package com.peachpasswords.ui.vault

import androidx.compose.foundation.background
import androidx.compose.foundation.border
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Arrangement
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.padding
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.layout.systemBarsPadding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.automirrored.rounded.ArrowBack
import androidx.compose.material.icons.outlined.DeleteOutline
import androidx.compose.material3.Icon
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.collectAsState
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.text.style.TextDecoration
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.hilt.navigation.compose.hiltViewModel
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import com.peachpasswords.ui.components.FaviconInitials
import com.peachpasswords.ui.components.PeachEmptyOrEndState
import com.peachpasswords.ui.components.PeachTopBar
import com.peachpasswords.ui.theme.LocalPeachAccent
import com.peachpasswords.ui.theme.PeachSpacing
import com.peachpasswords.ui.theme.PeachType
import com.peachpasswords.ui.theme.ShellBackground
import com.peachpasswords.ui.theme.peachColors
import com.peachpasswords.vault.VaultEntry
import com.peachpasswords.vault.VaultRepository
import com.peachpasswords.vault.domainKey
import dagger.hilt.android.lifecycle.HiltViewModel
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.asStateFlow
import kotlinx.coroutines.launch
import javax.inject.Inject

@HiltViewModel
class TrashViewModel @Inject constructor(
    private val vault: VaultRepository,
) : ViewModel() {
    private val _deleted = MutableStateFlow(vault.getDeletedEntries())
    val deleted: StateFlow<List<VaultEntry>> = _deleted.asStateFlow()

    /** Retention window in days, or null when set to "Never". */
    val retentionDays: Int? get() = vault.settings.value.trashRetentionDays?.takeIf { it > 0 }

    private fun refresh() {
        _deleted.value = vault.getDeletedEntries()
    }

    fun restore(id: String) = viewModelScope.launch { vault.restoreEntry(id); refresh() }
    fun purge(id: String) = viewModelScope.launch { vault.purgeEntry(id); refresh() }
    fun emptyTrash() = viewModelScope.launch { vault.purgeDeletedEntries(); refresh() }
}

@Composable
fun TrashScreen(
    onBack: () -> Unit,
    vm: TrashViewModel = hiltViewModel(),
) {
    val deleted by vm.deleted.collectAsState()
    var confirmEmptyAll by remember { mutableStateOf(false) }
    var confirmPurge by remember { mutableStateOf<VaultEntry?>(null) }

    ShellBackground {
        Column(
            modifier = Modifier
                .fillMaxSize()
                .systemBarsPadding()
                .padding(horizontal = PeachSpacing.lg, vertical = PeachSpacing.md),
        ) {
            PeachTopBar(
                title = "Trash",
                leading = {
                    Icon(
                        Icons.AutoMirrored.Rounded.ArrowBack,
                        contentDescription = "back",
                        tint = peachColors.T0,
                        modifier = Modifier
                            .size(22.dp)
                            .clip(RoundedCornerShape(PeachSpacing.sm))
                            .clickable(onClick = onBack),
                    )
                },
                actions = {
                    if (deleted.isNotEmpty()) {
                        GhostPill("Empty trash", peachColors.Breach) { confirmEmptyAll = true }
                    }
                },
            )

            Spacer(Modifier.size(PeachSpacing.lg))

            if (deleted.isEmpty()) {
                Box(Modifier.weight(1f).fillMaxWidth(), contentAlignment = Alignment.Center) {
                    PeachEmptyOrEndState(
                        message = "Trash is empty.",
                        detail = "Deleted entries will wait here before they are gone for good.",
                    )
                }
            } else {
                LazyColumn(modifier = Modifier.weight(1f)) {
                    items(deleted, key = { it.id }) { entry ->
                        DeletedRow(
                            entry = entry,
                            onRestore = { vm.restore(entry.id) },
                            onPurge = { confirmPurge = entry },
                        )
                    }
                    item {
                        val days = vm.retentionDays
                        if (days != null) {
                            Text(
                                "Entries are permanently deleted after $days days",
                                color = peachColors.T2,
                                style = PeachType.labelMono,
                                textAlign = TextAlign.Center,
                                modifier = Modifier
                                    .fillMaxWidth()
                                    .padding(vertical = PeachSpacing.md),
                            )
                        } else {
                            PeachEmptyOrEndState(
                                message = "End of trash.",
                                detail = "Nothing below this point will be removed automatically.",
                            )
                        }
                    }
                }
            }
        }
    }

    if (confirmEmptyAll) {
        ConfirmOverlay(
            message = "Permanently delete all ${deleted.size} entries? This cannot be undone.",
            confirmLabel = "Empty trash",
            onConfirm = { vm.emptyTrash(); confirmEmptyAll = false },
            onCancel = { confirmEmptyAll = false },
        )
    }
    confirmPurge?.let { target ->
        ConfirmOverlay(
            message = "Permanently delete ${target.title}? This cannot be undone.",
            confirmLabel = "Delete",
            onConfirm = { vm.purge(target.id); confirmPurge = null },
            onCancel = { confirmPurge = null },
        )
    }
}

@Composable
private fun DeletedRow(entry: VaultEntry, onRestore: () -> Unit, onPurge: () -> Unit) {
    Row(
        verticalAlignment = Alignment.CenterVertically,
        modifier = Modifier
            .fillMaxWidth()
            .padding(vertical = PeachSpacing.sm),
    ) {
        FaviconInitials(source = entry.url ?: entry.title, size = 26.dp)
        Spacer(Modifier.width(PeachSpacing.sm))
        Column(Modifier.weight(1f)) {
            Text(
                entry.title,
                color = peachColors.T1,
                style = PeachType.entryNameList.copy(textDecoration = TextDecoration.LineThrough),
            )
            val domain = entry.domainKey()
            if (!domain.isNullOrBlank()) {
                Text(domain, color = peachColors.T2, style = PeachType.tinyMono)
            }
        }
        GhostPill("Restore", LocalPeachAccent.current, onRestore)
        Spacer(Modifier.width(PeachSpacing.sm))
        Icon(
            Icons.Outlined.DeleteOutline,
            contentDescription = "delete forever",
            tint = peachColors.Breach,
            modifier = Modifier
                .size(20.dp)
                .clip(RoundedCornerShape(6.dp))
                .clickable(onClick = onPurge),
        )
    }
}

@Composable
private fun GhostPill(label: String, color: androidx.compose.ui.graphics.Color, onClick: () -> Unit) {
    Box(
        modifier = Modifier
            .clip(RoundedCornerShape(999.dp))
            .border(1.dp, color.copy(alpha = 0.4f), RoundedCornerShape(999.dp))
            .clickable(onClick = onClick)
            .padding(horizontal = 12.dp, vertical = 5.dp),
    ) {
        Text(label, color = color, style = PeachType.sortPill.copy(fontSize = 10.sp))
    }
}

@Composable
private fun ConfirmOverlay(
    message: String,
    confirmLabel: String,
    onConfirm: () -> Unit,
    onCancel: () -> Unit,
) {
    Box(
        modifier = Modifier
            .fillMaxSize()
            .background(androidx.compose.ui.graphics.Color(0xCC000000))
            .clickable(onClick = onCancel),
        contentAlignment = Alignment.Center,
    ) {
        Column(
            modifier = Modifier
                .padding(PeachSpacing.xxl)
                .clip(RoundedCornerShape(PeachSpacing.lg))
                .background(peachColors.S2)
                .border(1.dp, peachColors.T3, RoundedCornerShape(PeachSpacing.lg))
                .clickable(enabled = false) {}
                .padding(22.dp),
        ) {
            Text(message, color = peachColors.T0, style = PeachType.body)
            Spacer(Modifier.size(PeachSpacing.lg))
            Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.End) {
                GhostPill("Cancel", peachColors.T1, onCancel)
                Spacer(Modifier.width(PeachSpacing.sm))
                GhostPill(confirmLabel, peachColors.Breach, onConfirm)
            }
        }
    }
}