import { init } from '../helpers'
import { AuthTokenResponse, ServiceCollection, ServiceCollectionRequest } from '../models'
import { GuardService } from './guard'

/**
 * This service enables you to handle one authentication token per practice
 */
export class ApisPracticeManager {
    private practiceInstances = new Map<string, ServiceCollection>()

    /**
     * The constructor
     * @param serviceCollReq the services to initialize. Only filled urls will get corresponding service to be initialized.
     * It will be used each time a new practices needs a `ServiceCollection`
     * @param getAuthTokenCbk the callback function used to get a new JWT token
     * @param useLocalStorage (default: false) if true store tokens into local storage (only for browsers)
     */
    constructor(
        private serviceCollReq: ServiceCollectionRequest,
        private getAuthTokenCbk: (guard: GuardService, practiceUuid?: string) => Promise<AuthTokenResponse>,
        private useLocalStorage = false
    ) {
        // The refreshInstance will be a single instance that is used to refresh the tokens of others this way it will not interfere with requests made by other services 
        const newPracticeInstance = init(this.serviceCollReq, undefined, this.useLocalStorage)
        this.practiceInstances.set('refreshInstance', newPracticeInstance)
    }

    /**
     * This function is used to get a `ServiceCollection` associated to a practice. If missing, it will initialize a new `ServiceCollection`.
     * @param practiceUuid the uuid of the practice
     * @returns a promise holding a `ServiceCollection`
     */
    public async get(practiceUuid?: string): Promise<ServiceCollection> {
        const cacheKey = practiceUuid ?? 'none'
        const practiceInstance = this.practiceInstances.get(cacheKey)
        if (practiceInstance) return practiceInstance

        const newPracticeInstance = init(this.serviceCollReq, undefined, this.useLocalStorage)
        newPracticeInstance.apiService.setAuthRefreshFn(() => this.authTokenFunc(practiceUuid))
        this.practiceInstances.set(cacheKey, newPracticeInstance)

        return newPracticeInstance
    }

    /**
     * Uses the refresh intance to fetch a new auth token for the given practice
     * @param practiceUuid the uuid of the practice or key of a specific instance
     * @returns a new authentication token
     */
    public async authTokenFunc(practiceUuidOrInstanceName?: string): Promise<AuthTokenResponse> {
        // fetch the refresh intance and refresh the token for another practice
        const newPracticeInstance = await this.get('refreshInstance');
        if (newPracticeInstance.guardService) {
            console.log(`\x1b[36m[Auth] Refresh auth called (practiceUuid: ${practiceUuidOrInstanceName})\x1b[36m`)
            return await this.getAuthTokenCbk(newPracticeInstance.guardService, practiceUuidOrInstanceName)
        } else {
            throw Error('[Auth] Unable to refresh token guard service is undefined')
        }
    }
}