import { useRef, useState } from 'react'
import { createFileRoute, Link, redirect, useRouter } from '@tanstack/react-router'

import { StaffTabs } from '#/components/staff-tabs'
import { getCurrentStaffUser } from '#/lib/auth'
import { authClient } from '#/lib/auth-client'
import { getTables, setTableMarker } from '#/lib/reservations'
import { getReservationSettings, updateReservationSettings } from '#/lib/settings'
import { ACCEPTED_IMAGE_TYPES, MAX_TABLE_IMAGE_BYTES, readImageAsDataUrl } from '#/lib/table-image'

export const Route = createFileRoute('/staff/settings')({
  component: StaffSettings,
  beforeLoad: async () => {
    const staffUser = await getCurrentStaffUser()
    if (!staffUser) {
      throw redirect({ to: '/staff/login' })
    }
    if (staffUser.role !== 'admin') {
      throw redirect({ to: '/staff' })
    }
    return { staffUser }
  },
  loader: async ({ context }) => {
    const [settings, tables] = await Promise.all([getReservationSettings(), getTables()])
    return { staffUser: context.staffUser, settings, tables }
  },
})

type FormState = {
  reservationIntervalMinutes: number
  reservationDurationMinutes: number
  minLeadTimeMinutes: number
  maxLeadTimeDays: number
  tableDisplayMode: 'individual' | 'overview'
  tableOverviewImageUrl: string | null
}

const MAX_IMAGE_MB = Math.floor(MAX_TABLE_IMAGE_BYTES / 1_000_000)

function StaffSettings() {
  const router = useRouter()
  const { staffUser, settings, tables } = Route.useLoaderData()

  const [form, setForm] = useState<FormState>({
    reservationIntervalMinutes: settings.reservationIntervalMinutes,
    reservationDurationMinutes: settings.reservationDurationMinutes,
    minLeadTimeMinutes: settings.minLeadTimeMinutes,
    maxLeadTimeDays: settings.maxLeadTimeDays,
    tableDisplayMode: settings.tableDisplayMode === 'overview' ? 'overview' : 'individual',
    tableOverviewImageUrl: settings.tableOverviewImageUrl,
  })
  const [error, setError] = useState<string | null>(null)
  const [success, setSuccess] = useState<string | null>(null)
  const [isSubmitting, setIsSubmitting] = useState(false)
  const overviewFileInputRef = useRef<HTMLInputElement>(null)
  const [markerTableId, setMarkerTableId] = useState<string>('')
  const [isPlacingMarker, setIsPlacingMarker] = useState(false)
  const [markerError, setMarkerError] = useState<string | null>(null)
  const [markerSuccess, setMarkerSuccess] = useState<string | null>(null)

  const markerTable = tables.find((table) => String(table.id) === markerTableId)
  const tablesWithoutMarker = tables.filter((table) => table.markerX === null || table.markerY === null)

  async function handleLogout() {
    await authClient.signOut()
    await router.navigate({ to: '/staff/login' })
    await router.invalidate()
  }

  async function handleOverviewImageChange(event: React.ChangeEvent<HTMLInputElement>) {
    const file = event.target.files?.[0]
    event.target.value = ''
    if (!file) return

    if (!ACCEPTED_IMAGE_TYPES.includes(file.type)) {
      setError('Bild muss PNG, JPEG oder WebP sein')
      return
    }

    if (file.size > MAX_TABLE_IMAGE_BYTES) {
      setError(`Bild ist zu groß (max. ${MAX_IMAGE_MB} MB)`)
      return
    }

    setError(null)
    const dataUrl = await readImageAsDataUrl(file)
    setForm((f) => ({ ...f, tableOverviewImageUrl: dataUrl }))
  }

  async function handlePlaceMarker(event: React.MouseEvent<HTMLDivElement>) {
    if (!markerTable) {
      setMarkerError('Bitte zuerst einen Tisch für den Marker auswählen')
      return
    }

    const rect = event.currentTarget.getBoundingClientRect()
    const x = Math.min(100, Math.max(0, ((event.clientX - rect.left) / rect.width) * 100))
    const y = Math.min(100, Math.max(0, ((event.clientY - rect.top) / rect.height) * 100))

    setMarkerError(null)
    setMarkerSuccess(null)
    setIsPlacingMarker(true)
    try {
      await setTableMarker({ data: { id: markerTable.id, marker: { x, y } } })
      setMarkerSuccess(`Marker für ${markerTable.name} wurde gesetzt.`)
      await router.invalidate()
    } catch (err) {
      setMarkerError(err instanceof Error ? err.message : 'Etwas ist schiefgelaufen')
    } finally {
      setIsPlacingMarker(false)
    }
  }

  async function handleClearMarker() {
    if (!markerTable) return

    setMarkerError(null)
    setMarkerSuccess(null)
    setIsPlacingMarker(true)
    try {
      await setTableMarker({ data: { id: markerTable.id, marker: null } })
      setMarkerSuccess(`Marker für ${markerTable.name} wurde entfernt.`)
      await router.invalidate()
    } catch (err) {
      setMarkerError(err instanceof Error ? err.message : 'Etwas ist schiefgelaufen')
    } finally {
      setIsPlacingMarker(false)
    }
  }

  async function handleSubmit(event: React.FormEvent) {
    event.preventDefault()
    setError(null)
    setSuccess(null)
    setIsSubmitting(true)

    try {
      await updateReservationSettings({ data: form })
      setSuccess('Einstellungen wurden gespeichert.')
      await router.invalidate()
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Etwas ist schiefgelaufen')
    } finally {
      setIsSubmitting(false)
    }
  }

  return (
    <div className="staff-page">
      <div className="staff-nav">
        <header className="staff-topbar">
          <Link className="wordmark" to="/">
            Steakhaus <span>bei Mirko</span>
          </Link>
          <div className="staff-topbar-right">
            <span>Angemeldet als {staffUser.name}</span>
            <button type="button" className="btn btn-secondary" onClick={handleLogout}>
              Abmelden
            </button>
          </div>
        </header>

        <div className="staff-tabs-bar">
          <StaffTabs role={staffUser.role} />
        </div>
      </div>

      <main className="page staff-main">
        <h1 className="section-heading">Einstellungen</h1>

        <section className="staff-form-section">
          <h2 className="section-heading staff-subheading">Reservierungsregeln</h2>

          <form className="reservation-form" onSubmit={handleSubmit}>
            <label>
              Reservierungsintervall (Minuten)
              <input
                type="number"
                inputMode="numeric"
                min={5}
                max={120}
                step={5}
                value={form.reservationIntervalMinutes}
                onChange={(e) => setForm((f) => ({ ...f, reservationIntervalMinutes: Number(e.target.value) }))}
                required
              />
            </label>
            <p className="field-hint">Abstand zwischen den wählbaren Uhrzeiten im Buchungsformular.</p>

            <label>
              Reservierungsdauer (Minuten)
              <input
                type="number"
                inputMode="numeric"
                min={15}
                max={480}
                step={15}
                value={form.reservationDurationMinutes}
                onChange={(e) => setForm((f) => ({ ...f, reservationDurationMinutes: Number(e.target.value) }))}
                required
              />
            </label>
            <p className="field-hint">
              Wie lange ein Tisch nach einer Reservierung als belegt gilt — verhindert überlappende Buchungen.
            </p>

            <label>
              Mindestvorlaufzeit (Minuten)
              <input
                type="number"
                inputMode="numeric"
                min={0}
                max={10080}
                step={15}
                value={form.minLeadTimeMinutes}
                onChange={(e) => setForm((f) => ({ ...f, minLeadTimeMinutes: Number(e.target.value) }))}
                required
              />
            </label>
            <p className="field-hint">
              Wie kurzfristig frühestens reserviert werden kann, z. B. 60 für „mindestens eine Stunde im Voraus“.
            </p>

            <label>
              Buchbar bis zu (Tage im Voraus)
              <input
                type="number"
                inputMode="numeric"
                min={1}
                max={365}
                step={1}
                value={form.maxLeadTimeDays}
                onChange={(e) => setForm((f) => ({ ...f, maxLeadTimeDays: Number(e.target.value) }))}
                required
              />
            </label>
            <p className="field-hint">
              Wie weit im Voraus reserviert werden kann, z. B. 60 für „höchstens 60 Tage im Voraus“.
            </p>

            <fieldset className="table-display-fieldset">
              <legend>Tischfotos im Buchungsformular</legend>
              <label className="radio-option">
                <input
                  type="radio"
                  name="tableDisplayMode"
                  checked={form.tableDisplayMode === 'individual'}
                  onChange={() => setForm((f) => ({ ...f, tableDisplayMode: 'individual' }))}
                />
                Foto des gewählten Tisches
              </label>
              <label className="radio-option">
                <input
                  type="radio"
                  name="tableDisplayMode"
                  checked={form.tableDisplayMode === 'overview'}
                  onChange={() => setForm((f) => ({ ...f, tableDisplayMode: 'overview' }))}
                />
                Ein Übersichtsfoto für alle Tische
              </label>
            </fieldset>
            <p className="field-hint">
              „Foto des gewählten Tisches“ zeigt das jeweilige Foto aus der Tischverwaltung, sobald ein
              Tisch ausgewählt wird. „Übersichtsfoto“ zeigt stattdessen immer dasselbe Bild, z. B. eine
              Aufnahme des ganzen Raums.
            </p>

            {form.tableDisplayMode === 'overview' && (
              <>
                <label>
                  Übersichtsfoto
                  <div className="table-image-field">
                    {form.tableOverviewImageUrl && (
                      <img className="table-image-preview" src={form.tableOverviewImageUrl} alt="" />
                    )}
                    <input
                      ref={overviewFileInputRef}
                      type="file"
                      accept="image/png,image/jpeg,image/webp"
                      onChange={handleOverviewImageChange}
                    />
                    {form.tableOverviewImageUrl && (
                      <button
                        type="button"
                        className="btn btn-secondary"
                        onClick={() => setForm((f) => ({ ...f, tableOverviewImageUrl: null }))}
                      >
                        Bild entfernen
                      </button>
                    )}
                  </div>
                </label>
                <p className="field-hint">PNG, JPEG oder WebP, max. {MAX_IMAGE_MB} MB.</p>
              </>
            )}

            <button type="submit" disabled={isSubmitting}>
              {isSubmitting ? 'Wird gespeichert …' : 'Speichern'}
            </button>

            {error && <p className="message message-error">{error}</p>}
            {success && <p className="message message-success">{success}</p>}
          </form>
        </section>

        {settings.tableDisplayMode === 'overview' && settings.tableOverviewImageUrl && (
          <section className="staff-form-section">
            <h2 className="section-heading staff-subheading">Tisch-Marker</h2>
            <p className="field-hint">
              Wählen Sie einen Tisch aus und klicken Sie dann auf das gespeicherte Übersichtsfoto, um
              seinen Marker zu setzen oder zu verschieben.
            </p>

            <div className="reservation-form">
              <label>
                Marker setzen für
                <select value={markerTableId} onChange={(e) => setMarkerTableId(e.target.value)}>
                  <option value="" disabled>
                    Tisch auswählen
                  </option>
                  {tables.map((table) => (
                    <option key={table.id} value={table.id}>
                      {table.tableNumber === null ? table.name : `${table.tableNumber} — ${table.name}`}
                      {table.markerX === null || table.markerY === null ? '' : ' ✓'}
                    </option>
                  ))}
                </select>
              </label>

              <div
                className={`table-overview-wrap${isPlacingMarker ? ' is-busy' : ''}`}
                onClick={handlePlaceMarker}
              >
                <img className="table-overview-image" src={settings.tableOverviewImageUrl} alt="" />
                {tables
                  .filter((table) => table.markerX !== null && table.markerY !== null)
                  .map((table) => (
                    <span
                      key={table.id}
                      className={`table-marker${String(table.id) === markerTableId ? ' is-active' : ''}`}
                      style={{ left: `${table.markerX}%`, top: `${table.markerY}%` }}
                    >
                      <span className="table-marker-label">{table.tableNumber ?? '?'}</span>
                    </span>
                  ))}
              </div>

              {markerTable && (markerTable.markerX !== null || markerTable.markerY !== null) && (
                <button
                  type="button"
                  className="btn btn-secondary"
                  disabled={isPlacingMarker}
                  onClick={handleClearMarker}
                >
                  Marker für {markerTable.name} entfernen
                </button>
              )}

              {tablesWithoutMarker.length > 0 && (
                <p className="field-hint">
                  Noch ohne Marker: {tablesWithoutMarker.map((table) => table.name).join(', ')}
                </p>
              )}

              {markerError && <p className="message message-error">{markerError}</p>}
              {markerSuccess && <p className="message message-success">{markerSuccess}</p>}
            </div>
          </section>
        )}
      </main>
    </div>
  )
}