import type { Meta, SuggestHit, TreeQuery, TreeResponse, DefinitionPayload } from "./types";

async function json<T>(res: Response): Promise<T> {
  if (!res.ok) {
    const text = await res.text();
    throw new Error(text || res.statusText);
  }
  return res.json() as Promise<T>;
}

export const api = {
  meta: () => fetch("/api/meta").then((r) => json<Meta>(r)),
  suggest: (q: string) =>
    fetch(`/api/suggest?q=${encodeURIComponent(q)}&limit=18`).then((r) => json<{ hits: SuggestHit[] }>(r)),
  tree: (body: TreeQuery, signal?: AbortSignal) =>
    fetch("/api/tree", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(body),
      signal,
    }).then((r) => json<TreeResponse>(r)),
  node: (term: string, lang: string) =>
    fetch(`/api/node?term=${encodeURIComponent(term)}&lang=${encodeURIComponent(lang)}`).then((r) => json<Record<string, unknown>>(r)),
  define: (term: string, lang: string, iso?: string | null) => {
    const params = new URLSearchParams({ term, lang });
    if (iso) params.set("iso", iso);
    return fetch(`/api/define?${params}`).then((r) => json<DefinitionPayload>(r));
  },
  exportUrl: (body: TreeQuery) => {
    return fetch("/api/export?format=csv", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(body),
    }).then(async (r) => {
      const blob = await r.blob();
      const url = URL.createObjectURL(blob);
      const a = document.createElement("a");
      a.href = url;
      a.download = "reverse-etymology.csv";
      a.click();
      URL.revokeObjectURL(url);
    });
  },
};