import SwiftUI

struct MainContentRankingView: View {
    let onTapContent: (Int) -> Void

    @StateObject private var viewModel = MainContentRankingViewModel()

    init(onTapContent: @escaping (Int) -> Void = { _ in }) {
        self.onTapContent = onTapContent
    }

    var body: some View {
        ZStack {
            Color.black
                .ignoresSafeArea()

            VStack(spacing: 0) {
                MainContentRankingTypeTabBar(
                    items: AudioRankingType.allCases,
                    selectedItem: selectedTypeBinding,
                    title: { $0.title }
                )

                if viewModel.isLoading && !viewModel.hasLoaded {
                    ProgressView()
                        .progressViewStyle(CircularProgressViewStyle(tint: .white))
                        .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else if viewModel.shouldShowEmptyState {
                    MainContentAudioRankingEmptyStateView(message: viewModel.emptyStateMessage)
                        .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else {
                    rankingContent
                }
            }
        }
        .onAppear {
            if !viewModel.hasLoaded {
                viewModel.fetchRankings()
            }
        }
        .sodaToast(isPresented: $viewModel.isShowPopup, message: viewModel.errorMessage, autohideIn: 2)
    }

    private var rankingContent: some View {
        ScrollView(showsIndicators: false) {
            VStack(alignment: .leading, spacing: SodaSpacing.s8) {
                if let topItem {
                    MainContentAudioRankingTopCard(
                        item: topItem,
                        showRankChange: viewModel.showRankChange,
                        onTapContent: onTapContent
                    )
                }

                if !secondToSeventhRankItems.isEmpty {
                    LazyVGrid(columns: twoColumns, alignment: .center, spacing: SodaSpacing.s8) {
                        ForEach(secondToSeventhRankItems) { item in
                            MainContentAudioRankingThumbnailCard(
                                item: item,
                                showRankChange: viewModel.showRankChange,
                                columnsPerRow: 2,
                                onTapContent: onTapContent
                            )
                        }
                    }
                }

                if !eighthToTenthRankItems.isEmpty {
                    LazyVGrid(columns: threeColumns, alignment: .center, spacing: SodaSpacing.s8) {
                        ForEach(eighthToTenthRankItems) { item in
                            MainContentAudioRankingThumbnailCard(
                                item: item,
                                showRankChange: viewModel.showRankChange,
                                columnsPerRow: 3,
                                onTapContent: onTapContent
                            )
                        }
                    }
                }

                if !rowRankItems.isEmpty {
                    VStack(spacing: SodaSpacing.s8) {
                        ForEach(rowRankItems) { item in
                            MainContentAudioRankingRow(
                                item: item,
                                showRankChange: viewModel.showRankChange,
                                onTapContent: onTapContent
                            )
                        }
                    }
                }
            }
            .padding(.horizontal, SodaSpacing.s8)
            .padding(.vertical, SodaSpacing.s20)
        }
    }

    private var twoColumns: [GridItem] {
        [GridItem(.flexible()), GridItem(.flexible())]
    }

    private var threeColumns: [GridItem] {
        [GridItem(.flexible()), GridItem(.flexible()), GridItem(.flexible())]
    }

    private var selectedTypeBinding: Binding<AudioRankingType> {
        Binding(
            get: { viewModel.selectedType },
            set: { viewModel.selectType($0) }
        )
    }

    private var topItem: AudioRankingItemResponse? {
        viewModel.items.first { $0.rank == 1 }
    }

    private var secondToSeventhRankItems: [AudioRankingItemResponse] {
        viewModel.items.filter { 2...7 ~= $0.rank }
    }

    private var eighthToTenthRankItems: [AudioRankingItemResponse] {
        viewModel.items.filter { 8...10 ~= $0.rank }
    }

    private var rowRankItems: [AudioRankingItemResponse] {
        viewModel.items.filter { 11...20 ~= $0.rank }
    }
}

private struct MainContentRankingTypeTabBar: View {
    let items: [AudioRankingType]
    @Binding var selectedItem: AudioRankingType
    let title: (AudioRankingType) -> String

    var body: some View {
        ScrollView(.horizontal, showsIndicators: false) {
            LazyHStack(alignment: .center, spacing: SodaSpacing.s8) {
                ForEach(items, id: \.self) { item in
                    MainContentRankingTypeTabBarItem(
                        title: title(item),
                        isSelected: selectedItem == item,
                        action: { selectedItem = item }
                    )
                }
            }
            .padding(.horizontal, SodaSpacing.s14)
        }
        .frame(maxWidth: .infinity)
        .frame(height: 52, alignment: .center)
        .background(Color.black)
    }
}

private struct MainContentRankingTypeTabBarItem: View {
    let title: String
    let isSelected: Bool
    let action: () -> Void

    var body: some View {
        Button {
            action()
        } label: {
            Text(title)
                .appFont(size: 14, weight: .medium)
                .foregroundColor(isSelected ? Color.black : Color.white)
                .lineLimit(1)
                .padding(.horizontal, SodaSpacing.s12)
                .padding(.vertical, SodaSpacing.s8)
                .frame(height: 34)
                .background(isSelected ? Color.white : Color.black)
                .clipShape(Capsule())
                .overlay(
                    Capsule()
                        .stroke(isSelected ? Color.white : Color.gray700, lineWidth: 1)
                )
        }
        .buttonStyle(.plain)
    }
}