import type { AccountDevice, AuthCodeResponse, AuthOptions, AuthSession, AuthUser, StoredAuthSession } from "@/domain/auth";
import { createApiFailure, createNetworkFailure } from "@/infrastructure/userMessages";

const sessionStorageKey = "img-infinite-canvas.auth.session";
const accessTokenCookie = "usertoken";
const refreshTokenCookie = "refreshToken";

async function request<T>(path: string, body: unknown): Promise<T> {
  let response: Response;
  try {
    response = await fetch(path, {
      method: "POST",
      headers: {
        "Content-Type": "application/json"
      },
      body: JSON.stringify(body)
    });
  } catch (err) {
    throw createNetworkFailure("auth", err);
  }

  if (!response.ok) {
    const payload = await response.json().catch(() => ({ error: response.statusText }));
    throw createApiFailure("auth", response, payload);
  }

  return response.json() as Promise<T>;
}

async function get<T>(path: string): Promise<T> {
  let response: Response;
  try {
    response = await fetch(path, { cache: "no-store" });
  } catch (err) {
    throw createNetworkFailure("auth", err);
  }

  if (!response.ok) {
    const payload = await response.json().catch(() => ({ error: response.statusText }));
    throw createApiFailure("auth", response, payload);
  }

  return response.json() as Promise<T>;
}

async function apiRequest<T>(path: string, init: RequestInit = {}): Promise<T> {
  const headers = new Headers(init.headers);
  if (!(init.body instanceof FormData)) {
    headers.set("Content-Type", "application/json");
  }
  Object.entries(authHeaders()).forEach(([key, value]) => headers.set(key, value));

  let response: Response;
  try {
    response = await fetch(path, {
      ...init,
      headers,
      cache: "no-store"
    });
  } catch (err) {
    throw createNetworkFailure("auth", err);
  }

  if (!response.ok) {
    const payload = await response.json().catch(() => ({ error: response.statusText }));
    throw createApiFailure("auth", response, payload);
  }

  return response.json() as Promise<T>;
}

export const authGateway = {
  options() {
    return get<AuthOptions>("/api/auth/options");
  },

  requestGlobalEmailCode(email: string, turnstileToken: string) {
    return request<AuthCodeResponse>("/api/auth/global/email-code", { email, turnstileToken });
  },

  loginGlobalEmailCode(email: string, code: string) {
    return request<AuthSession>("/api/auth/global/email-login", { email, code });
  },

  loginGlobalGoogle(idToken: string) {
    return request<AuthSession>("/api/auth/global/google-login", { idToken });
  },

  profile() {
    return apiRequest<{ user: AuthUser }>("/api/account/profile");
  },

  updateProfile(userPatch: Partial<Pick<AuthUser, "name" | "avatarUrl">>) {
    return apiRequest<{ user: AuthUser }>("/api/account/profile", {
      method: "PATCH",
      body: JSON.stringify(userPatch)
    });
  },

  devices() {
    return apiRequest<{ devices: AccountDevice[] }>("/api/account/devices");
  },

  removeDevices() {
    return apiRequest<{ removed: number }>("/api/account/devices", {
      method: "DELETE"
    });
  },

  logoutAccount() {
    return apiRequest<{ removed: number }>("/api/account/logout", {
      method: "POST",
      body: JSON.stringify({})
    });
  },

  async uploadAvatar(file: File) {
    const upload = await apiRequest<{
      uploadUrl: string;
      publicUrl: string;
      headers: Record<string, string>;
    }>("/api/assets/upload-url", {
      method: "POST",
      body: JSON.stringify({
        fileName: file.name,
        contentType: file.type || "application/octet-stream",
        size: file.size
      })
    });

    if (upload.uploadUrl && !upload.uploadUrl.includes("/memory-assets/")) {
      await fetch(upload.uploadUrl, {
        method: "PUT",
        headers: upload.headers,
        body: file
      });
    }
    return upload.publicUrl;
  }
};

export function readStoredAuthSession(): StoredAuthSession | null {
  if (typeof window === "undefined") return null;
  const raw = window.localStorage.getItem(sessionStorageKey);
  if (!raw) return null;
  try {
    const session = JSON.parse(raw) as StoredAuthSession;
    if (!session.accessToken || isSessionExpired(session)) {
      clearStoredAuthSession();
      return null;
    }
    return session;
  } catch {
    clearStoredAuthSession();
    return null;
  }
}

export function storeAuthSession(session: AuthSession): StoredAuthSession {
  const stored = { ...session, savedAt: Date.now() };
  if (typeof window !== "undefined") {
    window.localStorage.setItem(sessionStorageKey, JSON.stringify(stored));
    setCookie(accessTokenCookie, session.accessToken, session.expiresIn);
    if (session.refreshToken && session.refreshExpiresIn) {
      setCookie(refreshTokenCookie, session.refreshToken, session.refreshExpiresIn);
    }
  }
  return stored;
}

export function updateStoredAuthUser(userPatch: Partial<AuthUser>): StoredAuthSession | null {
  const current = readStoredAuthSession();
  if (!current) return null;

  const stored = {
    ...current,
    user: {
      ...current.user,
      ...userPatch
    }
  };
  if (typeof window !== "undefined") {
    window.localStorage.setItem(sessionStorageKey, JSON.stringify(stored));
  }
  return stored;
}

export function clearStoredAuthSession() {
  if (typeof window === "undefined") return;
  window.localStorage.removeItem(sessionStorageKey);
  expireCookie(accessTokenCookie);
  expireCookie(refreshTokenCookie);
}

export function getAuthAccessToken() {
  return readStoredAuthSession()?.accessToken ?? "";
}

export function authHeaders() {
  const token = getAuthAccessToken();
  if (!token) return {};
  return {
    Authorization: `Bearer ${token}`,
    token
  } satisfies Record<string, string>;
}

function isSessionExpired(session: StoredAuthSession) {
  const expiresIn = Number(session.expiresIn || 0);
  return expiresIn > 0 && session.savedAt + expiresIn * 1000 <= Date.now() + 30_000;
}

function setCookie(name: string, value: string, maxAge: number) {
  document.cookie = `${name}=${encodeURIComponent(value)}; Path=/; Max-Age=${Math.max(0, Math.floor(maxAge))}; SameSite=Lax`;
}

function expireCookie(name: string) {
  document.cookie = `${name}=; Path=/; Max-Age=0; SameSite=Lax`;
}