import SwiftUI
import Charts

struct DashboardView: View {
    @EnvironmentObject var iapService: IAPService
    @StateObject private var viewModel: DashboardViewModel

    init() {
        _viewModel = StateObject(wrappedValue: DashboardViewModel())
    }

    var body: some View {
        NavigationStack {
            ScrollView {
                VStack(spacing: 20) {
                    if viewModel.hasData {
                        // Total Value Card
                        TotalValueCard(
                            totalValue: viewModel.portfolioSummary.formattedTotalValue,
                            dayChange: viewModel.portfolioSummary.formattedDayChange,
                            isPositive: viewModel.isDayChangePositive
                        )

                        // Evolution Chart
                        if !viewModel.evolutionData.isEmpty {
                            EvolutionChartCard(data: viewModel.evolutionData)
                        }

                        // Period Returns
                        PeriodReturnsCard(
                            monthChange: viewModel.portfolioSummary.formattedMonthChange,
                            yearChange: viewModel.portfolioSummary.formattedYearChange,
                            allTimeChange: viewModel.portfolioSummary.formattedAllTimeReturn,
                            isMonthPositive: viewModel.isMonthChangePositive,
                            isYearPositive: viewModel.isYearChangePositive,
                            isAllTimePositive: viewModel.portfolioSummary.allTimeReturn >= 0
                        )

                        // Category Breakdown
                        if !viewModel.categoryMetrics.isEmpty {
                            CategoryBreakdownCard(categories: viewModel.topCategories)
                        }

                        // Pending Updates
                        if !viewModel.sourcesNeedingUpdate.isEmpty {
                            PendingUpdatesCard(sources: viewModel.sourcesNeedingUpdate)
                        }
                    } else {
                        EmptyDashboardView()
                    }
                }
                .padding()
            }
            .navigationTitle("Dashboard")
            .refreshable {
                viewModel.refreshData()
            }
            .overlay {
                if viewModel.isLoading {
                    ProgressView()
                }
            }
        }
    }
}

// MARK: - Total Value Card

struct TotalValueCard: View {
    let totalValue: String
    let dayChange: String
    let isPositive: Bool

    var body: some View {
        VStack(spacing: 8) {
            Text("Total Portfolio Value")
                .font(.subheadline)
                .foregroundColor(.secondary)

            Text(totalValue)
                .font(.system(size: 42, weight: .bold, design: .rounded))
                .foregroundColor(.primary)

            HStack(spacing: 4) {
                Image(systemName: isPositive ? "arrow.up.right" : "arrow.down.right")
                    .font(.caption)
                Text(dayChange)
                    .font(.subheadline.weight(.medium))
                Text("today")
                    .font(.subheadline)
                    .foregroundColor(.secondary)
            }
            .foregroundColor(isPositive ? .positiveGreen : .negativeRed)
        }
        .frame(maxWidth: .infinity)
        .padding(.vertical, 24)
        .background(Color(.systemBackground))
        .cornerRadius(AppConstants.UI.cornerRadius)
        .shadow(color: .black.opacity(0.05), radius: 8, y: 2)
    }
}

// MARK: - Period Returns Card

struct PeriodReturnsCard: View {
    let monthChange: String
    let yearChange: String
    let allTimeChange: String
    let isMonthPositive: Bool
    let isYearPositive: Bool
    let isAllTimePositive: Bool

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Returns")
                .font(.headline)

            HStack(spacing: 16) {
                ReturnPeriodView(
                    period: "1M",
                    change: monthChange,
                    isPositive: isMonthPositive
                )

                Divider()

                ReturnPeriodView(
                    period: "1Y",
                    change: yearChange,
                    isPositive: isYearPositive
                )

                Divider()

                ReturnPeriodView(
                    period: "All",
                    change: allTimeChange,
                    isPositive: isAllTimePositive
                )
            }
            .frame(maxWidth: .infinity)
        }
        .padding()
        .background(Color(.systemBackground))
        .cornerRadius(AppConstants.UI.cornerRadius)
        .shadow(color: .black.opacity(0.05), radius: 8, y: 2)
    }
}

struct ReturnPeriodView: View {
    let period: String
    let change: String
    let isPositive: Bool

    var body: some View {
        VStack(spacing: 4) {
            Text(period)
                .font(.caption)
                .foregroundColor(.secondary)

            Text(change)
                .font(.subheadline.weight(.semibold))
                .foregroundColor(isPositive ? .positiveGreen : .negativeRed)
                .lineLimit(1)
                .minimumScaleFactor(0.8)
        }
        .frame(maxWidth: .infinity)
    }
}

// MARK: - Empty Dashboard View

struct EmptyDashboardView: View {
    var body: some View {
        VStack(spacing: 20) {
            Image(systemName: "chart.pie")
                .font(.system(size: 60))
                .foregroundColor(.secondary)

            Text("Welcome to Investment Tracker")
                .font(.title2.weight(.semibold))

            Text("Start by adding your first investment source to track your portfolio.")
                .font(.subheadline)
                .foregroundColor(.secondary)
                .multilineTextAlignment(.center)

            NavigationLink {
                AddSourceView()
            } label: {
                Label("Add Investment Source", systemImage: "plus")
                    .font(.headline)
                    .foregroundColor(.white)
                    .padding()
                    .frame(maxWidth: .infinity)
                    .background(Color.appPrimary)
                    .cornerRadius(AppConstants.UI.cornerRadius)
            }
        }
        .padding()
    }
}

// MARK: - Pending Updates Card

struct PendingUpdatesCard: View {
    let sources: [InvestmentSource]

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            HStack {
                Image(systemName: "bell.badge.fill")
                    .foregroundColor(.appWarning)
                Text("Pending Updates")
                    .font(.headline)
                Spacer()
                Text("\(sources.count)")
                    .font(.subheadline)
                    .foregroundColor(.secondary)
            }

            ForEach(sources.prefix(3)) { source in
                NavigationLink(destination: SourceDetailView(source: source)) {
                    HStack {
                        Circle()
                            .fill(source.category?.color ?? .gray)
                            .frame(width: 8, height: 8)

                        Text(source.name)
                            .font(.subheadline)

                        Spacer()

                        Text(source.latestSnapshot?.date.relativeDescription ?? "Never")
                            .font(.caption)
                            .foregroundColor(.secondary)

                        Image(systemName: "chevron.right")
                            .font(.caption)
                            .foregroundColor(.secondary)
                    }
                }
                .buttonStyle(.plain)
            }

            if sources.count > 3 {
                Text("+ \(sources.count - 3) more")
                    .font(.caption)
                    .foregroundColor(.secondary)
            }
        }
        .padding()
        .background(Color(.systemBackground))
        .cornerRadius(AppConstants.UI.cornerRadius)
        .shadow(color: .black.opacity(0.05), radius: 8, y: 2)
    }
}

#Preview {
    DashboardView()
        .environmentObject(IAPService())
}