export type DriftTick = {
  ts: string;
  market_index: number;
  symbol: string;
  oracle_price: number;
  mark_price?: number | null;
  oracle_slot?: number | null;
  source?: string;
};

type GraphQLError = { message: string };

function getApiUrl(): string | undefined {
  const v = (import.meta as any).env?.VITE_API_URL;
  if (v) return String(v);
  // Default to same-origin API proxy at /api (Vite dev server proxies /api -> trade-api).
  return '/api';
}

function getHasuraUrl(): string {
  return (import.meta as any).env?.VITE_HASURA_URL || '/graphql';
}

function getAuthToken(): string | undefined {
  const v = (import.meta as any).env?.VITE_HASURA_AUTH_TOKEN;
  return v ? String(v) : undefined;
}

function getAdminSecret(): string | undefined {
  const v = (import.meta as any).env?.VITE_HASURA_ADMIN_SECRET;
  return v ? String(v) : undefined;
}

export async function hasuraRequest<T>(query: string, variables: Record<string, unknown>): Promise<T> {
  const headers: Record<string, string> = {
    'content-type': 'application/json',
  };
  const token = getAuthToken();
  if (token) {
    headers.authorization = `Bearer ${token}`;
  } else {
    const secret = getAdminSecret();
    if (secret) headers['x-hasura-admin-secret'] = secret;
  }

  const res = await fetch(getHasuraUrl(), {
    method: 'POST',
    headers,
    body: JSON.stringify({ query, variables }),
  });

  const text = await res.text();
  if (!res.ok) throw new Error(`Hasura HTTP ${res.status}: ${text}`);

  const json = JSON.parse(text) as { data?: T; errors?: GraphQLError[] };
  if (json.errors?.length) throw new Error(json.errors.map((e) => e.message).join(' | '));
  if (!json.data) throw new Error('Hasura: empty response');
  return json.data;
}

export async function fetchLatestTicks(symbol: string, limit: number, source?: string): Promise<DriftTick[]> {
  const apiUrl = getApiUrl();
  if (apiUrl) {
    const u = new URL(apiUrl, window.location.origin);
    u.pathname = u.pathname && u.pathname !== '/' ? u.pathname.replace(/\/$/, '') + '/v1/ticks' : '/v1/ticks';
    u.searchParams.set('symbol', symbol);
    u.searchParams.set('limit', String(limit));
    if (source && source.trim()) u.searchParams.set('source', source.trim());

    const res = await fetch(u.toString());
    const text = await res.text();
    if (!res.ok) throw new Error(`API HTTP ${res.status}: ${text}`);
    const json = JSON.parse(text) as { ok?: boolean; ticks?: any[]; error?: string };
    if (!json.ok) throw new Error(json.error || 'API: error');

    return (json.ticks || []).map((t: any) => ({
      ts: String(t.ts),
      market_index: Number(t.market_index),
      symbol: String(t.symbol),
      oracle_price: Number(t.oracle_price),
      mark_price: t.mark_price == null ? null : Number(t.mark_price),
      oracle_slot: t.oracle_slot == null ? null : Number(t.oracle_slot),
      source: t.source == null ? undefined : String(t.source),
    }));
  }

  const where: any = { symbol: { _eq: symbol } };
  if (source && source.trim()) where.source = { _eq: source.trim() };

  const query = `
    query LatestTicks($where: drift_ticks_bool_exp!, $limit: Int!) {
      drift_ticks(where: $where, order_by: {ts: desc}, limit: $limit) {
        ts
        market_index
        symbol
        oracle_price
        mark_price
        oracle_slot
        source
      }
    }
  `;

  const data = await hasuraRequest<{
    drift_ticks: Array<Omit<DriftTick, 'oracle_price' | 'mark_price'> & { oracle_price: any; mark_price?: any }>;
  }>(query, { where, limit });

  return data.drift_ticks
    .map((t) => ({
      ...t,
      oracle_price: Number(t.oracle_price),
      mark_price: t.mark_price == null ? null : Number(t.mark_price),
    }))
    .reverse();
}