package com.syncflow.ui.log

import androidx.compose.foundation.layout.*
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.filled.*
import androidx.compose.material3.*
import androidx.compose.runtime.*
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import androidx.hilt.navigation.compose.hiltViewModel
import com.syncflow.domain.model.SyncEventType
import com.syncflow.ui.shared.iconAndTint
import com.syncflow.ui.shared.label
import java.time.Duration
import java.time.Instant
import java.time.ZoneId
import java.time.format.DateTimeFormatter
import java.time.format.FormatStyle

@Composable
fun LogScreen(
    modifier: Modifier = Modifier,
    vm: LogViewModel = hiltViewModel(),
) {
    val entries by vm.entries.collectAsState()

    if (entries.isEmpty()) {
        Box(
            modifier = modifier.fillMaxSize(),
            contentAlignment = Alignment.Center,
        ) {
            Column(
                horizontalAlignment = Alignment.CenterHorizontally,
                verticalArrangement = Arrangement.spacedBy(8.dp),
            ) {
                Icon(
                    Icons.Default.Notifications,
                    contentDescription = null,
                    modifier = Modifier.size(72.dp),
                    tint = MaterialTheme.colorScheme.primary.copy(alpha = 0.35f),
                )
                Text("No activity yet", style = MaterialTheme.typography.titleMedium)
                Text(
                    "Sync events will appear here",
                    style = MaterialTheme.typography.bodySmall,
                    color = MaterialTheme.colorScheme.onSurfaceVariant,
                )
            }
        }
    } else {
        LazyColumn(
            modifier = modifier.fillMaxSize(),
            contentPadding = PaddingValues(horizontal = 16.dp, vertical = 8.dp),
            verticalArrangement = Arrangement.spacedBy(0.dp),
        ) {
            // Group entries by calendar date
            val grouped = entries.groupBy { entry ->
                entry.event.timestamp.atZone(ZoneId.systemDefault()).toLocalDate()
            }
            grouped.forEach { (date, dayEntries) ->
                item(key = date.toString()) {
                    Text(
                        text = date.toRelativeLabel(),
                        style = MaterialTheme.typography.labelMedium,
                        color = MaterialTheme.colorScheme.primary,
                        modifier = Modifier.padding(top = 16.dp, bottom = 4.dp),
                    )
                }
                items(dayEntries, key = { it.event.id }) { entry ->
                    LogEntryRow(entry)
                    HorizontalDivider(
                        color = MaterialTheme.colorScheme.outline.copy(alpha = 0.3f),
                        modifier = Modifier.padding(start = 52.dp),
                    )
                }
            }
            item { Spacer(Modifier.height(80.dp)) }
        }
    }
}

@Composable
private fun LogEntryRow(entry: LogEntry) {
    val (icon, tint) = entry.event.eventType.iconAndTint()
    val timeFmt = DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT)
    val timeStr = entry.event.timestamp.atZone(ZoneId.systemDefault()).let { timeFmt.format(it) }

    Row(
        modifier = Modifier
            .fillMaxWidth()
            .padding(vertical = 10.dp),
        verticalAlignment = Alignment.Top,
    ) {
        // Icon bubble
        Surface(
            shape = RoundedCornerShape(10.dp),
            color = tint.copy(alpha = 0.12f),
            modifier = Modifier.size(36.dp),
        ) {
            Box(contentAlignment = Alignment.Center) {
                Icon(icon, contentDescription = null, Modifier.size(18.dp), tint = tint)
            }
        }
        Spacer(Modifier.width(12.dp))
        Column(modifier = Modifier.weight(1f)) {
            Row(
                modifier = Modifier.fillMaxWidth(),
                horizontalArrangement = Arrangement.SpaceBetween,
                verticalAlignment = Alignment.CenterVertically,
            ) {
                Text(
                    entry.pairName,
                    style = MaterialTheme.typography.labelMedium,
                    color = MaterialTheme.colorScheme.primary,
                    modifier = Modifier.weight(1f, fill = false),
                )
                Text(
                    timeStr,
                    style = MaterialTheme.typography.labelSmall,
                    color = MaterialTheme.colorScheme.onSurfaceVariant,
                )
            }
            Spacer(Modifier.height(2.dp))
            Text(
                text = entry.event.eventType.label(),
                style = MaterialTheme.typography.bodySmall,
            )
            val detail = entry.event.filePath ?: entry.event.message
            if (detail != null) {
                Text(
                    text = detail,
                    style = MaterialTheme.typography.labelSmall,
                    color = MaterialTheme.colorScheme.onSurfaceVariant,
                    maxLines = 1,
                )
            }
        }
    }
}

private fun java.time.LocalDate.toRelativeLabel(): String {
    val today = java.time.LocalDate.now()
    return when {
        this == today -> "Today"
        this == today.minusDays(1) -> "Yesterday"
        else -> DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).format(this)
    }
}