import { defineConnector, raw, type NormalizedBatch } from "@market-atlas/connector-sdk";
import { parseTimestamp } from "@market-atlas/market-model";
import { MAJOR_BASES } from "../_shared/crypto.js";
import { pairObservations, planPair } from "../_shared/pairs.js";

const BULLET_URL = "https://api.kucoin.com/api/v1/bullet-public";
const SYMBOLS = [...MAJOR_BASES.filter((b) => b !== "PAXG").map((b) => `${b}-USDT`), "EUR-USDT"];

/**
 * KuCoin spot ticker (`/market/ticker:<symbols>`). The public WebSocket endpoint is obtained through a
 * keyless "bullet" token request (no account), then one connection carries every symbol.
 */
export const kucoinWs = defineConnector({
  metadata: {
    id: "kucoin-ws",
    name: "KuCoin — spot ticker",
    version: "1.0.0",
    sourceId: "kucoin",
    organization: "KuCoin",
    sourceType: "WEBSOCKET",
    jurisdiction: "SC",
    rightsStatus: "PUBLIC_ATTRIBUTED",
    realtimeStatus: "REALTIME",
    expectedLatencyMs: 500,
    supportsStreaming: true,
    supportsHistorical: false,
    assetClasses: ["CRYPTO", "FOREX"],
    exchanges: ["kucoin"],
    homepage: "https://www.kucoin.com/docs/websocket/spot-trading/public-channels/ticker",
    description: "Public KuCoin spot ticker topic (last price, best bid/ask with sizes) for USDT majors and the EUR/USDT stablecoin market. Endpoint discovered via the keyless public bullet token.",
    rightsNotes: "Public market data displayed with attribution to KuCoin.",
    termsUrl: "https://www.kucoin.com/legal/terms-of-use",
    sourceFamily: "kucoin",
    enabled: true,
  },
  seeds: SYMBOLS.map((s) => {
    const [b, q] = s.split("-") as [string, string];
    return { symbol: s, hint: planPair(b, q, "kucoin").hint };
  }),
  defaultSymbols: SYMBOLS,
  rateLimits: { "api.kucoin.com": 1 },
  async start(ctx) {
    const res = await ctx.http.request(BULLET_URL, { method: "POST", conditional: false, timeoutMs: 15_000, headers: { "content-type": "application/json" } });
    const bullet = JSON.parse(res.text) as { data?: { token?: string; instanceServers?: Array<{ endpoint: string; pingInterval?: number }> } };
    const server = bullet.data?.instanceServers?.[0];
    const token = bullet.data?.token;
    if (!server || !token) throw new Error("kucoin bullet token unavailable");
    const url = `${server.endpoint}?token=${encodeURIComponent(token)}&connectId=market-atlas`;
    const ws = ctx.openWebSocket(url, {
      label: "kucoin",
      staleAfterMs: 60_000,
      heartbeat: { intervalMs: Math.max(5000, Math.min(server.pingInterval ?? 18_000, 30_000) - 3000), message: JSON.stringify({ id: "hb", type: "ping" }) },
      onOpen: (sock) => sock.send({ id: "1", type: "subscribe", topic: `/market/ticker:${ctx.watchedSymbols().join(",")}`, response: true }),
      onMessage: (data) => {
        let msg: any;
        try {
          msg = JSON.parse(data);
        } catch {
          return;
        }
        if (msg?.type === "message" && typeof msg.topic === "string" && msg.topic.startsWith("/market/ticker:") && msg.data) ctx.emit(raw("kucoin-ws", "kucoin", "ticker", msg));
        else if (msg?.type === "error") ctx.reportError(new Error(String(msg.data ?? "kucoin error")));
      },
    });
    ws.connect();
  },
  normalize(r): NormalizedBatch {
    const m = r.payload as { topic?: string; data?: Record<string, unknown> };
    const d = m.data;
    if (r.kind !== "ticker" || typeof m.topic !== "string" || !d) return { observations: [] };
    const symbol = m.topic.slice("/market/ticker:".length);
    const [base, quote] = symbol.split("-");
    if (!base || !quote) return { observations: [] };
    return {
      observations: pairObservations(symbol, base, quote, "kucoin", { last: d.price, bid: d.bestBid, bidSize: d.bestBidSize, ask: d.bestAsk, askSize: d.bestAskSize }, {
        sourceTimestamp: parseTimestamp(d.time),
        timestampTrust: "EXCHANGE",
        sequence: typeof d.sequence === "string" ? d.sequence : null,
        rightsStatus: "PUBLIC_ATTRIBUTED",
        realtimeStatus: "REALTIME",
      }),
    };
  },
  fixturesDir: "fixtures",
});