import { Provider } from './Provider'
import { Dictionary } from 'typescript-collections'

export interface ProviderCallback {
    (key: string, provider: Provider): void
}

const providers: Dictionary<string, Provider> = new Dictionary<string, Provider>()

const registerProvider = (provider: Provider): void => {
  const key = provider.getKey()
  if (providers.containsKey(key)) {
    throw new Error(`Provider with the key ${key} is already registered`)
  }
  providers.setValue(key, provider)
  console.info('Added provider to registry', { key: key })
}

const getProviderByKey = (key: string): Provider => {
  return providers.getValue(key)
}

const getKeys = ():string[] => {
  return providers.keys()
}

const forEachProvider = (callback: ProviderCallback): void => {
  return providers.forEach(callback)
}

const containsKey = (key:string):boolean => {
  return providers.containsKey(key)
}

export interface ProviderRegistry {
  registerProvider: (provider: Provider)=> void,
  getProviderByKey:(key: string)=> Provider
  forEachProvider:(callback: ProviderCallback)=> void
  getKeys:()=>string[]
  containsKey:(key:string)=>boolean
}

export const providerRegistry:ProviderRegistry = {
  registerProvider,
  getProviderByKey,
  forEachProvider,
  getKeys,
  containsKey
}