import SwiftUI

/// Fahrzeuge anlegen, umbenennen und entfernen.
struct ProfilesView: View {
    @Environment(DeviceStore.self) private var store
    @Environment(BluetoothManager.self) private var bluetooth
    @Environment(\.dismiss) private var dismiss

    @State private var editing: Profile?
    @State private var pendingDeletion: Profile?

    var body: some View {
        NavigationStack {
            List {
                Section {
                    ForEach(store.profiles) { profile in
                        row(for: profile)
                    }
                } footer: {
                    Text("Jedes Fahrzeug hat seine eigenen Geräte. Die App liest immer "
                         + "nur die des gewählten Fahrzeugs aus.")
                }

                Section {
                    Button("Fahrzeug hinzufügen", systemImage: "plus") {
                        let profile = store.addProfile(named: "Camper \(store.profiles.count + 1)")
                        editing = profile
                    }
                }
            }
            .navigationTitle("Fahrzeuge")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .confirmationAction) {
                    Button("Fertig") { dismiss() }
                }
            }
            .sheet(item: $editing) { profile in
                ProfileEditView(profile: profile)
            }
            .confirmationDialog("Fahrzeug entfernen?",
                                isPresented: .init(get: { pendingDeletion != nil },
                                                   set: { if !$0 { pendingDeletion = nil } }),
                                titleVisibility: .visible) {
                Button("Entfernen", role: .destructive) {
                    if let pendingDeletion {
                        store.removeProfile(pendingDeletion)
                        bluetooth.refreshConfiguration()
                    }
                    pendingDeletion = nil
                }
            } message: {
                if let pendingDeletion {
                    Text("„\(pendingDeletion.name)“ und die \(store.deviceCount(in: pendingDeletion)) "
                         + "darin eingerichteten Geräte werden gelöscht.")
                }
            }
        }
    }

    private func row(for profile: Profile) -> some View {
        HStack {
            Label {
                VStack(alignment: .leading, spacing: 2) {
                    Text(profile.name)
                    Text(deviceSummary(for: profile))
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }
            } icon: {
                Image(systemName: profile.symbol)
            }

            Spacer()

            if profile.id == store.activeProfileID {
                Image(systemName: "checkmark")
                    .foregroundStyle(.tint)
                    .fontWeight(.semibold)
            }
        }
        .contentShape(.rect)
        .onTapGesture {
            store.selectProfile(profile)
            bluetooth.refreshConfiguration()
        }
        .swipeActions(edge: .trailing) {
            // Das letzte Fahrzeug muss bleiben, sonst hätten Geräte keinen Ort.
            if store.hasMultipleProfiles {
                Button("Entfernen", systemImage: "trash", role: .destructive) {
                    pendingDeletion = profile
                }
            }
            Button("Bearbeiten", systemImage: "pencil") {
                editing = profile
            }
            .tint(.gray)
        }
    }

    private func deviceSummary(for profile: Profile) -> String {
        let count = store.deviceCount(in: profile)
        return count == 1 ? "1 Gerät" : "\(count) Geräte"
    }
}

/// Name und Symbol eines Fahrzeugs ändern.
private struct ProfileEditView: View {
    let profile: Profile

    @Environment(DeviceStore.self) private var store
    @Environment(\.dismiss) private var dismiss

    @State private var name = ""
    @State private var symbol = "box.truck"

    private let columns = [GridItem(.adaptive(minimum: 60), spacing: 12)]

    var body: some View {
        NavigationStack {
            Form {
                Section("Name") {
                    TextField("Name", text: $name)
                }
                Section("Symbol") {
                    LazyVGrid(columns: columns, spacing: 12) {
                        ForEach(Profile.symbols, id: \.self) { candidate in
                            Button {
                                symbol = candidate
                            } label: {
                                Image(systemName: candidate)
                                    .font(.title2)
                                    .frame(width: 52, height: 52)
                                    .background(symbol == candidate ? Color.accentColor.opacity(0.18)
                                                                    : Color.secondary.opacity(0.08),
                                                in: .rect(cornerRadius: 12))
                                    .foregroundStyle(symbol == candidate ? Color.accentColor : Color.primary)
                            }
                            .buttonStyle(.plain)
                        }
                    }
                    .padding(.vertical, 4)
                }
            }
            .navigationTitle("Fahrzeug")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button("Abbrechen") { dismiss() }
                }
                ToolbarItem(placement: .confirmationAction) {
                    Button("Sichern") {
                        var updated = profile
                        updated.name = name.trimmingCharacters(in: .whitespaces)
                        updated.symbol = symbol
                        store.update(updated)
                        dismiss()
                    }
                    .disabled(name.trimmingCharacters(in: .whitespaces).isEmpty)
                }
            }
            .onAppear {
                name = profile.name
                symbol = profile.symbol
            }
        }
    }
}