import SwiftUI

private let df: DateFormatter = {
    let df = DateFormatter()
    df.dateStyle = .short
    df.timeStyle = .short
    return df
}()

struct HistoryListItem: View {

    let entry: HistoryItem

    var entryTime: String {
        df.string(from: entry.outgoingDate)
    }

    var roundTripText: String {
        guard let time = entry.roundTripTime else {
            return ""
        }
        return "⇆ \(Int(time * 1000)) ms"
    }

    var counterText: String {
        let sentCounter = entry.outgoingMessage.content.id
        let startText = "🔗 \(sentCounter)"
        guard let rCounter = entry.incomingMessage?.content.id else {
            return startText
        }
        let diff = Int(rCounter) - Int(sentCounter)
        guard diff != 1 && diff != 0 else {
            return startText
        }
        return startText + " (\(diff))"
    }

    var timeOffsetText: String {
        guard let offset = entry.clockOffset, offset != 0 else {
            return ""
        }
        return "🕓 \(offset) s"
    }
    
    var body: some View {
        VStack {
            HStack {
                Text(entry.response?.description ?? "")
                    .font(.headline)
                Spacer()
                Text(entryTime)
            }.padding(.bottom, 1)
            HStack {
                Text(roundTripText)
                    .font(.subheadline)
                    .foregroundColor(.secondary)
                Text(counterText)
                    .font(.subheadline)
                    .foregroundColor(.secondary)
                Text(timeOffsetText)
                    .font(.subheadline)
                    .foregroundColor(.secondary)
                Spacer()
            }
        }.padding()
    }
}

struct HistoryListItem_Previews: PreviewProvider {
    static var previews: some View {
        HistoryListItem(entry: .mock)
    }
}

private extension HistoryItem {

    static var mock: HistoryItem {
        let mac = Data(repeating: 42, count: 32)
        let content = Message.Content(time: Date.now.timestamp, id: 123)
        let content2 = Message.Content(time: (Date.now + 1).timestamp, id: 124)
        return .init(
            sent: Message(mac: mac, content: content),
            date: .now)
        .didReceive(
            response: .openSesame,
            date: .now + 2,
            message: Message(mac: mac, content: content2))
    }
}