import SwiftUI

struct AddContactOrChannelScreen: View {
    @EnvironmentObject var store: AppStore

    enum Field {
        case account
        case contact
    }

    @FocusState private var focus: Field?

    @Binding var isPresented: Bool
    @State private var contactJID: String = ""
    @State private var ownerAccount: Account?

    @State private var isShowingLoader = false
    @State private var isShowingAlert = false
    @State private var errorMsg = ""

    var body: some View {
        ZStack {
            // Background color
            Color.Material.Background.light
                .ignoresSafeArea()

            // Content
            VStack(spacing: 0) {
                // Header
                SharedNavigationBar(
                    leftButton: .init(
                        image: Image(systemName: "chevron.left"),
                        action: {
                            isPresented = false
                        }
                    ),
                    centerText: .init(text: L10n.Contacts.Add.title),
                    rightButton: .init(
                        image: Image(systemName: "plus.viewfinder"),
                        action: {
                            print("Scan QR-code")
                        }
                    )
                )

                VStack(spacing: 16) {
                    // Explanation text

                    Text(L10n.Contacts.Add.explanation)
                        .font(.body3)
                        .foregroundColor(.Material.Shape.separator)
                        .multilineTextAlignment(.center)
                        .padding(.top, 16)

                    // Account selector
                    HStack(spacing: 0) {
                        Text("Use account:")
                            .font(.body2)
                            .foregroundColor(.Material.Text.main)
                            .frame(alignment: .leading)
                        Spacer()
                    }
                    UniversalInputCollection.DropDownMenu(
                        prompt: "Use account",
                        elements: store.state.accountsState.accounts,
                        selected: $ownerAccount,
                        focus: $focus,
                        fieldType: .account
                    )

                    // Contact text input
                    HStack(spacing: 0) {
                        Text("Contact JID:")
                            .font(.body2)
                            .foregroundColor(.Material.Text.main)
                            .frame(alignment: .leading)
                        Spacer()
                    }
                    UniversalInputCollection.TextField(
                        prompt: "Contact or channel JID",
                        text: $contactJID,
                        focus: $focus,
                        fieldType: .contact,
                        contentType: .emailAddress,
                        keyboardType: .emailAddress,
                        submitLabel: .done,
                        action: {
                            focus = .account
                        }
                    )

                    // Save button
                    Button {
                        save()
                    } label: {
                        Text(L10n.Global.save)
                    }
                    .buttonStyle(PrimaryButtonStyle())
                    .disabled(!inputValid)
                    .padding(.top)
                    Spacer()
                }
                .padding(.horizontal, 32)
            }
        }
        .onAppear {
            if let exists = store.state.accountsState.accounts.first, exists.isActive {
                ownerAccount = exists
            }
        }
        .loadingIndicator(isShowingLoader)
        .alert(isPresented: $isShowingAlert) {
            Alert(
                title: Text(L10n.Global.Error.title),
                message: Text(errorMsg),
                dismissButton: .default(Text(L10n.Global.ok))
            )
        }
        .onChange(of: store.state.rostersState.newAddedRosterJid) { jid in
            if jid != nil, isShowingLoader {
                isShowingLoader = false
                isPresented = false
            }
        }
        .onChange(of: store.state.rostersState.newAddedRosterError) { error in
            if let error = error, isShowingLoader {
                isShowingLoader = false
                errorMsg = error
                isShowingAlert = true
            }
        }
    }

    private var inputValid: Bool {
        ownerAccount != nil && !contactJID.isEmpty && UniversalInputCollection.Validators.isEmail(contactJID)
    }

    private func save() {
        guard let ownerAccount else { return }
        if let exists = store.state.rostersState.rosters.first(where: { $0.bareJid == ownerAccount.bareJid && $0.contactBareJid == contactJID }), exists.locallyDeleted {
            store.dispatch(.rostersAction(.unmarkRosterAsLocallyDeleted(ownerJID: ownerAccount.bareJid, contactJID: contactJID)))
            isPresented = false
        } else {
            isShowingLoader = true
            store.dispatch(.rostersAction(.addRoster(ownerJID: ownerAccount.bareJid, contactJID: contactJID, name: nil, groups: [])))
        }
    }
}