package com.bitcointxoko.gudariwallet.ui

import androidx.compose.foundation.layout.*
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.foundation.text.KeyboardActions
import androidx.compose.foundation.verticalScroll
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.ContentPaste
import androidx.compose.material3.*
import androidx.compose.runtime.*
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.platform.LocalClipboard
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.text.font.FontFamily
import androidx.compose.ui.text.input.ImeAction
import androidx.compose.ui.text.input.KeyboardType
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.unit.dp
import androidx.fragment.app.FragmentActivity
import androidx.lifecycle.compose.collectAsStateWithLifecycle
import com.bitcointxoko.gudariwallet.ui.send.Bolt11ConfirmCard
import com.bitcointxoko.gudariwallet.ui.send.LnurlInvoiceConfirmCard
import com.bitcointxoko.gudariwallet.ui.send.LnurlPayForm
import com.bitcointxoko.gudariwallet.util.SendInputDetector
import com.bitcointxoko.gudariwallet.util.feePpm
import kotlinx.coroutines.launch

@Composable
fun SendScreen(vm: WalletViewModel) {
    val sendState: SendState by vm.sendState.collectAsStateWithLifecycle()
    var input by remember { mutableStateOf("") }
    val context  = LocalContext.current
    val activity = context as FragmentActivity
    val clipboard = LocalClipboard.current
    val scope     = rememberCoroutineScope()

    // Read rate directly from VM cache — same source HomeTab uses.
    // Both are null when no currency is selected; fiat display is suppressed.
    val fiatRate     = vm.fiatRate       // Double?
    val fiatCurrency = vm.fiatCurrency   // String?

    DisposableEffect(Unit) { onDispose { vm.resetSendState() } }

    Column(
        modifier = Modifier
            .fillMaxSize()
            .verticalScroll(rememberScrollState())
            .padding(24.dp),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Top
    ) {
        Spacer(Modifier.height(16.dp))
        Text("Send", style = MaterialTheme.typography.headlineSmall)
        Spacer(Modifier.height(24.dp))

        if (sendState !is SendState.PaymentSent) {
            OutlinedTextField(
                value         = input,
                onValueChange = { input = SendInputDetector.normalize(it) },
                label         = { Text("Invoice, LNURL, or Lightning Address") },
                placeholder   = { Text("lnbc… / lnurl1… / user@domain.com") },
                modifier      = Modifier.fillMaxWidth(),
                enabled       = sendState is SendState.Idle || sendState is SendState.Error,
                singleLine    = false,
                maxLines      = 4,
                textStyle     = MaterialTheme.typography.bodySmall.copy(fontFamily = FontFamily.Monospace),
                keyboardOptions = KeyboardOptions(
                    keyboardType    = KeyboardType.Uri,
                    imeAction       = ImeAction.Go
                ),
                keyboardActions = KeyboardActions(
                    onGo = { if (input.isNotBlank()) vm.scan(input) }
                ),
            )
            Spacer(Modifier.height(8.dp))
        }

        when (val state = sendState) {
            is SendState.Idle -> {
                Button(
                    onClick = {
                        scope.launch {
                            val text = clipboard.getClipEntry()
                                ?.clipData
                                ?.getItemAt(0)
                                ?.text
                                ?.toString()
                            if (!text.isNullOrBlank()) {
                                input = SendInputDetector.normalize(text)
                                vm.scan(text)
                            }
                        }
                    },
                    modifier = Modifier.fillMaxWidth()
                ) {
                    Icon(
                        imageVector        = Icons.Filled.ContentPaste,
                        contentDescription = null,
                        modifier           = Modifier.size(18.dp)
                    )
                    Spacer(Modifier.width(8.dp))
                    Text("Paste")
                }
                Spacer(Modifier.height(8.dp))
                OutlinedButton(
                    onClick  = { if (input.isNotBlank()) vm.scan(input) },
                    enabled  = input.isNotBlank(),
                    modifier = Modifier.fillMaxWidth()
                ) { Text("Continue") }
            }

            is SendState.Scanning -> {
                Spacer(Modifier.height(16.dp))
                CircularProgressIndicator()
                Spacer(Modifier.height(8.dp))
                Text("Resolving…")
            }

            is SendState.Bolt11Decoded -> {
                Bolt11ConfirmCard(
                    state        = state,
                    activity      = activity,
                    vm           = vm,
                    fiatRate     = fiatRate,
                    fiatCurrency = fiatCurrency
                )
            }

            is SendState.LnurlReady -> {
                LnurlPayForm(
                    state        = state,
                    vm           = vm,
                    fiatRate     = fiatRate,
                    fiatCurrency = fiatCurrency
                )
            }

            is SendState.LnurlInvoiceReady -> {
                LnurlInvoiceConfirmCard(
                    state = state,
                    activity = activity,
                    vm = vm,
                    fiatRate = fiatRate,
                    fiatCurrency = fiatCurrency
                )
            }


            is SendState.Paying -> {
                Spacer(Modifier.height(16.dp))
                CircularProgressIndicator()
                Spacer(Modifier.height(8.dp))
                Text("Sending payment…")
            }

            is SendState.PaymentSent -> {
                Spacer(Modifier.height(32.dp))
                Text(
                    text  = "✓",
                    style = MaterialTheme.typography.displayLarge,
                    color = MaterialTheme.colorScheme.primary
                )
                Spacer(Modifier.height(8.dp))
                Text("Payment sent!", style = MaterialTheme.typography.headlineSmall)
                Spacer(Modifier.height(4.dp))
                Text(
                    text  = "${state.amountSats} sats",
                    color = MaterialTheme.colorScheme.onSurfaceVariant
                )

                Spacer(Modifier.height(4.dp))
                val feeText = when {
                    state.feeSats == null || state.feeSats == 0L -> "No fees"
                    else -> {
                        val ppm = feePpm(
                            amountMsat = state.amountSats * 1_000L,
                            feeMsat    = state.feeSats * 1_000L
                        )
                        val ppmSuffix = if (ppm != null) " (${ppm} ppm)" else ""
                        "Routing fee: ${state.feeSats} sat${if (state.feeSats == 1L) "" else "s"}$ppmSuffix"
                    }
                }
                Text(
                    text  = feeText,
                    style = MaterialTheme.typography.bodySmall,
                    color = MaterialTheme.colorScheme.onSurfaceVariant
                )
                Spacer(Modifier.height(32.dp))
                Button(
                    onClick  = { vm.resetSendState(); input = "" },
                    modifier = Modifier.fillMaxWidth()
                ) { Text("Send Another") }
            }

            is SendState.Error -> {
                Spacer(Modifier.height(8.dp))
                Text(
                    text      = state.message,
                    color     = MaterialTheme.colorScheme.error,
                    textAlign = TextAlign.Center
                )
                Spacer(Modifier.height(12.dp))
                Button(
                    onClick  = { if (input.isNotBlank()) vm.scan(input) },
                    enabled  = input.isNotBlank(),
                    modifier = Modifier.fillMaxWidth()
                ) { Text("Try Again") }
                Spacer(Modifier.height(8.dp))
                OutlinedButton(
                    onClick  = { vm.resetSendState(); input = "" },
                    modifier = Modifier.fillMaxWidth()
                ) { Text("Clear") }
            }
        }
    }
}