import { PLAN_LIMITS, type ConcreteNetwork, type Plan } from "@fetcha/core";
import { config } from "../config";

/**
 * Pricing service. Nothing in the execution path hardcodes prices: the executor reports
 * upstream cost + bytes + network and this module decides what the customer is charged.
 *
 * Model: base subscription (plan) + usage. Every request is priced as
 *   per-request component (plan overage rate, 0 while within the included quota — quota is
 *   enforced elsewhere) + bandwidth component for premium networks.
 */
export interface PriceInput {
  plan: Plan;
  network: ConcreteNetwork | null;
  bytes: number;
  upstreamCostUsd: number;
  attempts: number;
  success: boolean;
}

export interface PriceBreakdown {
  requestUsd: number;
  bandwidthUsd: number;
  totalUsd: number;
  marginUsd: number;
}

export function priceRequest(input: PriceInput): PriceBreakdown {
  const limits = PLAN_LIMITS[input.plan];
  // Private platform: the single plan has no unit prices → nothing is billed. Upstream cost is
  // still tracked for the admin's unit economics.
  if (limits.price_usd_month === 0 && limits.overage_per_1k_requests_usd === 0 && limits.residential_per_gb_usd === 0) {
    return { requestUsd: 0, bandwidthUsd: 0, totalUsd: 0, marginUsd: round6(-input.upstreamCostUsd) };
  }
  // Free/enterprise have no per-request rate; failed requests are never charged a request fee.
  const requestUsd = input.success ? limits.overage_per_1k_requests_usd / 1000 : 0;
  let bandwidthUsd = 0;
  if (input.network && input.network !== "datacenter") {
    const perGb = limits.residential_per_gb_usd || input.upstreamCostUsd > 0 ? limits.residential_per_gb_usd : 0;
    bandwidthUsd = perGb > 0 ? (input.bytes / 1_073_741_824) * perGb : input.upstreamCostUsd * config.defaultMargin;
  } else {
    bandwidthUsd = input.upstreamCostUsd * config.defaultMargin;
  }
  const totalUsd = round6(requestUsd + bandwidthUsd);
  return { requestUsd: round6(requestUsd), bandwidthUsd: round6(bandwidthUsd), totalUsd, marginUsd: round6(totalUsd - input.upstreamCostUsd) };
}

export function round6(n: number): number {
  return Math.round(n * 1e6) / 1e6;
}

export function formatUsd(n: number): string {
  if (n === 0) return "$0.00";
  if (n < 0.01) return `$${n.toFixed(5)}`;
  return `$${n.toFixed(2)}`;
}