import SwiftUI

struct MainHomeBannerSection: View {
    let items: [RecommendationBannerResponse]
    let onTapBanner: (RecommendationBannerResponse) -> Void

    init(
        items: [RecommendationBannerResponse],
        onTapBanner: @escaping (RecommendationBannerResponse) -> Void = { _ in }
    ) {
        self.items = items
        self.onTapBanner = onTapBanner
    }

    var body: some View {
        if !items.isEmpty {
            BannerCarousel(items: carouselItems) { item in
                guard let banner = banner(for: item) else { return }
                onTapBanner(banner)
            }
        }
    }

    private var carouselItems: [BannerCarouselItem] {
        items.enumerated().map { index, item in
            BannerCarouselItem(
                id: fallbackId(for: item, index: index),
                imageUrl: item.imageUrl
            )
        }
    }

    private func banner(for carouselItem: BannerCarouselItem) -> RecommendationBannerResponse? {
        items.enumerated().first { index, item in
            fallbackId(for: item, index: index) == carouselItem.id
        }?.element
    }

    private func fallbackId(for item: RecommendationBannerResponse, index: Int) -> String {
        if let eventItem = item.eventItem {
            return "banner-\(index)-event-\(eventItem.id)"
        }

        if let creatorId = item.creatorId {
            return "banner-\(index)-creator-\(creatorId)"
        }

        if let seriesId = item.seriesId {
            return "banner-\(index)-series-\(seriesId)"
        }

        if let link = item.link, !link.isEmpty {
            return "banner-\(index)-link-\(link)"
        }

        return "banner-\(index)-image-\(item.imageUrl)"
    }
}

struct MainHomeBannerSection_Previews: PreviewProvider {
    static var previews: some View {
        MainHomeBannerSection(
            items: [
                RecommendationBannerResponse(
                    imageUrl: "https://picsum.photos/500/500",
                    eventItem: nil,
                    creatorId: nil,
                    seriesId: nil,
                    link: nil
                ),
                RecommendationBannerResponse(
                    imageUrl: "https://picsum.photos/500/500",
                    eventItem: nil,
                    creatorId: 1,
                    seriesId: nil,
                    link: nil
                )
            ]
        )
        .background(Color.black)
        .previewLayout(.sizeThatFits)
    }
}