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

/**
 * Decodo (formerly Smartproxy) residential network. Gateway `gate.decodo.com`.
 * Port 7000 = rotating; ports 10001+ = sticky by port. We use the username grammar instead:
 * `user-<user>[-country-xx][-state-us_xx][-city-xxx][-session-<id>][-sessionduration-<min>]`.
 * Documentation: https://help.decodo.com/docs/residential-authentication-methods
 */
export class DecodoProvider implements ProxyProvider {
  readonly id = "decodo" as const;
  readonly label = "Decodo";
  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: 7 }) {
    this.username = env.DECODO_USERNAME?.trim() || undefined;
    this.password = env.DECODO_PASSWORD?.trim() || undefined;
    this.prices = prices;
  }

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

  supportsGeo(_geo: GeoTarget): boolean {
    return true;
  }

  pricePerGb(network: ConcreteNetwork): number {
    return this.prices[network] ?? this.prices.residential ?? 7;
  }

  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("Decodo is not configured");
    const base = this.username.replace(/^user-/, "");
    let user = `user-${base}`;
    if (req.geo.country) user += `-country-${req.geo.country.toLowerCase()}`;
    if (req.geo.region && req.geo.country === "US") user += `-state-us_${req.geo.region}`;
    if (req.geo.city) user += `-city-${req.geo.city.replace(/_/g, "")}`;
    if (req.sessionKey) {
      user += `-session-${sanitize(req.sessionKey)}`;
      user += `-sessionduration-${Math.min(Math.max(req.sessionMinutes ?? 10, 1), 30)}`;
    }
    return { host: "gate.decodo.com", port: 7000, 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.decodo.com/json");
  }
}

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