import { useEffect, useState, type FormEvent } from 'react'
import { useNavigate } from 'react-router-dom'
import { apiFetch, ApiError } from '../api'
import { useAuth } from '../AuthContext'

interface Route {
  id: number
  name: string
}

interface PurchaseRound {
  id: number
  name: string
  status: 'draft' | 'open' | 'closed'
  opens_at: string | null
  order_deadline_at: string | null
  pickup_at: string | null
  route_id: number
}

const statusLabels: Record<PurchaseRound['status'], string> = {
  draft: 'Kladde',
  open: 'Åben',
  closed: 'Lukket',
}

function formatDate(iso: string | null): string {
  return iso ? new Date(iso).toLocaleDateString('da-DK') : ''
}

function formatDateTime(iso: string | null): string {
  return iso ? new Date(iso).toLocaleString('da-DK') : ''
}

export function RoundsPage() {
  const navigate = useNavigate()
  const { currentUser, isElevated, elevatedToken } = useAuth()
  const [routeId, setRouteId] = useState<number | null>(null)
  const [rounds, setRounds] = useState<PurchaseRound[]>([])
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [newName, setNewName] = useState('')

  async function loadRounds(forRouteId: number) {
    setLoading(true)
    setError(null)
    try {
      const data = await apiFetch<PurchaseRound[]>(`/purchase-rounds?route_id=${forRouteId}&limit=500`)
      setRounds(data)
    } catch (err) {
      setError(err instanceof ApiError ? err.message : 'Kunne ikke hente runder')
    } finally {
      setLoading(false)
    }
  }

  useEffect(() => {
    apiFetch<Route[]>('/routes')
      .then((routes) => {
        if (routes.length === 0) {
          setError('Ingen ruter fundet for din organisation')
          setLoading(false)
          return
        }
        setRouteId(routes[0].id)
        return loadRounds(routes[0].id)
      })
      .catch((err) => {
        setError(err instanceof ApiError ? err.message : 'Kunne ikke hente ruter')
        setLoading(false)
      })
  }, [])

  async function handleCreate(event: FormEvent) {
    event.preventDefault()
    if (routeId === null) return
    setError(null)
    try {
      const created = await apiFetch<PurchaseRound>('/purchase-rounds', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ name: newName, route_id: routeId }),
      })
      navigate(`/runder/${created.id}`)
    } catch (err) {
      setError(err instanceof ApiError ? err.message : 'Kunne ikke oprette runde')
    }
  }

  async function handleCopy(round: PurchaseRound) {
    setError(null)
    try {
      const copy = await apiFetch<PurchaseRound>(`/purchase-rounds/${round.id}/copy`, { method: 'POST' })
      navigate(`/runder/${copy.id}`)
    } catch (err) {
      setError(err instanceof ApiError ? err.message : 'Kunne ikke kopiere runden')
    }
  }

  async function handleDelete(round: PurchaseRound) {
    if (routeId === null) return
    if (!window.confirm(`Slet "${round.name}"?`)) return
    setError(null)
    try {
      const token = round.status === 'closed' ? elevatedToken : undefined
      await apiFetch(`/purchase-rounds/${round.id}`, { method: 'DELETE' }, token)
      await loadRounds(routeId)
    } catch (err) {
      setError(err instanceof ApiError ? err.message : 'Kunne ikke slette runden')
    }
  }

  if (loading) return <p>Indlæser...</p>

  return (
    <div>
      <h1>Runder</h1>
      {error && <p className="error">{error}</p>}

      <form onSubmit={handleCreate} className="inline-form">
        <input placeholder="Navn på ny runde" value={newName} onChange={(e) => setNewName(e.target.value)} required />
        <button type="submit">Ny runde</button>
      </form>

      <table>
        <thead>
          <tr>
            <th>Navn</th>
            <th>Status</th>
            <th>Åbner</th>
            <th>Bestillingsfrist</th>
            <th>Afhentning</th>
            <th>Handlinger</th>
          </tr>
        </thead>
        <tbody>
          {rounds.map((round) => (
            <tr key={round.id}>
              <td>{round.name}</td>
              <td>{statusLabels[round.status]}</td>
              <td>{formatDate(round.opens_at)}</td>
              <td>{formatDate(round.order_deadline_at)}</td>
              <td>{formatDateTime(round.pickup_at)}</td>
              <td>
                <button onClick={() => navigate(`/runder/${round.id}`)}>Redigér</button>
                <button onClick={() => handleCopy(round)}>Kopiér</button>
                {(round.status === 'draft' ||
                  (round.status === 'closed' && currentUser?.is_superadmin && isElevated)) && (
                  <button onClick={() => handleDelete(round)}>Slet</button>
                )}
              </td>
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  )
}