import { useState } from 'react'
import { useAuth } from './context/AuthContext'
import Dashboard from './pages/Dashboard'
import ProfilePage from './pages/ProfilePage'
import ProgressPage from './pages/ProgressPage'
import WorkoutPage from './pages/WorkoutPage'
import WorkoutSelectPage from './pages/WorkoutSelectPage'
import './App.css'

const API_URL = '/api'

function App() {
  const { user, logout } = useAuth()
  const [view, setView] = useState('dashboard')
  const [program, setProgram] = useState(null)
  const [selectedDay, setSelectedDay] = useState(null)
  const [currentWeek, setCurrentWeek] = useState(1)
  const [logs, setLogs] = useState({})
  const [loading, setLoading] = useState(false)

  const userId = user?.id || 1
  const today = new Date().toISOString().split('T')[0]

  const fetchProgram = async () => {
    if (program) return // Already loaded
    try {
      const res = await fetch(`${API_URL}/programs/1`)
      const data = await res.json()
      setProgram(data)
    } catch (err) {
      console.error('Failed to fetch program:', err)
    }
  }

  const fetchLogs = async (dayId) => {
    try {
      const day = program.days.find(d => d.id === dayId)
      if (!day) return

      const newLogs = {}
      for (const exercise of day.exercises) {
        if (!exercise.id) continue
        const res = await fetch(`${API_URL}/logs?user_id=${userId}&date=${today}&program_exercise_id=${exercise.id}`)
        const data = await res.json()
        newLogs[exercise.id] = data
      }
      setLogs(newLogs)
    } catch (err) {
      console.error('Failed to fetch logs:', err)
    }
  }

  const fetchProgression = async (programExerciseId) => {
    try {
      const res = await fetch(`${API_URL}/progression/${programExerciseId}?user_id=${userId}`)
      return await res.json()
    } catch (err) {
      console.error('Failed to fetch progression:', err)
      return null
    }
  }

  const logSet = async (programExerciseId, setNumber, weight, reps, completed) => {
    try {
      const res = await fetch(`${API_URL}/logs`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          user_id: userId,
          program_exercise_id: programExerciseId,
          date: today,
          set_number: setNumber,
          weight: parseFloat(weight) || 0,
          reps: parseInt(reps) || 0,
          completed
        })
      })
      const data = await res.json()
      
      // Update local logs
      setLogs(prev => ({
        ...prev,
        [programExerciseId]: [
          ...(prev[programExerciseId] || []).filter(l => l.set_number !== setNumber),
          data
        ].sort((a, b) => a.set_number - b.set_number)
      }))
    } catch (err) {
      console.error('Failed to log set:', err)
    }
  }

  const startWorkout = async (day) => {
    await fetchProgram() // Ensure program is loaded
    setSelectedDay(day)
    setView('workout')
    fetchLogs(day.id)
  }

  // Dashboard view (default after login)
  if (view === 'dashboard') {
    return (
      <Dashboard 
        onStartWorkout={startWorkout}
        onNavigate={setView}
      />
    )
  }

  // Profile page
  if (view === 'profile') {
    return <ProfilePage onBack={() => setView('dashboard')} />
  }

  // Progress page
  if (view === 'progress') {
    return <ProgressPage onBack={() => setView('dashboard')} />
  }

  // Workout select page
  if (view === 'select-workout') {
    return (
      <WorkoutSelectPage 
        onBack={() => setView('dashboard')}
        onSelectWorkout={startWorkout}
      />
    )
  }

  // Workout view
  if (view === 'workout' && selectedDay) {
    return (
      <WorkoutPage
        day={selectedDay}
        week={currentWeek}
        logs={logs}
        onLogSet={logSet}
        onBack={() => setView('dashboard')}
        fetchProgression={fetchProgression}
      />
    )
  }

  // Fallback loading
  return (
    <div className="app loading">
      <div className="spinner"></div>
      <p>Laddar...</p>
    </div>
  )
}

export default App
