// Jupiter swap quote: read-only quote with human amounts. Zero dependencies.
import { pathToFileURL } from "node:url";

const API = "https://lite-api.jup.ag";
const KNOWN = {
  SOL: { mint: "So11111111111111111111111111111111111111112", symbol: "SOL", decimals: 9 },
  USDC: { mint: "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v", symbol: "USDC", decimals: 6 },
  USDT: { mint: "Es9vMFrzaCERmJfrF4H2FYD4KCoNkY11McCe8BenwNYB", symbol: "USDT", decimals: 6 },
};
const MINT_RE = /^[1-9A-HJ-NP-Za-km-z]{32,44}$/;

async function getJson(url) {
  const res = await fetch(url, { headers: { accept: "application/json" } });
  const body = await res.json().catch(() => null);
  if (!res.ok) throw new Error(body?.error ?? `Jupiter answered ${res.status}`);
  return body;
}

export async function resolveToken(input) {
  const upper = String(input ?? "").toUpperCase();
  if (KNOWN[upper]) return KNOWN[upper];
  const known = Object.values(KNOWN).find((k) => k.mint === input);
  if (known) return known;
  if (!MINT_RE.test(String(input ?? ""))) throw new Error(`Unknown token "${input}": use SOL, USDC, USDT or a mint address`);
  const list = await getJson(`${API}/tokens/v2/search?query=${input}`);
  const t = (Array.isArray(list) ? list : []).find((x) => x?.id === input);
  if (!t || !Number.isInteger(t.decimals)) throw new Error(`Jupiter does not know mint ${input}`);
  return { mint: t.id, symbol: t.symbol ?? null, decimals: t.decimals };
}

// Whole-token string -> integer base units, without floating point drift.
export function toBaseUnits(amount, decimals) {
  const s = String(amount).trim();
  if (!/^\d+(\.\d+)?$/.test(s)) throw new Error(`Invalid amount "${amount}"`);
  const [whole, frac = ""] = s.split(".");
  const units = BigInt(whole + frac.padEnd(decimals, "0").slice(0, decimals));
  if (units <= 0n) throw new Error("Amount must be above zero");
  return units;
}

export function fromBaseUnits(units, decimals) {
  const s = BigInt(units).toString().padStart(decimals + 1, "0");
  const whole = s.slice(0, s.length - decimals);
  const frac = s.slice(s.length - decimals).replace(/0+$/, "");
  return Number(frac ? `${whole}.${frac}` : whole);
}

export async function quote(from, to, amount, { slippageBps = 50 } = {}) {
  if (!from || !to || amount === undefined) throw new Error("Usage: quote.mjs <from> <to> <amount> [--slippage-bps 50]");
  slippageBps = Math.max(0, Math.min(1000, Math.round(Number(slippageBps) || 0)));
  const a = await resolveToken(from);
  const b = await resolveToken(to);
  if (a.mint === b.mint) throw new Error("From and to are the same token");
  const units = toBaseUnits(amount, a.decimals);
  const q = await getJson(
    `${API}/swap/v1/quote?inputMint=${a.mint}&outputMint=${b.mint}&amount=${units}&slippageBps=${slippageBps}`,
  );
  const outAmount = fromBaseUnits(q.outAmount, b.decimals);
  const inAmount = fromBaseUnits(q.inAmount, a.decimals);
  return {
    source: "jupiter",
    fetchedAt: new Date().toISOString(),
    input: { mint: a.mint, symbol: a.symbol, amount: inAmount },
    output: { mint: b.mint, symbol: b.symbol, amount: outAmount, minimum: fromBaseUnits(q.otherAmountThreshold, b.decimals) },
    slippageBps,
    priceImpactPct: Number(q.priceImpactPct) * 100,
    price: inAmount > 0 ? outAmount / inAmount : null,
    route: (q.routePlan ?? []).map((r) => ({ dex: r?.swapInfo?.label ?? "unknown", percent: r?.percent ?? null })),
    contextSlot: q.contextSlot ?? null,
  };
}

if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
  const args = process.argv.slice(2);
  const i = args.indexOf("--slippage-bps");
  const slippageBps = i >= 0 ? Number(args[i + 1]) : 50;
  if (i >= 0) args.splice(i, 2);
  quote(args[0], args[1], args[2], { slippageBps })
    .then((r) => console.log(JSON.stringify(r, null, 2)))
    .catch((e) => {
      console.log(JSON.stringify({ error: String(e?.message ?? e) }));
      process.exit(1);
    });
}