package com.example.barokahstore.ui.screens

import android.app.DatePickerDialog
import androidx.compose.animation.AnimatedVisibility
import androidx.compose.foundation.background
import androidx.compose.foundation.border
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.*
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.foundation.text.KeyboardOptions
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.graphics.Color
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.text.font.FontFamily
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.input.KeyboardType
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.compose.ui.window.Dialog
import com.example.barokahstore.data.DatabaseHelper
import com.example.barokahstore.data.Receivable
import com.example.barokahstore.data.ReceivablePayment
import com.example.barokahstore.data.User
import java.util.Calendar

@OptIn(ExperimentalLayoutApi::class, ExperimentalMaterial3Api::class)
@Composable
fun PiutangScreen(
    dbHelper: DatabaseHelper,
    currentUser: User
) {
    var selectedFilter by remember { mutableStateOf("all") } // 'all', 'unpaid', 'partial', 'paid'
    var receivablesList by remember { mutableStateOf(listOf<Receivable>()) }
    var searchQuery by remember { mutableStateOf("") }

    // Dialog installment states
    var showPayDialog by remember { mutableStateOf(false) }
    var selectedReceivable by remember { mutableStateOf<Receivable?>(null) }
    var payAmountText by remember { mutableStateOf("") }
    var noteText by remember { mutableStateOf("") }
    var alertMessage by remember { mutableStateOf("") }

    // Dialog manual receivable states
    var showAddManualDialog by remember { mutableStateOf(false) }
    var manualCustomerName by remember { mutableStateOf("") }
    var manualTotalAmountText by remember { mutableStateOf("") }
    var manualNotesText by remember { mutableStateOf("") }
    var manualAlertMessage by remember { mutableStateOf("") }

    // Expanded items for showing history logs
    val expandedItems = remember { mutableStateMapOf<Int, Boolean>() }

    val context = LocalContext.current
    val calendar = Calendar.getInstance()

    fun refreshReceivables() {
        val filter = if (selectedFilter == "all") null else selectedFilter
        var list = dbHelper.getAllReceivables(filter)
        if (searchQuery.isNotEmpty()) {
            list = list.filter { it.customerName.contains(searchQuery, ignoreCase = true) || it.invoiceNo.contains(searchQuery) }
        }
        receivablesList = list
    }

    LaunchedEffect(selectedFilter, searchQuery) {
        refreshReceivables()
    }

    Column(
        modifier = Modifier
            .fillMaxSize()
            .padding(16.dp),
        verticalArrangement = Arrangement.spacedBy(16.dp)
    ) {
        // Search & Add Button Row
        Row(
            modifier = Modifier.fillMaxWidth(),
            horizontalArrangement = Arrangement.spacedBy(12.dp),
            verticalAlignment = Alignment.CenterVertically
        ) {
            OutlinedTextField(
                value = searchQuery,
                onValueChange = { searchQuery = it },
                placeholder = { Text("Cari nama pelanggan / invoice...") },
                leadingIcon = { Icon(Icons.Default.Search, contentDescription = null) },
                singleLine = true,
                shape = RoundedCornerShape(12.dp),
                modifier = Modifier.weight(1f)
            )

            Button(
                onClick = {
                    manualCustomerName = ""
                    manualTotalAmountText = ""
                    manualNotesText = ""
                    manualAlertMessage = ""
                    showAddManualDialog = true
                },
                colors = ButtonDefaults.buttonColors(containerColor = Color(0xFF4F46E5)),
                shape = RoundedCornerShape(12.dp),
                modifier = Modifier.height(50.dp)
            ) {
                Icon(Icons.Default.Add, contentDescription = null)
                Spacer(modifier = Modifier.width(4.dp))
                Text("Manual")
            }
        }

        // Filter chips row
        FlowRow(
            modifier = Modifier.fillMaxWidth(),
            horizontalArrangement = Arrangement.spacedBy(8.dp),
            verticalArrangement = Arrangement.spacedBy(8.dp)
        ) {
            val filters = listOf(
                Pair("Semua", "all"),
                Pair("Belum Lunas", "unpaid"),
                Pair("Dicicil", "partial"),
                Pair("Lunas", "paid")
            )
            
            filters.forEach { (label, key) ->
                val isSelected = selectedFilter == key
                FilterChip(
                    selected = isSelected,
                    onClick = { selectedFilter = key },
                    label = { Text(label) }
                )
            }
        }

        // List
        Card(
            modifier = Modifier
                .fillMaxWidth()
                .weight(1f),
            shape = RoundedCornerShape(16.dp),
            colors = CardDefaults.cardColors(containerColor = Color.White),
            elevation = CardDefaults.cardElevation(defaultElevation = 2.dp)
        ) {
            if (receivablesList.isEmpty()) {
                Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
                    Text("Data piutang tidak ditemukan", color = Color.Gray, fontSize = 14.sp)
                }
            } else {
                LazyColumn(modifier = Modifier.padding(16.dp)) {
                    items(receivablesList) { rec ->
                        val isExpanded = expandedItems[rec.id] ?: false
                        
                        Column(
                            modifier = Modifier
                                .fillMaxWidth()
                                .padding(vertical = 8.dp)
                                .border(0.5.dp, Color(0xFFE5E7EB), RoundedCornerShape(10.dp))
                                .padding(12.dp)
                        ) {
                            // Summary Row
                            Row(
                                modifier = Modifier
                                    .fillMaxWidth()
                                    .clickable { expandedItems[rec.id] = !isExpanded },
                                horizontalArrangement = Arrangement.SpaceBetween,
                                verticalAlignment = Alignment.CenterVertically
                            ) {
                                Column(modifier = Modifier.weight(1f)) {
                                    Text(rec.customerName, fontWeight = FontWeight.Bold, fontSize = 14.sp)
                                    val dueText = if (rec.dueDate.isNullOrEmpty()) "Manual" else rec.dueDate
                                    Text("Invoice: ${rec.invoiceNo} • Jatuh Tempo: $dueText", fontSize = 11.sp, color = Color.Gray)
                                    if (!rec.notes.isNullOrEmpty()) {
                                        Text("Keterangan: ${rec.notes}", fontSize = 11.sp, color = Color.DarkGray, fontWeight = FontWeight.Medium)
                                    }
                                    
                                    val remaining = rec.totalAmount - rec.paidAmount
                                    Row(modifier = Modifier.padding(top = 4.dp), horizontalArrangement = Arrangement.spacedBy(12.dp)) {
                                        Text("Total: ${formatRupiah(rec.totalAmount)}", fontSize = 11.sp, color = Color.Gray)
                                        Text("Sisa: ${formatRupiah(remaining)}", fontSize = 12.sp, fontWeight = FontWeight.Bold, color = Color.Red)
                                    }
                                    
                                    if (!rec.paidBy.isNullOrEmpty()) {
                                        Text("Diterima oleh: ${rec.paidBy}", fontSize = 11.sp, color = Color(0xFF059669), fontWeight = FontWeight.Medium, modifier = Modifier.padding(top = 4.dp))
                                    }
                                }

                                Column(horizontalAlignment = Alignment.End, verticalArrangement = Arrangement.spacedBy(8.dp)) {
                                    Surface(
                                        color = when(rec.status) {
                                            "paid" -> Color(0xFFD1FAE5)
                                            "partial" -> Color(0xFFFEF3C7)
                                            else -> Color(0xFFFEE2E2)
                                        },
                                        shape = RoundedCornerShape(6.dp)
                                    ) {
                                        Text(
                                            text = when(rec.status) {
                                                "paid" -> "Lunas"
                                                "partial" -> "Cicilan"
                                                else -> "Belum Bayar"
                                            }.uppercase(),
                                            color = when(rec.status) {
                                                "paid" -> Color(0xFF059669)
                                                "partial" -> Color(0xFFD97706)
                                                else -> Color(0xFFDC2626)
                                            },
                                            fontSize = 10.sp,
                                            fontWeight = FontWeight.Bold,
                                            modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp)
                                        )
                                    }
                                    
                                    if (rec.status != "paid") {
                                        Row(
                                            horizontalArrangement = Arrangement.spacedBy(6.dp),
                                            verticalAlignment = Alignment.CenterVertically
                                        ) {
                                            IconButton(
                                                onClick = {
                                                    dbHelper.markReceivableAsPaid(rec.id, currentUser.name)
                                                    refreshReceivables()
                                                },
                                                modifier = Modifier
                                                    .size(32.dp)
                                                    .background(Color(0xFFD1FAE5), CircleShape)
                                            ) {
                                                Icon(
                                                    imageVector = Icons.Default.Check,
                                                    contentDescription = "Lunas",
                                                    tint = Color(0xFF059669),
                                                    modifier = Modifier.size(16.dp)
                                                )
                                            }

                                            Button(
                                                onClick = {
                                                    selectedReceivable = rec
                                                    payAmountText = ""
                                                    noteText = ""
                                                    alertMessage = ""
                                                    showPayDialog = true
                                                },
                                                contentPadding = PaddingValues(horizontal = 12.dp, vertical = 4.dp),
                                                shape = RoundedCornerShape(8.dp),
                                                colors = ButtonDefaults.buttonColors(containerColor = Color(0xFF059669)),
                                                modifier = Modifier.height(32.dp)
                                            ) {
                                                Text("Bayar", fontSize = 11.sp, fontWeight = FontWeight.Bold)
                                            }
                                        }
                                    }
                                }
                            }

                            // Installment Logs list
                            AnimatedVisibility(visible = isExpanded) {
                                Column(modifier = Modifier.padding(top = 12.dp)) {
                                    Divider(color = Color(0xFFE5E7EB))
                                    Spacer(modifier = Modifier.height(8.dp))
                                    Text("Riwayat Cicilan:", fontSize = 12.sp, fontWeight = FontWeight.Bold, color = Color.Gray)
                                    
                                    val payments = remember(rec.id) { dbHelper.getReceivablePayments(rec.id) }
                                    if (payments.isEmpty()) {
                                        Text("Belum ada cicilan", fontSize = 11.sp, color = Color.LightGray, modifier = Modifier.padding(vertical = 4.dp))
                                    } else {
                                        payments.forEach { pay ->
                                            Row(
                                                modifier = Modifier
                                                    .fillMaxWidth()
                                                    .padding(vertical = 4.dp),
                                                horizontalArrangement = Arrangement.SpaceBetween
                                            ) {
                                                Column {
                                                    Text(pay.note ?: "Cicilan", fontSize = 12.sp, fontWeight = FontWeight.Medium)
                                                    Text(pay.paymentDate, fontSize = 10.sp, color = Color.Gray)
                                                }
                                                Text(formatRupiah(pay.payAmount), fontSize = 12.sp, fontWeight = FontWeight.Bold, color = Color(0xFF059669))
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    // --- PAY INSTALLMENT DIALOG ---
    if (showPayDialog && selectedReceivable != null) {
        val remaining = selectedReceivable!!.totalAmount - selectedReceivable!!.paidAmount
        Dialog(onDismissRequest = { showPayDialog = false }) {
            Card(
                shape = RoundedCornerShape(16.dp),
                colors = CardDefaults.cardColors(containerColor = Color.White),
                modifier = Modifier
                    .fillMaxWidth()
                    .padding(16.dp)
            ) {
                Column(
                    modifier = Modifier.padding(24.dp),
                    verticalArrangement = Arrangement.spacedBy(16.dp)
                ) {
                    Text(
                        text = "Bayar Cicilan Piutang",
                        fontSize = 18.sp,
                        fontWeight = FontWeight.Bold,
                        color = Color(0xFF1F2937),
                        modifier = Modifier.fillMaxWidth(),
                        textAlign = TextAlign.Center
                    )

                    Text(
                        text = "Pelanggan: ${selectedReceivable!!.customerName}\nSisa Piutang: ${formatRupiah(remaining)}",
                        fontSize = 13.sp,
                        color = Color.DarkGray
                    )

                    if (alertMessage.isNotEmpty()) {
                        Text(alertMessage, color = Color.Red, fontSize = 13.sp)
                    }

                    OutlinedTextField(
                        value = payAmountText,
                        onValueChange = { payAmountText = it },
                        label = { Text("Jumlah Bayar (Rp)") },
                        keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
                        singleLine = true,
                        shape = RoundedCornerShape(10.dp),
                        modifier = Modifier.fillMaxWidth()
                    )

                    OutlinedTextField(
                        value = noteText,
                        onValueChange = { noteText = it },
                        label = { Text("Catatan / Keterangan") },
                        singleLine = true,
                        shape = RoundedCornerShape(10.dp),
                        modifier = Modifier.fillMaxWidth()
                    )

                    Row(
                        modifier = Modifier.fillMaxWidth(),
                        horizontalArrangement = Arrangement.spacedBy(12.dp)
                    ) {
                        OutlinedButton(
                            onClick = { showPayDialog = false },
                            modifier = Modifier.weight(1f)
                        ) {
                            Text("Batal")
                        }
                        Button(
                            onClick = {
                                if (payAmountText.isBlank()) {
                                    alertMessage = "Jumlah bayar harus diisi!"
                                    return@Button
                                }
                                val amount = payAmountText.toDoubleOrNull() ?: 0.0
                                if (amount <= 0) {
                                    alertMessage = "Jumlah bayar tidak valid!"
                                    return@Button
                                }
                                if (amount > remaining) {
                                    alertMessage = "Pembayaran melebihi sisa piutang!"
                                    return@Button
                                }

                                val success = dbHelper.payReceivableInstallment(
                                    receivableId = selectedReceivable!!.id,
                                    amount = amount,
                                    note = noteText.trim().ifEmpty { "Pembayaran cicilan" },
                                    paidBy = currentUser.name
                                )

                                if (success) {
                                    refreshReceivables()
                                    showPayDialog = false
                                } else {
                                    alertMessage = "Gagal memproses cicilan!"
                                }
                            },
                            colors = ButtonDefaults.buttonColors(containerColor = Color(0xFF059669)),
                            modifier = Modifier.weight(1f)
                        ) {
                            Text("Simpan")
                        }
                    }
                }
            }
        }
    }

    // --- ADD MANUAL RECEIVABLE DIALOG ---
    if (showAddManualDialog) {
        Dialog(onDismissRequest = { showAddManualDialog = false }) {
            Card(
                shape = RoundedCornerShape(16.dp),
                colors = CardDefaults.cardColors(containerColor = Color.White),
                modifier = Modifier
                    .fillMaxWidth()
                    .padding(16.dp)
            ) {
                LazyColumn(
                    modifier = Modifier.padding(24.dp),
                    verticalArrangement = Arrangement.spacedBy(16.dp)
                ) {
                    item {
                        Text(
                            text = "Tambah Piutang Manual",
                            fontSize = 18.sp,
                            fontWeight = FontWeight.Bold,
                            color = Color(0xFF1F2937),
                            modifier = Modifier.fillMaxWidth(),
                            textAlign = TextAlign.Center
                        )
                    }

                    if (manualAlertMessage.isNotEmpty()) {
                        item {
                            Text(manualAlertMessage, color = Color.Red, fontSize = 13.sp)
                        }
                    }

                    item {
                        OutlinedTextField(
                            value = manualCustomerName,
                            onValueChange = { manualCustomerName = it },
                            label = { Text("Nama Pelanggan") },
                            singleLine = true,
                            shape = RoundedCornerShape(10.dp),
                            modifier = Modifier.fillMaxWidth()
                        )
                    }

                    item {
                        OutlinedTextField(
                            value = manualTotalAmountText,
                            onValueChange = { manualTotalAmountText = it },
                            label = { Text("Jumlah Piutang (Rp)") },
                            keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
                            singleLine = true,
                            shape = RoundedCornerShape(10.dp),
                            modifier = Modifier.fillMaxWidth()
                        )
                    }

                    item {
                        OutlinedTextField(
                            value = manualNotesText,
                            onValueChange = { manualNotesText = it },
                            label = { Text("Keterangan") },
                            singleLine = false,
                            maxLines = 3,
                            shape = RoundedCornerShape(10.dp),
                            modifier = Modifier.fillMaxWidth()
                        )
                    }

                    item {
                        Row(
                            modifier = Modifier.fillMaxWidth(),
                            horizontalArrangement = Arrangement.spacedBy(12.dp)
                        ) {
                            OutlinedButton(
                                onClick = { showAddManualDialog = false },
                                modifier = Modifier.weight(1f)
                            ) {
                                Text("Batal")
                            }
                            Button(
                                onClick = {
                                    if (manualCustomerName.isBlank() || manualTotalAmountText.isBlank()) {
                                        manualAlertMessage = "Nama dan jumlah piutang harus diisi!"
                                        return@Button
                                    }
                                    val total = manualTotalAmountText.toDoubleOrNull() ?: 0.0
                                    if (total <= 0.0) {
                                        manualAlertMessage = "Jumlah piutang tidak valid!"
                                        return@Button
                                    }

                                    val success = dbHelper.insertManualReceivable(
                                        customerName = manualCustomerName.trim(),
                                        totalAmount = total,
                                        notes = manualNotesText.trim()
                                    )

                                    if (success) {
                                        refreshReceivables()
                                        showAddManualDialog = false
                                    } else {
                                        manualAlertMessage = "Gagal menyimpan piutang!"
                                    }
                                },
                                colors = ButtonDefaults.buttonColors(containerColor = Color(0xFF4F46E5)),
                                modifier = Modifier.weight(1f)
                            ) {
                                Text("Simpan")
                            }
                        }
                    }
                }
            }
        }
    }
}