import { Connection, clusterApiUrl, Keypair, PublicKey } from "@solana/web3.js";
import * as fs from "fs";
import * as os from "os";
import * as path from "path";

export const SIDE_UP = 0;
export const SIDE_DOWN = 1;

/**
 * Runtime configuration. Everything can be overridden via environment
 * variables; defaults target the local validator.
 */
export interface Config {
  /** RPC endpoint of the cluster (localnet by default). */
  rpcUrl: string;
  /** Localnet allows naive airdrops (to bettors and the house vault). */
  allowAirdrop: boolean;
  /** Program id. Defaults to the value embedded in the IDL. */
  programId: PublicKey;
  /** House admin/relayer keypair file path. */
  adminKeypairPath: string;
  /** Initial parameters used by `init` (must match on-chain constants). */
  minAmountLamports: number;
  maxAmountLamports: number;
  multiplierBps: number;
  expirySeconds: number;
}

function env(name: string, fallback: string): string {
  return process.env[name] ?? fallback;
}

function envNum(name: string, fallback: number): number {
  const raw = process.env[name];
  if (!raw) return fallback;
  const n = Number(raw);
  if (!Number.isFinite(n)) throw new Error(`Invalid number for env ${name}: ${raw}`);
  return n;
}

export function loadConfig(): Config {
  const rpcUrl = env("SMART_RPC_URL", "http://127.0.0.1:8899");
  const allowAirdrop = env("SMART_ALLOW_AIRDROP", "1") === "1";
  const adminKeypairPath =
    env("SMART_ADMIN_KEYPAIR", path.join(os.homedir(), ".config/solana/id.json"));

  return {
    rpcUrl,
    allowAirdrop,
    programId: PublicKey.default, // placeholder; real value read from the IDL below
    adminKeypairPath,
    minAmountLamports: envNum("SMART_MIN_AMOUNT", 100_000_000), // 0.1 SOL
    maxAmountLamports: envNum("SMART_MAX_AMOUNT", 10_000_000_000), // 10 SOL
    multiplierBps: envNum("SMART_MULTIPLIER_BPS", 13_000), // 1.3x
    expirySeconds: envNum("SMART_EXPIRY_SECONDS", 15),
  };
}

export function loadKeypair(pathOrJson: string): Keypair {
  const resolved = pathOrJson.startsWith("~")
    ? path.join(os.homedir(), pathOrJson.slice(1))
    : path.resolve(pathOrJson);
  const raw = fs.readFileSync(resolved, "utf8");
  return Keypair.fromSecretKey(Uint8Array.from(JSON.parse(raw)));
}