import SwiftUI
import Charts

struct EvolutionChartCard: View {
    let data: [(date: Date, value: Decimal)]

    @State private var selectedDataPoint: (date: Date, value: Decimal)?

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

                Spacer()

                if let selected = selectedDataPoint {
                    VStack(alignment: .trailing) {
                        Text(selected.value.compactCurrencyString)
                            .font(.subheadline.weight(.semibold))
                        Text(selected.date.monthYearString)
                            .font(.caption)
                            .foregroundColor(.secondary)
                    }
                }
            }

            if data.count >= 2 {
                Chart {
                    ForEach(data, id: \.date) { item in
                        LineMark(
                            x: .value("Date", item.date),
                            y: .value("Value", NSDecimalNumber(decimal: item.value).doubleValue)
                        )
                        .foregroundStyle(Color.appPrimary)
                        .interpolationMethod(.catmullRom)

                        AreaMark(
                            x: .value("Date", item.date),
                            y: .value("Value", NSDecimalNumber(decimal: item.value).doubleValue)
                        )
                        .foregroundStyle(
                            LinearGradient(
                                colors: [Color.appPrimary.opacity(0.3), Color.appPrimary.opacity(0.0)],
                                startPoint: .top,
                                endPoint: .bottom
                            )
                        )
                        .interpolationMethod(.catmullRom)
                    }

                    if let selected = selectedDataPoint {
                        RuleMark(x: .value("Selected", selected.date))
                            .foregroundStyle(Color.gray.opacity(0.3))
                            .lineStyle(StrokeStyle(lineWidth: 1, dash: [5, 5]))

                        PointMark(
                            x: .value("Date", selected.date),
                            y: .value("Value", NSDecimalNumber(decimal: selected.value).doubleValue)
                        )
                        .foregroundStyle(Color.appPrimary)
                        .symbolSize(100)
                    }
                }
                .chartXAxis {
                    AxisMarks(values: .stride(by: .month, count: 3)) { value in
                        AxisValueLabel(format: .dateTime.month(.abbreviated))
                    }
                }
                .chartYAxis {
                    AxisMarks(position: .leading) { value in
                        AxisValueLabel {
                            if let doubleValue = value.as(Double.self) {
                                Text(Decimal(doubleValue).shortCurrencyString)
                                    .font(.caption)
                            }
                        }
                    }
                }
                .chartOverlay { proxy in
                    GeometryReader { geometry in
                        Rectangle()
                            .fill(.clear)
                            .contentShape(Rectangle())
                            .gesture(
                                DragGesture(minimumDistance: 0)
                                    .onChanged { value in
                                        let x = value.location.x - geometry[proxy.plotAreaFrame].origin.x
                                        guard let date: Date = proxy.value(atX: x) else { return }

                                        if let closest = data.min(by: {
                                            abs($0.date.timeIntervalSince(date)) < abs($1.date.timeIntervalSince(date))
                                        }) {
                                            selectedDataPoint = closest
                                        }
                                    }
                                    .onEnded { _ in
                                        selectedDataPoint = nil
                                    }
                            )
                    }
                }
                .frame(height: 200)
            } else {
                Text("Not enough data to display chart")
                    .font(.subheadline)
                    .foregroundColor(.secondary)
                    .frame(height: 200)
                    .frame(maxWidth: .infinity)
            }
        }
        .padding()
        .background(Color(.systemBackground))
        .cornerRadius(AppConstants.UI.cornerRadius)
        .shadow(color: .black.opacity(0.05), radius: 8, y: 2)
    }
}

// MARK: - Mini Sparkline

struct SparklineView: View {
    let data: [(date: Date, value: Decimal)]
    let color: Color

    var body: some View {
        if data.count >= 2 {
            Chart(data, id: \.date) { item in
                LineMark(
                    x: .value("Date", item.date),
                    y: .value("Value", NSDecimalNumber(decimal: item.value).doubleValue)
                )
                .foregroundStyle(color)
                .interpolationMethod(.catmullRom)
            }
            .chartXAxis(.hidden)
            .chartYAxis(.hidden)
            .chartLegend(.hidden)
        } else {
            Rectangle()
                .fill(Color.gray.opacity(0.1))
        }
    }
}

#Preview {
    let sampleData: [(date: Date, value: Decimal)] = [
        (Date().adding(months: -6), 10000),
        (Date().adding(months: -5), 10500),
        (Date().adding(months: -4), 10200),
        (Date().adding(months: -3), 11000),
        (Date().adding(months: -2), 11500),
        (Date().adding(months: -1), 11200),
        (Date(), 12000)
    ]

    return EvolutionChartCard(data: sampleData)
        .padding()
}