import { create } from "zustand";
import { requestOnlineJson } from "./onlineAccountClient";
import type { PlayerSession } from "./types";
import {
  DEFAULT_DUNGEON_QUEUE_POLICY,
  normalizeDungeonQueuePolicy,
  type DungeonQueueMode,
  type DungeonQueuePolicy,
} from "../game/dungeonQueuePolicy";

interface PublishedPolicy {
  readonly revision: number;
  readonly updatedAt: number | null;
  readonly updatedBy?: string | null;
  readonly config: DungeonQueuePolicy;
}

interface PolicyState extends PublishedPolicy {
  readonly draft: DungeonQueuePolicy;
  readonly loading: boolean;
  readonly saving: boolean;
  readonly dirty: boolean;
  readonly error: string | null;
  refresh: (session: PlayerSession | null) => Promise<void>;
  setEnabled: (mode: DungeonQueueMode, dungeonId: string, enabled: boolean) => void;
  resetDraft: () => void;
  publish: (session: PlayerSession | null) => Promise<boolean>;
}

const CACHE_KEY = "healer-man.dungeon-queue-policy.v1";

function cached(): PublishedPolicy {
  try {
    const value = JSON.parse(globalThis.localStorage?.getItem(CACHE_KEY) ?? "null") as PublishedPolicy;
    if (!Number.isInteger(value.revision)) throw new Error("missing");
    return { ...value, config: normalizeDungeonQueuePolicy(value.config) };
  } catch {
    return { revision: 0, updatedAt: null, config: DEFAULT_DUNGEON_QUEUE_POLICY };
  }
}

function cache(value: PublishedPolicy): void {
  try { globalThis.localStorage?.setItem(CACHE_KEY, JSON.stringify(value)); } catch { /* offline cache is optional */ }
}

function normalized(value: PublishedPolicy): PublishedPolicy {
  return { ...value, config: normalizeDungeonQueuePolicy(value.config) };
}

/** Fetch for each random roll so a newly published GM setting is used without a reload. */
export async function loadDungeonQueuePolicy(): Promise<DungeonQueuePolicy> {
  try {
    const value = normalized(await requestOnlineJson<PublishedPolicy>("/api/dungeon-queue-policy"));
    cache(value);
    useDungeonQueuePolicyStore.setState((state) => state.dirty ? state : { ...value, draft: value.config });
    return value.config;
  } catch {
    return cached().config;
  }
}

const initial = cached();
export const useDungeonQueuePolicyStore = create<PolicyState>((set, get) => ({
  ...initial,
  draft: initial.config,
  loading: false,
  saving: false,
  dirty: false,
  error: null,
  refresh: async (session) => {
    set({ loading: true, error: null });
    try {
      const gm = Boolean(session?.accessToken && session.roles?.includes("gm"));
      const value = normalized(await requestOnlineJson<PublishedPolicy>(
        gm ? "/api/gm/dungeon-queue-policy" : "/api/dungeon-queue-policy",
        {}, gm ? session?.accessToken : undefined,
      ));
      cache(value);
      set({ ...value, draft: value.config, loading: false, dirty: false });
    } catch (error) {
      set({ loading: false, error: error instanceof Error ? error.message : "Could not load dungeon queue settings." });
    }
  },
  setEnabled: (mode, dungeonId, enabled) => set((state) => {
    const ids = new Set(state.draft.disabled[mode]);
    if (enabled) ids.delete(dungeonId);
    else ids.add(dungeonId);
    return {
      draft: { schemaVersion: 1, disabled: { ...state.draft.disabled, [mode]: [...ids].sort() } },
      dirty: true,
      error: null,
    };
  }),
  resetDraft: () => set((state) => ({ draft: state.config, dirty: false, error: null })),
  publish: async (session) => {
    if (!session?.accessToken || !session.roles?.includes("gm")) {
      set({ error: "Game Master access is required." });
      return false;
    }
    set({ saving: true, error: null });
    try {
      const value = normalized(await requestOnlineJson<PublishedPolicy>("/api/gm/dungeon-queue-policy", {
        method: "PUT", body: JSON.stringify({ expectedRevision: get().revision, config: get().draft }),
      }, session.accessToken));
      cache(value);
      set({ ...value, draft: value.config, saving: false, dirty: false });
      return true;
    } catch (error) {
      set({ saving: false, error: error instanceof Error ? error.message : "Could not publish dungeon queue settings." });
      return false;
    }
  },
}));