import ParameterType from './ParameterType.js'

export default class ParameterTypeMatcher {
  private readonly match: RegExpExecArray | null

  constructor(
    public readonly parameterType: ParameterType<unknown>,
    private readonly regexpString: string,
    private readonly text: string,
    private matchPosition: number = 0
  ) {
    const captureGroupRegexp = new RegExp(`(${regexpString})`)
    this.match = captureGroupRegexp.exec(text.slice(this.matchPosition))
  }

  public advanceTo(newMatchPosition: number) {
    for (let advancedPos = newMatchPosition; advancedPos < this.text.length; advancedPos++) {
      const matcher = new ParameterTypeMatcher(
        this.parameterType,
        this.regexpString,
        this.text,
        advancedPos
      )

      if (matcher.find) {
        return matcher
      }
    }

    return new ParameterTypeMatcher(
      this.parameterType,
      this.regexpString,
      this.text,
      this.text.length
    )
  }

  get find() {
    return this.match && this.group !== '' && this.fullWord
  }

  get start() {
    if (!this.match) throw new Error('No match')
    return this.matchPosition + this.match.index
  }

  get fullWord() {
    return this.matchStartWord && this.matchEndWord
  }

  get matchStartWord() {
    return this.start === 0 || this.text[this.start - 1].match(/\p{Z}|\p{P}|\p{S}/u)
  }

  get matchEndWord() {
    const nextCharacterIndex = this.start + this.group.length
    return (
      nextCharacterIndex === this.text.length ||
      this.text[nextCharacterIndex].match(/\p{Z}|\p{P}|\p{S}/u)
    )
  }

  get group() {
    if (!this.match) throw new Error('No match')
    return this.match[0]
  }

  public static compare(a: ParameterTypeMatcher, b: ParameterTypeMatcher) {
    const posComparison = a.start - b.start
    if (posComparison !== 0) {
      return posComparison
    }
    const lengthComparison = b.group.length - a.group.length
    if (lengthComparison !== 0) {
      return lengthComparison
    }
    return 0
  }
}