import { useEffect, useState, useRef } from 'react'
import { Link, useNavigate } from 'react-router-dom'
import { Dog, Plus, Search, Calendar, Hash, ArrowRight, Trash2 } from 'lucide-react'
import axios from 'axios'
import DogForm from '../components/DogForm'
import { ChampionBadge, ChampionBloodlineBadge } from '../components/ChampionBadge'

const LIMIT = 50

function DogList() {
  const [dogs, setDogs] = useState([])
  const [total, setTotal] = useState(0)
  const [page, setPage] = useState(1)
  const [search, setSearch] = useState('')
  const [sexFilter, setSexFilter] = useState('all')
  const [loading, setLoading] = useState(true)
  const [showAddModal, setShowAddModal] = useState(false)
  const [deleteTarget, setDeleteTarget] = useState(null)  // { id, name }
  const [deleting, setDeleting] = useState(false)
  const searchTimerRef = useRef(null)

  useEffect(() => { fetchDogs(1, '', 'all') }, [])  // eslint-disable-line

  const fetchDogs = async (p, q, s) => {
    setLoading(true)
    try {
      const params = { page: p, limit: LIMIT }
      if (q) params.search = q
      if (s !== 'all') params.sex = s
      const res = await axios.get('/api/dogs', { params })
      setDogs(res.data.data)
      setTotal(res.data.total)
      setPage(p)
    } catch (error) {
      console.error('Error fetching dogs:', error)
    } finally {
      setLoading(false)
    }
  }

  const handleSearchChange = (value) => {
    setSearch(value)
    if (searchTimerRef.current) clearTimeout(searchTimerRef.current)
    searchTimerRef.current = setTimeout(() => fetchDogs(1, value, sexFilter), 300)
  }

  const handleSexChange = (value) => {
    setSexFilter(value)
    fetchDogs(1, search, value)
  }

  const handleClearFilters = () => {
    setSearch('')
    setSexFilter('all')
    fetchDogs(1, '', 'all')
  }

  const handleSave = () => { fetchDogs(page, search, sexFilter) }

  const handleDelete = async () => {
    if (!deleteTarget) return
    setDeleting(true)
    try {
      await axios.delete(`/api/dogs/${deleteTarget.id}`)
      setDeleteTarget(null)
      fetchDogs(page, search, sexFilter)
    } catch (err) {
      console.error('Delete failed:', err)
      alert('Failed to delete dog. Please try again.')
    } finally {
      setDeleting(false)
    }
  }

  const totalPages = Math.ceil(total / LIMIT)

  const calculateAge = (birthDate) => {
    if (!birthDate) return null
    const today = new Date()
    const birth = new Date(birthDate)
    let years = today.getFullYear() - birth.getFullYear()
    let months = today.getMonth() - birth.getMonth()
    if (months < 0) { years--; months += 12 }
    if (years === 0) return `${months}mo`
    if (months === 0) return `${years}y`
    return `${years}y ${months}mo`
  }

  const hasChampionBlood = (dog) =>
    (dog.sire && dog.sire.is_champion) || (dog.dam && dog.dam.is_champion)

  if (loading) {
    return <div className="container loading">Loading dogs...</div>
  }

  return (
    <div className="container" style={{ paddingTop: '2rem', paddingBottom: '3rem' }}>
      <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: '2rem' }}>
        <div>
          <h1 style={{ marginBottom: '0.25rem' }}>Dogs</h1>
          <p style={{ color: 'var(--text-secondary)', fontSize: '0.875rem' }}>
            {total} {total === 1 ? 'dog' : 'dogs'}
            {search || sexFilter !== 'all' ? ' matching filters' : ' total'}
          </p>
        </div>
        <button className="btn btn-primary" onClick={() => setShowAddModal(true)}>
          <Plus size={18} />
          Add Dog
        </button>
      </div>

      {/* Search and Filter Bar */}
      <div className="card" style={{ marginBottom: '1.5rem', padding: '1rem' }}>
        <div style={{ display: 'grid', gridTemplateColumns: '1fr auto auto', gap: '1rem', alignItems: 'center' }}>
          <div style={{ position: 'relative' }}>
            <Search size={18} style={{ position: 'absolute', left: '0.875rem', top: '50%', transform: 'translateY(-50%)', color: 'var(--text-muted)' }} />
            <input
              type="text"
              className="input"
              placeholder="Search by name or registration..."
              value={search}
              onChange={(e) => handleSearchChange(e.target.value)}
              style={{ paddingLeft: '2.75rem' }}
            />
          </div>
          <select className="input" value={sexFilter} onChange={(e) => handleSexChange(e.target.value)} style={{ width: '140px' }}>
            <option value="all">All Dogs</option>
            <option value="male">Males ♂</option>
            <option value="female">Females ♀</option>
          </select>
          {(search || sexFilter !== 'all') && (
            <button
              className="btn btn-ghost"
              onClick={handleClearFilters}
              style={{ padding: '0.625rem 1rem', fontSize: '0.875rem' }}
            >
              Clear
            </button>
          )}
        </div>
      </div>

      {/* Dogs List */}
      {dogs.length === 0 ? (
        <div className="card" style={{ textAlign: 'center', padding: '4rem 2rem' }}>
          <Dog size={64} style={{ color: 'var(--text-muted)', margin: '0 auto 1rem', opacity: 0.5 }} />
          <h3 style={{ marginBottom: '0.5rem' }}>
            {search || sexFilter !== 'all' ? 'No dogs found' : 'No dogs yet'}
          </h3>
          <p style={{ color: 'var(--text-secondary)', marginBottom: '2rem' }}>
            {search || sexFilter !== 'all'
              ? 'Try adjusting your search or filters'
              : 'Add your first dog to get started'}
          </p>
          {!search && sexFilter === 'all' && (
            <button className="btn btn-primary" onClick={() => setShowAddModal(true)}>
              <Plus size={18} />
              Add Your First Dog
            </button>
          )}
        </div>
      ) : (
        <div style={{ display: 'grid', gap: '1rem' }}>
          {dogs.map(dog => (
            <div
              key={dog.id}
              className="card"
              style={{
                padding: '1rem',
                display: 'flex',
                gap: '1rem',
                alignItems: 'center',
                transition: 'var(--transition)',
              }}
              onMouseEnter={(e) => {
                e.currentTarget.style.borderColor = 'var(--primary)'
                e.currentTarget.style.transform = 'translateY(-2px)'
                e.currentTarget.style.boxShadow = '0 8px 16px rgba(0, 0, 0, 0.3)'
              }}
              onMouseLeave={(e) => {
                e.currentTarget.style.borderColor = 'var(--border)'
                e.currentTarget.style.transform = 'translateY(0)'
                e.currentTarget.style.boxShadow = 'var(--shadow-sm)'
              }}
            >
              {/* Avatar */}
              <Link
                to={`/dogs/${dog.id}`}
                style={{ flexShrink: 0, textDecoration: 'none' }}
              >
                <div style={{
                  width: '80px', height: '80px',
                  borderRadius: 'var(--radius)',
                  background: 'var(--bg-primary)',
                  border: dog.is_champion
                    ? '2px solid var(--champion-gold)'
                    : hasChampionBlood(dog)
                      ? '2px solid var(--bloodline-amber)'
                      : '2px solid var(--border)',
                  display: 'flex', alignItems: 'center', justifyContent: 'center',
                  overflow: 'hidden',
                  boxShadow: dog.is_champion
                    ? '0 0 8px var(--champion-glow)'
                    : hasChampionBlood(dog)
                      ? '0 0 8px var(--bloodline-glow)'
                      : 'none'
                }}>
                  {dog.photo_urls && dog.photo_urls.length > 0 ? (
                    <img
                      src={dog.photo_urls[0]}
                      alt={dog.name}
                      style={{ width: '100%', height: '100%', objectFit: 'cover' }}
                    />
                  ) : (
                    <Dog size={32} style={{ color: 'var(--text-muted)', opacity: 0.5 }} />
                  )}
                </div>
              </Link>

              {/* Info — clicking navigates to detail */}
              <Link
                to={`/dogs/${dog.id}`}
                style={{ flex: 1, minWidth: 0, textDecoration: 'none', color: 'inherit' }}
              >
                <h3 style={{
                  fontSize: '1.125rem',
                  marginBottom: '0.25rem',
                  display: 'flex', alignItems: 'center', gap: '0.5rem',
                  flexWrap: 'wrap'
                }}>
                  <span style={{ overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>
                    {dog.name}
                  </span>
                  <span style={{ color: dog.sex === 'male' ? 'var(--primary)' : '#ec4899', fontSize: '1rem' }}>
                    {dog.sex === 'male' ? '♂' : '♀'}
                  </span>
                  {dog.is_champion ? <ChampionBadge /> : hasChampionBlood(dog) ? <ChampionBloodlineBadge /> : null}
                </h3>

                <div style={{
                  display: 'flex', flexWrap: 'wrap', gap: '0.75rem',
                  fontSize: '0.8125rem', color: 'var(--text-secondary)', marginBottom: '0.5rem'
                }}>
                  <span>{dog.breed}</span>
                  {dog.birth_date && (
                    <>
                      <span>·</span>
                      <span style={{ display: 'flex', alignItems: 'center', gap: '0.25rem' }}>
                        <Calendar size={12} />
                        {calculateAge(dog.birth_date)}
                      </span>
                    </>
                  )}
                  {dog.color && (
                    <>
                      <span>·</span>
                      <span>{dog.color}</span>
                    </>
                  )}
                </div>

                {dog.registration_number && (
                  <div style={{
                    display: 'inline-flex', alignItems: 'center', gap: '0.25rem',
                    padding: '0.25rem 0.5rem',
                    background: 'var(--bg-primary)',
                    border: '1px solid var(--border)',
                    borderRadius: 'var(--radius-sm)',
                    fontSize: '0.75rem', fontFamily: 'monospace',
                    color: 'var(--text-muted)'
                  }}>
                    <Hash size={10} />
                    {dog.registration_number}
                  </div>
                )}
                {dog.chic_number && (
                  <div style={{
                    display: 'inline-flex', alignItems: 'center', gap: '0.25rem',
                    padding: '0.25rem 0.5rem',
                    background: 'rgba(99,102,241,0.1)',
                    border: '1px solid rgba(99,102,241,0.3)',
                    borderRadius: 'var(--radius-sm)',
                    fontSize: '0.75rem', fontWeight: 600,
                    color: '#818cf8', marginLeft: '0.5rem'
                  }}>
                    CHIC #{dog.chic_number}
                  </div>
                )}
              </Link>

              {/* Actions */}
              <div style={{ display: 'flex', gap: '0.5rem', flexShrink: 0, alignItems: 'center' }}>
                <Link
                  to={`/dogs/${dog.id}`}
                  style={{ opacity: 0.5, transition: 'var(--transition)', color: 'inherit' }}
                >
                  <ArrowRight size={20} color="var(--text-muted)" />
                </Link>
                <button
                  className="btn btn-ghost"
                  title={`Delete ${dog.name}`}
                  onClick={(e) => { e.stopPropagation(); setDeleteTarget({ id: dog.id, name: dog.name }) }}
                  style={{
                    padding: '0.4rem',
                    color: 'var(--text-muted)',
                    border: '1px solid transparent',
                    borderRadius: 'var(--radius-sm)',
                    display: 'flex', alignItems: 'center',
                    transition: 'var(--transition)'
                  }}
                  onMouseEnter={(e) => {
                    e.currentTarget.style.color = '#ef4444'
                    e.currentTarget.style.borderColor = '#ef4444'
                    e.currentTarget.style.background = 'rgba(239,68,68,0.08)'
                  }}
                  onMouseLeave={(e) => {
                    e.currentTarget.style.color = 'var(--text-muted)'
                    e.currentTarget.style.borderColor = 'transparent'
                    e.currentTarget.style.background = 'transparent'
                  }}
                >
                  <Trash2 size={16} />
                </button>
              </div>
            </div>
          ))}
        </div>
      )}

      {/* Pagination */}
      {totalPages > 1 && (
        <div style={{ display: 'flex', justifyContent: 'center', alignItems: 'center', gap: '1rem', marginTop: '1.5rem' }}>
          <button
            className="btn btn-ghost"
            onClick={() => fetchDogs(page - 1, search, sexFilter)}
            disabled={page <= 1 || loading}
            style={{ padding: '0.5rem 1rem' }}
          >
            Previous
          </button>
          <span style={{ color: 'var(--text-secondary)', fontSize: '0.875rem' }}>
            Page {page} of {totalPages}
          </span>
          <button
            className="btn btn-ghost"
            onClick={() => fetchDogs(page + 1, search, sexFilter)}
            disabled={page >= totalPages || loading}
            style={{ padding: '0.5rem 1rem' }}
          >
            Next
          </button>
        </div>
      )}

      {/* Add Dog Modal */}
      {showAddModal && (
        <DogForm
          onClose={() => setShowAddModal(false)}
          onSave={handleSave}
        />
      )}

      {/* Delete Confirmation Modal */}
      {deleteTarget && (
        <div style={{
          position: 'fixed', inset: 0,
          background: 'rgba(0,0,0,0.65)',
          display: 'flex', alignItems: 'center', justifyContent: 'center',
          zIndex: 1000,
          backdropFilter: 'blur(4px)'
        }}>
          <div className="card" style={{ maxWidth: 420, width: '90%', padding: '2rem', textAlign: 'center' }}>
            <div style={{
              width: 56, height: 56,
              borderRadius: '50%',
              background: 'rgba(239,68,68,0.12)',
              display: 'flex', alignItems: 'center', justifyContent: 'center',
              margin: '0 auto 1rem'
            }}>
              <Trash2 size={26} style={{ color: '#ef4444' }} />
            </div>
            <h3 style={{ margin: '0 0 0.5rem', fontSize: '1.25rem' }}>Delete Dog?</h3>
            <p style={{ color: 'var(--text-secondary)', marginBottom: '1.75rem', lineHeight: 1.6 }}>
              <strong style={{ color: 'var(--text-primary)' }}>{deleteTarget.name}</strong> will be
              permanently removed along with all parent relationships, health records,
              and heat cycles. This cannot be undone.
            </p>
            <div style={{ display: 'flex', gap: '0.75rem', justifyContent: 'center' }}>
              <button
                className="btn btn-ghost"
                onClick={() => setDeleteTarget(null)}
                disabled={deleting}
                style={{ minWidth: 100 }}
              >
                Cancel
              </button>
              <button
                className="btn"
                onClick={handleDelete}
                disabled={deleting}
                style={{
                  minWidth: 140,
                  background: '#ef4444',
                  color: '#fff',
                  border: '1px solid #ef4444',
                  display: 'flex', alignItems: 'center', justifyContent: 'center', gap: '0.5rem'
                }}
              >
                <Trash2 size={15} />
                {deleting ? 'Deleting…' : 'Yes, Delete'}
              </button>
            </div>
          </div>
        </div>
      )}
    </div>
  )
}

export default DogList