import { PublicKey } from '@solana/web3.js';
import { mints } from '../../helpers/constants';
import { makePairKey, readPair, writePair, readGlobal, writeGlobal } from '../../helpers/disk-cache';

type DammV2Pool = { pool_address: string; token_a_mint: string; token_b_mint: string; token_a_amount?: number | string; token_b_amount?: number | string; liquidity?: string | number; tvl?: number | string };

async function fetchAllPoolsPaginated(): Promise<DammV2Pool[]> {
	const base = 'https://dammv2-api.meteora.ag/pools';
	const limit = 500;
	let offset = 0;
	const results: DammV2Pool[] = [];
	while (true) {
		const res = await fetch(`${base}?limit=${limit}&offset=${offset}`, { method: 'GET' });
		if (!res.ok) break;
		const json: any = await res.json();
		const batch: any[] = Array.isArray(json?.data) ? json.data : Array.isArray(json) ? json : [];
		if (batch.length === 0) break;
		results.push(...batch as DammV2Pool[]);
		if (batch.length < limit) break;
		offset += limit;
	}
	const map = new Map<string, DammV2Pool>();
	for (const it of results) if ((it as any)?.pool_address) map.set((it as any).pool_address, it);
	return Array.from(map.values());
}

function chooseBestPool(items: DammV2Pool[], targetMint: string, wsolMint: string): DammV2Pool | null {
	const subset = items.filter((it) => {
		const mx = (it as any)?.token_a_mint; const my = (it as any)?.token_b_mint;
		return !!mx && !!my && ((mx === targetMint && my === wsolMint) || (my === targetMint && mx === wsolMint));
	});
	if (subset.length === 0) return null;
	const best = subset.reduce((acc: any, it: DammV2Pool) => {
		const tokenIsA = (it as any).token_a_mint === targetMint;
		const tokenReserveRaw = tokenIsA ? (it as any).token_a_amount : (it as any).token_b_amount;
		const tokenReserve = typeof tokenReserveRaw === 'string' ? parseFloat(tokenReserveRaw) : Number(tokenReserveRaw ?? 0);
		const tvlRaw = (it as any).tvl ?? (it as any).liquidity;
		const tvl = typeof tvlRaw === 'string' ? parseFloat(tvlRaw) : Number(tvlRaw ?? 0);
		const score = tokenReserve > 0 ? tokenReserve : tvl;
		if (!acc || score > acc.score) return { it, score };
		return acc;
	}, null as null | { it: DammV2Pool; score: number });
	return best?.it ?? null;
}

export async function findDammV2PoolAddress(mint: PublicKey): Promise<PublicKey> {
	const token = mint.toBase58();
	const wsol = mints.WSOL;
	const pairKey = makePairKey(token, wsol);
	const cached = readPair('damm_v2', pairKey);
	if (cached?.address) return new PublicKey(cached.address);

	let global = readGlobal('damm_v2');
	if (!global) {
		try {
			global = await fetchAllPoolsPaginated();
			writeGlobal('damm_v2', global);
		} catch { global = null }
	}
	if (global) {
		const best = chooseBestPool(global as DammV2Pool[], token, wsol);
		if (best?.pool_address) {
			writePair('damm_v2', pairKey, best.pool_address);
			return new PublicKey(best.pool_address);
		}
	}

	const res = await fetch(`https://dammv2-api.meteora.ag/pools?token_a_mint=${encodeURIComponent(token)}&token_b_mint=${encodeURIComponent(wsol)}&limit=300`, { method: 'GET' });
	const json: any = await res.json();
	const items: DammV2Pool[] = Array.isArray(json?.data) ? json.data : [];
	const best = chooseBestPool(items, token, wsol);
	if (!best?.pool_address) throw new Error('Meteora DAMM v2 pool for mint-WSOL not found');
	writePair('damm_v2', pairKey, best.pool_address);
	return new PublicKey(best.pool_address);
}