import SwiftUI
import CryptoKit

let keyManager = try! KeyManagement()
let server = Client(server: URL(string: "https://christophhagen.de/sesame/")!)

struct ContentView: View {
    
    @State var state: ClientState = .initial
    
    var canShareKey = false
    
    @State var showNewKeyWarning = false
    
    @State var showKeyGenerationFailedWarning = false
    
    @State var showShareSheetForNewKeys = false
    
    @State var activeRequestCount = 0
    
    var isPerformingRequests: Bool {
        activeRequestCount > 0
    }
    
    var keyText: String {
        let totalKeys = keyManager.numberOfKeys
        guard totalKeys > 0 else {
            return "No keys available"
        }
        let unusedKeys = keyManager.unusedKeyCount
        guard unusedKeys > 0 else {
            return "All keys used"
        }
        return "\(totalKeys - unusedKeys) / \(totalKeys) keys used"
    }
    
    private let buttonWidth: CGFloat = 200
    
    private let topButtonHeight: CGFloat = 60
    
    var body: some View {
        VStack(spacing: 20) {
            Text(keyText)
            Button("Generate new keys", action: {
                showNewKeyWarning = true
                print("Key regeneration requested")
            })
                .padding()
                .frame(width: buttonWidth, height: topButtonHeight)
                .background(.blue)
                .foregroundColor(.white)
                .cornerRadius(topButtonHeight / 2)
            Button("Share one-time key", action: shareKey)
                .padding()
                .frame(width: buttonWidth, height: topButtonHeight)
                .background(.mint)
                .foregroundColor(.white)
                .cornerRadius(topButtonHeight / 2)
                .disabled(!canShareKey)
            
            Spacer()
            HStack {
                if isPerformingRequests {
                    ProgressView()
                        .progressViewStyle(CircularProgressViewStyle())
                }
                Text(state.description)
                    .padding()
            }
            Button(state.openButtonText, action: mainButtonPressed)
                .frame(width: buttonWidth, height: 80, alignment: .center)
                .background(state.openButtonColor)
                .cornerRadius(100)
                .foregroundColor(.white)
                .font(.title2)
                .disabled(!state.openActionIsEnabled)
        }
        .padding(20)
        .onAppear {
            checkInitialDeviceStatus()
        }.alert(isPresented: $showKeyGenerationFailedWarning) {
            Alert(title: Text("The keys could not be generated"),
                  message: Text("All previous keys will be deleted and the lock will be blocked. Are you sure?"),
                  dismissButton: .default(Text("Okay")))
        }.shareSheet(isPresented: $showShareSheetForNewKeys, items: [keyManager.exportFile])
            .alert(isPresented: $showNewKeyWarning) {
                Alert(title: Text("Generate new keys"),
                      message: Text("All previous keys will be deleted and the lock will be blocked. Are you sure?"),
                      primaryButton: .destructive(Text("Generate"), action: regenerateKeys),
                      secondaryButton: .cancel())
            }
    }
    
    func mainButtonPressed() {
        print("Main button pressed")
        if state.canSendKey {
            sendKey()
        } else {
            checkInitialDeviceStatus()
        }
    }
    
    func sendKey() {
        guard let key = keyManager.useNextKey() else {
            state = .allKeysUsed
            return
        }
        state = .waitingForResponse
        activeRequestCount += 1
        print("Sending key \(key.id)")
        Task {
            let newState = try await server.keyResponse(key: key.key, id: key.id)
            activeRequestCount -= 1
            state = newState
        }
    }
    
    func checkInitialDeviceStatus() {
        print("Checking device status")
        Task {
            do {
                activeRequestCount += 1
                let newState = try await server.deviceStatus()
                activeRequestCount -= 1
                print("Device status: \(newState)")
                switch newState {
                case .noKeysAvailable, .allKeysUsed:
                    return
                default:
                    state = newState
                }
            } catch {
                print("Failed to get device status: \(error)")
                state = .statusRequestFailed
            }
        }
    }
    
    func regenerateKeys() {
        print("Regenerate keys")
        do {
            try keyManager.regenerateKeys()
            state = .newKeysGenerated
            showKeyGenerationFailedWarning = false
            showShareSheetForNewKeys = true
            checkInitialDeviceStatus()
        } catch {
            state = .noKeysAvailable
            showKeyGenerationFailedWarning = true
            showShareSheetForNewKeys = false
        }
    }
    
    func shareKey() {
        
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
            .previewDevice("iPhone 8")
    }
}