import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.collectAsState
import androidx.compose.runtime.getValue
import androidx.compose.ui.Modifier
import at.mocode.frontend.core.auth.data.AuthTokenManager
import at.mocode.frontend.core.auth.presentation.LoginScreen
import at.mocode.frontend.core.auth.presentation.LoginViewModel
import at.mocode.frontend.core.designsystem.theme.AppTheme
import at.mocode.frontend.core.domain.PlatformType
import at.mocode.frontend.core.domain.currentPlatform
import at.mocode.frontend.core.navigation.AppScreen
import at.mocode.ping.feature.presentation.PingScreen
import at.mocode.ping.feature.presentation.PingViewModel
import navigation.StateNavigationPort
import org.koin.compose.koinInject
import org.koin.compose.viewmodel.koinViewModel
import screens.*

@Composable
fun MainApp() {
  AppTheme {
    Surface(
      modifier = Modifier.fillMaxSize(),
      color = MaterialTheme.colorScheme.background
    ) {
      val navigationPort = koinInject<StateNavigationPort>()
      val currentScreen by navigationPort.currentScreen.collectAsState()
      val authTokenManager = koinInject<AuthTokenManager>()
      val pingViewModel: PingViewModel = koinViewModel()
      val loginViewModel: LoginViewModel = koinViewModel()

      when (val screen = currentScreen) {
        is AppScreen.Landing -> {
          if (currentPlatform() == PlatformType.DESKTOP) {
            val authState = authTokenManager.authState.collectAsState().value
            if (authState.isAuthenticated) {
              DashboardScreen(
                authTokenManager = authTokenManager,
                onLogout = {
                  authTokenManager.clearToken()
                  navigationPort.navigateToScreen(AppScreen.Login(returnTo = AppScreen.Dashboard))
                },
                onCreateTournament = { navigationPort.navigateToScreen(AppScreen.CreateTournament) }
              )
            } else {
              LaunchedEffect(Unit) {
                navigationPort.navigateToScreen(AppScreen.Login(returnTo = AppScreen.Dashboard))
              }
            }
          } else {
            LandingScreen(
              onPrimaryCta = { navigationPort.navigateToScreen(AppScreen.Login(returnTo = AppScreen.Dashboard)) },
              onOpenPing = { navigationPort.navigateToScreen(AppScreen.Login(returnTo = AppScreen.OrganizerProfile)) }
            )
          }
        }

        is AppScreen.Dashboard -> DashboardScreen(
          authTokenManager = authTokenManager,
          onNennungOeffnen = { navigationPort.navigateToScreen(AppScreen.Nennung) },
          onLogout = {
            authTokenManager.clearToken()
            if (currentPlatform() == PlatformType.DESKTOP) {
              navigationPort.navigateToScreen(AppScreen.Login(returnTo = AppScreen.Dashboard))
            } else {
              navigationPort.navigateToScreen(AppScreen.Landing)
            }
          },
          onCreateTournament = { navigationPort.navigateToScreen(AppScreen.CreateTournament) }
        )

        is AppScreen.Home -> DashboardScreen(
          authTokenManager = authTokenManager,
          onLogout = {
            authTokenManager.clearToken()
            if (currentPlatform() == PlatformType.DESKTOP) {
              navigationPort.navigateToScreen(AppScreen.Login(returnTo = AppScreen.Dashboard))
            } else {
              navigationPort.navigateToScreen(AppScreen.Landing)
            }
          },
          onCreateTournament = { navigationPort.navigateToScreen(AppScreen.CreateTournament) }
        )

        is AppScreen.CreateTournament -> CreateTournamentScreen(
          onBack = { navigationPort.navigateToScreen(AppScreen.Dashboard) },
          onSave = { navigationPort.navigateToScreen(AppScreen.Dashboard) }
        )

        is AppScreen.Login -> {
          LoginScreen(
            viewModel = loginViewModel,
            onLoginSuccess = {
              val returnTo = screen.returnTo
              if (returnTo != null) {
                navigationPort.navigateToScreen(returnTo)
              } else {
                navigationPort.navigateToScreen(AppScreen.Dashboard)
              }
            },
            onBack = {
              if (currentPlatform() == PlatformType.DESKTOP) {
                // Desktop hat keine Landing Page — bleibt auf Login
              } else {
                navigationPort.navigateToScreen(AppScreen.Landing)
              }
            }
          )
        }

        is AppScreen.Ping -> PingScreen(
          viewModel = pingViewModel,
          onBack = {
            if (currentPlatform() == PlatformType.DESKTOP) {
              navigationPort.navigateToScreen(AppScreen.Dashboard)
            } else {
              navigationPort.navigateToScreen(AppScreen.Landing)
            }
          }
        )

        is AppScreen.Nennung -> {
          // NennungsMaske wird über das nennung-feature eingebunden (jvmMain only)
          // Placeholder, bis das Feature vollständig integriert ist
          NennungScreenContent()
        }

        is AppScreen.OrganizerProfile -> OrganizerProfileScreen(
          authTokenManager = authTokenManager,
          onLogout = {
            authTokenManager.clearToken()
            navigationPort.navigateToScreen(AppScreen.Landing)
          },
          onNavigateToDashboard = { navigationPort.navigateToScreen(AppScreen.Dashboard) }
        )

        is AppScreen.AuthCallback -> { /* OIDC Callback wird vom Auth-Modul verarbeitet */
        }

        is AppScreen.Profile -> AuthStatusScreen(
          authTokenManager = authTokenManager,
          onNavigateToLogin = {
            navigationPort.navigateToScreen(AppScreen.Login(returnTo = AppScreen.Profile))
          },
          onNavigateToPing = { navigationPort.navigateToScreen(AppScreen.Ping) },
          onBackToHome = {
            if (currentPlatform() == PlatformType.DESKTOP) {
              navigationPort.navigateToScreen(AppScreen.Dashboard)
            } else {
              navigationPort.navigateToScreen(AppScreen.Landing)
            }
          }
        )

        else -> {}
      }
    }
  }
}