package com.example.gudariwallet.ui

import android.content.ClipboardManager
import android.util.Log
import androidx.compose.animation.AnimatedVisibility
import androidx.compose.animation.core.tween
import androidx.compose.animation.fadeIn
import androidx.compose.animation.fadeOut
import androidx.compose.animation.slideInVertically
import androidx.compose.animation.slideOutVertically
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.navigationBarsPadding
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.layout.statusBarsPadding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.automirrored.filled.Send
import androidx.compose.material.icons.filled.Close
import androidx.compose.material.icons.filled.ContentPaste
import androidx.compose.material.icons.filled.QrCode
import androidx.compose.material.icons.filled.QrCodeScanner
import androidx.compose.material3.CircularProgressIndicator
import androidx.compose.material3.FilledIconButton
import androidx.compose.material3.Icon
import androidx.compose.material3.IconButton
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.NavigationBarItem
import androidx.compose.material3.Scaffold
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.*
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.vector.ImageVector
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.unit.dp
import androidx.compose.ui.zIndex
import androidx.lifecycle.compose.collectAsStateWithLifecycle
import androidx.lifecycle.viewmodel.compose.viewModel
import androidx.navigation.NavGraph.Companion.findStartDestination
import androidx.navigation.NavType
import androidx.navigation.compose.NavHost
import androidx.navigation.compose.composable
import androidx.navigation.compose.currentBackStackEntryAsState
import androidx.navigation.compose.rememberNavController
import androidx.navigation.navArgument
import com.example.gudariwallet.MainActivity
import com.example.gudariwallet.util.SendInputType
import kotlinx.coroutines.delay

// ── Tab destinations ──────────────────────────────────────────────────────────

sealed class TabItem(val route: String, val label: String, val icon: ImageVector) {
    data object Receive : TabItem("receive", "Receive", Icons.Filled.QrCode)
    data object Send    : TabItem("send",    "Send", Icons.AutoMirrored.Filled.Send)
}

private const val ROUTE_HOME           = "home"
private const val ROUTE_SCANNER        = "scanner"
private const val ROUTE_HISTORY        = "history"
private const val ROUTE_PAYMENT_DETAIL = "payment_detail/{paymentHash}"

@Composable
fun WalletScreen(
    vm                : WalletViewModel,
    pendingPaymentHash: MutableState<String?>,
    pendingPaymentUri : MutableState<String?>   // SESSION 09: deep link / intent URI
) {
    val navController = rememberNavController()
    val context       = LocalContext.current
    val historyFactory = remember {
        HistoryViewModelFactory(
            repo             = vm.repo,
            aliasRepo        = vm.aliasRepo,
            paymentCache     = vm.paymentCache,
            fiatCurrency    = vm.selectedCurrency,
            fiatSatsPerUnit = vm.fiatSatsPerUnit
        )
    }
    val historyVm: HistoryViewModel = viewModel(factory = historyFactory)

    val navBackStackEntry by navController.currentBackStackEntryAsState()
    val currentRoute = navBackStackEntry?.destination?.route

    val showBottomBar = currentRoute != ROUTE_PAYMENT_DETAIL
            && currentRoute != ROUTE_SCANNER
            && currentRoute != ROUTE_HISTORY

    val isFullScreenDestination = currentRoute == ROUTE_HISTORY
            || currentRoute == ROUTE_PAYMENT_DETAIL
            || currentRoute == ROUTE_SCANNER

    // ── Notification tap ──────────────────────────────────────────────────────
    val hash = pendingPaymentHash.value
    LaunchedEffect(hash) {
        if (hash != null) {
            navController.navigate("payment_detail/$hash") {
                launchSingleTop = true
            }
            pendingPaymentHash.value = null
        }
    }

    val activity = context as MainActivity
    LaunchedEffect(Unit) {
        activity.windowFocusEvents.collect {
            val cm   = context.getSystemService(ClipboardManager::class.java)
            val text = cm?.primaryClip?.getItemAt(0)
                ?.coerceToText(context)?.toString()
            vm.checkClipboard(text)
        }
    }

    LaunchedEffect(Unit) {
        vm.navigateToReceive.collect {
            Log.d("WalletScreen", "LNURL-WITHDRAW [NAV RECEIVED] switching to Receive tab")
            navController.navigate(TabItem.Receive.route) {
                popUpTo(navController.graph.findStartDestination().id) {
                    saveState = true
                }
                launchSingleTop = true
                restoreState    = true
            }
        }
    }

    val intentUri = pendingPaymentUri.value
    LaunchedEffect(intentUri) {
        if (intentUri != null) {
            Log.d("WalletScreen", "INTENT [URI] deep link received: $intentUri")
            pendingPaymentUri.value = null          // consume immediately
            vm.scan(intentUri)
            navController.navigate(TabItem.Send.route) {
                launchSingleTop = true
            }
        }
    }

    val clipboardOffer by vm.clipboardOfferState.collectAsStateWithLifecycle()

    // Auto-dismiss banner after 8 seconds
    LaunchedEffect(clipboardOffer) {
        if (clipboardOffer is ClipboardOfferState.Detected) {
            delay(8_000)
            vm.dismissClipboardOffer()
        }
    }

    Scaffold(
        bottomBar = {
            if (showBottomBar) {
                // ── Floating island nav bar: Receive | [Scan] | Send ──────────
                Box(
                    modifier = Modifier
                        .fillMaxWidth()
                        .navigationBarsPadding()
                        .padding(horizontal = 24.dp)
                        .padding(bottom = 16.dp),
                    contentAlignment = Alignment.Center
                ) {
                    Surface(
                        shape           = MaterialTheme.shapes.extraLarge,
                        color           = MaterialTheme.colorScheme.surfaceContainer,
                        tonalElevation  = 6.dp,
                        shadowElevation = 6.dp,
                        modifier        = Modifier.fillMaxWidth()
                    ) {
                        Row(
                            modifier          = Modifier
                                .fillMaxWidth()
                                .padding(horizontal = 8.dp, vertical = 4.dp),
                            verticalAlignment = Alignment.CenterVertically
                        ) {
                            // Receive
                            NavigationBarItem(
                                selected = currentRoute == TabItem.Receive.route,
                                icon     = { Icon(TabItem.Receive.icon, contentDescription = TabItem.Receive.label) },
                                label    = { Text(TabItem.Receive.label) },
                                modifier = Modifier.weight(1f),
                                onClick  = {
                                    if (currentRoute != TabItem.Receive.route) {
                                        navController.navigate(TabItem.Receive.route) {
                                            popUpTo(navController.graph.findStartDestination().id) {
                                                saveState = true
                                            }
                                            launchSingleTop = true
                                            restoreState    = true
                                        }
                                    }
                                }
                            )

                            // Scan — centre, elevated, not a nav destination
                            Box(
                                modifier         = Modifier.weight(1f),
                                contentAlignment = Alignment.Center
                            ) {
                                FilledIconButton(
                                    onClick  = { navController.navigate(ROUTE_SCANNER) },
                                    modifier = Modifier.size(52.dp),
                                    shape    = CircleShape
                                ) {
                                    Icon(
                                        imageVector        = Icons.Filled.QrCodeScanner,
                                        contentDescription = "Scan",
                                        modifier           = Modifier.size(26.dp)
                                    )
                                }
                            }

                            // Send
                            NavigationBarItem(
                                selected = currentRoute == TabItem.Send.route,
                                icon     = { Icon(TabItem.Send.icon, contentDescription = TabItem.Send.label) },
                                label    = { Text(TabItem.Send.label) },
                                modifier = Modifier.weight(1f),
                                onClick  = {
                                    if (currentRoute != TabItem.Send.route) {
                                        navController.navigate(TabItem.Send.route) {
                                            popUpTo(navController.graph.findStartDestination().id) {
                                                saveState = true
                                            }
                                            launchSingleTop = true
                                            restoreState    = true
                                        }
                                    }
                                }
                            )
                        }
                    }
                }
            }
        }
    ) { innerPadding ->
        Box(
            modifier = Modifier
                .fillMaxSize()
                .padding(bottom = innerPadding.calculateBottomPadding())
        ) {
            NavHost(
                navController    = navController,
                startDestination = ROUTE_HOME,
                modifier         = if (isFullScreenDestination)
                    Modifier.fillMaxSize()
                else
                    Modifier
                        .fillMaxSize()
                        .statusBarsPadding()
            ) {
                composable(ROUTE_HOME) {
                    HomeTab(
                        vm             = vm,
                        onHistoryClick = {
                            navController.navigate(ROUTE_HISTORY) {
                                launchSingleTop = true
                            }
                        }
                    )
                }
                composable(TabItem.Receive.route) { ReceiveScreen(vm) }
                composable(TabItem.Send.route)    { SendScreen(vm) }

                // Scanner — full screen, no bottom chrome
                composable(ROUTE_SCANNER) {
                    QrScannerScreen(
                        onScanned = { scanned ->
                            navController.popBackStack()
                            vm.scan(scanned)
                            navController.navigate(TabItem.Send.route) {
                                launchSingleTop = true
                            }
                        },
                        onDismiss = { navController.popBackStack() }
                    )
                }

                // History — full screen, no bottom chrome, close → home
                composable(
                    ROUTE_HISTORY,
                    enterTransition = { fadeIn(animationSpec = tween(150)) },
                    popExitTransition = { fadeOut(animationSpec = tween(150)) }

                ) {
                    HistoryScreen(
                        vm             = historyVm,
                        onClose        = {
                            navController.popBackStack(ROUTE_HOME, inclusive = false)
                        },
                        onPaymentClick = { payment ->
                            navController.navigate("payment_detail/${payment.paymentHash}")
                        }
                    )
                }

                // Payment detail — back → history (natural back stack)
                composable(
                    route     = ROUTE_PAYMENT_DETAIL,
                    arguments = listOf(navArgument("paymentHash") { type = NavType.StringType })
                ) { backStackEntry ->
                    val paymentHash = backStackEntry.arguments?.getString("paymentHash") ?: ""
                    val historyState by historyVm.state.collectAsState()
                    val payment = (historyState as? HistoryState.Success)
                        ?.payments
                        ?.firstOrNull { it.paymentHash == paymentHash }

                    if (payment != null) {
                        PaymentDetailScreen(
                            payment = payment,
                            vm      = historyVm,
                            onBack  = { navController.popBackStack() }
                        )
                    } else {
                        LaunchedEffect(paymentHash) { historyVm.refresh() }
                        Box(
                            modifier         = Modifier.fillMaxSize(),
                            contentAlignment = Alignment.Center
                        ) {
                            CircularProgressIndicator()
                        }
                    }
                }
            }

            // ── Clipboard banner — floats over content, slides in from top ────
            AnimatedVisibility(
                visible  = clipboardOffer is ClipboardOfferState.Detected,
                enter    = slideInVertically(initialOffsetY = { -it }),
                exit     = slideOutVertically(targetOffsetY = { -it }),
                modifier = Modifier
                    .align(Alignment.TopCenter)
                    .zIndex(1f)
                    .fillMaxWidth()
                    .statusBarsPadding()
            ) {
                if (clipboardOffer is ClipboardOfferState.Detected) {
                    val offer = clipboardOffer as ClipboardOfferState.Detected
                    val label = when (offer.inputType) {
                        is SendInputType.Bolt11           -> "Invoice"
                        is SendInputType.Lnurl            -> "LNURL"
                        is SendInputType.LightningAddress -> "Lightning Address"
                        else                              -> "Payment"
                    }
                    val subLabel = when (offer.inputType) {
                        is SendInputType.Lnurl -> "Tap to open"
                        else                   -> "Tap to pay"
                    }
                    Surface(
                        color    = MaterialTheme.colorScheme.primaryContainer,
                        modifier = Modifier
                            .fillMaxWidth()
                            .clickable {
                                vm.dismissClipboardOffer()
                                vm.scan(offer.raw)
                                navController.navigate(TabItem.Send.route) {
                                    launchSingleTop = true
                                }
                            }
                    ) {
                        Row(
                            modifier          = Modifier.padding(horizontal = 16.dp, vertical = 10.dp),
                            verticalAlignment = Alignment.CenterVertically
                        ) {
                            Icon(Icons.Default.ContentPaste, contentDescription = null)
                            Spacer(Modifier.width(12.dp))
                            Column(Modifier.weight(1f)) {
                                Text(
                                    "$label detected in clipboard",
                                    style = MaterialTheme.typography.bodyMedium
                                )
                                Text(
                                    subLabel,
                                    style = MaterialTheme.typography.bodySmall,
                                    color = MaterialTheme.colorScheme.onPrimaryContainer.copy(alpha = 0.7f)
                                )
                            }
                            IconButton(onClick = { vm.dismissClipboardOffer() }) {
                                Icon(Icons.Default.Close, contentDescription = "Dismiss")
                            }
                        }
                    }
                }
            }
        }
    }
}