import { GetServerSideProps, NextApiHandler, NextApiRequest } from 'next'
import React, { useEffect, useState } from 'react'
import Footer from '../../../../components/footer'
import Header from '../../../../components/header'
import Input from '../../../../components/input'
import Select from '../../../../components/select'
import { AdditionalCost, BillDocument } from '../../../../db/bill'
import { BookingDocument } from '../../../../db/booking'
import { BILL_STATUS, MILAGE_TARIFS } from '../../../../db/enums'
import { getBookingByUUID, getMilageMax } from '../../../../db/index'
import { dateFormatFrontend } from '../../../../helpers/date'
import { getBillTotal } from '../../../../helpers/bill'
import { getBookingStatus } from '../../../../helpers/booking'
import authenticate from '../../../../lib/authenticate'
import withSession from '../../../../lib/session'

export const getServerSideProps: GetServerSideProps = withSession(
  async ({ req, res, params }) => {
    const { uuid: uuids } = params

    const authenticatedUser = authenticate(req, res)
    if (!authenticatedUser) {
      // TODO: not sure if needed
      req?.session.destroy()
      return { props: {} }
    }

    req.session.set('user', authenticatedUser)
    await req.session.save()

    const uuid = Array.isArray(uuids) ? uuids[0] : uuids
    const booking = await getBookingByUUID(uuid)

    if (!booking) {
      res.statusCode = 404
      res.end()
      return { props: {} }
    }

    const milageMax = await getMilageMax()
    await booking.populate('booker').populate('bill').execPopulate()

    // TODO: hack, not sure why _id is not serilizable
    const bookingJSON = JSON.parse(JSON.stringify(booking.toJSON()))
    return {
      props: { booking: bookingJSON, milageMax },
    }
  }
)

const milageTarifOptions = Object.values(MILAGE_TARIFS).map((tarif) => {
  return (
    <option value={tarif} key={tarif}>
      {getTarifLabel(tarif)}
    </option>
  )
})

const bookingStatusOptions = Object.values(BILL_STATUS).map((status) => {
  return (
    <option value={status} key={status}>
      {getBillStatusLabel(status)}
    </option>
  )
})

function getTarifLabel(tarif: MILAGE_TARIFS) {
  switch (tarif) {
    case MILAGE_TARIFS.EXTERN:
      return 'Extern'
    case MILAGE_TARIFS.INTERN:
      return 'Intern'
    case MILAGE_TARIFS.NOCHARGE:
      return 'Frei von Kosten'
    default:
      return 'Keine'
  }
}

function getBillStatusLabel(status: BILL_STATUS) {
  switch (status) {
    case BILL_STATUS.UNINVOICED:
      return 'Nicht gestellt'
    case BILL_STATUS.INVOICED:
      return 'Gestellt'
    case BILL_STATUS.PAID:
      return 'Bezahlt'
    default:
      return 'Unbekannt!!!'
  }
}

async function saveBill(
  booking: BookingDocument,
  bill: {
    milageStart: number
    milageEnd: number
    milage?: number
    tarif: MILAGE_TARIFS
    additionalCosts: AdditionalCost[]
    status: BILL_STATUS
  }
): Promise<BillDocument> {
  const response = await fetch(`/api/booking/${booking.uuid}/bill`, {
    method: booking.bill?._id ? 'PATCH' : 'POST',
    mode: 'cors',
    cache: 'no-cache',
    credentials: 'same-origin',
    headers: {
      'Content-Type': 'application/json',
    },
    referrerPolicy: 'no-referrer',
    body: JSON.stringify(bill),
  })
  return response.json()
}

export default function BillPage({
  booking: bookingProp,
  milageMax,
}: {
  booking: BookingDocument
  milageMax: number
}) {
  const [booking, setBooking] = useState(bookingProp)
  const [milageStart, setMilageStart] = useState(
    booking?.bill?.milageStart || milageMax
  )
  const [milageEnd, setMilageEnd] = useState(booking?.bill?.milageEnd)
  const [tarif, setTarif] = useState(
    booking?.bill?.tarif || MILAGE_TARIFS.EXTERN
  )
  const [status, setStatus] = useState(booking?.bill?.status)
  const [additionalCosts, setAdditionalCosts] = useState([])
  const [storingInProgress, setStoringInProgress] = useState(false)
  const [storingError, setStoringError] = useState(null)
  const milage =
    (0 < milageStart && milageStart < milageEnd && milageEnd - milageStart) || 0
  const total = getBillTotal({ tarif, milage, additionalCosts })

  // in case the props change, update the internal state
  useEffect(() => setBooking(bookingProp), [bookingProp])

  const onSubmit = async (event: React.FormEvent<HTMLFormElement>) => {
    event.preventDefault()
    setStoringInProgress(true)
    setStoringError(null)

    try {
      const bill = await saveBill(booking, {
        milageStart,
        milageEnd,
        milage,
        tarif,
        status,
        additionalCosts,
      })

      booking.bill = bill
      setBooking(booking)
    } catch (error) {
      setStoringError('Buchung konnte nicht gespeichert werden!')
      console.error('Failed to store booking', error)
    }
    setStoringInProgress(false)
  }

  const onAddAdditionalCost = function (
    event: React.MouseEvent<HTMLButtonElement>
  ) {
    event.preventDefault()
    setAdditionalCosts([...additionalCosts, { name: '', value: 0 }])
  }

  const onRemoveAdditionalCost = function (
    event: React.MouseEvent<HTMLButtonElement>,
    index: number
  ) {
    event.preventDefault()
    setAdditionalCosts([
      ...additionalCosts.slice(0, index),
      ...additionalCosts.slice(index + 1),
    ])
  }

  return (
    <div className="mx-3 flex flex-col min-h-screen">
      <Header />
      <main className="flex-grow">
        <h2 className="text-3xl">Abrechnung</h2>
        {booking && (
          <form className="form" onSubmit={onSubmit}>
            <div>
              <strong>Buchungszeitraum:</strong>{' '}
              {dateFormatFrontend(new Date(booking.startDate))} -{' '}
              {dateFormatFrontend(new Date(booking.endDate))}
            </div>
            <div>
              <strong>Bucher:</strong> {booking.booker.name}
            </div>
            <div>
              <strong>Buchungsstatus:</strong> {getBookingStatus(booking)}
            </div>
            <div>
              <Input
                label="Anfangskilometer"
                name="milageStart"
                required
                value={milageStart}
                type="number"
                onChange={(e: React.ChangeEvent<React.ElementRef<'input'>>) =>
                  setMilageStart(Number(e.target.value))
                }
              />
              <Input
                label="Endkilometer"
                name="milageEnd"
                required
                value={milageEnd}
                type="number"
                onChange={(e: React.ChangeEvent<React.ElementRef<'input'>>) =>
                  setMilageEnd(Number(e.target.value))
                }
              />
              <Input label="Gefahren" name="milage" readOnly value={milage} />
              <Select
                label="Rate"
                value={tarif}
                onChange={(e) => setTarif(e.target.value as MILAGE_TARIFS)}
              >
                {milageTarifOptions}
              </Select>
              <div className="mb-3">
                <button
                  className="ibtn btn-gray mr-3"
                  onClick={onAddAdditionalCost}
                  title="Zusätzliche Kosten hinzufügen"
                >
                  +
                </button>
                <label className="flabel inline">Zusätzliche Kosten</label>
              </div>
              {additionalCosts.map((_, index) => {
                return (
                  <>
                    <div className="mb-3" key={`label${index}`}>
                      <button
                        className="ibtn btn-gray mr-3"
                        onClick={(event) =>
                          onRemoveAdditionalCost(event, index)
                        }
                        title="Entfernen"
                      >
                        -
                      </button>
                      <label className="flabel inline">{`Kostenpunkt ${
                        index + 1
                      }`}</label>
                    </div>
                    <div className="ml-10 mb-3" key={`input{index}`}>
                      <Input
                        label={`Name`}
                        name={`additionalCostName${index}`}
                        key={`additionalCostName${index}`}
                        value={additionalCosts[index].name}
                        onChange={(event) => {
                          const newAdditonalCosts = [...additionalCosts]
                          newAdditonalCosts[index] = {
                            value: newAdditonalCosts[index].value,
                            name: event.target.value,
                          }
                          setAdditionalCosts(newAdditonalCosts)
                        }}
                      />
                      <Input
                        label={`Betrag`}
                        name={`additionalCostValue${index}`}
                        key={`additionalCostValue${index}`}
                        value={additionalCosts[index].value}
                        type="number"
                        onChange={(event) => {
                          const newAdditonalCosts = [...additionalCosts]
                          newAdditonalCosts[index] = {
                            name: newAdditonalCosts[index].name,
                            value: Number(event.target.value),
                          }
                          setAdditionalCosts(newAdditonalCosts)
                        }}
                      />
                    </div>
                  </>
                )
              })}
              <Input label="Summe" name="total" readOnly value={total} />
            </div>
            <Select
              label="Status"
              value={status}
              onChange={(e) => setStatus(e.target.value as BILL_STATUS)}
            >
              {bookingStatusOptions}
            </Select>
            {storingError && (
              <div className="error-message flex-grow mt-6">{storingError}</div>
            )}
            <button
              type="submit"
              className="btn btn-blue mt-3"
              disabled={storingInProgress}
            >
              Rechnung {booking.bill?._id ? 'Updaten' : 'Erstellen'}
            </button>
          </form>
        )}
      </main>

      <Footer />
    </div>
  )
}