import { getConfig, getWorkforceShifts, upsertWorkforceShifts } from '../db.js'
import { fetchShifts, fetchTimesheetShifts } from './workforce.js'

function fmtDate(d) {
  return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}-${String(d.getDate()).padStart(2, '0')}`
}

export async function runRotaSync() {
  const deptIds = (await getConfig('workforce_departments', [])) || []
  if (!deptIds.length) throw new Error('No HK departments selected — configure in Category Settings')

  const today = new Date()
  const fromDate = new Date(today); fromDate.setDate(fromDate.getDate() - 7)
  const toDate   = new Date(today); toDate.setDate(toDate.getDate() + 28)
  const from = fmtDate(fromDate)
  const to   = fmtDate(toDate)

  // API limit: max 7 days per request — split into weekly chunks
  const chunks = []
  const cur = new Date(fromDate)
  while (cur <= toDate) {
    const chunkFrom = fmtDate(cur)
    const chunkToDate = new Date(cur)
    chunkToDate.setDate(chunkToDate.getDate() + 6)
    if (chunkToDate > toDate) chunkToDate.setTime(toDate.getTime())
    chunks.push({ from: chunkFrom, to: fmtDate(chunkToDate) })
    cur.setDate(cur.getDate() + 7)
  }

  const staffMap = {}
  for (const chunk of chunks) {
    const chunkStaff = await fetchShifts(chunk.from, chunk.to, deptIds)
    for (const member of chunkStaff) {
      if (!staffMap[member.id]) staffMap[member.id] = { id: member.id, name: member.name, days: {} }
      Object.assign(staffMap[member.id].days, member.days)
    }
  }

  const byDate = {}
  for (const member of Object.values(staffMap)) {
    for (const [date, shift] of Object.entries(member.days)) {
      if (!byDate[date]) byDate[date] = []
      byDate[date].push({ id: member.id, name: member.name, hours: shift.hours, times: shift.times })
    }
  }

  // Skip dates already replaced with timesheet actuals
  const existing = await getWorkforceShifts(from, to)
  const timesheetDates = new Set(
    Object.entries(existing).filter(([, d]) => d.source === 'timesheet').map(([date]) => date)
  )

  const dailyRows = []
  const day = new Date(fromDate)
  while (day <= toDate) {
    const d = fmtDate(day)
    if (!timesheetDates.has(d)) dailyRows.push({ date: d, staff: byDate[d] || [], source: 'workforce' })
    day.setDate(day.getDate() + 1)
  }

  await upsertWorkforceShifts(dailyRows)
  return { ok: true, from, to, dates_synced: dailyRows.length }
}

export async function runTimesheetSync(days = 7) {
  const deptIds = (await getConfig('workforce_departments', [])) || []
  if (!deptIds.length) throw new Error('No HK departments selected — configure in Category Settings')

  const today = new Date()
  const fromDate = new Date(today); fromDate.setDate(fromDate.getDate() - days)
  const from = fmtDate(fromDate)
  const to   = fmtDate(today)

  const staffList = await fetchTimesheetShifts(from, to, deptIds)

  const byDate = {}
  for (const member of staffList) {
    for (const [date, shift] of Object.entries(member.days)) {
      if (!byDate[date]) byDate[date] = []
      byDate[date].push({ id: member.id, name: member.name, hours: shift.hours, times: shift.times, status: shift.status })
    }
  }

  const dailyRows = []
  const day = new Date(fromDate)
  while (day <= today) {
    const d = fmtDate(day)
    dailyRows.push({ date: d, staff: byDate[d] || [], source: 'timesheet' })
    day.setDate(day.getDate() + 1)
  }

  await upsertWorkforceShifts(dailyRows)
  return { ok: true, from, to, dates_synced: dailyRows.length }
}