//
//  KeyView.swift
//  OTP
//
//  Created by Shadowfacts on 8/21/21.
//

import SwiftUI
import OTPKit

struct KeyView: View {
    let key: TOTPKey
    let currentCode: TOTPCode
    @State private var copying = false
    
    private var formattedCode: String {
        let code = currentCode.code
        let mid = code.index(code.startIndex, offsetBy: code.count / 2)
        return "\(code[code.startIndex..<mid]) \(code[mid...])"
    }
    
    init(key: TOTPKey, currentCode: TOTPCode) {
        self.key = key
        self.currentCode = currentCode
    }
    
    var body: some View {
        Button(action: self.copy) {
            HStack {
                VStack(alignment: .leading) {
                    Text(key.issuer)
                        .font(.title3)
                    
                    if let label = key.label, !label.isEmpty {
                        Text(label)
                            .font(.footnote)
                    }
                }
                
                Spacer()
                

                if copying {
                    Text("Copied!")
                        .font(.title2)
                        .transition(.move(edge: .trailing).combined(with: .opacity))
                } else {
                    Text(formattedCode)
                        .font(.system(.title2, design: .monospaced))
                        .transition(.asymmetric(insertion: .move(edge: .trailing), removal: .move(edge: .leading)).combined(with: .opacity))
                }
                
    //            Text("\(currentCode.validUntil, style: .relative)")
    //                .font(.body.monospacedDigit())
                
                // I don't think this TimelineView should be necessary since the CodeHolder timer fires every .5 seconds
                TimelineView(.animation) { (ctx) in
                    ZStack {
                        CircularProgressView(progress: progress(at: Date()), colorChangeThreshold: 5.0 / Double(key.period))
                        
                        Text(Int(round(currentCode.validUntil.timeIntervalSinceNow)).description)
                            .font(.caption.monospacedDigit())
                    }
                    .frame(width: 30)
                }
            }
        }
        .tint(Color(UIColor.label))
    }
    
    private func progress(at date: Date) -> Double {
        let seconds = round(date.timeIntervalSince(currentCode.validFrom))
        let progress = 1 - seconds / Double(key.period)
        return progress
    }
    
    private func copy() {
        UIPasteboard.general.string = currentCode.code
        withAnimation(.easeInOut(duration: 0.5)) {
            copying = true
        }
        withAnimation(.easeInOut(duration: 0.5).delay(0.65)) {
            copying = false
        }
    }
}

struct KeyView_Previews: PreviewProvider {
    static var key: TOTPKey {
        TOTPKey(urlComponents: URLComponents(string: "otpauth://totp/Example:alice@google.com?secret=JBSWY3DPEHPK3PXP&issuer=Example")!)!
    }
    static var code: TOTPCode {
        OTPGenerator.generate(key: key)
    }
    static var previews: some View {
        KeyView(key: key, currentCode: code)
    }
}