investor-flow/app/src/lib/trpc.ts

// Thin typed client over the tRPC backend (DESIGN.md §2). Slice 1 uses a fetch wrapper
// rather than @trpc/client to keep the Next app decoupled from the server's Node-native
// type graph; the server is a real tRPC server and full end-to-end client types can be
// layered later without changing this surface.
export interface Quote {
  symbol: string;
  price: number;
  bid?: number | null;
  ask?: number | null;
  change?: number | null;
  changePercent?: number | null;
  iv?: number | null;
}
export interface PriceCandle {
  ts: string;
  o: number;
  h: number;
  l: number;
  c: number;
  v: number;
  adjClose?: number | null;
}
export interface SymbolMeta {
  symbol: string;
  name?: string | null;
  sector?: string | null;
  industry?: string | null;
  exchange?: string | null;
  tickerKind: string;
  peers?: string[] | null;
}
export interface Snapshot {
  symbol: string;
  quote: Quote | null;
  candles: PriceCandle[] | null;
  sector: SymbolMeta | null;
  stale: { quote: boolean; candles: boolean; sector: boolean };
}
export interface AuthUser {
  userId: string;
  email?: string;
  complexity?: string;
  riskTolerance?: string;
  convexityPosture?: string;
}

async function parse<T>(res: Response): Promise<T> {
  const json = await res.json();
  if (json?.error) {
    const msg = json.error.message ?? `tRPC error ${json.error.data?.code ?? ""}`;
    throw new Error(typeof msg === "string" ? msg : "tRPC error");
  }
  return json.result.data as T;
}

async function trpcQuery<T>(procedure: string, input?: unknown): Promise<T> {
  const search = input ? `?input=${encodeURIComponent(JSON.stringify(input))}` : "";
  const res = await fetch(`/api/trpc/${procedure}${search}`, {
    headers: { "content-type": "application/json" },
    credentials: "include",
  });
  return parse<T>(res);
}

async function trpcMutate<T>(procedure: string, input: unknown): Promise<T> {
  const res = await fetch(`/api/trpc/${procedure}`, {
    method: "POST",
    headers: { "content-type": "application/json" },
    credentials: "include",
    body: JSON.stringify(input),
  });
  return parse<T>(res);
}

export const api = {
  market: { snapshot: (symbol: string) => trpcQuery<Snapshot>("market.snapshot", { symbol }) },
  auth: {
    signup: (email: string, password: string) => trpcMutate<{ userId: string }>("auth.signup", { email, password }),
    login: (email: string, password: string, totp?: string) => trpcMutate<{ userId: string }>("auth.login", { email, password, ...(totp ? { totp } : {}) }),
    logout: () => trpcMutate<{ ok: boolean }>("auth.logout", {}),
    me: () => trpcQuery<AuthUser | null>("auth.me"),
    enable2fa: () => trpcMutate<{ totpSecret: string; qrUrl: string; backupCodes: string[] }>("auth.enable2fa", {}),
    confirm2fa: (totp: string) => trpcMutate<{ ok: boolean }>("auth.confirm2fa", { totp }),
    oauthStart: (provider: "github" | "google", redirectUri: string) => trpcMutate<{ redirectUrl: string; state: string }>("auth.oauthStart", { provider, redirectUri }),
  },
};