import SwiftUI

struct AddTransactionView: View {
    @Environment(\.dismiss) private var dismiss
    let onSave: (TransactionType, Date, Decimal?, Decimal?, Decimal?, String?) -> Void

    @State private var type: TransactionType = .buy
    @State private var date = Date()
    @State private var shares = ""
    @State private var price = ""
    @State private var amount = ""
    @State private var notes = ""

    var body: some View {
        NavigationStack {
            Form {
                Section {
                    Picker("Type", selection: $type) {
                        ForEach(TransactionType.allCases) { transactionType in
                            Text(transactionType.displayName).tag(transactionType)
                        }
                    }

                    DatePicker("Date", selection: $date, displayedComponents: .date)
                } header: {
                    Text("Transaction")
                }

                Section {
                    TextField("Shares", text: $shares)
                        .keyboardType(.decimalPad)

                    TextField("Price per share", text: $price)
                        .keyboardType(.decimalPad)

                    TextField("Total amount", text: $amount)
                        .keyboardType(.decimalPad)
                } header: {
                    Text("Amounts")
                } footer: {
                    Text("Enter shares and price or just a total amount.")
                }

                Section {
                    TextField("Notes", text: $notes, axis: .vertical)
                        .lineLimit(2...4)
                } header: {
                    Text("Notes (Optional)")
                }
            }
            .navigationTitle("Add Transaction")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .navigationBarLeading) {
                    Button("Cancel") { dismiss() }
                }
                ToolbarItem(placement: .navigationBarTrailing) {
                    Button("Save") { save() }
                        .disabled(!isValid)
                }
            }
        }
        .presentationDetents([.medium, .large])
    }

    private var isValid: Bool {
        parseDecimal(shares) != nil || parseDecimal(amount) != nil
    }

    private func save() {
        onSave(
            type,
            date,
            parseDecimal(shares),
            parseDecimal(price),
            parseDecimal(amount),
            notes.isEmpty ? nil : notes
        )
        dismiss()
    }

    private func parseDecimal(_ value: String) -> Decimal? {
        let cleaned = value
            .replacingOccurrences(of: ",", with: ".")
            .trimmingCharacters(in: .whitespaces)
        guard !cleaned.isEmpty else { return nil }
        return Decimal(string: cleaned)
    }
}

#Preview {
    AddTransactionView { _, _, _, _, _, _ in }
}