// Single API client: one place for fetch, JSON, the error envelope, and request
// cancellation. Every method accepts an optional { signal } from cancellable().
export const BASE = "/api/v1";

// The API refuses every request without the session cookie, and every mutation
// without this token echoed back. The token is readable only same-origin, which is
// what makes it proof that the caller is this app and not another page.
let csrfToken = null;

async function session() {
  if (csrfToken === null) {
    const response = await fetch(BASE + "/session", { credentials: "same-origin" });
    const body = await response.json().catch(() => null);
    csrfToken = (body && body.csrf_token) || null;
  }
  return csrfToken || "";
}

async function send(path, { signal, ...options }) {
  return fetch(BASE + path, {
    credentials: "same-origin",
    signal,
    ...options,
    headers: {
      "Content-Type": "application/json",
      "X-CSRF-Token": await session(),
      ...(options.headers || {}),
    },
  });
}

async function request(path, { signal, ...options } = {}) {
  let response;
  try {
    response = await send(path, { signal, ...options });
    // A restarted server issues a new session; re-bootstrap once rather than
    // stranding an open tab on 401.
    if (response.status === 401) {
      csrfToken = null;
      response = await send(path, { signal, ...options });
    }
  } catch (error) {
    // A caller-cancelled fetch is not a failure; tag it so views can ignore it.
    if (error.name === "AbortError") {
      error.code = "cancelled";
    }
    throw error;
  }
  let body = null;
  try {
    body = await response.json();
  } catch (_) {
    body = null;
  }
  if (!response.ok) {
    const envelope = body && body.error ? body.error : {};
    const error = new Error(envelope.message || response.statusText);
    error.status = response.status;
    error.code = envelope.code || "error";
    throw error;
  }
  return body;
}

// Cancellation: hand callers a signal to pass into any request and a cancel() to
// abort the in-flight fetch. Aborted requests reject with code "cancelled".
export function cancellable() {
  const controller = new AbortController();
  return { signal: controller.signal, cancel: () => controller.abort() };
}

export const api = {
  listAssets: (params = {}, opts = {}) =>
    request("/inventory/assets?" + new URLSearchParams(params).toString(), opts),
  listClusters: (params = {}, opts = {}) =>
    request("/duplicates/clusters?" + new URLSearchParams(params).toString(), opts),
  getCluster: (id, params = {}, opts = {}) => {
    const query = new URLSearchParams(params).toString();
    return request(`/duplicates/clusters/${encodeURIComponent(id)}${query ? `?${query}` : ""}`, opts);
  },
  decide: (id, payload, opts = {}) =>
    request(`/duplicates/clusters/${encodeURIComponent(id)}/decision`, {
      method: "POST",
      body: JSON.stringify(payload),
      ...opts,
    }),
  thumbnailUrl: (assetId, size = 512) =>
    `${BASE}/assets/${encodeURIComponent(assetId)}/thumbnail?size=${size}`,

  // ── Jobs ────────────────────────────────────────────────────────────────
  startJob: (payload, opts = {}) =>
    request("/jobs", { method: "POST", body: JSON.stringify(payload), ...opts }),
  getJob: (id, opts = {}) => request(`/jobs/${encodeURIComponent(id)}`, opts),
  cancelJob: (id, opts = {}) =>
    request(`/jobs/${encodeURIComponent(id)}/cancel`, { method: "POST", ...opts }),
  jobEvents: (id, after = 0, opts = {}) =>
    request(`/jobs/${encodeURIComponent(id)}/events?after=${after}`, opts),
  jobEventsStreamUrl: (id, after = 0) =>
    `${BASE}/jobs/${encodeURIComponent(id)}/events/stream?after=${after}`,

  // ── Workflow / safety / analysis / library ──────────────────────────────
  workflow: (opts = {}) => request("/workflow", opts),
  safetyQueue: (params = {}, opts = {}) =>
    request("/safety/queue?" + new URLSearchParams(params).toString(), opts),
  safetyDecide: (payload, opts = {}) =>
    request("/safety/decisions", { method: "POST", body: JSON.stringify(payload), ...opts }),
  safetyScoreJob: (opts = {}) => request("/safety/jobs", { method: "POST", ...opts }),
  analysisCounts: (opts = {}) => request("/analysis/counts", opts),
  analysisJob: (opts = {}) => request("/analysis/jobs", { method: "POST", ...opts }),
  libraryAssets: (params = {}, opts = {}) =>
    request("/library/assets?" + new URLSearchParams(params).toString(), opts),
  libraryStats: (opts = {}) => request("/library/stats", opts),

  // ── Albums: evidence and naming proposals ───────────────────────────────
  albumEvidence: (params = {}, opts = {}) =>
    request("/albums/evidence?" + new URLSearchParams(params).toString(), opts),
  albumProposals: (params = {}, opts = {}) =>
    request("/albums/proposals?" + new URLSearchParams(params).toString(), opts),
  generateProposals: (payload = {}, opts = {}) =>
    request("/albums/proposals", { method: "POST", body: JSON.stringify(payload), ...opts }),
  editProposal: (album, payload, opts = {}) =>
    request(`/albums/proposals/${encodeURIComponent(album)}/edit`, {
      method: "POST",
      body: JSON.stringify(payload),
      ...opts,
    }),
  approveProposal: (album, payload, opts = {}) =>
    request(`/albums/proposals/${encodeURIComponent(album)}/approve`, {
      method: "POST",
      body: JSON.stringify(payload),
      ...opts,
    }),

  // ── Renames: plan, confirm, apply, recover ──────────────────────────────
  listPlans: (opts = {}) => request("/rename-plans", opts),
  buildPlan: (opts = {}) => request("/rename-plans", { method: "POST", ...opts }),
  getPlan: (id, opts = {}) => request(`/rename-plans/${encodeURIComponent(id)}`, opts),
  applyPlan: (id, payload, opts = {}) =>
    request(`/rename-plans/${encodeURIComponent(id)}/apply`, {
      method: "POST",
      body: JSON.stringify(payload),
      ...opts,
    }),
  rollbackPlan: (id, opts = {}) =>
    request(`/rename-plans/${encodeURIComponent(id)}/rollback`, { method: "POST", ...opts }),
  renameRecovery: (opts = {}) => request("/rename-recovery", opts),
  resolveRecovery: (opts = {}) => request("/rename-recovery/resolve", { method: "POST", ...opts }),

  // ── Uploads: preflight, batches, verification ───────────────────────────
  // The API key never travels through here: preflight reports only whether one is
  // configured, and every command preview arrives already redacted.
  uploadPreflight: (payload = {}, opts = {}) =>
    request("/upload-preflight", { method: "POST", body: JSON.stringify(payload), ...opts }),
  createUploadBatches: (payload, opts = {}) =>
    request("/upload-batches", { method: "POST", body: JSON.stringify(payload), ...opts }),
  listUploadBatches: (opts = {}) => request("/upload-batches", opts),
  getUploadBatch: (id, opts = {}) => request(`/upload-batches/${encodeURIComponent(id)}`, opts),
  startUploadBatch: (id, opts = {}) =>
    request(`/upload-batches/${encodeURIComponent(id)}/start`, { method: "POST", ...opts }),
  cancelUploadBatch: (id, opts = {}) =>
    request(`/upload-batches/${encodeURIComponent(id)}/cancel`, { method: "POST", ...opts }),
  verifyUploadBatch: (id, opts = {}) =>
    request(`/upload-batches/${encodeURIComponent(id)}/verify`, { method: "POST", ...opts }),
  resolveUploadItem: (id, payload, opts = {}) =>
    request(`/upload-batches/${encodeURIComponent(id)}/resolve`, {
      method: "POST",
      body: JSON.stringify(payload),
      ...opts,
    }),
  uploadVerifications: (id, opts = {}) =>
    request(`/upload-batches/${encodeURIComponent(id)}/verifications`, opts),

  // ── Archive and restore: destinations, preflight, plans, recovery ────────
  archiveLocations: (opts = {}) => request("/archive-locations", opts),
  registerArchiveLocation: (payload, opts = {}) =>
    request("/archive-locations", { method: "POST", body: JSON.stringify(payload), ...opts }),
  archivePreflight: (payload, opts = {}) =>
    request("/archive-preflight", { method: "POST", body: JSON.stringify(payload), ...opts }),
  createArchivePlan: (payload, opts = {}) =>
    request("/archive-plans", { method: "POST", body: JSON.stringify(payload), ...opts }),
  listArchivePlans: (opts = {}) => request("/archive-plans", opts),
  getArchivePlan: (id, opts = {}) => request(`/archive-plans/${encodeURIComponent(id)}`, opts),
  applyArchivePlan: (id, opts = {}) =>
    request(`/archive-plans/${encodeURIComponent(id)}/apply`, { method: "POST", ...opts }),
  archiveRecovery: (opts = {}) => request("/archive-recovery", opts),
  resolveArchiveRecovery: (opts = {}) =>
    request("/archive-recovery/resolve", { method: "POST", ...opts }),
  restorePreflight: (payload, opts = {}) =>
    request("/restore-preflight", { method: "POST", body: JSON.stringify(payload), ...opts }),
  createRestorePlan: (payload, opts = {}) =>
    request("/restore-plans", { method: "POST", body: JSON.stringify(payload), ...opts }),
  listRestorePlans: (opts = {}) => request("/restore-plans", opts),
  getRestorePlan: (id, opts = {}) => request(`/restore-plans/${encodeURIComponent(id)}`, opts),
  applyRestorePlan: (id, opts = {}) =>
    request(`/restore-plans/${encodeURIComponent(id)}/apply`, { method: "POST", ...opts }),
  restoreRecovery: (opts = {}) => request("/restore-recovery", opts),
  resolveRestoreRecovery: (opts = {}) =>
    request("/restore-recovery/resolve", { method: "POST", ...opts }),
};