import { config } from '../config.js'
import { withLocks } from './keyedLock.js'
import { getDocument, updateDocument } from './appwriteAdmin.js'

/**
 * Zeit fuer ein Git-Push-Arbeitsblatt eintragen (Push-Zeitmail). Ergebnis wie "Zeit nachtragen" in
 * WOMS: Startzeit = Push-Zeit (Endzeit) minus Dauer, totalTime = Minuten, isComment = false.
 * Eine schon eingetragene Zeit wird nie ueberschrieben - Aendern geht nur in WOMS.
 */

export const MAX_MINUTES = 720

const pad = (n) => String(n).padStart(2, '0')

/**
 * Wand-Uhrzeit rueckwaerts rechnen ('tt.mm.jjjj', 'hhmm'); reine Kalenderrechnung, ohne Zeitzone
 * (wie "Zeit nachtragen" in WOMS). Ungueltiges Datum/Uhrzeit -> null.
 */
export function startFromEnd(endDate, endTime, minutes) {
  const date = String(endDate || '').match(/^(\d{2})\.(\d{2})\.(\d{4})$/)
  const time = String(endTime || '').match(/^(\d{2})(\d{2})$/)
  if (!date || !time) return null
  const [day, month, year] = [Number(date[1]), Number(date[2]), Number(date[3])]
  const [hours, mins] = [Number(time[1]), Number(time[2])]
  const end = new Date(Date.UTC(year, month - 1, day, hours, mins))
  // 31.02. o. ae. rollt in Date.UTC weiter - dann ist das Datum ungueltig
  if (end.getUTCDate() !== day || end.getUTCMonth() !== month - 1 || hours > 23 || mins > 59) return null
  const start = new Date(end.getTime() - minutes * 60 * 1000)
  return {
    startDate: `${pad(start.getUTCDate())}.${pad(start.getUTCMonth() + 1)}.${start.getUTCFullYear()}`,
    startTime: `${pad(start.getUTCHours())}${pad(start.getUTCMinutes())}`,
  }
}

/** Git-Push ohne eingetragene Zeit (wie needsTimeEntry in WOMS) */
export function needsTimeEntry(ws) {
  return ws?.serviceType === 'GIT' && !(ws.startTime && Number(ws.totalTime) > 0)
}

/** Ganze Minuten 1-720 aus Formular/Query, sonst null */
export function parseMinutes(raw) {
  if (raw === null || raw === undefined) return null
  const text = String(raw).trim()
  if (!/^\d+$/.test(text)) return null
  const value = Number(text)
  return value >= 1 && value <= MAX_MINUTES ? value : null
}

/** 15 -> '15 Min', 60 -> '1 Std', 90 -> '1,5 Std', 130 -> '2 Std 10 Min' */
export function formatMinutes(min) {
  const total = Number(min) || 0
  if (total < 60) return `${total} Min`
  const hours = Math.floor(total / 60)
  const rest = total % 60
  if (rest === 0) return `${hours} Std`
  if (rest === 30) return `${hours},5 Std`
  return `${hours} Std ${rest} Min`
}

/**
 * @returns {Promise<{ status: 'saved' | 'already' | 'missing' | 'not_git' | 'invalid', worksheet?: object }>}
 *   invalid: Push-Datum/-Uhrzeit im Arbeitsblatt unbrauchbar (nichts gespeichert).
 *   Andere Appwrite-Fehler als 404 werden weitergeworfen.
 */
export async function applyPushTime(worksheetId, minutes) {
  return withLocks([`ws-time:${worksheetId}`], async () => {
    let ws
    try {
      ws = await getDocument(config.collections.worksheets, worksheetId)
    } catch (err) {
      if (err?.status === 404) return { status: 'missing' }
      throw err
    }
    if (ws.serviceType !== 'GIT') return { status: 'not_git', worksheet: ws }
    if (!needsTimeEntry(ws)) return { status: 'already', worksheet: ws }

    const start = startFromEnd(ws.endDate, ws.endTime, minutes)
    if (!start) return { status: 'invalid', worksheet: ws }
    const { startDate, startTime } = start
    const worksheet = await updateDocument(config.collections.worksheets, worksheetId, {
      startDate,
      startTime,
      totalTime: minutes,
      isComment: false,
    })
    return { status: 'saved', worksheet }
  })
}