import { JournalApi } from "../api/JournalApi";

const UPLOAD_PERMISSION_KEY = "journal:can-upload";
let cachedCanUpload: boolean | null = null;
let pendingCheck: Promise<boolean> | null = null;

function parseCachedValue(value: unknown): boolean | null {
	if (value === true || value === false) {
		return value;
	}
	if (value === "true") {
		return true;
	}
	if (value === "false") {
		return false;
	}
	return null;
}

export default class Permission {
	/** 获取缓存的上传权限（不存在则返回 null） */
	static getCachedUploadPermission(): boolean | null {
		if (cachedCanUpload !== null) {
			return cachedCanUpload;
		}
		try {
			const value = wx.getStorageSync(UPLOAD_PERMISSION_KEY);
			const parsed = parseCachedValue(value);
			if (parsed !== null) {
				cachedCanUpload = parsed;
				return parsed;
			}
		} catch (error) {
			console.warn("读取上传权限缓存失败", error);
		}
		return null;
	}

	/** 检查并缓存上传权限 */
	static async checkAndCacheUploadPermission(): Promise<boolean> {
		if (pendingCheck) {
			return await pendingCheck;
		}
		pendingCheck = (async () => {
			try {
				const canUpload = await JournalApi.canUpload();
				cachedCanUpload = !!canUpload;
				wx.setStorageSync(UPLOAD_PERMISSION_KEY, cachedCanUpload);
				return cachedCanUpload;
			} catch (error) {
				console.error("检查上传权限失败", error);
				const cached = this.getCachedUploadPermission();
				const fallback = cached !== null ? cached : false;
				return fallback;
			} finally {
				pendingCheck = null;
			}
		})();
		return await pendingCheck;
	}
}