/**
 * CoinGecko price feed with 5-minute in-memory cache.
 * Provides USD prices for native coins and ERC-20 tokens.
 */

// CoinGecko chain ID → platform ID mapping
const CHAIN_PLATFORM: Record<string, string> = {
	"1": "ethereum",
	"10": "optimistic-ethereum",
	"100": "xdai",
	"137": "polygon-pos",
	"8453": "base",
	"42161": "arbitrum-one",
	"56": "binance-smart-chain",
	"43114": "avalanche",
	"42220": "celo",
	"324": "zksync",
};

// CoinGecko native coin IDs per chain
const NATIVE_COIN_ID: Record<string, string> = {
	"1": "ethereum",
	"10": "ethereum",
	"100": "dai",
	"137": "matic-network",
	"8453": "ethereum",
	"42161": "ethereum",
	"56": "binancecoin",
	"43114": "avalanche-2",
	"42220": "celo",
	"324": "ethereum",
};

interface CacheEntry {
	prices: Map<string, number>; // address (lowercase) → USD price
	nativePrice: number;
	ts: number;
}

const TTL = 5 * 60 * 1000; // 5 minutes
const cache = new Map<string, CacheEntry>();
const inFlight = new Map<string, Promise<CacheEntry>>();

async function cgFetch(url: string): Promise<any> {
	const res = await fetch(url, {
		headers: { accept: "application/json" },
		signal: AbortSignal.timeout(10000),
	});
	if (res.status === 429) {
		console.warn("[price-feed] CoinGecko rate limited, waiting 60s...");
		await new Promise((r) => setTimeout(r, 60000));
		const retry = await fetch(url, {
			headers: { accept: "application/json" },
			signal: AbortSignal.timeout(10000),
		});
		if (!retry.ok) return null;
		return retry.json();
	}
	if (!res.ok) return null;
	return res.json();
}

/** Fetch native coin price for a chain */
export async function getNativePrice(chainId: string): Promise<number> {
	const entry = cache.get(chainId);
	if (entry && Date.now() - entry.ts < TTL) return entry.nativePrice;

	const coinId = NATIVE_COIN_ID[chainId];
	if (!coinId) return 0;

	const data = await cgFetch(
		`https://api.coingecko.com/api/v3/simple/price?ids=${coinId}&vs_currencies=usd`,
	);
	return data?.[coinId]?.usd ?? 0;
}

/** Fetch token prices for contract addresses on a chain (1 per request for free tier) */
export async function getTokenPrices(
	chainId: string,
	addresses: string[],
): Promise<Map<string, number>> {
	const platform = CHAIN_PLATFORM[chainId];
	if (!platform || addresses.length === 0) return new Map();

	const lower = [...new Set(addresses.map((a) => a.toLowerCase()))];
	const result = new Map<string, number>();

	// CoinGecko free tier: 1 contract address per request, ~30 req/min
	// Process in batches of 3 with a short delay between batches
	const BATCH = 3;
	for (let i = 0; i < lower.length; i += BATCH) {
		const batch = lower.slice(i, i + BATCH);
		const fetches = batch.map(async (addr) => {
			const data = await cgFetch(
				`https://api.coingecko.com/api/v3/simple/token_price/${platform}?contract_addresses=${addr}&vs_currencies=usd`,
			);
			if (data?.[addr]?.usd) result.set(addr, data[addr].usd);
		});
		await Promise.allSettled(fetches);
		if (i + BATCH < lower.length) await new Promise((r) => setTimeout(r, 1500));
	}
	return result;
}

/** Fetch and cache all prices for a chain (native + tokens) */
async function fetchChainPrices(
	chainId: string,
	tokenAddresses: string[],
): Promise<CacheEntry> {
	const existing = cache.get(chainId);
	if (existing && Date.now() - existing.ts < TTL) return existing;

	// Deduplicate concurrent requests for same chain
	const key = chainId;
	const pending = inFlight.get(key);
	if (pending) return pending;

	const promise = (async (): Promise<CacheEntry> => {
		try {
			const [nativePrice, tokenPrices] = await Promise.all([
				getNativePrice(chainId),
				getTokenPrices(chainId, tokenAddresses),
			]);
			const entry: CacheEntry = {
				prices: tokenPrices,
				nativePrice,
				ts: Date.now(),
			};
			cache.set(chainId, entry);
			return entry;
		} finally {
			inFlight.delete(key);
		}
	})();

	inFlight.set(key, promise);
	return promise;
}

interface BalanceItem {
	tokenAddress: string | null;
	token: { name: string; symbol: string; decimals: number };
	balance: string;
	fiatBalance: string;
	fiatConversion: string;
}

/**
 * Enrich balance items with USD prices from CoinGecko.
 * Fills in fiatBalance and fiatConversion for items that have "0" values.
 */
export async function enrichWithPrices(
	balances: BalanceItem[],
	chainId: string,
	options?: { filterSpam?: boolean },
): Promise<BalanceItem[]> {
	// Skip testnets and unsupported chains — no CoinGecko data to verify against
	if (!CHAIN_PLATFORM[chainId] && !NATIVE_COIN_ID[chainId]) return balances;

	// Check if any balance actually needs pricing
	const needsPricing = balances.some(
		(b) =>
			BigInt(b.balance || "0") > 0n &&
			(b.fiatBalance === "0" || b.fiatBalance === "" || !b.fiatBalance),
	);
	if (!needsPricing) return balances;

	const tokenAddresses = balances
		.filter((b) => b.tokenAddress && b.tokenAddress !== "0x0000000000000000000000000000000000000000")
		.map((b) => b.tokenAddress!);

	try {
		const priceData = await fetchChainPrices(chainId, tokenAddresses);

		const enriched = balances.map((b) => {
			// Skip if already has a real fiat value
			if (b.fiatBalance && b.fiatBalance !== "0" && parseFloat(b.fiatBalance) > 0) {
				return b;
			}

			const balWei = BigInt(b.balance || "0");
			if (balWei === 0n) return b;

			let price = 0;
			if (!b.tokenAddress || b.tokenAddress === "0x0000000000000000000000000000000000000000") {
				// Native token
				price = priceData.nativePrice;
			} else {
				price = priceData.prices.get(b.tokenAddress.toLowerCase()) ?? 0;
			}

			if (price === 0) return b;

			const decimals = b.token?.decimals ?? 18;
			const balHuman = Number(balWei) / Math.pow(10, decimals);
			const fiatValue = balHuman * price;

			return {
				...b,
				fiatConversion: String(price),
				fiatBalance: String(fiatValue),
			};
		});

		if (options?.filterSpam) {
			return enriched.filter((b) => {
				// Native tokens always pass
				if (!b.tokenAddress || b.tokenAddress === "0x0000000000000000000000000000000000000000") return true;
				// CoinGecko recognized this token
				if (priceData.prices.has(b.tokenAddress.toLowerCase())) return true;
				// Safe API independently valued it at >= $1
				if (parseFloat(b.fiatBalance || "0") >= 1) return true;
				// Unknown ERC-20 with no verified value = spam
				return false;
			});
		}

		return enriched;
	} catch (e) {
		console.warn(`[price-feed] Failed to enrich prices for chain ${chainId}:`, e);
		return balances;
	}
}