import SwiftUI

struct GiftDetailView: View {
    @Environment(\.openURL) private var openURL
    @StateObject private var viewModel: GiftDetailViewModel
    @StateObject private var recipientAddressViewModel: GiftRecipientAddressViewModel
    @State private var hasAppeared = false
    @State private var isActive = false

    init(applicationNo: String) {
        let detailViewModel = GiftDetailViewModel(applicationNo: applicationNo) { canceledApplicationNo, completion in
            AppState.shared.replaceCurrentAppStep(
                step: .giftDetail(applicationNo: canceledApplicationNo),
                ifCurrentStep: { step in
                    guard case .giftDetail(let currentApplicationNo) = step else { return false }
                    return currentApplicationNo == canceledApplicationNo
                },
                completion: completion
            )
        }
        _viewModel = StateObject(wrappedValue: detailViewModel)
        _recipientAddressViewModel = StateObject(wrappedValue: GiftRecipientAddressViewModel(applicationNo: applicationNo, onSubmitted: {
            detailViewModel.fetch()
        }))
    }

    var body: some View {
        VStack(spacing: 0) {
            DetailNavigationBar(title: navigationTitle)
                .disabled(viewModel.isCancelSubmitting || isRecipientAddressBusy)
            BaseView(isLoading: .constant(viewModel.isLoading || recipientAddressViewModel.isSubmitting)) {
                ZStack {
                    switch viewModel.renderState {
                    case .sent(let model):
                        detailContent {
                            SentGiftDetailContentView(model: model)
                        }
                        .safeAreaInset(edge: .bottom, spacing: 0) {
                            GiftDetailActionBar(
                                model: model,
                                onCancel: viewModel.presentCancelDialog,
                                onPolicy: openGiftTerms
                            )
                        }
                    case .received(let model):
                        if model.recipientAddressRequired {
                            VStack(spacing: 0) {
                                GiftRecipientAddressFormView(model: model, viewModel: recipientAddressViewModel)
                                if recipientAddressViewModel.hasSubmitted && !viewModel.isLoading && !viewModel.errorMessage.isEmpty {
                                    retryContent
                                }
                            }
                        } else {
                            detailContent {
                                ReceivedGiftDetailContentView(model: model)
                            }
                            .safeAreaInset(edge: .bottom, spacing: 0) {
                                if model.status == .undeliverable {
                                    ReceivedGiftDetailActionBar(onPolicy: openGiftTerms)
                                }
                            }
                        }
                    case .canceled(let model):
                        detailContent {
                            GiftCancelCompleteView(model: model)
                        }
                    case nil:
                        Color.clear.accessibilityHidden(true)
                    }

                    if viewModel.renderState == nil && !viewModel.errorMessage.isEmpty {
                        retryContent
                    }
                }
            }
            .disabled(isRecipientAddressBusy)
        }
        .background(Color.black.ignoresSafeArea())
        .allowsHitTesting(!viewModel.isShowingCancelDialog && !viewModel.isCancelSubmitting)
        .accessibilityHidden(viewModel.isShowingCancelDialog)
        .overlay {
            if viewModel.isShowingCancelDialog {
                SodaV2ActionModal(
                    title: "신청 취소",
                    message: cancelMessage,
                    button1: SodaV2ActionModalButton(label: "취소하기", action: viewModel.confirmCancel),
                    button2: SodaV2ActionModalButton(label: "나가기", action: viewModel.dismissCancelDialog),
                    onDimmedTap: viewModel.dismissCancelDialog,
                    primaryTextColor: .red400
                )
                .disabled(viewModel.isCancelSubmitting)
                .allowsHitTesting(!viewModel.isCancelSubmitting)
            }
        }
        .overlay {
            if viewModel.isCancelSubmitting {
                LoadingView()
            }
        }
        .sodaToast(isPresented: $viewModel.isShowPopup, message: viewModel.errorMessage)
        .sodaToast(isPresented: $recipientAddressViewModel.isShowPopup, message: recipientAddressViewModel.errorMessage)
        .sodaToast(isPresented: $recipientAddressViewModel.isShowSuccessToast, message: recipientAddressViewModel.successMessage)
        .onChange(of: recipientAddressViewModel.isShowSuccessToast) { isPresented in
            if !isPresented && isActive {
                recipientAddressViewModel.successToastDidDismiss()
            }
        }
        .onAppear {
            isActive = true
            recipientAddressViewModel.successToastDidDismiss()
            guard !hasAppeared else { return }
            hasAppeared = true
            viewModel.fetch()
        }
        .onDisappear {
            isActive = false
        }
    }

    private func openGiftTerms() {
        guard let url = GiftConstants.termsURL else { return }
        openURL(url)
    }

    private var isRecipientAddressBusy: Bool {
        recipientAddressViewModel.isSubmitting || recipientAddressViewModel.isShowSuccessToast
            || (recipientAddressViewModel.hasSubmitted && viewModel.isLoading)
    }

    private var retryContent: some View {
        VStack(spacing: SodaSpacing.s16) {
            Text(viewModel.errorMessage)
                .appFont(.body3)
                .foregroundColor(.gray500)
                .multilineTextAlignment(.center)
                .fixedSize(horizontal: false, vertical: true)
            Button(action: viewModel.fetch) {
                Text("다시 시도")
                    .appFont(.body2)
                    .foregroundColor(.white)
                    .padding(.horizontal, SodaSpacing.s16)
                    .frame(minHeight: SodaSpacing.s48)
                    .background(Color.gray800)
                    .clipShape(Capsule())
            }
            .buttonStyle(.plain)
            .disabled(viewModel.isLoading)
        }
        .padding(SodaSpacing.s24)
    }

    private func detailContent<Content: View>(@ViewBuilder content: () -> Content) -> some View {
        ScrollView {
            LazyVStack(alignment: .leading, spacing: SodaSpacing.s32) {
                content()
            }
            .padding(.horizontal, SodaSpacing.s14)
            .padding(.top, SodaSpacing.s24)
            .padding(.bottom, SodaSpacing.s32)
        }
    }

    private var navigationTitle: String {
        if case .canceled = viewModel.renderState {
            return "취소 완료"
        }
        return "선물 상세"
    }

    private var cancelMessage: String {
        let firstLine: String
        if case .sent(let model) = viewModel.renderState,
           let nickname = model.recipientCreatorNickname?.trimmingCharacters(in: .whitespacesAndNewlines),
           !nickname.isEmpty {
            firstLine = "\(nickname)에게 보내는 선물을 취소할까요?"
        } else {
            firstLine = "보내는 선물을 취소할까요?"
        }
        return firstLine + "\n선물 보내기 규정에 따라 선물 취소 및 사용한 캔이 모두 환불됩니다."
    }
}