import { Capacitor } from "@capacitor/core";
import { create } from "zustand";
import {
  listCharacters,
  replaceCharactersForOwner,
  setRosterChangeListener,
  loadUiPreferences,
  loadAccountBossCards,
  saveUiPreferences,
  type AccountResult,
} from "./accountRepository";
import type { CharacterProfile, PlayerSession } from "./types";
import type { OnlineGroupSnapshot, StartOnlineGroupActivityInput } from "./onlineGroupTypes";
import type { OnlineSessionSnapshot, OnlineSessionSyncInput } from "./onlineSessionTypes";

const NATIVE_API_ORIGIN = "https://iwanttoheal.phenomrom.com";
const SAVE_DEBOUNCE_MS = 500;

interface AuthResponse {
  account: { id: string; username: string; roles?: readonly "gm"[] };
  token: string;
}

interface CloudSaveResponse {
  revision: number;
  updatedAt: number | null;
  data: { version?: number; characters?: unknown; uiPreferences?: unknown; bossCards?: unknown };
}

interface MeResponse {
  account: { id: string; username: string; roles?: readonly "gm"[] };
}

class OnlineApiError extends Error {
  constructor(message: string, readonly status: number) {
    super(message);
    this.name = "OnlineApiError";
  }
}

export function isOnlineAuthenticationError(error: unknown): boolean {
  return error instanceof OnlineApiError && error.status === 401;
}

let activeSession: PlayerSession | null = null;
let suppressUpload = false;
let pendingCharacters: CharacterProfile[] | null = null;
let saveTimer: ReturnType<typeof setTimeout> | null = null;
let saveQueue = Promise.resolve();
export const useCloudSaveStatus = create<{ state: "local" | "pending" | "synced" | "error"; message: string }>(() => ({ state: "local", message: "" }));
let saveSequence = 0;

export function onlineApiOrigin(): string {
  const configured = String(import.meta.env.VITE_API_BASE_URL ?? "").replace(/\/+$/, "");
  if (configured) return configured;
  return Capacitor.isNativePlatform() ? NATIVE_API_ORIGIN : "";
}

export async function requestOnlineJson<T>(pathname: string, init: RequestInit = {}, token?: string): Promise<T> {
  const headers = new Headers(init.headers);
  headers.set("Accept", "application/json");
  if (init.body !== undefined) headers.set("Content-Type", "application/json");
  if (token) headers.set("Authorization", `Bearer ${token}`);
  let response: Response;
  try {
    response = await fetch(`${onlineApiOrigin()}${pathname}`, { ...init, headers });
  } catch {
    throw new OnlineApiError("The online server is unavailable. Check your connection or play offline.", 0);
  }
  const body = await response.json().catch(() => ({})) as { error?: string };
  if (!response.ok) throw new OnlineApiError(body.error ?? `Server request failed (${response.status}).`, response.status);
  return body as T;
}

function accountResult(response: AuthResponse): AccountResult {
  return {
    ok: true,
    session: {
      kind: "account",
      ownerId: response.account.id,
      displayName: response.account.username,
      roles: response.account.roles ?? [],
      accessToken: response.token,
    },
  };
}

async function authenticate(pathname: string, username: string, password: string): Promise<AccountResult> {
  try {
    const response = await requestOnlineJson<AuthResponse>(pathname, {
      method: "POST",
      body: JSON.stringify({ username, password }),
    });
    return accountResult(response);
  } catch (error) {
    return { ok: false, error: error instanceof Error ? error.message : "Online authentication failed." };
  }
}

export function loginOnlineAccount(username: string, password: string): Promise<AccountResult> {
  return authenticate("/api/auth/login", username, password);
}

export function createOnlineAccount(username: string, password: string): Promise<AccountResult> {
  return authenticate("/api/auth/register", username, password);
}

function flushCloudSave(): void {
  const session = activeSession;
  const characters = pendingCharacters;
  pendingCharacters = null;
  if (!session?.accessToken || !characters) return;
  const uiPreferences = loadUiPreferences(session.ownerId);
  const bossCards = loadAccountBossCards(session.ownerId);
  const sequence = saveSequence;
  saveQueue = saveQueue.then(async () => {
    await requestOnlineJson<CloudSaveResponse>("/api/cloud-save", {
      method: "PUT",
      body: JSON.stringify({ data: { version: 2, characters, uiPreferences, bossCards } }),
    }, session.accessToken);
    if (activeSession?.ownerId === session.ownerId && sequence === saveSequence) useCloudSaveStatus.setState({ state: "synced", message: "Saved to your account." });
  }).catch((error) => {
    console.error("Healer Man cloud save failed", error);
    if (activeSession?.ownerId === session.ownerId && sequence === saveSequence) useCloudSaveStatus.setState({ state: "error", message: "Saved on this device. Cloud upload failed; retry before switching devices." });
  });
}

function queueCloudSave(ownerId: string, characters: readonly CharacterProfile[]): void {
  if (suppressUpload || !activeSession?.accessToken || activeSession.ownerId !== ownerId) return;
  saveSequence += 1;
  useCloudSaveStatus.setState({ state: "pending", message: "Uploading to your account…" });
  pendingCharacters = characters.map((character) => ({ ...character }));
  if (saveTimer) clearTimeout(saveTimer);
  saveTimer = setTimeout(() => {
    saveTimer = null;
    flushCloudSave();
  }, SAVE_DEBOUNCE_MS);
}

setRosterChangeListener(queueCloudSave);

export function activateOnlineSession(session: PlayerSession | null): void {
  if (activeSession?.ownerId !== session?.ownerId && saveTimer) {
    clearTimeout(saveTimer); saveTimer = null; flushCloudSave();
  }
  activeSession = session?.accessToken ? session : null;
}

export function retryCloudSave(): void {
  if (activeSession) queueCloudSave(activeSession.ownerId, listCharacters(activeSession.ownerId));
}

export async function hydrateOnlineSession(session: PlayerSession): Promise<CharacterProfile[]> {
  if (!session.accessToken) return listCharacters(session.ownerId);
  activateOnlineSession(session);
  const cloud = await requestOnlineJson<CloudSaveResponse>("/api/cloud-save", {}, session.accessToken);
  suppressUpload = true;
  let characters: CharacterProfile[];
  try {
    saveUiPreferences(session.ownerId, cloud.data?.uiPreferences);
    characters = replaceCharactersForOwner(session.ownerId, cloud.data?.characters ?? [], undefined, cloud.data?.bossCards);
  } finally {
    suppressUpload = false;
  }
  // Publish migrated logs even if the player has not earned another card yet.
  if (JSON.stringify(cloud.data?.bossCards) !== JSON.stringify(loadAccountBossCards(session.ownerId))) {
    queueCloudSave(session.ownerId, characters);
  }
  return characters;
}

export async function refreshOnlineSession(session: PlayerSession): Promise<PlayerSession> {
  if (!session.accessToken) return { ...session, roles: [] };
  const response = await requestOnlineJson<MeResponse>("/api/me", {}, session.accessToken);
  return {
    ...session,
    ownerId: response.account.id,
    displayName: response.account.username,
    roles: response.account.roles ?? [],
  };
}

export async function logoutOnlineSession(session: PlayerSession | null): Promise<void> {
  if (saveTimer) {
    clearTimeout(saveTimer);
    saveTimer = null;
    flushCloudSave();
  }
  if (session?.accessToken) {
    await saveQueue;
    await requestOnlineJson("/api/auth/logout", { method: "POST" }, session.accessToken).catch(() => undefined);
  }
  if (activeSession?.ownerId === session?.ownerId) activeSession = null;
}

function onlineGroupRequest<T>(session: PlayerSession, pathname: string, init: RequestInit = {}): Promise<T> {
  if (!session.accessToken) throw new OnlineApiError("Online grouping requires a signed-in account.", 401);
  return requestOnlineJson<T>(pathname, init, session.accessToken);
}

export function fetchOnlineGroup(session: PlayerSession): Promise<OnlineGroupSnapshot> {
  return onlineGroupRequest(session, "/api/online-group");
}

export async function inviteOnlineGroupPlayer(session: PlayerSession, username: string): Promise<OnlineGroupSnapshot> {
  const response = await onlineGroupRequest<{ state: OnlineGroupSnapshot }>(session, "/api/online-group/invite", {
    method: "POST",
    body: JSON.stringify({ username }),
  });
  return response.state;
}

export function respondToOnlineGroupInvite(
  session: PlayerSession,
  inviteId: string,
  accept: boolean,
): Promise<OnlineGroupSnapshot> {
  return onlineGroupRequest(session, "/api/online-group/invite/respond", {
    method: "POST",
    body: JSON.stringify({ inviteId, accept }),
  });
}

export function leaveOnlineGroup(session: PlayerSession): Promise<OnlineGroupSnapshot> {
  return onlineGroupRequest(session, "/api/online-group/leave", { method: "POST" });
}

export function removeOnlineGroupPlayer(session: PlayerSession, accountId: string): Promise<OnlineGroupSnapshot> {
  return onlineGroupRequest(session, "/api/online-group/remove", {
    method: "POST",
    body: JSON.stringify({ accountId }),
  });
}

export function updateOnlineGroupMember(
  session: PlayerSession,
  character: CharacterProfile,
  role: string,
): Promise<OnlineGroupSnapshot> {
  return onlineGroupRequest(session, "/api/online-group/member", {
    method: "PUT",
    body: JSON.stringify({ character, role }),
  });
}

export function startOnlineGroupActivity(
  session: PlayerSession,
  activity: StartOnlineGroupActivityInput,
): Promise<OnlineGroupSnapshot> {
  return onlineGroupRequest(session, "/api/online-group/activity", {
    method: "POST",
    body: JSON.stringify(activity),
  });
}

export function clearOnlineGroupActivity(session: PlayerSession): Promise<OnlineGroupSnapshot> {
  return onlineGroupRequest(session, "/api/online-group/activity/clear", { method: "POST" });
}

export function synchronizeOnlineSession(
  session: PlayerSession,
  input: OnlineSessionSyncInput,
): Promise<OnlineSessionSnapshot> {
  return onlineGroupRequest(session, "/api/online-session/sync", {
    method: "POST",
    body: JSON.stringify(input),
  });
}