import SwiftUI

struct MainHomeRankingView: View {
    let onTapCreator: (Int) -> Void

    @StateObject private var viewModel = MainHomeRankingViewModel()

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

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

            if viewModel.isLoading && !viewModel.hasLoaded {
                ProgressView()
                    .progressViewStyle(CircularProgressViewStyle(tint: .white))
            } else if viewModel.items.isEmpty {
                MainHomeRankingEmptyStateView()
            } else {
                rankingContent
            }
        }
        .onAppear {
            if !viewModel.hasLoaded {
                viewModel.fetchRankings()
            }
        }
    }

    private var rankingContent: some View {
        ScrollView(showsIndicators: false) {
            VStack(alignment: .leading, spacing: SodaSpacing.s8) {
                ForEach(firstRankItems) { item in
                    MainHomeRankingCard(
                        item: item,
                        showRankChange: viewModel.showRankChange,
                        columnsPerRow: 1,
                        onTapCreator: onTapCreator
                    )
                }

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

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

                if !rowRankItems.isEmpty {
                    VStack(spacing: SodaSpacing.s8) {
                        ForEach(rowRankItems) { item in
                            MainHomeRankingRow(
                                item: item,
                                showRankChange: viewModel.showRankChange,
                                onTapCreator: onTapCreator
                            )
                        }
                    }
                }
            }
            .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 firstRankItems: [MainHomeCreatorRankingItem] {
        viewModel.items.filter { $0.rank == 1 }
    }

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

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

    private var rowRankItems: [MainHomeCreatorRankingItem] {
        viewModel.items.filter { $0.rank >= 11 }
    }
}

struct MainHomeRankingView_Previews: PreviewProvider {
    static var previews: some View {
        MainHomeRankingView()
    }
}