//
//  Keychain.swift
//  AT-IRC
//
//  Minimal generic-password Keychain storage for the session blob.
//

import Foundation
import Security

enum Keychain {
    private static let service = "com.fedfork.irc.AT-IRC"

    static func set(_ data: Data, for key: String, accessible: CFString = kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly) {
        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: service,
            kSecAttrAccount as String: key,
        ]
        SecItemDelete(query as CFDictionary)
        var attributes = query
        attributes[kSecValueData as String] = data
        attributes[kSecAttrAccessible as String] = accessible
        SecItemAdd(attributes as CFDictionary, nil)
    }

    static func get(_ key: String) -> Data? {
        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: service,
            kSecAttrAccount as String: key,
            kSecReturnData as String: true,
            kSecMatchLimit as String: kSecMatchLimitOne,
        ]
        var result: CFTypeRef?
        guard SecItemCopyMatching(query as CFDictionary, &result) == errSecSuccess else {
            return nil
        }
        return result as? Data
    }

    static func delete(_ key: String) {
        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: service,
            kSecAttrAccount as String: key,
        ]
        SecItemDelete(query as CFDictionary)
    }
}