import SwiftUI

struct GiftSendView: View {
    private let recipientCreatorProfileImageUrl: String
    @StateObject private var viewModel: GiftSendViewModel
    @State private var hasAppeared = false

    init(recipientMemberId: Int, recipientCreatorNickname: String, recipientCreatorProfileImageUrl: String) {
        self.recipientCreatorProfileImageUrl = recipientCreatorProfileImageUrl
        _viewModel = StateObject(wrappedValue: GiftSendViewModel(
            recipientMemberId: recipientMemberId,
            recipientCreatorNickname: recipientCreatorNickname,
            onCreated: { applicationNo in
                AppState.shared.replaceCurrentAppStep(
                    step: .giftDetail(applicationNo: applicationNo),
                    ifCurrentStep: { step in
                        guard case .giftSend(let memberId, let nickname, _) = step else { return false }
                        return memberId == recipientMemberId && nickname == recipientCreatorNickname
                    }
                )
            }
        ))
    }

    var body: some View {
        VStack(spacing: 0) {
            DetailNavigationBar(title: "선물 보내기")
                .frame(height: 54)
                .allowsHitTesting(!viewModel.isSubmitting)
            BaseView(isLoading: .constant(viewModel.isLoading || viewModel.isSubmitting)) {
                ScrollView {
                    VStack(alignment: .leading, spacing: SodaSpacing.s24) {
                        GiftSendBannerView()
                        recipientSection
                        sectionDivider
                        sizeSection
                        categorySection
                        sectionDivider
                        GiftSenderFormView(
                            name: $viewModel.senderName,
                            phoneNumber: $viewModel.senderPhoneNumber,
                            zipCode: $viewModel.senderZipCode,
                            address: $viewModel.senderAddress,
                            addressDetail: $viewModel.senderAddressDetail
                        )
                        sectionDivider
                        agreementsSection
                    }
                    .padding(.horizontal, SodaSpacing.s14)
                    .padding(.vertical, SodaSpacing.s16)
                }
                .scrollDismissesKeyboard(.interactively)
                .safeAreaInset(edge: .bottom, spacing: 0) {
                    Button {
                        viewModel.submitGift()
                    } label: {
                        SelectedButtonView(
                            title: viewModel.selectedSize.map { "\($0.salePriceCan)캔으로 선물 보내기" } ?? "선물 보내기",
                            isActive: viewModel.canSubmit,
                            isSelected: false
                        )
                    }
                    .disabled(!viewModel.canSubmit)
                    .padding(SodaSpacing.s14)
                    .background(Color.black)
                }
            }
            .sodaToast(isPresented: $viewModel.isShowPopup, message: viewModel.errorMessage)
        }
        .background(Color.black)
            .onAppear {
                guard !hasAppeared else { return }
                hasAppeared = true
                viewModel.fetchFormOptions()
            }
    }

    private var recipientSection: some View {
        VStack(alignment: .leading, spacing: SodaSpacing.s14) {
            sectionTitle("받는 크리에이터")
            HStack(spacing: SodaSpacing.s12) {
                DownsampledKFImage(url: URL(string: recipientCreatorProfileImageUrl), size: CGSize(width: 38, height: 38))
                    .clipShape(Circle())
                    .accessibilityHidden(true)
                Text(viewModel.recipientCreatorNickname)
                    .appFont(size: 16, weight: .bold)
                    .foregroundColor(.white)
                Spacer(minLength: 0)
            }
            .padding(SodaSpacing.s14)
            .background(Color.gray900)
            .cornerRadius(SodaRadius.r8)
        }
    }

    private var sizeSection: some View {
        VStack(alignment: .leading, spacing: SodaSpacing.s12) {
            sectionTitle("선물 사이즈")
            helper("시작은 부담 없이 작은 크기를 선택해 주세요")
            ForEach(viewModel.sizes, id: \.sizeCode) { size in
                Button {
                    viewModel.selectedSize = size
                } label: {
                    HStack(spacing: SodaSpacing.s12) {
                        VStack(alignment: .leading, spacing: SodaSpacing.s6) {
                            Text(sizeTitle(size.sizeCode))
                                .appFont(size: 16, weight: .bold)
                                .foregroundColor(.white)
                            if let description = GiftDisplayPolicy.sizeDescription(for: size.sizeCode) {
                                helper(description)
                            }
                        }
                        Spacer(minLength: 0)
                        VStack(alignment: .trailing, spacing: SodaSpacing.s4) {
                            if size.basePriceCan != size.salePriceCan {
                                Text("\(size.basePriceCan)캔")
                                    .strikethrough()
                                    .appFont(size: 12, weight: .regular)
                                    .foregroundColor(.gray500)
                            }
                            Text("\(size.salePriceCan)캔")
                                .appFont(size: 16, weight: .bold)
                                .foregroundColor(.soda400)
                        }
                    }
                    .padding(SodaSpacing.s16)
                    .frame(minHeight: 77)
                    .background(Color.gray900)
                    .cornerRadius(SodaRadius.r8)
                    .overlay(RoundedRectangle(cornerRadius: SodaRadius.r8)
                        .stroke(viewModel.selectedSize?.sizeCode == size.sizeCode ? Color.soda400 : .clear, lineWidth: 1))
                }
                .buttonStyle(.plain)
                .accessibilityAddTraits(viewModel.selectedSize?.sizeCode == size.sizeCode ? .isSelected : [])
            }
        }
    }

    private var categorySection: some View {
        VStack(alignment: .leading, spacing: SodaSpacing.s12) {
            sectionTitle("카테고리")
            helper("택배 기간에는 제한되는 카테고리의 특별한 점들을 꼭 확인합니다")
            Menu {
                ForEach(viewModel.categories, id: \.categoryId) { category in
                    Button(category.name) { viewModel.selectCategory(category) }
                }
            } label: {
                HStack {
                    Text(viewModel.selectedCategory?.name ?? "카테고리 선택")
                        .appFont(.body3)
                    Spacer()
                    Image(systemName: "chevron.down")
                }
                .foregroundColor(viewModel.selectedCategory == nil ? .gray500 : .white)
                .padding(SodaSpacing.s14)
                .background(Color.gray900)
                .cornerRadius(SodaRadius.r14)
            }
            .disabled(viewModel.categories.isEmpty)
            if viewModel.selectedCategory?.requiresDamageWaiver == true {
                GiftAgreementRow(title: "파손 및 분실 면책 사항에 동의합니다.", isAgreed: $viewModel.damageWaiverAgreed,
                                 policyURL: GiftConstants.damagePolicyURL)
            }
        }
    }

    private var agreementsSection: some View {
        VStack(alignment: .leading, spacing: SodaSpacing.s16) {
            sectionTitle("이용 약관 동의")
            VStack(alignment: .leading, spacing: SodaSpacing.s12) {
                Text("선물 보내기 신청 전 꼭 확인해 주세요")
                    .appFont(size: 14, weight: .bold)
                    .foregroundColor(.grayee)
                ForEach(shippingRules, id: \.self) { rule in
                    HStack(alignment: .top, spacing: SodaSpacing.s6) {
                        helper("•")
                        helper(rule)
                    }
                }
            }
            .padding(SodaSpacing.s14)
            .background(Color.gray900)
            .cornerRadius(SodaRadius.r8)
            GiftAgreementRow(title: "소다라이브 크리에이터 선물 보내기 이용약관에 동의합니다.",
                             isAgreed: $viewModel.senderTermsAgreed)
            GiftAgreementRow(title: "선물 보내기를 위한 개인정보 수집·이용에 동의합니다.",
                             isAgreed: $viewModel.senderPrivacyAgreed)
        }
    }

    private var shippingRules: [String] {
        [
            "일반 공산품 중 세 변 합 100cm 이하, 5kg 이하, 내품가 40만원 이하의 소형 선물만 접수합니다.",
            "신선식품은 접수할 수 없으며, 아크릴·피규어·응원봉 등 파손 위험이 있는 상품은 별도 동의가 필요할 수 있습니다.",
            "선물 보내기에 필요한 개인정보는 회원 주소록처럼 장기 저장하지 않고 전달 절차에 필요한 기간에만 일시적으로 이용합니다.",
            "선물은 반드시 배송비 선불로 발송해 주세요. 착불로 발송된 선물은 수취가 거부됩니다."
        ]
    }

    private var sectionDivider: some View {
        Color.gray900.frame(height: 7).padding(.horizontal, -SodaSpacing.s14)
    }

    private func sectionTitle(_ title: String) -> some View {
        Text(title).appFont(.heading3).foregroundColor(.white)
    }

    private func helper(_ text: String) -> some View {
        Text(text).appFont(size: 12, weight: .regular).foregroundColor(.gray500)
            .fixedSize(horizontal: false, vertical: true)
    }

    private func sizeTitle(_ code: String) -> String {
        switch GiftSize(rawValue: code) {
        case .small: return "소형"
        case .medium: return "중형"
        case .large: return "대형"
        case nil: return code
        }
    }
}