/* api.js — thin REST client over fetch(). Throws on non-2xx so callers can
 * try/catch. Returns parsed JSON.
 */

const Api = (() => {

  async function _req(method, url, body) {
    const opts = { method, headers: {} };
    if (body !== undefined) {
      opts.headers["content-type"] = "application/json";
      opts.body = JSON.stringify(body);
    }
    const res = await fetch(url, opts);
    if (!res.ok) {
      let msg = res.statusText;
      try { msg = (await res.json()).error || msg; } catch {}
      const err = new Error(`${res.status} ${msg}`);
      err.status = res.status;
      throw err;
    }
    if (res.status === 204) return null;
    const ct = res.headers.get("content-type") || "";
    return ct.includes("application/json") ? res.json() : res.text();
  }

  return {
    // Projects
    listProjects:   ()              => _req("GET",    "/api/projects"),
    getProject:     (id)            => _req("GET",    `/api/projects/${id}`),
    createProject:  (name, data)    => _req("POST",   "/api/projects", { name, data }),
    updateProject:  (id, payload)   => _req("PUT",    `/api/projects/${id}`, payload),
    deleteProject:  (id)            => _req("DELETE", `/api/projects/${id}`),

    // Snapshots
    listSnapshots:    (projectId) => _req("GET",  `/api/projects/${projectId}/snapshots`),
    getSnapshot:      (sid)       => _req("GET",  `/api/snapshots/${sid}`),
    restoreSnapshot:  (sid)       => _req("POST", `/api/snapshots/${sid}/restore`),

    // Presets
    listPresets:   ()                => _req("GET",    "/api/presets"),
    createPreset:  (name, params)    => _req("POST",   "/api/presets", { name, params }),
    updatePreset:  (id, payload)     => _req("PUT",    `/api/presets/${id}`, payload),
    deletePreset:  (id)              => _req("DELETE", `/api/presets/${id}`),
  };
})();