import { Dict } from './dict';
import { Factory, FactoryDefinition } from './factory';

export interface RegistrationOptions {
  singleton?: boolean;
  instantiate?: boolean;
}

export interface Injection {
  property: string,
  source: string
}

export interface RegistryWriter {
  register(specifier: string, factory: any, options?: RegistrationOptions): void;
  unregister(specifier: string): void;
  registerOption(specifier: string, option: string, value: any): void;
  unregisterOption(specifier: string, option: string): void;
  registerInjection(specifier: string, property: string, source: string): void;
}

export interface RegistryReader {
  registration(specifier: string): any;
  registeredOption(specifier: string, option: string): any;
  registeredOptions(specifier: string): any;
  registeredInjections(specifier: string): Injection[];
}

export interface RegistryOptions {
  fallback?: RegistryReader;
}

export interface RegistryAccessor extends RegistryReader, RegistryWriter {}

export default class Registry implements RegistryAccessor {
  private _registrations: Dict<FactoryDefinition<any>>;
  private _registeredOptions: Dict<any>;
  private _registeredInjections: Dict<Injection[]>;
  private _fallback: RegistryReader;

  constructor(options?: RegistryOptions) {
    this._registrations = {};
    this._registeredOptions = {};
    this._registeredInjections = {};
    if (options && options.fallback) {
      this._fallback = options.fallback;
    }
  }

  register(specifier: string, factoryDefinition: FactoryDefinition<any>, options?: RegistrationOptions): void {
    this._registrations[specifier] = factoryDefinition;
    if (options) {
      this._registeredOptions[specifier] = options;
    }
  }

  registration(specifier: string): FactoryDefinition<any> {
    let registration = this._registrations[specifier];
    if (registration === undefined && this._fallback) {
      registration = this._fallback.registration(specifier);
    }
    return registration;
  }

  unregister(specifier: string): void {
    delete this._registrations[specifier];
    delete this._registeredOptions[specifier];
    delete this._registeredInjections[specifier];
  }

  registerOption(specifier: string, option: string, value: any): void {
    let options = this._registeredOptions[specifier];

    if (!options) {
      options = {};
      this._registeredOptions[specifier] = options;
    }

    options[option] = value;
  }

  registeredOption(specifier: string, option: string): any {
    let result: Boolean;
    let options = this.registeredOptions(specifier);

    if (options) {
      result = options[option];
    }

    if (result === undefined && this._fallback !== undefined) {
      result = this._fallback.registeredOption(specifier, option);
    }

    return result;
  }

  registeredOptions(specifier: string): any {
    let options = this._registeredOptions[specifier];
    if (options === undefined) {
      let [type] = specifier.split(':');
      options = this._registeredOptions[type];
    }
    return options;
  }

  unregisterOption(specifier: string, option: string): void {
    let options = this._registeredOptions[specifier];

    if (options) {
      delete options[option];
    }
  }

  registerInjection(specifier: string, property: string, source: string): void {
    let injections = this._registeredInjections[specifier];
    if (injections === undefined) {
      this._registeredInjections[specifier] = injections = [];
    }
    injections.push({
      property,
      source
    });
  }

  registeredInjections(specifier: string): Injection[] {
    let [type] = specifier.split(':');
    let injections: Injection[] = this._fallback ? this._fallback.registeredInjections(specifier) : [];
    Array.prototype.push.apply(injections, this._registeredInjections[type]);
    Array.prototype.push.apply(injections, this._registeredInjections[specifier]);
    return injections;
  }
}