import SwiftUI
import SwiftData

struct ContentView: View {
    @State private var viewModel = MoneyCounterViewModel()
    @FocusState private var focusedField: UUID?
    @FocusState private var isFloatFocused: Bool
    
    @AppStorage("currentSessionNotes") private var sessionNotes: String = ""
    @Environment(\.modelContext) private var modelContext
    
    @State private var showingNotes = false
    @State private var showingHistory = false
    @State private var showingResetAlert = false

    var body: some View {
        VStack(spacing: 0) {
            // Header
            HStack {
                Menu {
                    Button(action: { showingNotes = true }) {
                        Label("Session Notes", systemImage: "note.text")
                    }
                    Button(action: { showingHistory = true }) {
                        Label("Saved History", systemImage: "clock.arrow.circlepath")
                    }
                    Divider()
                    Button(action: saveCurrentSession) {
                        Label("Save This Total", systemImage: "square.and.arrow.down")
                    }
                } label: {
                    Image(systemName: "ellipsis.circle")
                        .font(.title)
                        .foregroundColor(.white)
                }
                
                Spacer()
                Text("Money Counter")
                    .font(.title2).bold()
                    .foregroundColor(.white)
                Spacer()
                
                Button(action: { showingResetAlert = true }) {
                    Image(systemName: "arrow.counterclockwise")
                        .font(.title)
                        .foregroundColor(.white)
                }
            }
            .padding()
            .background(Color(red: 0.4, green: 0.7, blue: 0.4))

            // Scrolling Denominations
            ScrollView {
                VStack(spacing: 24) {
                    ForEach($viewModel.looseDenominations) { $denom in
                        DenominationRow(denomination: $denom, focusedField: $focusedField, valueColor: Color(UIColor.systemGreen))
                    }
                    
                    VStack(alignment: .leading, spacing: 8) {
                        Divider().background(Color.gray)
                        Text("Rolls")
                            .font(.title3)
                            .bold()
                            .foregroundColor(.secondary)
                    }
                    .padding(.top, 8)
                    
                    ForEach($viewModel.rollDenominations) { $denom in
                        DenominationRow(denomination: $denom, focusedField: $focusedField, valueColor: Color(UIColor.systemRed))
                    }
                }
                .padding()
            }
            .contentShape(Rectangle())
            .onTapGesture { dismissKeyboard() }
            // 1. Native drag-to-dismiss behavior
            .scrollDismissesKeyboard(.interactively)

            // Footer (Math & Totals)
            VStack(spacing: 8) {
                HStack {
                    Text("Starting Float")
                        .font(.headline)
                        .foregroundColor(.secondary)
                    Spacer()
                    
                    HStack(spacing: 2) {
                        Text("$")
                            .foregroundColor(.secondary)
                        TextField("0.00", value: $viewModel.startingFloat, format: .number.precision(.fractionLength(2)))
                            .keyboardType(.decimalPad)
                            .focused($isFloatFocused)
                            .multilineTextAlignment(.trailing)
                    }
                    .font(.headline)
                    .padding(6)
                    .frame(width: 100)
                    .background(Color(UIColor.tertiarySystemFill), in: RoundedRectangle(cornerRadius: 8))
                }
                
                if viewModel.startingFloat > 0 {
                    HStack {
                        Text(viewModel.discrepancy >= 0 ? "Deposit Amount" : "Shortage")
                            .font(.headline)
                        Spacer()
                        Text(String(format: "$%.2f", viewModel.discrepancy))
                            .font(.headline)
                            .foregroundColor(viewModel.discrepancy >= 0 ? .primary : .red)
                    }
                }
                
                Divider()
                
                HStack {
                    Text("Total")
                        .font(.largeTitle)
                        .bold()
                    Spacer()
                    Text(String(format: "$%.2f", viewModel.total))
                        .font(.largeTitle)
                        .bold()
                }
            }
            .padding()
            .background(Color(UIColor.secondarySystemBackground))
            .foregroundColor(.primary)
        }
        .background(Color(UIColor.systemBackground))
        // 2. Adds the "Done" button directly above the keyboard
        .toolbar {
            ToolbarItemGroup(placement: .keyboard) {
                Spacer()
                Button("Done") {
                    dismissKeyboard()
                }
                .font(.headline)
                .foregroundColor(.blue)
            }
        }
        .onChange(of: viewModel.looseDenominations) { _, _ in viewModel.saveCache() }
        .onChange(of: viewModel.rollDenominations) { _, _ in viewModel.saveCache() }
        .onChange(of: viewModel.startingFloat) { _, _ in viewModel.saveCache() }
        .sheet(isPresented: $showingNotes) {
            NotesView(notes: $sessionNotes, total: viewModel.total, discrepancy: viewModel.discrepancy, expectedFloat: viewModel.startingFloat)
        }
        .sheet(isPresented: $showingHistory) {
            HistoryView(viewModel: viewModel)
        }
        .confirmationDialog("Reset Everything?", isPresented: $showingResetAlert) {
            Button("Reset Counts & Notes", role: .destructive) {
                withAnimation { viewModel.reset() }
                sessionNotes = ""
            }
            Button("Reset Counts Only", role: .destructive) {
                withAnimation { viewModel.reset() }
            }
            Button("Cancel", role: .cancel) { }
        }
    }
    
    private func dismissKeyboard() {
        focusedField = nil
        isFloatFocused = false
    }
    
    private func saveCurrentSession() {
        let newSave = SavedCount(
            total: viewModel.total,
            startingFloat: viewModel.startingFloat,
            notes: sessionNotes,
            snapshotData: viewModel.generateSnapshot()
        )
        modelContext.insert(newSave)
    }
}

// DenominationRow remains exactly the same as the previous iteration
struct DenominationRow: View {
    @Binding var denomination: MoneyCounterViewModel.Denomination
    var focusedField: FocusState<UUID?>.Binding
    var valueColor: Color
    
    var body: some View {
        HStack(spacing: 16) {
            HStack {
                Text(formatValue(denomination.value))
                    .font(.title2).bold()
                    .foregroundColor(valueColor)
                    .frame(width: 70, alignment: .leading)
                Spacer()
            }
            .contentShape(Rectangle())
            .onTapGesture { focusedField.wrappedValue = nil }

            Button(action: {
                denomination.count += 1
                focusedField.wrappedValue = nil
            }) {
                Image(systemName: "plus.circle.fill")
                    .foregroundColor(Color(UIColor.systemGreen))
                    .font(.title)
            }

            Button(action: {
                if denomination.count > 0 { denomination.count -= 1 }
                focusedField.wrappedValue = nil
            }) {
                Image(systemName: "minus.circle.fill")
                    .foregroundColor(Color(UIColor.systemRed))
                    .font(.title)
            }

            TextField("0", value: $denomination.count, format: .number)
                .keyboardType(.numberPad)
                .multilineTextAlignment(.center)
                .font(.title2).bold()
                .frame(width: 80)
                .padding(.vertical, 4)
                .focused(focusedField, equals: denomination.id)
                .overlay(
                    Rectangle()
                        .frame(height: 1)
                        .foregroundColor(Color(UIColor.separator)),
                    alignment: .bottom
                )
                .foregroundColor(.primary)
        }
    }
    
    private func formatValue(_ value: Double) -> String {
        if value >= 1.0 { return String(format: "%.1f", value) }
        else { return String(format: "%.2f", value) }
    }
}