import SwiftUI

struct AllocationTargetsView: View {
    @StateObject private var categoryRepository = CategoryRepository()
    @State private var targetValues: [UUID: String] = [:]

    var body: some View {
        List {
            Section {
                HStack {
                    Text("Total Targets")
                    Spacer()
                    Text(String(format: "%.0f%%", totalTargets))
                        .foregroundColor(totalTargets == 100 ? .positiveGreen : .secondary)
                }

                if totalTargets != 100 {
                    Text("Targets don't need to be perfect, but aiming for 100% keeps the drift view accurate.")
                        .font(.caption)
                        .foregroundColor(.secondary)
                }
            }

            Section {
                ForEach(categoryRepository.categories) { category in
                    let categoryId = category.id
                    HStack {
                        HStack(spacing: 8) {
                            Circle()
                                .fill(category.color)
                                .frame(width: 10, height: 10)
                            Text(category.name)
                        }

                        Spacer()

                        TextField("0", text: targetBinding(for: categoryId))
                            .keyboardType(.decimalPad)
                            .multilineTextAlignment(.trailing)
                            .frame(width: 60)

                        Text("%")
                            .foregroundColor(.secondary)
                    }
                }
            } header: {
                Text("Targets by Category")
            } footer: {
                Text("Set your desired allocation percentages to track drift over time.")
            }
        }
        .navigationTitle("Allocation Targets")
        .navigationBarTitleDisplayMode(.inline)
        .onAppear {
            preloadTargets()
        }
    }

    private var totalTargets: Double {
        let ids = categoryRepository.categories.compactMap { $0.id }
        return AllocationTargetStore.totalTargetPercentage(for: ids)
    }

    private func preloadTargets() {
        targetValues = categoryRepository.categories.reduce(into: [:]) { result, category in
            let id = category.id
            if let target = AllocationTargetStore.target(for: id) {
                result[id] = String(format: "%.0f", target)
            }
        }
    }

    private func targetBinding(for categoryId: UUID) -> Binding<String> {
        Binding(
            get: { targetValues[categoryId] ?? "" },
            set: { newValue in
                targetValues[categoryId] = newValue
                let sanitized = newValue.replacingOccurrences(of: ",", with: ".")
                let value = Double(sanitized) ?? 0
                AllocationTargetStore.setTarget(value, for: categoryId)
            }
        )
    }
}

#Preview {
    NavigationStack {
        AllocationTargetsView()
    }
}