import { useState, useEffect, useRef, useMemo } from 'react'
import Modal from '../shared/Modal'
import CustomSelect from '../shared/CustomSelect'
import { Plane, Hotel, Utensils, Train, Car, Ship, Ticket, FileText, Users, Paperclip, X, ExternalLink, Link2 } from 'lucide-react'
import { useToast } from '../shared/Toast'
import { useTranslation } from '../../i18n'
import { CustomDatePicker } from '../shared/CustomDateTimePicker'
import CustomTimePicker from '../shared/CustomTimePicker'
import type { Day, Place, Reservation, TripFile, AssignmentsMap, Accommodation } from '../../types'

const TYPE_OPTIONS = [
  { value: 'flight',     labelKey: 'reservations.type.flight',     Icon: Plane },
  { value: 'hotel',      labelKey: 'reservations.type.hotel',      Icon: Hotel },
  { value: 'restaurant', labelKey: 'reservations.type.restaurant', Icon: Utensils },
  { value: 'train',      labelKey: 'reservations.type.train',      Icon: Train },
  { value: 'car',        labelKey: 'reservations.type.car',        Icon: Car },
  { value: 'cruise',     labelKey: 'reservations.type.cruise',     Icon: Ship },
  { value: 'event',      labelKey: 'reservations.type.event',      Icon: Ticket },
  { value: 'tour',       labelKey: 'reservations.type.tour',       Icon: Users },
  { value: 'other',      labelKey: 'reservations.type.other',      Icon: FileText },
]

function buildAssignmentOptions(days, assignments, t, locale) {
  const options = []
  for (const day of (days || [])) {
    const da = (assignments?.[String(day.id)] || []).slice().sort((a, b) => a.order_index - b.order_index)
    if (da.length === 0) continue
    const dayLabel = day.title || t('dayplan.dayN', { n: day.day_number })
    const dateStr = day.date ? ` · ${formatDate(day.date, locale)}` : ''
    const groupLabel = `${dayLabel}${dateStr}`
    // Group header (non-selectable)
    options.push({ value: `_header_${day.id}`, label: groupLabel, disabled: true, isHeader: true })
    for (let i = 0; i < da.length; i++) {
      const place = da[i].place
      if (!place) continue
      const timeStr = place.place_time ? ` · ${place.place_time}${place.end_time ? ' – ' + place.end_time : ''}` : ''
      options.push({
        value: da[i].id,
        label: `  ${i + 1}. ${place.name}${timeStr}`,
        searchLabel: place.name,
        groupLabel,
        dayDate: day.date || null,
      })
    }
  }
  return options
}

interface ReservationModalProps {
  isOpen: boolean
  onClose: () => void
  onSave: (data: Record<string, string | number | null>) => Promise<void> | void
  reservation: Reservation | null
  days: Day[]
  places: Place[]
  assignments: AssignmentsMap
  selectedDayId: number | null
  files?: TripFile[]
  onFileUpload: (fd: FormData) => Promise<void>
  onFileDelete: (fileId: number) => Promise<void>
  accommodations?: Accommodation[]
}

export function ReservationModal({ isOpen, onClose, onSave, reservation, days, places, assignments, selectedDayId, files = [], onFileUpload, onFileDelete, accommodations = [] }: ReservationModalProps) {
  const toast = useToast()
  const { t, locale } = useTranslation()
  const fileInputRef = useRef(null)

  const [form, setForm] = useState({
    title: '', type: 'other', status: 'pending',
    reservation_time: '', reservation_end_time: '', location: '', confirmation_number: '',
    notes: '', assignment_id: '', accommodation_id: '',
    meta_airline: '', meta_flight_number: '', meta_departure_airport: '', meta_arrival_airport: '',
    meta_train_number: '', meta_platform: '', meta_seat: '',
    meta_check_in_time: '', meta_check_out_time: '',
    hotel_place_id: '', hotel_start_day: '', hotel_end_day: '',
  })
  const [isSaving, setIsSaving] = useState(false)
  const [uploadingFile, setUploadingFile] = useState(false)
  const [pendingFiles, setPendingFiles] = useState([])

  const assignmentOptions = useMemo(
    () => buildAssignmentOptions(days, assignments, t, locale),
    [days, assignments, t, locale]
  )

  useEffect(() => {
    if (reservation) {
      const meta = typeof reservation.metadata === 'string' ? JSON.parse(reservation.metadata || '{}') : (reservation.metadata || {})
      setForm({
        title: reservation.title || '',
        type: reservation.type || 'other',
        status: reservation.status || 'pending',
        reservation_time: reservation.reservation_time ? reservation.reservation_time.slice(0, 16) : '',
        reservation_end_time: reservation.reservation_end_time || '',
        location: reservation.location || '',
        confirmation_number: reservation.confirmation_number || '',
        notes: reservation.notes || '',
        assignment_id: reservation.assignment_id || '',
        accommodation_id: reservation.accommodation_id || '',
        meta_airline: meta.airline || '',
        meta_flight_number: meta.flight_number || '',
        meta_departure_airport: meta.departure_airport || '',
        meta_arrival_airport: meta.arrival_airport || '',
        meta_train_number: meta.train_number || '',
        meta_platform: meta.platform || '',
        meta_seat: meta.seat || '',
        meta_check_in_time: meta.check_in_time || '',
        meta_check_out_time: meta.check_out_time || '',
        hotel_place_id: (() => { const acc = accommodations.find(a => a.id == reservation.accommodation_id); return acc?.place_id || '' })(),
        hotel_start_day: (() => { const acc = accommodations.find(a => a.id == reservation.accommodation_id); return acc?.start_day_id || '' })(),
        hotel_end_day: (() => { const acc = accommodations.find(a => a.id == reservation.accommodation_id); return acc?.end_day_id || '' })(),
      })
    } else {
      setForm({
        title: '', type: 'other', status: 'pending',
        reservation_time: '', reservation_end_time: '', location: '', confirmation_number: '',
        notes: '', assignment_id: '', accommodation_id: '',
        meta_airline: '', meta_flight_number: '', meta_departure_airport: '', meta_arrival_airport: '',
        meta_train_number: '', meta_platform: '', meta_seat: '',
        meta_check_in_time: '', meta_check_out_time: '',
      })
      setPendingFiles([])
    }
  }, [reservation, isOpen, selectedDayId])

  const set = (field, value) => setForm(prev => ({ ...prev, [field]: value }))

  const handleSubmit = async (e) => {
    e.preventDefault()
    if (!form.title.trim()) return
    setIsSaving(true)
    try {
      const metadata: Record<string, string> = {}
      if (form.type === 'flight') {
        if (form.meta_airline) metadata.airline = form.meta_airline
        if (form.meta_flight_number) metadata.flight_number = form.meta_flight_number
        if (form.meta_departure_airport) metadata.departure_airport = form.meta_departure_airport
        if (form.meta_arrival_airport) metadata.arrival_airport = form.meta_arrival_airport
      } else if (form.type === 'hotel') {
        if (form.meta_check_in_time) metadata.check_in_time = form.meta_check_in_time
        if (form.meta_check_out_time) metadata.check_out_time = form.meta_check_out_time
      } else if (form.type === 'train') {
        if (form.meta_train_number) metadata.train_number = form.meta_train_number
        if (form.meta_platform) metadata.platform = form.meta_platform
        if (form.meta_seat) metadata.seat = form.meta_seat
      }
      const saveData: Record<string, any> = {
        title: form.title, type: form.type, status: form.status,
        reservation_time: form.reservation_time, reservation_end_time: form.reservation_end_time,
        location: form.location, confirmation_number: form.confirmation_number,
        notes: form.notes,
        assignment_id: form.assignment_id || null,
        accommodation_id: form.type === 'hotel' ? (form.accommodation_id || null) : null,
        metadata: Object.keys(metadata).length > 0 ? metadata : null,
      }
      // If hotel with place + days, pass hotel data for auto-creation or update
      if (form.type === 'hotel' && form.hotel_place_id && form.hotel_start_day && form.hotel_end_day) {
        saveData.create_accommodation = {
          place_id: form.hotel_place_id,
          start_day_id: form.hotel_start_day,
          end_day_id: form.hotel_end_day,
          check_in: form.meta_check_in_time || null,
          check_out: form.meta_check_out_time || null,
          confirmation: form.confirmation_number || null,
        }
      }
      const saved = await onSave(saveData)
      if (!reservation?.id && saved?.id && pendingFiles.length > 0) {
        for (const file of pendingFiles) {
          const fd = new FormData()
          fd.append('file', file)
          fd.append('reservation_id', saved.id)
          fd.append('description', form.title)
          await onFileUpload(fd)
        }
      }
    } finally {
      setIsSaving(false)
    }
  }

  const handleFileChange = async (e) => {
    const file = (e.target as HTMLInputElement).files?.[0]
    if (!file) return
    if (reservation?.id) {
      setUploadingFile(true)
      try {
        const fd = new FormData()
        fd.append('file', file)
        fd.append('reservation_id', reservation.id)
        fd.append('description', reservation.title)
        await onFileUpload(fd)
        toast.success(t('reservations.toast.fileUploaded'))
      } catch {
        toast.error(t('reservations.toast.uploadError'))
      } finally {
        setUploadingFile(false)
        e.target.value = ''
      }
    } else {
      setPendingFiles(prev => [...prev, file])
      e.target.value = ''
    }
  }

  const attachedFiles = reservation?.id ? files.filter(f => f.reservation_id === reservation.id) : []

  const inputStyle = {
    width: '100%', border: '1px solid var(--border-primary)', borderRadius: 10,
    padding: '8px 12px', fontSize: 13, fontFamily: 'inherit',
    outline: 'none', boxSizing: 'border-box', color: 'var(--text-primary)', background: 'var(--bg-input)',
  }
  const labelStyle = { display: 'block', fontSize: 11, fontWeight: 600, color: 'var(--text-faint)', marginBottom: 5, textTransform: 'uppercase', letterSpacing: '0.03em' }

  return (
    <Modal isOpen={isOpen} onClose={onClose} title={reservation ? t('reservations.editTitle') : t('reservations.newTitle')} size="2xl">
      <form onSubmit={handleSubmit} style={{ display: 'flex', flexDirection: 'column', gap: 14 }}>

        {/* Type selector */}
        <div>
          <label style={labelStyle}>{t('reservations.bookingType')}</label>
          <div style={{ display: 'flex', flexWrap: 'wrap', gap: 5 }}>
            {TYPE_OPTIONS.map(({ value, labelKey, Icon }) => (
              <button key={value} type="button" onClick={() => set('type', value)} style={{
                display: 'flex', alignItems: 'center', gap: 4,
                padding: '5px 10px', borderRadius: 99, border: '1px solid',
                fontSize: 11, fontWeight: 500, cursor: 'pointer', fontFamily: 'inherit', transition: 'all 0.12s',
                background: form.type === value ? 'var(--text-primary)' : 'var(--bg-card)',
                borderColor: form.type === value ? 'var(--text-primary)' : 'var(--border-primary)',
                color: form.type === value ? 'var(--bg-primary)' : 'var(--text-muted)',
              }}>
                <Icon size={11} /> {t(labelKey)}
              </button>
            ))}
          </div>
        </div>

        {/* Title */}
        <div>
          <label style={labelStyle}>{t('reservations.titleLabel')} *</label>
          <input type="text" value={form.title} onChange={e => set('title', e.target.value)} required
            placeholder={t('reservations.titlePlaceholder')} style={inputStyle} />
        </div>

        {/* Assignment Picker + Date (hidden for hotels) */}
        {form.type !== 'hotel' && (
        <div style={{ display: 'flex', gap: 8 }}>
          {assignmentOptions.length > 0 && (
            <div style={{ flex: 1, minWidth: 0 }}>
              <label style={labelStyle}>
                <Link2 size={10} style={{ display: 'inline', verticalAlign: '-1px', marginRight: 3 }} />
                {t('reservations.linkAssignment')}
              </label>
              <CustomSelect
                value={form.assignment_id}
                onChange={value => {
                  set('assignment_id', value)
                  const opt = assignmentOptions.find(o => o.value === value)
                  if (opt?.dayDate) {
                    setForm(prev => {
                      if (prev.reservation_time) return prev
                      return { ...prev, reservation_time: opt.dayDate }
                    })
                  }
                }}
                placeholder={t('reservations.pickAssignment')}
                options={[
                  { value: '', label: t('reservations.noAssignment') },
                  ...assignmentOptions,
                ]}
                searchable
                size="sm"
              />
            </div>
          )}
          <div style={{ flex: 1, minWidth: 0 }}>
            <label style={labelStyle}>{t('reservations.date')}</label>
            <CustomDatePicker
              value={(() => { const [d] = (form.reservation_time || '').split('T'); return d || '' })()}
              onChange={d => {
                const [, t] = (form.reservation_time || '').split('T')
                set('reservation_time', d ? (t ? `${d}T${t}` : d) : '')
              }}
            />
          </div>
        </div>
        )}

        {/* Start Time + End Time + Status */}
        <div style={{ display: 'flex', gap: 8 }}>
          {form.type !== 'hotel' && (
            <>
              <div style={{ flex: 1, minWidth: 0 }}>
                <label style={labelStyle}>{t('reservations.startTime')}</label>
                <CustomTimePicker
                  value={(() => { const [, t] = (form.reservation_time || '').split('T'); return t || '' })()}
                  onChange={t => {
                    const [d] = (form.reservation_time || '').split('T')
                    const date = d || new Date().toISOString().split('T')[0]
                    set('reservation_time', t ? `${date}T${t}` : date)
                  }}
                />
              </div>
              <div style={{ flex: 1, minWidth: 0 }}>
                <label style={labelStyle}>{t('reservations.endTime')}</label>
                <CustomTimePicker value={form.reservation_end_time} onChange={v => set('reservation_end_time', v)} />
              </div>
            </>
          )}
          <div style={{ flex: 1, minWidth: 0 }}>
            <label style={labelStyle}>{t('reservations.status')}</label>
            <CustomSelect
              value={form.status}
              onChange={value => set('status', value)}
              options={[
                { value: 'pending', label: t('reservations.pending') },
                { value: 'confirmed', label: t('reservations.confirmed') },
              ]}
              size="sm"
            />
          </div>
        </div>

        {/* Location + Booking Code */}
        <div className="grid grid-cols-1 sm:grid-cols-2 gap-3">
          <div>
            <label style={labelStyle}>{t('reservations.locationAddress')}</label>
            <input type="text" value={form.location} onChange={e => set('location', e.target.value)}
              placeholder={t('reservations.locationPlaceholder')} style={inputStyle} />
          </div>
          <div>
            <label style={labelStyle}>{t('reservations.confirmationCode')}</label>
            <input type="text" value={form.confirmation_number} onChange={e => set('confirmation_number', e.target.value)}
              placeholder={t('reservations.confirmationPlaceholder')} style={inputStyle} />
          </div>
        </div>

        {/* Type-specific fields */}
        {form.type === 'flight' && (
          <div className="grid grid-cols-2 sm:grid-cols-4 gap-3">
            <div>
              <label style={labelStyle}>{t('reservations.meta.airline') || 'Airline'}</label>
              <input type="text" value={form.meta_airline} onChange={e => set('meta_airline', e.target.value)}
                placeholder="Lufthansa" style={inputStyle} />
            </div>
            <div>
              <label style={labelStyle}>{t('reservations.meta.flightNumber') || 'Flight No.'}</label>
              <input type="text" value={form.meta_flight_number} onChange={e => set('meta_flight_number', e.target.value)}
                placeholder="LH 123" style={inputStyle} />
            </div>
            <div>
              <label style={labelStyle}>{t('reservations.meta.from') || 'From'}</label>
              <input type="text" value={form.meta_departure_airport} onChange={e => set('meta_departure_airport', e.target.value)}
                placeholder="FRA" style={inputStyle} />
            </div>
            <div>
              <label style={labelStyle}>{t('reservations.meta.to') || 'To'}</label>
              <input type="text" value={form.meta_arrival_airport} onChange={e => set('meta_arrival_airport', e.target.value)}
                placeholder="NRT" style={inputStyle} />
            </div>
          </div>
        )}

        {form.type === 'hotel' && (
          <>
            {/* Hotel place + day range */}
            <div className="grid grid-cols-1 sm:grid-cols-3 gap-3">
              <div>
                <label style={labelStyle}>{t('reservations.meta.hotelPlace')}</label>
                <CustomSelect
                  value={form.hotel_place_id}
                  onChange={value => {
                    set('hotel_place_id', value)
                    const p = places.find(pl => pl.id === value)
                    if (p) {
                      if (!form.title) set('title', p.name)
                      if (!form.location && p.address) set('location', p.address)
                    }
                  }}
                  placeholder={t('reservations.meta.pickHotel')}
                  options={[
                    { value: '', label: '—' },
                    ...places.map(p => ({ value: p.id, label: p.name })),
                  ]}
                  searchable
                  size="sm"
                />
              </div>
              <div>
                <label style={labelStyle}>{t('reservations.meta.fromDay')}</label>
                <CustomSelect
                  value={form.hotel_start_day}
                  onChange={value => set('hotel_start_day', value)}
                  placeholder={t('reservations.meta.selectDay')}
                  options={days.map(d => ({ value: d.id, label: d.title || `${t('dayplan.dayN', { n: d.day_number })}${d.date ? ` · ${formatDate(d.date, locale)}` : ''}` }))}
                  size="sm"
                />
              </div>
              <div>
                <label style={labelStyle}>{t('reservations.meta.toDay')}</label>
                <CustomSelect
                  value={form.hotel_end_day}
                  onChange={value => set('hotel_end_day', value)}
                  placeholder={t('reservations.meta.selectDay')}
                  options={days.map(d => ({ value: d.id, label: d.title || `${t('dayplan.dayN', { n: d.day_number })}${d.date ? ` · ${formatDate(d.date, locale)}` : ''}` }))}
                  size="sm"
                />
              </div>
            </div>
            {/* Check-in/out times */}
            <div className="grid grid-cols-2 gap-3">
              <div>
                <label style={labelStyle}>{t('reservations.meta.checkIn')}</label>
                <CustomTimePicker value={form.meta_check_in_time} onChange={v => set('meta_check_in_time', v)} />
              </div>
              <div>
                <label style={labelStyle}>{t('reservations.meta.checkOut')}</label>
                <CustomTimePicker value={form.meta_check_out_time} onChange={v => set('meta_check_out_time', v)} />
              </div>
            </div>
          </>
        )}

        {form.type === 'train' && (
          <div className="grid grid-cols-3 gap-3">
            <div>
              <label style={labelStyle}>{t('reservations.meta.trainNumber') || 'Train No.'}</label>
              <input type="text" value={form.meta_train_number} onChange={e => set('meta_train_number', e.target.value)}
                placeholder="ICE 123" style={inputStyle} />
            </div>
            <div>
              <label style={labelStyle}>{t('reservations.meta.platform') || 'Platform'}</label>
              <input type="text" value={form.meta_platform} onChange={e => set('meta_platform', e.target.value)}
                placeholder="12" style={inputStyle} />
            </div>
            <div>
              <label style={labelStyle}>{t('reservations.meta.seat') || 'Seat'}</label>
              <input type="text" value={form.meta_seat} onChange={e => set('meta_seat', e.target.value)}
                placeholder="42A" style={inputStyle} />
            </div>
          </div>
        )}

        {/* Notes */}
        <div>
          <label style={labelStyle}>{t('reservations.notes')}</label>
          <textarea value={form.notes} onChange={e => set('notes', e.target.value)} rows={2}
            placeholder={t('reservations.notesPlaceholder')}
            style={{ ...inputStyle, resize: 'none', lineHeight: 1.5 }} />
        </div>

        {/* Files */}
        <div>
          <label style={labelStyle}>{t('files.title')}</label>
          <div style={{ display: 'flex', flexDirection: 'column', gap: 4 }}>
            {attachedFiles.map(f => (
              <div key={f.id} style={{ display: 'flex', alignItems: 'center', gap: 8, padding: '5px 10px', background: 'var(--bg-secondary)', borderRadius: 8 }}>
                <FileText size={12} style={{ color: 'var(--text-muted)', flexShrink: 0 }} />
                <span style={{ flex: 1, fontSize: 12, color: 'var(--text-secondary)', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{f.original_name}</span>
                <a href={f.url} target="_blank" rel="noreferrer" style={{ color: 'var(--text-faint)', display: 'flex', flexShrink: 0 }}><ExternalLink size={11} /></a>
                {onFileDelete && (
                  <button type="button" onClick={() => onFileDelete(f.id)} style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex', padding: 0, flexShrink: 0 }}>
                    <X size={11} />
                  </button>
                )}
              </div>
            ))}
            {pendingFiles.map((f, i) => (
              <div key={i} style={{ display: 'flex', alignItems: 'center', gap: 8, padding: '5px 10px', background: 'var(--bg-secondary)', borderRadius: 8 }}>
                <FileText size={12} style={{ color: 'var(--text-muted)', flexShrink: 0 }} />
                <span style={{ flex: 1, fontSize: 12, color: 'var(--text-secondary)', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{f.name}</span>
                <button type="button" onClick={() => setPendingFiles(prev => prev.filter((_, j) => j !== i))}
                  style={{ background: 'none', border: 'none', cursor: 'pointer', color: 'var(--text-faint)', display: 'flex', padding: 0, flexShrink: 0 }}>
                  <X size={11} />
                </button>
              </div>
            ))}
            <input ref={fileInputRef} type="file" accept=".pdf,.doc,.docx,.txt,image/*" style={{ display: 'none' }} onChange={handleFileChange} />
            <button type="button" onClick={() => fileInputRef.current?.click()} disabled={uploadingFile} style={{
              display: 'flex', alignItems: 'center', gap: 5, padding: '6px 10px',
              border: '1px dashed var(--border-primary)', borderRadius: 8, background: 'none',
              fontSize: 11, color: 'var(--text-faint)', cursor: uploadingFile ? 'default' : 'pointer', fontFamily: 'inherit',
            }}>
              <Paperclip size={11} />
              {uploadingFile ? t('reservations.uploading') : t('reservations.attachFile')}
            </button>
          </div>
        </div>

        {/* Actions */}
        <div style={{ display: 'flex', justifyContent: 'flex-end', gap: 8, paddingTop: 4, borderTop: '1px solid var(--border-secondary)' }}>
          <button type="button" onClick={onClose} style={{ padding: '8px 16px', borderRadius: 10, border: '1px solid var(--border-primary)', background: 'none', fontSize: 12, cursor: 'pointer', fontFamily: 'inherit', color: 'var(--text-muted)' }}>
            {t('common.cancel')}
          </button>
          <button type="submit" disabled={isSaving || !form.title.trim()} style={{ padding: '8px 20px', borderRadius: 10, border: 'none', background: 'var(--text-primary)', color: 'var(--bg-primary)', fontSize: 12, fontWeight: 600, cursor: 'pointer', fontFamily: 'inherit', opacity: isSaving || !form.title.trim() ? 0.5 : 1 }}>
            {isSaving ? t('common.saving') : reservation ? t('common.update') : t('common.add')}
          </button>
        </div>
      </form>
    </Modal>
  )
}

function formatDate(dateStr, locale) {
  if (!dateStr) return ''
  const d = new Date(dateStr + 'T00:00:00')
  return d.toLocaleDateString(locale || 'de-DE', { day: 'numeric', month: 'short' })
}