import { useState } from 'react'
import { Link } from 'react-router-dom'
import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
import { getShowEvents, createShowEvent, addShowToEvent } from '../api'
import Button from './Button'

// Modal launched from a row's "Add to Event" button in the Shows browser.
// Lets the user drop the ARBA show into an existing event or spin up a new one
// inline (design doc §6 "Adding Shows to an Event Flow").
function AddToEventModal({ show, onClose }) {
  const queryClient = useQueryClient()
  const { data: events, isLoading } = useQuery({ queryKey: ['show-events'], queryFn: getShowEvents })

  const [mode, setMode] = useState('existing') // 'existing' | 'new'
  const [selectedId, setSelectedId] = useState('')
  const [newName, setNewName] = useState('')
  const [newNotes, setNewNotes] = useState('')
  const [result, setResult] = useState(null) // { id, name } once added

  // No events yet → force the create path.
  const hasEvents = (events?.length ?? 0) > 0
  const effectiveMode = hasEvents ? mode : 'new'

  const mutation = useMutation({
    mutationFn: async () => {
      let eventId
      let eventName
      if (effectiveMode === 'new') {
        const created = await createShowEvent({ name: newName.trim(), notes: newNotes.trim() || null })
        eventId = created.id
        eventName = created.name
      } else {
        eventId = Number(selectedId)
        eventName = events.find((e) => e.id === eventId)?.name ?? 'event'
      }
      await addShowToEvent(eventId, show)
      return { id: eventId, name: eventName }
    },
    onSuccess: (added) => {
      setResult(added)
      queryClient.invalidateQueries({ queryKey: ['show-events'] })
      queryClient.invalidateQueries({ queryKey: ['show-event', added.id] })
    },
  })

  const canSubmit =
    effectiveMode === 'new' ? newName.trim().length > 0 : selectedId !== ''

  return (
    <div
      className="fixed inset-0 z-30 flex items-center justify-center bg-black/40 p-4"
      onMouseDown={(e) => {
        if (e.target === e.currentTarget) onClose()
      }}
    >
      <div className="w-full max-w-md rounded-lg border border-border bg-surface-raised p-6 shadow-xl">
        {result ? (
          <div className="flex flex-col gap-4">
            <h2 className="font-display text-lg text-text-primary">Added to event</h2>
            <p className="font-body text-sm text-text-secondary">
              <span className="font-medium text-text-primary">{show.club_name}</span> was added to{' '}
              <span className="font-medium text-text-primary">{result.name}</span>.
            </p>
            <div className="flex justify-end gap-3">
              <Button variant="secondary" onClick={onClose}>
                Close
              </Button>
              <Link to={`/shows/events/${result.id}`}>
                <Button variant="primary">View Event</Button>
              </Link>
            </div>
          </div>
        ) : (
          <div className="flex flex-col gap-4">
            <div>
              <h2 className="font-display text-lg text-text-primary">Add to Event</h2>
              <p className="mt-1 font-body text-sm text-text-secondary">
                {show.club_name} — {show.raw_date || show.date}
              </p>
            </div>

            {hasEvents && (
              <div className="flex gap-1 rounded-md border border-border bg-surface p-1">
                <button
                  type="button"
                  onClick={() => setMode('existing')}
                  className={`flex-1 rounded px-3 py-1.5 font-body text-sm ${
                    effectiveMode === 'existing' ? 'bg-accent text-surface' : 'text-text-primary hover:bg-surface-sunken'
                  }`}
                >
                  Existing event
                </button>
                <button
                  type="button"
                  onClick={() => setMode('new')}
                  className={`flex-1 rounded px-3 py-1.5 font-body text-sm ${
                    effectiveMode === 'new' ? 'bg-accent text-surface' : 'text-text-primary hover:bg-surface-sunken'
                  }`}
                >
                  New event
                </button>
              </div>
            )}

            {effectiveMode === 'existing' ? (
              <div>
                <label className="block font-body text-sm font-medium text-text-primary">Event</label>
                <select
                  value={selectedId}
                  onChange={(e) => setSelectedId(e.target.value)}
                  className="mt-1 w-full rounded-md border border-border bg-surface-raised px-3 py-2 font-body text-sm focus:outline-none focus:ring-2 focus:ring-accent"
                >
                  <option value="">{isLoading ? 'Loading…' : 'Select an event'}</option>
                  {events?.map((event) => (
                    <option key={event.id} value={event.id}>
                      {event.name} ({event.show_count} show{event.show_count === 1 ? '' : 's'})
                    </option>
                  ))}
                </select>
              </div>
            ) : (
              <div className="flex flex-col gap-3">
                <div>
                  <label className="block font-body text-sm font-medium text-text-primary">
                    Event name <span className="text-danger">*</span>
                  </label>
                  <input
                    type="text"
                    value={newName}
                    onChange={(e) => setNewName(e.target.value)}
                    placeholder="e.g. Spring Circuit Weekend"
                    className="mt-1 w-full rounded-md border border-border px-3 py-2 font-body text-sm focus:outline-none focus:ring-2 focus:ring-accent"
                  />
                </div>
                <div>
                  <label className="block font-body text-sm font-medium text-text-primary">Notes</label>
                  <textarea
                    value={newNotes}
                    onChange={(e) => setNewNotes(e.target.value)}
                    rows={2}
                    className="mt-1 w-full rounded-md border border-border px-3 py-2 font-body text-sm focus:outline-none focus:ring-2 focus:ring-accent"
                  />
                </div>
              </div>
            )}

            {mutation.isError && (
              <p className="font-body text-sm text-danger">{mutation.error.message}</p>
            )}

            <div className="flex justify-end gap-3">
              <Button variant="secondary" onClick={onClose} disabled={mutation.isPending}>
                Cancel
              </Button>
              <Button
                variant="primary"
                onClick={() => mutation.mutate()}
                disabled={!canSubmit || mutation.isPending}
              >
                {mutation.isPending ? 'Adding…' : 'Add'}
              </Button>
            </div>
          </div>
        )}
      </div>
    </div>
  )
}

export default AddToEventModal