import type { ConcreteNetwork, GeoTarget } from "@fetcha/core";
import { executeHttp } from "./http";
import type { ProviderHealth, ProviderRequest, ProviderResponse, ProxyEndpoint, ProxyProvider } from "./types";
import { probeHealth } from "./probe";

/**
 * Oxylabs residential network. Gateway `pr.oxylabs.io:7777`.
 * Username grammar: `customer-<user>[-cc-XX][-st-<state>][-city-<city>][-sessid-<id>][-sesstime-<min>]`.
 * Documentation: https://developers.oxylabs.io/proxies/residential-proxies
 */
export class OxylabsProvider implements ProxyProvider {
  readonly id = "oxylabs" as const;
  readonly label = "Oxylabs";
  readonly networks: ConcreteNetwork[] = ["residential"];
  private readonly username: string | undefined;
  private readonly password: string | undefined;
  private readonly prices: Record<string, number>;

  constructor(env: NodeJS.ProcessEnv = process.env, prices: Record<string, number> = { residential: 8 }) {
    this.username = env.OXYLABS_USERNAME?.trim() || undefined;
    this.password = env.OXYLABS_PASSWORD?.trim() || undefined;
    this.prices = prices;
  }

  isConfigured(): boolean {
    return Boolean(this.username && this.password);
  }

  supportsGeo(_geo: GeoTarget): boolean {
    return true; // worldwide residential coverage
  }

  pricePerGb(network: ConcreteNetwork): number {
    return this.prices[network] ?? this.prices.residential ?? 8;
  }

  estimateCost(network: ConcreteNetwork, bytes: number): number {
    return (bytes / 1_073_741_824) * this.pricePerGb(network);
  }

  /** Build the upstream gateway endpoint for a request (exposed for contract tests; never returned to customers). */
  endpoint(req: Pick<ProviderRequest, "geo" | "sessionKey" | "sessionMinutes">): ProxyEndpoint {
    if (!this.username || !this.password) throw new Error("Oxylabs is not configured");
    // Base username may already be `customer-xxx` or `customer-xxx-cc-US`; strip any geo suffix we control.
    let user = this.username.replace(/-cc-[a-z]{2}(-.*)?$/i, "");
    if (!user.startsWith("customer-")) user = `customer-${user}`;
    if (req.geo.country) user += `-cc-${req.geo.country.toUpperCase()}`;
    if (req.geo.region && (req.geo.country === "US" || req.geo.country === "CA")) user += `-st-${req.geo.country.toLowerCase()}_${req.geo.region}`;
    if (req.geo.city) user += `-city-${req.geo.city}`;
    if (req.sessionKey) {
      user += `-sessid-${sanitize(req.sessionKey)}`;
      user += `-sesstime-${Math.min(Math.max(req.sessionMinutes ?? 10, 1), 30)}`;
    }
    return { host: "pr.oxylabs.io", port: 7777, username: user, password: this.password };
  }

  proxyEndpoint(req: Pick<ProviderRequest, "geo" | "sessionKey" | "sessionMinutes">): ProxyEndpoint | null {
    return this.endpoint(req);
  }

  async fetch(request: ProviderRequest): Promise<ProviderResponse> {
    return executeHttp(this.id, this.endpoint(request), request);
  }

  async health(network: ConcreteNetwork = "residential"): Promise<ProviderHealth> {
    if (!this.isConfigured()) return { provider: this.id, network, status: "unconfigured", latencyMs: null, checkedAt: new Date(), detail: "Missing credentials" };
    return probeHealth(this, network, "https://ip.oxylabs.io/location");
  }
}

function sanitize(s: string): string {
  return s.replace(/[^a-zA-Z0-9]/g, "").slice(0, 32) || "s";
}