/**
 * Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the MIT License.
 */

import Globalize from 'globalize'
import { recognizeNumber } from '@microsoft/recognizers-text-number'
import * as locales from '../i18n'
import { TurnContext } from '@microsoft/agents-hosting'
import { Prompt, PromptOptions, PromptRecognizerResult, PromptValidator } from './prompt'
import { InputHints } from '@microsoft/agents-activity'

// Load all registered locales into Globalize library
Object.values(locales).forEach((locale) => Globalize.load(locale))

/**
 * Prompts a user to enter a number.
 *
 * @remarks
 * By default the prompt will return to the calling dialog a `number` representing the users input.
 *
 */
export class NumberPrompt extends Prompt<number> {
  /**
     * The prompts default locale that should be recognized.
     */
  defaultLocale?: string

  /**
     * Creates a new NumberPrompt instance.
     *
     * @param dialogId Unique ID of the dialog within its parent {@link DialogSet} or {@link ComponentDialog}.
     * @param validator (Optional) validator that will be called each time the user responds to the prompt.
     * @param defaultLocale (Optional) locale to use if the `TurnContext.activity.locale` is not specified. Defaults to a value of `en-us`.
     */
  constructor (dialogId: string, validator?: PromptValidator<number>, defaultLocale?: string) {
    super(dialogId, validator)
    this.defaultLocale = defaultLocale
  }

  /**
     * Prompts the user for input.
     *
     * @param context {@link TurnContext} context for the current
     * turn of conversation with the user.
     * @param state Contains state for the current instance of the prompt on the dialog stack.
     * @param options A {@link PromptOptions} object constructed
     * from the options initially provided in the call to Prompt.
     * @param isRetry `true` if this is the first time this prompt dialog instance
     * on the stack is prompting the user for input; otherwise, false.
     * @returns A `Promise` representing the asynchronous operation.
     */
  protected async onPrompt (
    context: TurnContext,
    state: unknown,
    options: PromptOptions,
    isRetry: boolean
  ): Promise<void> {
    if (isRetry && options.retryPrompt) {
      await context.sendActivity(options.retryPrompt, undefined, InputHints.ExpectingInput)
    } else if (options.prompt) {
      await context.sendActivity(options.prompt, undefined, InputHints.ExpectingInput)
    }
  }

  /**
     * Attempts to recognize the user's input.
     *
     * @param context {@link TurnContext}, context for the current
     * turn of conversation with the user.
     * @param _state Contains state for the current instance of the prompt on the dialog stack.
     * @param _options A {@link PromptOptions} object constructed
     * from the options initially provided in the call to Prompt.
     * @returns A `Promise` representing the asynchronous operation.
     */
  protected async onRecognize (
    context: TurnContext,
    _state: unknown,
    _options: PromptOptions
  ): Promise<PromptRecognizerResult<number>> {
    const result: PromptRecognizerResult<number> = { succeeded: false }
    const activity = context.activity

    const utterance = activity.text
    if (!utterance) {
      return result
    }

    const defaultLocale = this.defaultLocale || 'en-us'
    const locale = activity.locale || defaultLocale

    const [{ resolution = null } = {}] = recognizeNumber(utterance, locale) || []
    if (resolution) {
      result.succeeded = true

      // Note: if we encounter an exception loading a globalize number parser, fall back to the
      // parser for the default locale
      const parser = Globalize(this.getCultureFormattedForGlobalize(locale))
      let numberParser: (value: string) => number
      try {
        numberParser = parser.numberParser()
      } catch {
        numberParser = Globalize(this.getCultureFormattedForGlobalize(defaultLocale)).numberParser()
      }

      result.value = numberParser(resolution.value)
    }

    return result
  }

  /**
     * @private
     * The portions of the Globalize parsing library we use only need the first letters for internationalization culture
     */
  private getCultureFormattedForGlobalize (culture: string): string {
    return culture.slice(0, 2).toLowerCase()
  }
}