import { Inject, Injectable, InjectionToken } from '@angular/core';
import { ResolveEnd, Router } from '@angular/router';
import { BehaviorSubject, Observable } from 'rxjs';
import { filter, take } from 'rxjs/operators';
import { cloneDeep, isEqual, merge, set } from 'lodash-es';
import { Config } from './config';
import { environment } from 'projects/core/src//environment';

// Create the injection token for the custom settings
export const MW_APP_CONFIG = new InjectionToken('mwAppCustomConfig');

const DefaultConfig: Config = {
  resetLayoutOnRoutingEnd: true,
  form: {
    sidebarPosition: 'left',
    bottomActionsPosition: 'nonSticky',
  },
  layout: {
    fullWidth: false,
  },
};

@Injectable()
export class MwAppConfigService {
  static nextId = 1;
  readonly id: string = `${
    environment.clientId
  }-${MwAppConfigService.nextId++}`;

  private configSubject$: BehaviorSubject<Config>;
  private readonly localDefaultConfig: Config;

  constructor(
    private router: Router,
    @Inject(MW_APP_CONFIG) private config: any
  ) {
    this.localDefaultConfig = merge({}, DefaultConfig, this.config);
    this.configSubject$ = new BehaviorSubject(
      cloneDeep(this.localDefaultConfig)
    );

    // Initialize the service
    this._init();
  }

  set config$(value) {
    // Get the value from the behavior subject
    let config: Config = this.configSubject$.getValue();

    // Merge the new config
    config = { ...config, ...value };

    // Notify the observers
    this.configSubject$.next(config);
  }

  get config$(): Observable<Config> {
    return this.configSubject$.asObservable();
  }

  get defaultConfig(): Config {
    return this.localDefaultConfig;
  }

  private _init(): void {
    // Set the config from the default config

    // Reload the default layout config on every RoutesRecognized event
    // if the current layout config is different from the default one
    this.router.events
      .pipe(filter((event) => event instanceof ResolveEnd))
      .subscribe(() => {
        const config = this.getInstantConfig();

        if (!config || !config.resetLayoutOnRoutingEnd) {
          return;
        }

        if (!isEqual(config.layout, this.localDefaultConfig.layout)) {
          // Clone the current config
          const newConfig = cloneDeep(config);

          // Reset the layout from the default config
          newConfig.layout = cloneDeep(this.localDefaultConfig.layout);

          // Set the config
          this.configSubject$.next(newConfig);
        }
      });
  }

  setConfig(value: any, opts = { emitEvent: true }): void {
    // Get the value from the behavior subject
    let config = this.configSubject$.getValue();

    // Merge the new config
    config = merge({}, config, value);

    // If emitEvent option is true...
    if (opts.emitEvent === true) {
      // Notify the observers
      this.configSubject$.next(config);
    }
  }

  setConfigChunk(path: string, value: any): void {
    // Get the value from the behavior subject
    let config = this.configSubject$.getValue();

    // Set value based on path
    config = set(config, path, value);

    // Notify the observers
    this.configSubject$.next(config);
  }

  getConfig(): Observable<Config> {
    return this.configSubject$.asObservable();
  }

  getInstantConfig(): Config | null {
    let config: Config | null = null;

    this.getConfig()
      .pipe(take(1))
      .subscribe((_config) => (config = _config));

    return config;
  }

  resetToDefaults(): void {
    // Set the config from the default config
    this.configSubject$.next(cloneDeep(this.localDefaultConfig));
  }
}