import { date, datatype } from 'faker'

import { BioimpedanceWithWeight } from '../models'
import { CompetitionCompetitor, CompetitionHistory } from '../../../models/ranking'

import { DecreaseActualWeightCalculator } from './decrease-actual-weight.calculator'

describe('DecreaseActualWeightCalculator', () => {
  describe('#calcule', () => {
    const bioimpedance = BioimpedanceWithWeight.toInstance({})
    const competitor = CompetitionCompetitor.toInstance({})
    let weight = 0
    let history: CompetitionHistory[]

    beforeEach(() => {
      bioimpedance.weight = weight
      competitor.history = history
    })

    describe('when the value is null', () => {
      beforeAll(() => {
        weight = null
      })

      it('returns the values with 0', () => {
        expect(DecreaseActualWeightCalculator.calcule({ bioimpedance, competitor })).toEqual({ value: 0, score: 0 })
      })
    })

    describe('when the value is undefined', () => {
      beforeAll(() => {
        weight = undefined
      })

      it('returns the values with 0', () => {
        expect(DecreaseActualWeightCalculator.calcule({ bioimpedance, competitor })).toEqual({ value: 0, score: 0 })
      })
    })

    describe('when is the first score', () => {
      beforeAll(() => {
        weight = 30
        history = []
      })

      it('returns with the value and score 0', () => {
        expect(DecreaseActualWeightCalculator.calcule({ bioimpedance, competitor })).toEqual({
          value: weight,
          score: 0,
        })
      })
    })

    describe('when is not the first score', () => {
      let previousValue: number

      beforeAll(() => {
        weight = 30
        previousValue = datatype.number({ min: weight, max: 100 })
        history = [CompetitionHistory.toInstance({ done_at: new Date(), value: previousValue })]
      })

      it('returns with the value and score calculed', () => {
        const score = ((previousValue - weight) * 100) / previousValue

        expect(DecreaseActualWeightCalculator.calcule({ bioimpedance, competitor })).toEqual({ value: weight, score })
      })

      describe('when has more than one history', () => {
        beforeAll(() => {
          weight = 30
          history = [
            CompetitionHistory.toInstance({ done_at: date.past(), value: previousValue }),
            CompetitionHistory.toInstance({ done_at: date.recent(), value: previousValue * 10 }),
          ]
        })

        it('returns with the value and score calculed with the first value from history', () => {
          const score = ((previousValue - weight) * 100) / previousValue

          expect(DecreaseActualWeightCalculator.calcule({ bioimpedance, competitor })).toEqual({ value: weight, score })
        })
      })
    })
  })
})