import type {
  AdminRegisterPayload,
  AdminSettingsResponse,
  AdminStats,
  AuthResponse,
  CreateWorldPayload,
  CreateWorldResponse,
  EditWorldPayload,
  EditWorldResponse,
  EmbeddingsProbeResult,
  EmbeddingsTestResult,
  HealthResponse,
  IterateResponse,
  LlmLog,
  LlmLogDetail,
  LlmTestResult,
  LlmToolsTestResult,
  LoginPayload,
  Paginated,
  PresetListItem,
  RecreateCollectionsResult,
  RegisterPayload,
  RetryResponse,
  SessionState,
  UploadIconResult,
  User,
  World,
  WorldListItem,
  WorldPreset,
} from "@/types";

// Use VITE_API_BASE_URL if set (for local `npm run dev` pointing at a separate
// backend); otherwise default to relative "/api" which works behind the nginx
// reverse proxy in the Docker deployment.
const BASE_URL = (import.meta.env.VITE_API_BASE_URL as string | undefined)?.replace(/\/$/, "") || "/api";
const ACCESS_TOKEN_KEY = "airpg_access_token";
const REFRESH_TOKEN_KEY = "airpg_refresh_token";

export class ApiError extends Error {
  status: number;
  details?: unknown;
  constructor(status: number, message: string, details?: unknown) {
    super(message);
    this.name = "ApiError";
    this.status = status;
    this.details = details;
  }
}

export function getAccessToken(): string | null {
  try {
    return localStorage.getItem(ACCESS_TOKEN_KEY);
  } catch {
    return null;
  }
}

export function getRefreshToken(): string | null {
  try {
    return localStorage.getItem(REFRESH_TOKEN_KEY);
  } catch {
    return null;
  }
}

export function setTokens(access: string, refresh?: string): void {
  try {
    localStorage.setItem(ACCESS_TOKEN_KEY, access);
    if (refresh) localStorage.setItem(REFRESH_TOKEN_KEY, refresh);
  } catch {
    /* ignore */
  }
}

export function clearTokens(): void {
  try {
    localStorage.removeItem(ACCESS_TOKEN_KEY);
    localStorage.removeItem(REFRESH_TOKEN_KEY);
  } catch {
    /* ignore */
  }
}

type QueryValue = string | number | boolean | undefined | null;
type Query = Record<string, QueryValue>;

function buildUrl(path: string, query?: Query): string {
  const url = `${BASE_URL}${path.startsWith("/") ? path : `/${path}`}`;
  if (!query) return url;
  const params = new URLSearchParams();
  for (const [k, v] of Object.entries(query)) {
    if (v !== undefined && v !== null && v !== "") params.append(k, String(v));
  }
  const qs = params.toString();
  return qs ? `${url}?${qs}` : url;
}

function toQuery(obj: Record<string, QueryValue>): Query {
  return obj;
}

interface RequestOptions {
  method?: "GET" | "POST" | "PATCH" | "PUT" | "DELETE";
  body?: unknown;
  query?: Query;
  formData?: FormData;
  raw?: boolean;
}

async function parseResponse<T>(res: Response): Promise<T> {
  if (res.status === 204) return undefined as T;
  const text = await res.text();
  if (!text) return undefined as T;
  try {
    return JSON.parse(text) as T;
  } catch {
    return text as unknown as T;
  }
}

let unauthorizedHandler: (() => void) | null = null;

export function setUnauthorizedHandler(handler: () => void): void {
  unauthorizedHandler = handler;
}

async function refreshAccessToken(): Promise<string | null> {
  const refresh = getRefreshToken();
  if (!refresh) return null;
  try {
    const res = await fetch(`${BASE_URL}/auth/refresh`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ refresh_token: refresh }),
    });
    if (!res.ok) return null;
    const data = await parseResponse<AuthResponse>(res);
    setTokens(data.access_token, data.refresh_token);
    return data.access_token;
  } catch {
    return null;
  }
}

export async function request<T>(path: string, opts: RequestOptions = {}): Promise<T> {
  const { method = "GET", body, query, formData, raw } = opts;
  const url = buildUrl(path, query);

  const doFetch = (token: string | null): Promise<Response> => {
    const headers: Record<string, string> = {};
    if (token) headers.Authorization = `Bearer ${token}`;
    if (formData) {
      // Let the browser set the multipart Content-Type with boundary
      return fetch(url, { method, headers, body: formData });
    }
    if (body !== undefined) headers["Content-Type"] = "application/json";
    return fetch(url, {
      method,
      headers,
      body: body !== undefined ? JSON.stringify(body) : undefined,
    });
  };

  let res = await doFetch(getAccessToken());

  // Try token refresh on 401
  if (res.status === 401 && getRefreshToken()) {
    const newToken = await refreshAccessToken();
    if (newToken) {
      res = await doFetch(newToken);
    }
  }

  if (res.status === 401) {
    clearTokens();
    unauthorizedHandler?.();
    const data = (await parseResponse<{ detail?: string }>(res).catch(() => ({}))) as { detail?: string };
    throw new ApiError(401, data?.detail || "Unauthorized");
  }

  if (!res.ok) {
    const data = (await parseResponse<{ detail?: string; message?: string }>(res).catch(() => ({}))) as { detail?: string; message?: string };
    const message = data?.detail || data?.message || `Request failed (${res.status})`;
    throw new ApiError(res.status, message, data);
  }

  if (raw) return res as unknown as T;
  return parseResponse<T>(res);
}

// ===== Auth API =====
export const AuthApi = {
  register: (payload: RegisterPayload) =>
    request<User>("/register", { method: "POST", body: payload }),
  registerAdmin: (payload: AdminRegisterPayload) =>
    request<User>("/register/admin", { method: "POST", body: payload }),
  login: (payload: LoginPayload) =>
    request<AuthResponse>("/auth/login", { method: "POST", body: payload }),
  refresh: (refreshToken: string) =>
    request<AuthResponse>("/auth/refresh", { method: "POST", body: { refresh_token: refreshToken } }),
  logout: () => request<void>("/auth/logout", { method: "POST" }),
  me: () => request<User>("/auth/me"),
};

// ===== Worlds API =====
export type ListWorldsQuery = {
  page?: number;
  per_page?: number;
  status_filter?: string;
};

export const WorldsApi = {
  list: (query: ListWorldsQuery = {}) =>
    request<Paginated<WorldListItem>>("/worlds", { query: { ...query } }),
  get: (id: string) => request<World>(`/worlds/${id}`),
  create: (payload: CreateWorldPayload) =>
    request<CreateWorldResponse>("/worlds", { method: "POST", body: payload }),
  update: (id: string, payload: Partial<World>) =>
    request<World>(`/worlds/${id}`, { method: "PATCH", body: payload }),
  remove: (id: string) => request<void>(`/worlds/${id}`, { method: "DELETE" }),
  edit: (id: string, payload: EditWorldPayload) =>
    request<EditWorldResponse>(`/worlds/${id}/edit`, { method: "POST", body: payload }),
};

// ===== Sessions API =====
export const SessionsApi = {
  state: (worldId: string) =>
    request<SessionState>(`/sessions/worlds/${worldId}/state`),
  iterate: (worldId: string, action: string, actionSource: string) =>
    request<IterateResponse>(`/sessions/worlds/${worldId}/iterate`, {
      method: "POST",
      body: { action, action_source: actionSource },
    }),
  retry: (worldId: string) =>
    request<RetryResponse>(`/sessions/worlds/${worldId}/retry`, { method: "POST" }),
  rollback: (worldId: string) =>
    request<void>(`/sessions/worlds/${worldId}/rollback`, { method: "POST" }),
  // SSE stream URLs (used by SSE client)
  iterateStreamUrl: (worldId: string, stepId: string) =>
    buildUrl(`/sessions/worlds/${worldId}/iterate/stream`, { step_id: stepId }),
  builderStreamUrl: (worldId: string) =>
    buildUrl(`/sessions/worlds/${worldId}/builder/stream`),
  editorStreamUrl: (worldId: string, instruction: string) =>
    buildUrl(`/sessions/worlds/${worldId}/editor/stream`, { instruction }),
};

// ===== Presets API =====
export const PresetsApi = {
  list: () => request<Paginated<PresetListItem>>("/presets"),
  get: (id: string) => request<WorldPreset>(`/presets/${id}`),
  create: (payload: Omit<WorldPreset, "id" | "created_at" | "status" | "version">) =>
    request<WorldPreset>("/presets", { method: "POST", body: payload }),
  update: (id: string, payload: Partial<WorldPreset>) =>
    request<WorldPreset>(`/presets/${id}`, { method: "PATCH", body: payload }),
  remove: (id: string) => request<void>(`/presets/${id}`, { method: "DELETE" }),
};

// ===== Admin API =====
export type LlmLogsQuery = {
  world_id?: string;
  stage?: string;
  status_filter?: string;
  page?: number;
  per_page?: number;
};

export const AdminApi = {
  settings: () => request<AdminSettingsResponse>("/admin/settings"),
  updateSettings: (settings: Record<string, string>) =>
    request<AdminSettingsResponse>("/admin/settings", { method: "PATCH", body: { settings } }),
  llmLogs: (query: LlmLogsQuery = {}) =>
    request<Paginated<LlmLog>>("/admin/llm-logs", { query: { ...query } }),
  llmLog: (id: string) => request<LlmLogDetail>(`/admin/llm-logs/${id}`),
  users: () => request<Paginated<User>>("/admin/users"),
  updateUser: (id: string, payload: { is_admin?: boolean; is_active?: boolean }) =>
    request<User>(`/admin/users/${id}`, { method: "PATCH", body: payload }),
  stats: () => request<AdminStats>("/admin/stats"),
  testLlm: (apiUrl: string, apiKey: string, model: string) =>
    request<LlmTestResult>(
      "/admin/test/llm",
      { method: "POST", query: { api_url: apiUrl, api_key: apiKey, model } },
    ),
  testLlmTools: (params: Record<string, string>) =>
    request<LlmToolsTestResult>("/admin/test/llm-tools", { method: "POST", query: params }),
  testEmbeddings: (params: Record<string, string>) =>
    request<EmbeddingsTestResult>("/admin/test/embeddings", { method: "POST", query: params }),
  probeDimension: (params: Record<string, string>) =>
    request<EmbeddingsProbeResult>(
      "/admin/test/embeddings/probe-dimension",
      { method: "POST", query: params },
    ),
  recreateCollections: () =>
    request<RecreateCollectionsResult>("/admin/embeddings/recreate-collections", { method: "POST" }),
  uploadIcon: (file: File, kind: "favicon" | "logo" | "og_image") => {
    const fd = new FormData();
    fd.append("file", file);
    fd.append("kind", kind);
    return request<UploadIconResult>("/admin/upload-icon", { method: "POST", formData: fd });
  },
};

export const MiscApi = {
  health: () => request<HealthResponse>("/health"),
};