// DexScreener trends: most-boosted tokens with live market data. Zero dependencies.
import { pathToFileURL } from "node:url";

const API = "https://api.dexscreener.com";

async function getJson(url) {
  const res = await fetch(url, { headers: { accept: "application/json" } });
  if (!res.ok) throw new Error(`DexScreener answered ${res.status} for ${new URL(url).pathname}`);
  return res.json();
}

function num(v) {
  const n = Number(v);
  return Number.isFinite(n) ? n : null;
}

export async function trends({ chain = null, limit = 10 } = {}) {
  limit = Math.max(1, Math.min(30, Number(limit) || 10));
  const boosts = await getJson(`${API}/token-boosts/top/v1`);
  if (!Array.isArray(boosts)) throw new Error("Unexpected boosts response");
  const picked = [];
  const seen = new Set();
  for (const b of boosts) {
    if (!b?.chainId || !b?.tokenAddress) continue;
    if (chain && b.chainId !== chain) continue;
    const key = b.chainId + ":" + b.tokenAddress;
    if (seen.has(key)) continue;
    seen.add(key);
    picked.push(b);
    if (picked.length >= limit) break;
  }

  // One request per chain for up to 30 addresses: the most liquid pair of each token.
  const best = new Map();
  const byChain = new Map();
  for (const b of picked) byChain.set(b.chainId, [...(byChain.get(b.chainId) ?? []), b.tokenAddress]);
  for (const [chainId, addrs] of byChain) {
    const pairs = await getJson(`${API}/tokens/v1/${chainId}/${addrs.join(",")}`);
    for (const p of Array.isArray(pairs) ? pairs : []) {
      const addr = p?.baseToken?.address;
      if (!addr) continue;
      const key = chainId + ":" + addr;
      const prev = best.get(key);
      if (!prev || (num(p.liquidity?.usd) ?? 0) > (num(prev.liquidity?.usd) ?? 0)) best.set(key, p);
    }
  }

  const tokens = picked.map((b, i) => {
    const p = best.get(b.chainId + ":" + b.tokenAddress);
    return {
      rank: i + 1,
      chainId: b.chainId,
      address: b.tokenAddress,
      symbol: p?.baseToken?.symbol ?? null,
      name: p?.baseToken?.name ?? null,
      boosts: num(b.totalAmount) ?? num(b.amount) ?? 0,
      priceUsd: num(p?.priceUsd),
      change24hPct: num(p?.priceChange?.h24),
      volume24hUsd: num(p?.volume?.h24),
      liquidityUsd: num(p?.liquidity?.usd),
      marketCapUsd: num(p?.marketCap),
      pairUrl: p?.url ?? b.url ?? null,
    };
  });
  return { source: "dexscreener", fetchedAt: new Date().toISOString(), chain: chain ?? "all", tokens };
}

function parseArgs(argv) {
  const out = {};
  for (let i = 0; i < argv.length; i++) {
    if (argv[i] === "--chain") out.chain = argv[++i];
    else if (argv[i] === "--limit") out.limit = Number(argv[++i]);
  }
  return out;
}

if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
  trends(parseArgs(process.argv.slice(2)))
    .then((r) => console.log(JSON.stringify(r, null, 2)))
    .catch((e) => {
      console.log(JSON.stringify({ error: String(e?.message ?? e) }));
      process.exit(1);
    });
}