// Thin fetch wrapper. Throws on non-2xx with a structured ApiError.

export class ApiError extends Error {
  status: number;
  field?: string;
  constructor(status: number, message: string, field?: string) {
    super(message);
    this.status = status;
    this.field = field;
  }
}

const INGEST_BASE = import.meta.env.VITE_API_BASE_URL ?? '/api/ingest';
const ROTOR_BASE  = import.meta.env.VITE_ROTOR_BASE_URL ?? '/api/rotor';
const BULKER_BASE = import.meta.env.VITE_BULKER_BASE_URL ?? '/api/bulker';

async function request<T>(base: string, path: string, init?: RequestInit): Promise<T> {
  const res = await fetch(`${base}${path}`, {
    ...init,
    headers: {
      'content-type': 'application/json',
      ...(init?.headers ?? {}),
    },
  });
  const text = await res.text();
  const data = text ? safeJSON(text) : undefined;
  if (!res.ok) {
    const msg = (data as { error?: string })?.error ?? res.statusText;
    const field = (data as { field?: string })?.field;
    throw new ApiError(res.status, msg, field);
  }
  return data as T;
}

function safeJSON(text: string): unknown {
  try {
    return JSON.parse(text);
  } catch {
    return text;
  }
}

// ---------------------------------------------------------------------------
// Ingest API
// ---------------------------------------------------------------------------

export const ingest = {
  health: () => request<{ status: string }>(INGEST_BASE, '/health'),
  ready:  () => request<{ status: string }>(INGEST_BASE, '/ready'),

  track: (writeKey: string, body: Record<string, unknown>) =>
    request<{ ok: boolean }>(INGEST_BASE, '/track', {
      method: 'POST',
      headers: { Authorization: `Bearer ${writeKey}` },
      body: JSON.stringify(body),
    }),
};

// ---------------------------------------------------------------------------
// Rotor API
// ---------------------------------------------------------------------------

export interface RunRequest {
  code: string;
  event: Record<string, unknown>;
}
export interface RunResponse {
  result: unknown;
}

export const rotor = {
  run: (body: RunRequest) =>
    request<RunResponse>(ROTOR_BASE, '/v1/run', {
      method: 'POST',
      body: JSON.stringify(body),
    }),
  upsert: (body: { workspace_id: string; slug: string; code: string }) =>
    request<{ ok: boolean }>(ROTOR_BASE, '/v1/functions', {
      method: 'POST',
      body: JSON.stringify(body),
    }),
};

// ---------------------------------------------------------------------------
// Bulker API
// ---------------------------------------------------------------------------

export const bulker = {
  health: () => request<{ status: string }>(BULKER_BASE, '/health'),
};