import Combine
import SwiftUI

struct DashboardView: View {
    @State private var store = AppStore.shared
    @State private var session = SessionStore.shared
    private let refreshTimer = Timer.publish(every: 20, on: .main, in: .common).autoconnect()
    private let columns = [GridItem(.adaptive(minimum: 220), spacing: 14)]

    var body: some View {
        ScrollView {
            VStack(alignment: .leading, spacing: 20) {
                header

                if let error = store.errorMessage {
                    errorBanner(error)
                }

                if store.isLoading && store.lastRefreshAt == nil {
                    loadingPanel
                } else {
                    metricsGrid
                    liveStatusPanel
                    followUpLoadPanel
                    leadFocusPanel
                    inventoryPanel
                }
            }
            .padding(20)
        }
        .background(VelocityTheme.background)
        .scrollContentBackground(.hidden)
        .task { await store.refresh() }
        .refreshable { await store.refresh() }
        .onReceive(refreshTimer) { _ in
            Task { await store.refresh(silent: true) }
        }
    }

    private var header: some View {
        HStack(alignment: .top) {
            VStack(alignment: .leading, spacing: 4) {
                Text("Dashboard")
                    .font(.system(size: 28, weight: .bold))
                    .foregroundStyle(VelocityTheme.foreground)
                Text("Live mobile operator posture for canonical CRM pipeline, inventory, and follow-up load.")
                    .font(.system(size: 12))
                    .foregroundStyle(VelocityTheme.mutedFg)
            }
            Spacer()
            VStack(alignment: .trailing, spacing: 8) {
                statusBadge(
                    label: session.isConfigured ? "Live backend" : "Config required",
                    color: session.isConfigured ? VelocityTheme.success : VelocityTheme.warning
                )
                if let lastRefresh = store.lastRefreshAt {
                    Text("Updated \(lastRefresh.relativeShort)")
                        .font(.system(size: 11, weight: .medium))
                        .foregroundStyle(VelocityTheme.mutedFg)
                }
            }
        }
    }

    private var metricsGrid: some View {
        LazyVGrid(columns: columns, spacing: 14) {
            MetricCard(title: "Leads", value: "\(store.metrics.leadCount)", subtitle: "Live CRM records", color: VelocityTheme.accent)
            MetricCard(title: "Whale Leads", value: "\(store.metrics.whaleLeadCount)", subtitle: "Score 90+ or whale qualified", color: VelocityTheme.success)
            MetricCard(title: "Pending Tasks", value: "\(store.metrics.pendingTaskCount)", subtitle: "Canonical CRM reminders", color: VelocityTheme.warning)
            MetricCard(title: "Urgent Tasks", value: "\(store.metrics.urgentTaskCount)", subtitle: "High and urgent follow-ups", color: VelocityTheme.danger)
            MetricCard(title: "Inventory", value: "\(store.metrics.propertyCount)", subtitle: "Property rows available", color: VelocityTheme.warning)
            MetricCard(title: "Today", value: "\(store.metrics.todayCalendarCount)", subtitle: "Calendar slots scheduled", color: Color(red: 0.60, green: 0.57, blue: 0.99))
        }
    }

    private var liveStatusPanel: some View {
        VStack(alignment: .leading, spacing: 14) {
            HStack {
                Text("Live Status")
                    .font(.system(size: 16, weight: .semibold))
                    .foregroundStyle(VelocityTheme.foreground)
                Spacer()
                statusBadge(label: session.authModeDescription, color: VelocityTheme.accent)
            }

            detailRow(title: "Endpoint", value: session.endpointDisplay)
            detailRow(title: "Operator", value: session.operatorIdentity)
            detailRow(title: "Pending CRM tasks", value: "\(store.metrics.pendingTaskCount)")
            detailRow(title: "Pending insights", value: "\(store.metrics.pendingInsights)")
            detailRow(title: "Pending transcriptions", value: "\(store.metrics.pendingTranscriptions)")
        }
        .padding(20)
        .glassCard(cornerRadius: 18)
    }

    private var followUpLoadPanel: some View {
        VStack(alignment: .leading, spacing: 14) {
            Text("Follow-Up Load")
                .font(.system(size: 16, weight: .semibold))
                .foregroundStyle(VelocityTheme.foreground)

            if store.prioritizedTasks.isEmpty {
                emptyMessage("No canonical CRM reminder tasks are pending for this operator right now.")
            } else {
                ForEach(store.prioritizedTasks.prefix(4)) { task in
                    HStack(alignment: .top, spacing: 14) {
                        VStack(alignment: .leading, spacing: 5) {
                            Text(task.title)
                                .font(.system(size: 14, weight: .semibold))
                                .foregroundStyle(VelocityTheme.foreground)
                            Text("\(task.ownerLabel) · \(task.dueLabel)")
                                .font(.system(size: 12))
                                .foregroundStyle(VelocityTheme.mutedFg)
                            Text(taskNote(task))
                                .font(.system(size: 12))
                                .foregroundStyle(VelocityTheme.mutedFg)
                                .lineLimit(2)
                        }
                        Spacer()
                        Text(task.priorityLabel)
                            .font(.system(size: 10, weight: .semibold))
                            .foregroundStyle(priorityColor(for: task.priority))
                    }
                    .padding(14)
                    .background(
                        RoundedRectangle(cornerRadius: 14)
                            .fill(VelocityTheme.surface)
                            .overlay(
                                RoundedRectangle(cornerRadius: 14)
                                    .stroke(VelocityTheme.borderSubtle, lineWidth: 1)
                            )
                    )
                }
            }
        }
        .padding(20)
        .glassCard(cornerRadius: 18)
    }

    private var leadFocusPanel: some View {
        VStack(alignment: .leading, spacing: 14) {
            Text("Client Focus")
                .font(.system(size: 16, weight: .semibold))
                .foregroundStyle(VelocityTheme.foreground)

            if store.highlightedLeads.isEmpty {
                emptyMessage("No canonical CRM contacts with active lead context have been returned by the backend yet.")
            } else {
                ForEach(store.highlightedLeads) { lead in
                    HStack(alignment: .top, spacing: 14) {
                        VStack(alignment: .leading, spacing: 5) {
                            Text(lead.name)
                                .font(.system(size: 14, weight: .semibold))
                                .foregroundStyle(VelocityTheme.foreground)
                            Text("\(lead.unitInterest) · \(lead.budget)")
                                .font(.system(size: 12))
                                .foregroundStyle(VelocityTheme.mutedFg)
                        }
                        Spacer()
                        VStack(alignment: .trailing, spacing: 4) {
                            Text("\(lead.score)")
                                .font(.system(size: 20, weight: .bold))
                                .foregroundStyle(VelocityTheme.foreground)
                            Text(lead.kanbanStatus.replacingOccurrences(of: "_", with: " ").capitalized)
                                .font(.system(size: 10, weight: .medium))
                                .foregroundStyle(VelocityTheme.accent)
                        }
                    }
                    .padding(14)
                    .background(
                        RoundedRectangle(cornerRadius: 14)
                            .fill(VelocityTheme.surface)
                            .overlay(
                                RoundedRectangle(cornerRadius: 14)
                                    .stroke(VelocityTheme.borderSubtle, lineWidth: 1)
                            )
                    )
                }
            }
        }
        .padding(20)
        .glassCard(cornerRadius: 18)
    }

    private var inventoryPanel: some View {
        VStack(alignment: .leading, spacing: 14) {
            Text("Inventory Coverage")
                .font(.system(size: 16, weight: .semibold))
                .foregroundStyle(VelocityTheme.foreground)

            if store.properties.isEmpty {
                emptyMessage("No live inventory properties are available yet for this operator scope.")
            } else {
                ForEach(store.properties.prefix(4)) { property in
                    VStack(alignment: .leading, spacing: 6) {
                        Text(property.projectName)
                            .font(.system(size: 14, weight: .semibold))
                            .foregroundStyle(VelocityTheme.foreground)
                        Text("\(property.developerName) · \(property.propertyType.capitalized)")
                            .font(.system(size: 12))
                            .foregroundStyle(VelocityTheme.mutedFg)
                        Text(property.locationSummary)
                            .font(.system(size: 12))
                            .foregroundStyle(VelocityTheme.mutedFg)
                    }
                    .padding(14)
                    .frame(maxWidth: .infinity, alignment: .leading)
                    .background(
                        RoundedRectangle(cornerRadius: 14)
                            .fill(VelocityTheme.surface)
                            .overlay(
                                RoundedRectangle(cornerRadius: 14)
                                    .stroke(VelocityTheme.borderSubtle, lineWidth: 1)
                            )
                    )
                }
            }
        }
        .padding(20)
        .glassCard(cornerRadius: 18)
    }

    private func detailRow(title: String, value: String) -> some View {
        VStack(alignment: .leading, spacing: 4) {
            Text(title.uppercased())
                .font(.system(size: 10, weight: .semibold))
                .tracking(1)
                .foregroundStyle(VelocityTheme.mutedFg)
            Text(value)
                .font(.system(size: 14))
                .foregroundStyle(VelocityTheme.foreground)
        }
    }

    private func emptyMessage(_ message: String) -> some View {
        Text(message)
            .font(.system(size: 13))
            .foregroundStyle(VelocityTheme.mutedFg)
            .frame(maxWidth: .infinity, alignment: .leading)
    }

    private func statusBadge(label: String, color: Color) -> some View {
        Text(label)
            .font(.system(size: 11, weight: .semibold))
            .foregroundStyle(color)
            .padding(.horizontal, 10)
            .padding(.vertical, 6)
            .background(
                Capsule()
                    .fill(color.opacity(0.12))
                    .overlay(Capsule().stroke(color.opacity(0.22), lineWidth: 1))
            )
    }

    private var loadingPanel: some View {
        VStack(alignment: .leading, spacing: 12) {
            ProgressView()
                .progressViewStyle(CircularProgressViewStyle(tint: VelocityTheme.accent))
            Text("Loading live dashboard data...")
                .font(.system(size: 14, weight: .semibold))
                .foregroundStyle(VelocityTheme.foreground)
            Text("Velocity is reading canonical CRM contacts, reminders, alerts, calendar events, and inventory summaries from the backend.")
                .font(.system(size: 12))
                .foregroundStyle(VelocityTheme.mutedFg)
        }
        .padding(20)
        .glassCard(cornerRadius: 18)
    }

    private func errorBanner(_ message: String) -> some View {
        Text(message)
            .font(.system(size: 13, weight: .medium))
            .foregroundStyle(VelocityTheme.danger)
            .padding(14)
            .frame(maxWidth: .infinity, alignment: .leading)
            .background(
                RoundedRectangle(cornerRadius: 14)
                    .fill(VelocityTheme.danger.opacity(0.10))
                    .overlay(
                        RoundedRectangle(cornerRadius: 14)
                            .stroke(VelocityTheme.danger.opacity(0.22), lineWidth: 1)
                    )
            )
    }

    private func priorityColor(for priority: String) -> Color {
        switch priority.lowercased() {
        case "urgent":
            return VelocityTheme.danger
        case "high":
            return VelocityTheme.warning
        default:
            return VelocityTheme.accent
        }
    }

    private func taskNote(_ task: VelocityTaskDTO) -> String {
        let note = task.notes?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        return note.isEmpty ? "No operator note yet." : note
    }
}

private struct MetricCard: View {
    let title: String
    let value: String
    let subtitle: String
    let color: Color

    var body: some View {
        VStack(alignment: .leading, spacing: 10) {
            Text(title.uppercased())
                .font(.system(size: 10, weight: .semibold))
                .tracking(1)
                .foregroundStyle(VelocityTheme.mutedFg)
            Text(value)
                .font(.system(size: 28, weight: .bold))
                .foregroundStyle(VelocityTheme.foreground)
            Text(subtitle)
                .font(.system(size: 12))
                .foregroundStyle(VelocityTheme.mutedFg)
            RoundedRectangle(cornerRadius: 4)
                .fill(color)
                .frame(width: 52, height: 4)
        }
        .padding(18)
        .frame(maxWidth: .infinity, alignment: .leading)
        .glassCard(cornerRadius: 16)
    }
}

#Preview {
    DashboardView()
}