import type { LocationOption, SelectionState, UsageTemplate } from "./types";

const json = async <T>(path: string): Promise<T> => {
  const response = await fetch(path);
  if (!response.ok) {
    let details = "";
    try {
      const payload = (await response.json()) as { message?: string };
      details = payload.message ?? "";
    } catch {
      // Ignore non-JSON error payloads.
    }

    throw new Error(details || `Request failed for ${path} (${response.status})`);
  }

  return (await response.json()) as T;
};

export const api = {
  health: () => json<{ status: string; message?: string }>("/api/health"),
  locations: () => json<LocationOption[]>("/api/locations"),
  publishers: (location: string) => json<string[]>(`/api/publishers?location=${encodeURIComponent(location)}`),
  offers: (location: string, publisher: string) =>
    json<string[]>(`/api/offers?location=${encodeURIComponent(location)}&publisher=${encodeURIComponent(publisher)}`),
  skus: (location: string, publisher: string, offer: string) =>
    json<string[]>(
      `/api/skus?location=${encodeURIComponent(location)}&publisher=${encodeURIComponent(publisher)}&offer=${encodeURIComponent(offer)}`
    ),
  versions: (location: string, publisher: string, offer: string, sku: string) =>
    json<string[]>(
      `/api/versions?location=${encodeURIComponent(location)}&publisher=${encodeURIComponent(publisher)}&offer=${encodeURIComponent(offer)}&sku=${encodeURIComponent(sku)}`
    ),
  templates: () => json<UsageTemplate[]>("/api/templates"),
  render: async (templateFile: string, selection: SelectionState): Promise<string> => {
    const response = await fetch("/api/render", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ templateFile, selection })
    });

    if (!response.ok) {
      throw new Error("Failed to render template");
    }

    const payload = (await response.json()) as { rendered: string };
    return payload.rendered;
  },
  skuExport: async (location: string, publisher: string, offer: string): Promise<string> => {
    const payload = await json<{ rendered: string }>(
      `/api/sku-export?location=${encodeURIComponent(location)}&publisher=${encodeURIComponent(publisher)}&offer=${encodeURIComponent(offer)}`
    );
    return payload.rendered;
  }
};