import {
    MiddlewareConsumer,
    Module,
    NestModule,
    OnApplicationBootstrap,
    OnApplicationShutdown,
} from '@nestjs/common';
import { ModuleRef } from '@nestjs/core';
import { RequestHandler } from 'express';

import { ApiModule } from './api/api.module';
import { ConfigurableOperationDef } from './common/configurable-operation';
import { Injector } from './common/injector';
import { InjectableStrategy } from './common/types/injectable-strategy';
import { ConfigModule } from './config/config.module';
import { ConfigService } from './config/config.service';
import { Logger } from './config/logger/vendure-logger';
import { HealthCheckModule } from './health-check/health-check.module';
import { I18nModule } from './i18n/i18n.module';
import { I18nService } from './i18n/i18n.service';
import { PluginModule } from './plugin/plugin.module';
import { ProcessContextModule } from './process-context/process-context.module';

@Module({
    imports: [
        ConfigModule,
        I18nModule,
        ApiModule,
        PluginModule.forRoot(),
        ProcessContextModule.forRoot(),
        HealthCheckModule,
    ],
})
export class AppModule implements NestModule, OnApplicationBootstrap, OnApplicationShutdown {
    constructor(
        private configService: ConfigService,
        private i18nService: I18nService,
        private moduleRef: ModuleRef,
    ) {}

    async onApplicationBootstrap() {
        await this.initInjectableStrategies();
        await this.initConfigurableOperations();
    }

    configure(consumer: MiddlewareConsumer) {
        const { adminApiPath, shopApiPath, middleware } = this.configService.apiOptions;
        const i18nextHandler = this.i18nService.handle();
        const defaultMiddleware: Array<{ handler: RequestHandler; route?: string }> = [
            { handler: i18nextHandler, route: adminApiPath },
            { handler: i18nextHandler, route: shopApiPath },
        ];
        const allMiddleware = defaultMiddleware.concat(middleware);
        const middlewareByRoute = this.groupMiddlewareByRoute(allMiddleware);
        for (const [route, handlers] of Object.entries(middlewareByRoute)) {
            consumer.apply(...handlers).forRoutes(route);
        }
    }

    async onApplicationShutdown(signal?: string) {
        await this.destroyInjectableStrategies();
        await this.destroyConfigurableOperations();
        if (signal) {
            Logger.info('Received shutdown signal:' + signal);
        }
    }

    /**
     * Groups middleware handlers together in an object with the route as the key.
     */
    private groupMiddlewareByRoute(
        middlewareArray: Array<{ handler: RequestHandler; route?: string }>,
    ): { [route: string]: RequestHandler[] } {
        const result = {} as { [route: string]: RequestHandler[] };
        for (const middleware of middlewareArray) {
            const route = middleware.route || this.configService.apiOptions.adminApiPath;
            if (!result[route]) {
                result[route] = [];
            }
            result[route].push(middleware.handler);
        }
        return result;
    }

    private async initInjectableStrategies() {
        const injector = new Injector(this.moduleRef);
        for (const strategy of this.getInjectableStrategies()) {
            if (typeof strategy.init === 'function') {
                await strategy.init(injector);
            }
        }
    }

    private async destroyInjectableStrategies() {
        for (const strategy of this.getInjectableStrategies()) {
            if (typeof strategy.destroy === 'function') {
                await strategy.destroy();
            }
        }
    }

    private async initConfigurableOperations() {
        const injector = new Injector(this.moduleRef);
        for (const operation of this.getConfigurableOperations()) {
            await operation.init(injector);
        }
    }

    private async destroyConfigurableOperations() {
        for (const operation of this.getConfigurableOperations()) {
            await operation.destroy();
        }
    }

    private getInjectableStrategies(): InjectableStrategy[] {
        const {
            assetNamingStrategy,
            assetPreviewStrategy,
            assetStorageStrategy,
        } = this.configService.assetOptions;
        const { adminAuthenticationStrategy, shopAuthenticationStrategy } = this.configService.authOptions;
        const { taxCalculationStrategy, taxZoneStrategy } = this.configService.taxOptions;
        const { jobQueueStrategy } = this.configService.jobQueueOptions;
        const {
            mergeStrategy,
            checkoutMergeStrategy,
            priceCalculationStrategy,
            process,
            orderCodeStrategy,
        } = this.configService.orderOptions;
        const { entityIdStrategy } = this.configService;
        return [
            ...adminAuthenticationStrategy,
            ...shopAuthenticationStrategy,
            assetNamingStrategy,
            assetPreviewStrategy,
            assetStorageStrategy,
            taxCalculationStrategy,
            taxZoneStrategy,
            jobQueueStrategy,
            mergeStrategy,
            checkoutMergeStrategy,
            orderCodeStrategy,
            entityIdStrategy,
            priceCalculationStrategy,
            ...process,
        ];
    }

    private getConfigurableOperations(): Array<ConfigurableOperationDef<any>> {
        const { paymentMethodHandlers } = this.configService.paymentOptions;
        const { collectionFilters } = this.configService.catalogOptions;
        const { promotionActions, promotionConditions } = this.configService.promotionOptions;
        const { shippingCalculators, shippingEligibilityCheckers } = this.configService.shippingOptions;
        return [
            ...paymentMethodHandlers,
            ...collectionFilters,
            ...(promotionActions || []),
            ...(promotionConditions || []),
            ...(shippingCalculators || []),
            ...(shippingEligibilityCheckers || []),
        ];
    }
}