import type { RouteObject } from 'react-router';
import { createStore, type StoreApi } from 'zustand';
import { immer } from 'zustand/middleware/immer';
import { DynamicStore } from './DynamicStore';
import type { DynamicModule } from './types';

class DynamicModuleContext extends DynamicStore {
	constructor(
		private readonly module: DynamicModule,
		store: StoreApi<any>,
	) {
		super(store);
	}
}

export class ModuleService {
	readonly store = createStore(
		immer(() => {
			return {};
		}),
	);

	private instances: ModuleInstance[] = [];

	get modules() {
		return this.instances.map((v) => v.module);
	}

	constructor(public loader: (name: string) => Promise<DynamicModule>) {}

	async loadModules(names: string[]) {
		const last = this.instances.map((v) => v.name);
		names = names.filter((v) => last.indexOf(v) < 0);
		const loaded = await Promise.all(
			names.map(async (name) => {
				const module = await this.loader(name);
				return { module, name, context: new DynamicModuleContext(module, this.store) };
			}),
		);
		// ensure order
		await Promise.all(
			loaded.map(async ({ module, context }) => {
				if ('onModuleInit' in module) {
					await module.onModuleInit?.(context);
				}
			}),
		);
		this.instances = [...this.instances, ...loaded];
		// wait to next tick, ensure the SetState take effects
		await Promise.resolve();
	}

	async createRoutes(): Promise<RouteObject[]> {
		const all = await Promise.all(this.instances.map((v) => v.module?.createRoutes?.(v.context)));
		return all.flat().filter((x): x is NonNullable<typeof x> => Boolean(x));
	}
}

interface ModuleInstance {
	context: DynamicModuleContext;
	module: DynamicModule;
	name: string;
}