'use client';
/** Browser-side fetches: same origin `/api/v1/*` (Next rewrite → FastAPI). Never import server `api.ts` in client components. */
import type { ChangeEvent, Claim, Page, ProvenanceDetail, SearchPayload, Suggestion } from './types';

export class ClientApiError extends Error {
  readonly status: number;
  constructor(status: number, path: string) {
    super(`API ${status} on ${path}`);
    this.name = 'ClientApiError';
    this.status = status;
  }
}

async function get<T>(path: string, signal?: AbortSignal): Promise<T> {
  const res = await fetch(`/api/v1${path}`, { headers: { accept: 'application/json' }, signal });
  if (!res.ok) throw new ClientApiError(res.status, path);
  return (await res.json()) as T;
}

const enc = encodeURIComponent;

export const clientApi = {
  suggest: (q: string, signal?: AbortSignal) => get<{ items: Suggestion[] }>(`/search/suggest?q=${enc(q)}`, signal),
  search: (q: string, limit = 10, signal?: AbortSignal) => get<SearchPayload>(`/search?q=${enc(q)}&limit=${limit}`, signal),
  changes: (qs: string, signal?: AbortSignal) => get<Page<ChangeEvent>>(`/changes?${qs}`, signal),
  /** Events of one entity (watchlist): `/changes?entity=<slug>&limit=`. */
  entityChanges: (slug: string, limit = 20, signal?: AbortSignal) => get<Page<ChangeEvent>>(`/changes?entity=${enc(slug)}&limit=${limit}`, signal),
  /** 1.1 — full evidence behind one displayed value. 404 until the API stream lands → callers fall back to the inline provenance. */
  provenance: (slug: string, property: string, signal?: AbortSignal) => get<ProvenanceDetail>(`/entities/${enc(slug)}/provenance/${enc(property)}`, signal),
  /** Claim history of one property (exists today): used by the evidence drawer for the claim id, validity and conflicts. */
  history: (slug: string, property: string, signal?: AbortSignal) => get<{ items: Claim[] }>(`/entities/${enc(slug)}/history?property=${enc(property)}`, signal),
  /** Page-view beacon (1 req/s/IP server-side). Fire-and-forget. */
  view: (path: string) =>
    fetch('/api/v1/views', { method: 'POST', headers: { 'content-type': 'application/json' }, body: JSON.stringify({ path }), keepalive: true }).catch(() => undefined),
};

// ---- D2 (intelligence) ----
import type { CostContextPayload, CostPayload, Price } from './types';
/** Browser-side calls used by the price terminal (lazy row sparklines), the calculator and provider pages. */
export const clientIntel = {
  /** Full price history of one model (optionally one provider). */
  priceHistory: (model: string, provider?: string, signal?: AbortSignal) => get<{ items: Price[] }>(`/prices/history?model=${enc(model)}${provider ? `&provider=${enc(provider)}` : ''}`, signal),
  /** `/cost` — query string already built by the caller (`model=&input_tokens=…`). */
  cost: (qs: string, signal?: AbortSignal) => get<CostPayload>(`/cost?${qs}`, signal),
  /** `/cost/context?tokens=`. */
  costContext: (qs: string, signal?: AbortSignal) => get<CostContextPayload>(`/cost/context?${qs}`, signal),
};
// ---- /D2 ----

// ---- D3 (temporal/graph/admin) ----
import type { GraphExploreMode, GraphExplorePayload } from './types';
/** Graph explorer: root change and progressive neighbourhood expansion (merged client-side). */
export function clientGraphExplore(node: string, mode: GraphExploreMode, depth: 1 | 2 = 1, limit = 150, signal?: AbortSignal): Promise<GraphExplorePayload> {
  return get<GraphExplorePayload>(`/graph/explore?node=${enc(node)}&mode=${enc(mode)}&depth=${depth}&limit=${limit}`, signal);
}
/** Same-origin GET of any public route for the /developers request builder (returns status + parsed body or text). */
export async function clientTry(path: string, signal?: AbortSignal): Promise<{ status: number; ms: number; body: unknown; headers: Record<string, string> }> {
  const t0 = performance.now();
  const res = await fetch(`/api/v1${path}`, { headers: { accept: 'application/json' }, signal });
  const text = await res.text();
  let body: unknown = text;
  try {
    body = JSON.parse(text);
  } catch {
    /* keep text */
  }
  const headers: Record<string, string> = {};
  for (const k of ['x-api-version', 'etag', 'cache-control', 'content-type']) {
    const v = res.headers.get(k);
    if (v) headers[k] = v;
  }
  return { status: res.status, ms: Math.round(performance.now() - t0), body, headers };
}
// ---- /D3 ----