package com.example.ui.screens

import android.content.Intent
import android.net.Uri
import androidx.compose.foundation.horizontalScroll
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.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.Add
import androidx.compose.material.icons.filled.ArrowForward
import androidx.compose.material.icons.filled.Call
import androidx.compose.material.icons.filled.Chat
import androidx.compose.material.icons.filled.CheckCircle
import androidx.compose.material.icons.filled.Event
import androidx.compose.material.icons.filled.FilterList
import androidx.compose.material.icons.filled.Person
import androidx.compose.material3.AlertDialog
import androidx.compose.material3.Button
import androidx.compose.material3.ButtonDefaults
import androidx.compose.material3.Card
import androidx.compose.material3.CardDefaults
import androidx.compose.material3.FilterChip
import androidx.compose.material3.FilterChipDefaults
import androidx.compose.material3.FloatingActionButton
import androidx.compose.material3.Icon
import androidx.compose.material3.IconButton
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.OutlinedButton
import androidx.compose.material3.OutlinedTextField
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.runtime.Composable
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.graphics.Color
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.platform.testTag
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.lifecycle.compose.collectAsStateWithLifecycle
import com.example.data.local.entity.LeadEntity
import com.example.ui.components.StatusBadge
import com.example.ui.theme.EmeraldDark
import com.example.ui.theme.EmeraldLight
import com.example.ui.theme.EmeraldPrimary
import com.example.ui.theme.TealSecondary
import com.example.ui.viewmodel.AppScreen
import com.example.ui.viewmodel.MarketingViewModel
import java.text.NumberFormat
import java.util.Locale

@Composable
fun LeadsCrmScreen(
    viewModel: MarketingViewModel,
    modifier: Modifier = Modifier
) {
    val context = LocalContext.current
    val leads by viewModel.leads.collectAsStateWithLifecycle()

    var selectedStageFilter by remember { mutableStateOf<String?>(null) }
    var showAddLeadModal by remember { mutableStateOf(false) }

    val stages = listOf("NEW", "CONTACTED", "INTERESTED", "FOLLOW_UP", "QUOTATION_SENT", "CONVERTED", "LOST")

    val filteredLeads = if (selectedStageFilter == null) {
        leads
    } else {
        leads.filter { it.status == selectedStageFilter }
    }

    val totalPipeline = leads.filter { it.status != "LOST" }.sumOf { it.conversionValue }
    val convertedTotal = leads.filter { it.status == "CONVERTED" }.sumOf { it.conversionValue }

    Box(modifier = modifier.fillMaxSize()) {
        Column(
            modifier = Modifier
                .fillMaxSize()
                .padding(horizontal = 16.dp)
        ) {
            Spacer(modifier = Modifier.height(8.dp))

            // Pipeline Summary Card
            Card(
                modifier = Modifier.fillMaxWidth(),
                shape = RoundedCornerShape(14.dp),
                colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surface),
                elevation = CardDefaults.cardElevation(defaultElevation = 2.dp)
            ) {
                Row(
                    modifier = Modifier
                        .fillMaxWidth()
                        .padding(16.dp),
                    horizontalArrangement = Arrangement.SpaceBetween
                ) {
                    Column {
                        Text("Active Pipeline Value", fontSize = 12.sp, color = MaterialTheme.colorScheme.onSurfaceVariant)
                        Text(
                            text = "₹ ${(totalPipeline / 100000).toInt()} Lakhs",
                            fontSize = 20.sp,
                            fontWeight = FontWeight.Bold,
                            color = EmeraldPrimary
                        )
                    }
                    Column(horizontalAlignment = Alignment.End) {
                        Text("Total Converted Revenue", fontSize = 12.sp, color = MaterialTheme.colorScheme.onSurfaceVariant)
                        Text(
                            text = "₹ ${(convertedTotal / 100000).toInt()} Lakhs",
                            fontSize = 20.sp,
                            fontWeight = FontWeight.Bold,
                            color = Color(0xFF0284C7)
                        )
                    }
                }
            }

            Spacer(modifier = Modifier.height(12.dp))

            // Status stage filters
            Row(
                modifier = Modifier
                    .fillMaxWidth()
                    .horizontalScroll(rememberScrollState()),
                horizontalArrangement = Arrangement.spacedBy(6.dp)
            ) {
                FilterChip(
                    selected = selectedStageFilter == null,
                    onClick = { selectedStageFilter = null },
                    label = { Text("All Stages (${leads.size})", fontSize = 11.sp) },
                    colors = FilterChipDefaults.filterChipColors(
                        selectedContainerColor = EmeraldPrimary.copy(alpha = 0.15f),
                        selectedLabelColor = EmeraldPrimary
                    )
                )

                stages.forEach { stage ->
                    val count = leads.count { it.status == stage }
                    FilterChip(
                        selected = selectedStageFilter == stage,
                        onClick = {
                            selectedStageFilter = if (selectedStageFilter == stage) null else stage
                        },
                        label = { Text("${stage.replace("_", " ")} ($count)", fontSize = 11.sp) },
                        colors = FilterChipDefaults.filterChipColors(
                            selectedContainerColor = EmeraldPrimary.copy(alpha = 0.15f),
                            selectedLabelColor = EmeraldPrimary
                        )
                    )
                }
            }

            Spacer(modifier = Modifier.height(10.dp))

            // Leads List
            if (filteredLeads.isEmpty()) {
                Box(
                    modifier = Modifier
                        .fillMaxSize()
                        .weight(1f),
                    contentAlignment = Alignment.Center
                ) {
                    Text(
                        text = "No leads in this stage.",
                        fontSize = 14.sp,
                        color = MaterialTheme.colorScheme.onSurfaceVariant
                    )
                }
            } else {
                LazyColumn(
                    modifier = Modifier.weight(1f),
                    verticalArrangement = Arrangement.spacedBy(12.dp)
                ) {
                    items(filteredLeads) { lead ->
                        LeadCard(
                            lead = lead,
                            onAdvanceStage = {
                                val nextStage = when (lead.status) {
                                    "NEW" -> "CONTACTED"
                                    "CONTACTED" -> "INTERESTED"
                                    "INTERESTED" -> "FOLLOW_UP"
                                    "FOLLOW_UP" -> "QUOTATION_SENT"
                                    "QUOTATION_SENT" -> "CONVERTED"
                                    else -> "CONVERTED"
                                }
                                viewModel.updateLeadStatus(lead.id, nextStage)
                            },
                            onOpenChat = {
                                viewModel.navigateTo(AppScreen.INBOX)
                            },
                            onCall = {
                                val dialIntent = Intent(Intent.ACTION_DIAL, Uri.parse("tel:${lead.mobileNumber}"))
                                context.startActivity(dialIntent)
                            }
                        )
                    }
                    item {
                        Spacer(modifier = Modifier.height(72.dp))
                    }
                }
            }
        }

        // FAB to Add Lead
        FloatingActionButton(
            onClick = { showAddLeadModal = true },
            modifier = Modifier
                .align(Alignment.BottomEnd)
                .padding(20.dp)
                .testTag("add_lead_fab"),
            containerColor = EmeraldPrimary,
            contentColor = Color.White
        ) {
            Icon(Icons.Default.Add, contentDescription = "Add Lead")
        }

        if (showAddLeadModal) {
            AddLeadDialog(
                onDismiss = { showAddLeadModal = false },
                onSave = { newLead ->
                    viewModel.addNewLead(newLead)
                    showAddLeadModal = false
                }
            )
        }
    }
}

@Composable
fun LeadCard(
    lead: LeadEntity,
    onAdvanceStage: () -> Unit,
    onOpenChat: () -> Unit,
    onCall: () -> Unit
) {
    Card(
        modifier = Modifier.fillMaxWidth(),
        shape = RoundedCornerShape(12.dp),
        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surface),
        elevation = CardDefaults.cardElevation(defaultElevation = 1.dp)
    ) {
        Column(modifier = Modifier.padding(14.dp)) {
            Row(
                modifier = Modifier.fillMaxWidth(),
                horizontalArrangement = Arrangement.SpaceBetween,
                verticalAlignment = Alignment.Top
            ) {
                Column(modifier = Modifier.weight(1f)) {
                    Text(
                        text = lead.customerName,
                        fontWeight = FontWeight.Bold,
                        fontSize = 15.sp,
                        color = MaterialTheme.colorScheme.onSurface
                    )
                    Text(
                        text = "${lead.businessName} • Phone: ${lead.mobileNumber}",
                        fontSize = 12.sp,
                        color = MaterialTheme.colorScheme.onSurfaceVariant
                    )
                    Text(
                        text = "Source: ${lead.campaignSource}",
                        fontSize = 11.sp,
                        color = EmeraldPrimary,
                        fontWeight = FontWeight.Medium
                    )
                }

                StatusBadge(status = lead.status)
            }

            Spacer(modifier = Modifier.height(8.dp))

            Surface(
                color = Color(0xFFF8FAFC),
                shape = RoundedCornerShape(8.dp),
                modifier = Modifier.fillMaxWidth()
            ) {
                Column(modifier = Modifier.padding(8.dp)) {
                    Text(
                        text = "Interest: ${lead.productInterest}",
                        fontWeight = FontWeight.SemiBold,
                        fontSize = 12.sp,
                        color = MaterialTheme.colorScheme.onSurface
                    )
                    Text(
                        text = lead.enquiryDescription,
                        fontSize = 11.sp,
                        color = MaterialTheme.colorScheme.onSurfaceVariant
                    )
                    if (lead.salesNotes.isNotBlank()) {
                        Spacer(modifier = Modifier.height(4.dp))
                        Text(
                            text = "Notes: ${lead.salesNotes}",
                            fontSize = 11.sp,
                            color = Color(0xFF475569)
                        )
                    }
                }
            }

            Spacer(modifier = Modifier.height(8.dp))

            Row(
                modifier = Modifier.fillMaxWidth(),
                horizontalArrangement = Arrangement.SpaceBetween,
                verticalAlignment = Alignment.CenterVertically
            ) {
                Row(verticalAlignment = Alignment.CenterVertically) {
                    Icon(Icons.Default.Event, contentDescription = null, tint = Color.Gray, modifier = Modifier.size(14.dp))
                    Spacer(modifier = Modifier.width(4.dp))
                    Text(
                        text = "Follow-up: ${lead.followUpDate} • ${lead.assignedTo}",
                        fontSize = 11.sp,
                        color = MaterialTheme.colorScheme.onSurfaceVariant
                    )
                }

                Text(
                    text = "₹ ${lead.conversionValue.toInt()}",
                    fontWeight = FontWeight.Bold,
                    fontSize = 14.sp,
                    color = EmeraldPrimary
                )
            }

            Spacer(modifier = Modifier.height(10.dp))

            // Action row
            Row(
                modifier = Modifier.fillMaxWidth(),
                horizontalArrangement = Arrangement.SpaceBetween,
                verticalAlignment = Alignment.CenterVertically
            ) {
                Row(horizontalArrangement = Arrangement.spacedBy(6.dp)) {
                    IconButton(onClick = onCall, modifier = Modifier.size(34.dp)) {
                        Icon(Icons.Default.Call, contentDescription = "Call", tint = EmeraldPrimary, modifier = Modifier.size(18.dp))
                    }
                    IconButton(onClick = onOpenChat, modifier = Modifier.size(34.dp)) {
                        Icon(Icons.Default.Chat, contentDescription = "Chat", tint = Color(0xFF0284C7), modifier = Modifier.size(18.dp))
                    }
                }

                if (lead.status != "CONVERTED" && lead.status != "LOST") {
                    OutlinedButton(
                        onClick = onAdvanceStage,
                        shape = RoundedCornerShape(8.dp)
                    ) {
                        Text("Advance Stage", fontSize = 11.sp)
                        Spacer(modifier = Modifier.width(4.dp))
                        Icon(Icons.Default.ArrowForward, contentDescription = null, modifier = Modifier.size(12.dp))
                    }
                }
            }
        }
    }
}

@Composable
fun AddLeadDialog(
    onDismiss: () -> Unit,
    onSave: (LeadEntity) -> Unit
) {
    var name by remember { mutableStateOf("") }
    var phone by remember { mutableStateOf("") }
    var company by remember { mutableStateOf("") }
    var interest by remember { mutableStateOf("Commercial Solar Rooftop") }
    var valueStr by remember { mutableStateOf("250000") }
    var followUpDate by remember { mutableStateOf("2026-10-25") }
    var notes by remember { mutableStateOf("") }

    AlertDialog(
        onDismissRequest = onDismiss,
        title = { Text("Create New Sales Lead") },
        text = {
            Column(
                modifier = Modifier.fillMaxWidth(),
                verticalArrangement = Arrangement.spacedBy(8.dp)
            ) {
                OutlinedTextField(
                    value = name,
                    onValueChange = { name = it },
                    label = { Text("Prospect Name *") },
                    singleLine = true,
                    modifier = Modifier.fillMaxWidth()
                )
                OutlinedTextField(
                    value = phone,
                    onValueChange = { phone = it },
                    label = { Text("Phone Number (+91...) *") },
                    singleLine = true,
                    modifier = Modifier.fillMaxWidth()
                )
                OutlinedTextField(
                    value = company,
                    onValueChange = { company = it },
                    label = { Text("Business / Company Name") },
                    singleLine = true,
                    modifier = Modifier.fillMaxWidth()
                )
                OutlinedTextField(
                    value = interest,
                    onValueChange = { interest = it },
                    label = { Text("Product / Project Interest") },
                    singleLine = true,
                    modifier = Modifier.fillMaxWidth()
                )
                OutlinedTextField(
                    value = valueStr,
                    onValueChange = { valueStr = it },
                    label = { Text("Estimated Deal Value (₹)") },
                    singleLine = true,
                    modifier = Modifier.fillMaxWidth()
                )
                OutlinedTextField(
                    value = followUpDate,
                    onValueChange = { followUpDate = it },
                    label = { Text("Follow-Up Date (YYYY-MM-DD)") },
                    singleLine = true,
                    modifier = Modifier.fillMaxWidth()
                )
                OutlinedTextField(
                    value = notes,
                    onValueChange = { notes = it },
                    label = { Text("Enquiry Notes") },
                    modifier = Modifier.fillMaxWidth()
                )
            }
        },
        confirmButton = {
            Button(
                onClick = {
                    if (name.isNotBlank() && phone.isNotBlank()) {
                        onSave(
                            LeadEntity(
                                customerName = name,
                                mobileNumber = if (phone.startsWith("+")) phone else "+91$phone",
                                businessName = company,
                                campaignSource = "Direct WhatsApp Lead",
                                productInterest = interest,
                                enquiryDescription = notes.ifEmpty { "Manual lead creation" },
                                status = "NEW",
                                assignedTo = "Rahul Sharma",
                                followUpDate = followUpDate,
                                conversionValue = valueStr.toDoubleOrNull() ?: 0.0,
                                salesNotes = notes
                            )
                        )
                    }
                },
                colors = ButtonDefaults.buttonColors(containerColor = EmeraldPrimary)
            ) {
                Text("Save Lead")
            }
        },
        dismissButton = {
            TextButton(onClick = onDismiss) { Text("Cancel") }
        }
    )
}