].developerCount - extraChurn);
    }
  }

  return {
    apiTiers: updated,
    apiRevenue: Math.max(0, apiRevenue),
    totalApiTokenDemand: totalTokens,
  };
}