//
//  KeychainDemo.swift
//  SecureStorgageSample
//
//  Demonstrates Keychain storage with LocalData package.
//

import SwiftUI
import LocalData

struct KeychainDemo: View {
    @State private var username = ""
    @State private var password = ""
    @State private var storedCredential = ""
    @State private var statusMessage = ""
    @State private var isLoading = false
    @State private var selectedAccessibility: KeychainAccessibility = .afterFirstUnlock
    @State private var selectedAccessControl: KeychainAccessControl? = nil
    @FocusState private var focusedField: Bool
    
    var body: some View {
        Form {
            Section {
                Text("Keychain provides hardware-backed secure storage for sensitive data like passwords, tokens, and keys.")
                    .font(.caption)
                    .foregroundStyle(.secondary)
            }
            
            Section("Credentials") {
                TextField("Username", text: $username)
                    .focused($focusedField)
                SecureField("Password", text: $password)
                    .focused($focusedField)
            }
            
            Section("Accessibility") {
                Picker("When Accessible", selection: $selectedAccessibility) {
                    ForEach(KeychainAccessibility.allCases, id: \.self) { option in
                        Text(option.displayName).tag(option)
                    }
                }
                .pickerStyle(.menu)
            }
            
            Section("Access Control (Optional)") {
                Picker("Require Authentication", selection: $selectedAccessControl) {
                    Text("None").tag(nil as KeychainAccessControl?)
                    ForEach(KeychainAccessControl.allCases, id: \.self) { option in
                        Text(option.displayName).tag(option as KeychainAccessControl?)
                    }
                }
                .pickerStyle(.menu)
            }
            
            Section("Actions") {
                Button(action: saveCredentials) {
                    HStack {
                        Image(systemName: "lock.fill")
                        Text("Save to Keychain")
                    }
                }
                .disabled(username.isEmpty || password.isEmpty || isLoading)
                
                Button(action: loadCredentials) {
                    HStack {
                        Image(systemName: "key.fill")
                        Text("Retrieve from Keychain")
                    }
                }
                .disabled(isLoading)
                
                Button(action: deleteCredentials) {
                    HStack {
                        Image(systemName: "trash")
                        Text("Delete from Keychain")
                    }
                }
                .foregroundStyle(.red)
                .disabled(isLoading)
            }
            
            if !storedCredential.isEmpty {
                Section("Retrieved Data") {
                    Text(storedCredential)
                        .font(.system(.body, design: .monospaced))
                }
            }
            
            if !statusMessage.isEmpty {
                Section {
                    Text(statusMessage)
                        .font(.caption)
                        .foregroundStyle(statusMessage.contains("Error") ? .red : .green)
                }
            }
            
            Section("Example Key Configuration") {
                LabeledContent("Domain", value: "Keychain")
                LabeledContent("Security", value: "Keychain Policy")
                LabeledContent("Serializer", value: "JSON")
                LabeledContent("Platform", value: "Phone Only")
            }
        }
        .navigationTitle("Keychain")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItemGroup(placement: .keyboard) {
                Spacer()
                Button("Done") {
                    focusedField = false
                }
            }
        }
    }
    
    private func saveCredentials() {
        isLoading = true
        Task {
            do {
                let key = StorageKeys.CredentialsKey(
                    accessibility: selectedAccessibility,
                    accessControl: selectedAccessControl
                )
                let credential = Credential(username: username, password: password)
                try await StorageRouter.shared.set(credential, for: key)
                statusMessage = "✓ Saved to Keychain securely"
            } catch {
                statusMessage = "Error: \(error.localizedDescription)"
            }
            isLoading = false
        }
    }
    
    private func loadCredentials() {
        isLoading = true
        Task {
            do {
                let key = StorageKeys.CredentialsKey(
                    accessibility: selectedAccessibility,
                    accessControl: selectedAccessControl
                )
                let credential = try await StorageRouter.shared.get(key)
                storedCredential = "Username: \(credential.username)\nPassword: ****"
                statusMessage = "✓ Retrieved from Keychain"
            } catch StorageError.notFound {
                storedCredential = ""
                statusMessage = "No credentials stored"
            } catch {
                statusMessage = "Error: \(error.localizedDescription)"
            }
            isLoading = false
        }
    }
    
    private func deleteCredentials() {
        isLoading = true
        Task {
            do {
                let key = StorageKeys.CredentialsKey(
                    accessibility: selectedAccessibility,
                    accessControl: selectedAccessControl
                )
                try await StorageRouter.shared.remove(key)
                storedCredential = ""
                statusMessage = "✓ Deleted from Keychain"
            } catch {
                statusMessage = "Error: \(error.localizedDescription)"
            }
            isLoading = false
        }
    }
}

#Preview {
    NavigationStack {
        KeychainDemo()
    }
}