import { Emitter } from '@rocket.chat/emitter';
import { createContext, useContext, useMemo, useCallback } from 'react';
import { useSubscription, Subscription, Unsubscribe } from 'use-subscription';

import { IRole } from '../../definition/IUser';

type IRoles = { [_id: string]: IRole };

export class RoleStore extends Emitter<{
	change: IRoles;
}> {
	roles: IRoles = {};
}

export type AuthorizationContextValue = {
	queryPermission(permission: string | Mongo.ObjectID, scope?: string | Mongo.ObjectID): Subscription<boolean>;
	queryAtLeastOnePermission(permission: (string | Mongo.ObjectID)[], scope?: string | Mongo.ObjectID): Subscription<boolean>;
	queryAllPermissions(permission: (string | Mongo.ObjectID)[], scope?: string | Mongo.ObjectID): Subscription<boolean>;
	queryRole(role: string | Mongo.ObjectID): Subscription<boolean>;
	roleStore: RoleStore;
};

export const AuthorizationContext = createContext<AuthorizationContextValue>({
	queryPermission: () => ({
		getCurrentValue: (): boolean => false,
		subscribe: (): Unsubscribe => (): void => undefined,
	}),
	queryAtLeastOnePermission: () => ({
		getCurrentValue: (): boolean => false,
		subscribe: (): Unsubscribe => (): void => undefined,
	}),
	queryAllPermissions: () => ({
		getCurrentValue: (): boolean => false,
		subscribe: (): Unsubscribe => (): void => undefined,
	}),
	queryRole: () => ({
		getCurrentValue: (): boolean => false,
		subscribe: (): Unsubscribe => (): void => undefined,
	}),
	roleStore: new RoleStore(),
});

export const usePermission = (permission: string | Mongo.ObjectID, scope?: string | Mongo.ObjectID): boolean => {
	const { queryPermission } = useContext(AuthorizationContext);
	const subscription = useMemo(() => queryPermission(permission, scope), [queryPermission, permission, scope]);
	return useSubscription(subscription);
};

export const useAtLeastOnePermission = (permissions: (string | Mongo.ObjectID)[], scope?: string | Mongo.ObjectID): boolean => {
	const { queryAtLeastOnePermission } = useContext(AuthorizationContext);
	const subscription = useMemo(() => queryAtLeastOnePermission(permissions, scope), [queryAtLeastOnePermission, permissions, scope]);
	return useSubscription(subscription);
};

export const useAllPermissions = (permissions: (string | Mongo.ObjectID)[], scope?: string | Mongo.ObjectID): boolean => {
	const { queryAllPermissions } = useContext(AuthorizationContext);
	const subscription = useMemo(() => queryAllPermissions(permissions, scope), [queryAllPermissions, permissions, scope]);
	return useSubscription(subscription);
};

export const useRolesDescription = (): ((ids: Array<string>) => [string]) => {
	const { roleStore } = useContext(AuthorizationContext);

	const subscription = useMemo(
		() => ({
			getCurrentValue: (): IRoles => roleStore.roles,
			subscribe: (callback: () => void): (() => void) => {
				roleStore.on('change', callback);
				return (): void => {
					roleStore.off('change', callback);
				};
			},
		}),
		[roleStore],
	);

	const roles = useSubscription<IRoles>(subscription);

	return useCallback((values) => values.map((role: string) => (roles[role] && roles[role].description) || role), [roles]) as (
		ids: Array<string>,
	) => [string];
};

export const useRole = (role: string | Mongo.ObjectID): boolean => {
	const { queryRole } = useContext(AuthorizationContext);
	const subscription = useMemo(() => queryRole(role), [queryRole, role]);
	return useSubscription(subscription);
};