import { useState } from 'react'
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
import api from '../utils/api'
import { formatDistance, formatDuration, formatDate, formatPace, sportIcon } from '../utils/format'

export default function RoutesPage() {
  const [selected, setSelected] = useState(null)
  const [showCreate, setShowCreate] = useState(false)
  const [newRoute, setNewRoute] = useState({ name: '', activity_id: '' })
  const qc = useQueryClient()

  const { data: routes } = useQuery({
    queryKey: ['routes'],
    queryFn: () => api.get('/routes/').then(r => r.data),
  })

  const { data: routeActivities } = useQuery({
    queryKey: ['route-activities', selected?.id],
    queryFn: () => api.get(`/routes/${selected.id}/activities`).then(r => r.data),
    enabled: !!selected,
  })

  const { data: recentActivities } = useQuery({
    queryKey: ['recent-activities-for-route'],
    queryFn: () => api.get('/routes/recent-activities').then(r => r.data),
    enabled: showCreate,
  })

  const createRoute = useMutation({
    mutationFn: (data) => api.post('/routes/', data).then(r => r.data),
    onSuccess: (route) => {
      qc.invalidateQueries({ queryKey: ['routes'] })
      setShowCreate(false)
      setNewRoute({ name: '', activity_id: '' })
      setSelected(route)
    },
  })

  const fastest = routeActivities?.[0]

  return (
    <div className="p-6 space-y-6">
      <div className="flex items-center justify-between">
        <div>
          <h1 className="text-2xl font-bold text-white">Named Routes</h1>
          <p className="text-xs text-gray-500 mt-1">
            Routes are auto-detected when you run the same path twice. You can also create them manually.
          </p>
        </div>
        <button onClick={() => setShowCreate(true)}
          className="bg-blue-600 hover:bg-blue-700 text-white text-sm px-4 py-2 rounded-lg transition-colors">
          + New route
        </button>
      </div>

      {/* Create route */}
      {showCreate && (
        <div className="bg-gray-900 border border-gray-700 rounded-xl p-5 space-y-4">
          <h3 className="text-sm font-semibold text-white">Create named route</h3>
          <p className="text-xs text-gray-500">
            Select an activity to use as the reference GPS track. Future activities on the same route will be linked automatically.
          </p>
          <div className="space-y-3">
            <div>
              <label className="text-xs text-gray-400 mb-1 block">Route name</label>
              <input value={newRoute.name}
                onChange={e => setNewRoute(r => ({ ...r, name: e.target.value }))}
                className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2 text-sm text-white focus:outline-none focus:ring-2 focus:ring-blue-500"
                placeholder="e.g. Morning park loop" />
            </div>
            <div>
              <label className="text-xs text-gray-400 mb-1 block">Reference activity (last 2 weeks)</label>
              {recentActivities?.length === 0 ? (
                <p className="text-xs text-gray-600 py-2">No recent activities found.</p>
              ) : (
                <select
                  value={newRoute.activity_id}
                  onChange={e => setNewRoute(r => ({ ...r, activity_id: e.target.value }))}
                  className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2 text-sm text-white focus:outline-none focus:ring-2 focus:ring-blue-500"
                >
                  <option value="">Select an activity…</option>
                  {recentActivities?.map(a => (
                    <option key={a.id} value={a.id}>
                      {sportIcon(a.sport_type)} {a.name} — {formatDistance(a.distance_m)} on {formatDate(a.start_time)}
                    </option>
                  ))}
                </select>
              )}
            </div>
          </div>
          <div className="flex gap-3">
            <button
              onClick={() => createRoute.mutate({ ...newRoute, activity_id: parseInt(newRoute.activity_id) })}
              disabled={!newRoute.name || !newRoute.activity_id || createRoute.isPending}
              className="bg-blue-600 hover:bg-blue-700 disabled:opacity-40 text-white text-sm px-4 py-2 rounded-lg transition-colors">
              Create
            </button>
            <button onClick={() => setShowCreate(false)}
              className="text-gray-400 hover:text-white text-sm px-4 py-2 rounded-lg transition-colors">
              Cancel
            </button>
          </div>
        </div>
      )}

      <div className="grid grid-cols-1 lg:grid-cols-3 gap-6">
        {/* Route list */}
        <div className="space-y-2">
          {routes?.length === 0 && !showCreate && (
            <div className="text-center py-12 text-gray-600">
              <p className="text-3xl mb-2">🗺️</p>
              <p className="text-sm">No named routes yet</p>
              <p className="text-xs mt-1">Routes are created automatically when you repeat a run, or create one manually above.</p>
            </div>
          )}
          {routes?.map(route => (
            <button key={route.id} onClick={() => setSelected(route)}
              className={`w-full text-left p-4 rounded-xl border transition-all ${
                selected?.id === route.id ? 'bg-blue-900/20 border-blue-700' : 'bg-gray-900 border-gray-800 hover:border-gray-600'
              }`}>
              <div className="flex items-start justify-between">
                <p className="font-medium text-white">{route.name}</p>
                {route.auto_detected && (
                  <span className="text-xs bg-gray-800 text-gray-400 px-2 py-0.5 rounded-full ml-2">auto</span>
                )}
              </div>
              <div className="flex gap-3 mt-1 text-xs text-gray-500">
                <span>{formatDistance(route.distance_m)}</span>
                {route.sport_type && <span className="capitalize">{route.sport_type}</span>}
                <span>{formatDate(route.created_at)}</span>
              </div>
            </button>
          ))}
        </div>

        {/* Route detail */}
        {selected && (
          <div className="lg:col-span-2 space-y-4">
            <div className="bg-gray-900 rounded-xl border border-gray-800 p-5">
              <div className="flex items-start justify-between mb-3">
                <h2 className="text-lg font-semibold text-white">{selected.name}</h2>
                {selected.auto_detected && (
                  <span className="text-xs bg-blue-900/40 text-blue-400 border border-blue-700/40 px-2 py-0.5 rounded-full">
                    Auto-detected
                  </span>
                )}
              </div>

              {fastest && (
                <div className="bg-yellow-900/20 border border-yellow-700/40 rounded-lg p-3 mb-4">
                  <p className="text-xs text-yellow-600 mb-1">Course record 🏆</p>
                  <div className="flex items-center gap-4">
                    <span className="text-xl font-bold text-yellow-400">{formatDuration(fastest.duration_s)}</span>
                    <span className="text-sm text-gray-400">
                      {formatDate(fastest.start_time)} · {formatPace(fastest.avg_speed_ms, selected.sport_type)}
                    </span>
                  </div>
                </div>
              )}

              <h3 className="text-sm font-medium text-gray-400 mb-2">
                All runs ({routeActivities?.length ?? 0})
              </h3>
              <div className="space-y-2">
                {routeActivities?.map((act, i) => (
                  <div key={act.id} className="flex items-center gap-4 py-2 border-b border-gray-800/50 text-sm">
                    <span className="text-gray-600 w-5 text-right">{i + 1}</span>
                    <span className="text-gray-400 flex-1">{formatDate(act.start_time)}</span>
                    <span className="font-mono text-white font-medium">{formatDuration(act.duration_s)}</span>
                    <span className="text-gray-500">{formatPace(act.avg_speed_ms, selected.sport_type)}</span>
                    {act.avg_heart_rate && (
                      <span className="text-red-400 text-xs">{Math.round(act.avg_heart_rate)} bpm</span>
                    )}
                    {i === 0 && (
                      <span className="text-xs bg-yellow-900/40 text-yellow-400 px-2 py-0.5 rounded-full border border-yellow-700/40">CR</span>
                    )}
                  </div>
                ))}
              </div>
            </div>
          </div>
        )}
      </div>
    </div>
  )
}