import Combine
import Foundation
import SwiftUI
import Swinject

struct TagCloudView: View {
    var tags: [String]

    @State private var totalHeight
//          = CGFloat.zero       // << variant for ScrollView/List
        = CGFloat.infinity // << variant for VStack
    var body: some View {
        VStack {
            GeometryReader { geometry in
                self.generateContent(in: geometry)
            }
        }
//        .frame(height: totalHeight)// << variant for ScrollView/List
        .frame(maxHeight: totalHeight) // << variant for VStack
    }

    private func generateContent(in g: GeometryProxy) -> some View {
        var width = CGFloat.zero
        var height = CGFloat.zero

        return ZStack(alignment: .topLeading) {
            ForEach(self.tags, id: \.self) { tag in
                self.item(for: tag)
                    .padding([.horizontal, .vertical], 2)
                    .alignmentGuide(.leading, computeValue: { d in
                        if abs(width - d.width) > g.size.width
                        {
                            width = 0
                            height -= d.height
                        }
                        let result = width
                        if tag == self.tags.last! {
                            width = 0 // last item
                        } else {
                            width -= d.width
                        }
                        return result
                    })
                    .alignmentGuide(.top, computeValue: { _ in
                        let result = height
                        if tag == self.tags.last! {
                            height = 0 // last item
                        }
                        return result
                    })
            }
        }.background(viewHeightReader($totalHeight))
    }

    private func item(for textTag: String) -> some View {
        var colorOfTag: Color {
            switch textTag {
            case textTag where textTag.contains("SMB Delivery Ratio:"):
                return .uam
            case textTag where textTag.contains("Bolus"):
                return .green
            case textTag where textTag.contains("TDD:"),
                 textTag where textTag.contains("tdd_factor"),
                 textTag where textTag.contains("Sigmoid function"),
                 textTag where textTag.contains("Logarithmic formula"),
                 textTag where textTag.contains("AF:"),
                 textTag where textTag.contains("Autosens/Dynamic Limit:"),
                 textTag where textTag.contains("Dynamic ISF/CR"),
                 textTag where textTag.contains("Basal ratio"),
                 textTag where textTag.contains("SMB Ratio"):
                return .zt
            default:
                return .insulin
            }
        }

        return ZStack { Text(textTag)
            .padding(.vertical, 2)
            .padding(.horizontal, 4)
            .font(.subheadline)
            .background(colorOfTag.opacity(0.8))
            .foregroundColor(Color.white)
            .cornerRadius(2) }
    }

    private func viewHeightReader(_ binding: Binding<CGFloat>) -> some View {
        GeometryReader { geometry -> Color in
            let rect = geometry.frame(in: .local)
            DispatchQueue.main.async {
                binding.wrappedValue = rect.size.height
            }
            return .clear
        }
    }
}

struct TestTagCloudView: View {
    var body: some View {
        VStack {
            Text("Header").font(.largeTitle)
            TagCloudView(tags: ["Ninetendo", "XBox", "PlayStation", "PlayStation 2", "PlayStation 3", "PlayStation 4"])
            Text("Some other text")
            Divider()
            Text("Some other cloud")
            TagCloudView(tags: ["Apple", "Google", "Amazon", "Microsoft", "Oracle", "Facebook"])
        }
    }
}