//
//  KeychainServices.swift
//  Plugin
//
//  Created by  Quéau Jean Pierre on 04/05/2021.
//  Copyright © 2021 Max Lynch. All rights reserved.
//  Copyright (c) 2020 Razeware LLC

import Foundation

struct KeychainWrapperError: Error {
    var message: String?
    var type: KeychainErrorType

    enum KeychainErrorType {
        case badData
        case servicesError
        case itemNotFound
        case unableToConvertToString
    }

    init(status: OSStatus, type: KeychainErrorType) {
        self.type = type
        if let errorMessage = SecCopyErrorMessageString(status, nil) {
            self.message = String(errorMessage)
        } else {
            self.message = "Status Code: \(status)"
        }
    }

    init(type: KeychainErrorType) {
        self.type = type
    }

    init(message: String, type: KeychainErrorType) {
        self.message = message
        self.type = type
    }
}

class KeychainWrapper {
    func storeGenericPasswordFor(
        account: String,
        service: String,
        password: String
    ) throws {
        if password.isEmpty {
            try deleteGenericPasswordFor(account: account, service: service)
            return
        }
        guard let passwordData = password.data(using: .utf8) else {
            print("Error converting value to data.")
            throw KeychainWrapperError(type: .badData)
        }
        // 1
        let query: [String: Any] = [
            // 2
            kSecClass as String: kSecClassGenericPassword,
            // 3
            kSecAttrAccount as String: account,
            // 4
            kSecAttrService as String: service,
            // 5
            kSecValueData as String: passwordData
        ]

        // 1
        let status = SecItemAdd(query as CFDictionary, nil)
        switch status {
        // 2
        case errSecSuccess:
            break
        case errSecDuplicateItem:
            try updateGenericPasswordFor(
                account: account,
                service: service,
                password: password)
        // 3
        default:
            throw KeychainWrapperError(status: status, type: .servicesError)
        }
    }

    func getGenericPasswordFor(account: String, service: String) throws -> String {
        let query: [String: Any] = [
            // 1
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrAccount as String: account,
            kSecAttrService as String: service,
            // 2
            kSecMatchLimit as String: kSecMatchLimitOne,
            kSecReturnAttributes as String: true,

            // 3
            kSecReturnData as String: true
        ]

        var item: CFTypeRef?
        let status = SecItemCopyMatching(query as CFDictionary, &item)
        guard status != errSecItemNotFound else {
            throw KeychainWrapperError(type: .itemNotFound)
        }
        guard status == errSecSuccess else {
            throw KeychainWrapperError(status: status, type: .servicesError)
        }

        guard let existingItem = item as? [String: Any],
              // 2
              let valueData = existingItem[kSecValueData as String] as? Data,
              // 3
              let value = String(data: valueData, encoding: .utf8)
        else {
            // 4
            throw KeychainWrapperError(type: .unableToConvertToString)
        }

        //5
        return value
    }

    func updateGenericPasswordFor(
        account: String,
        service: String,
        password: String
    ) throws {
        guard let passwordData = password.data(using: .utf8) else {
            print("Error converting value to data.")
            return
        }
        // 1
        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrAccount as String: account,
            kSecAttrService as String: service
        ]

        // 2
        let attributes: [String: Any] = [
            kSecValueData as String: passwordData
        ]

        // 3
        let status = SecItemUpdate(query as CFDictionary, attributes as CFDictionary)
        guard status != errSecItemNotFound else {
            throw KeychainWrapperError(message: "Matching Item Not Found", type: .itemNotFound)
        }
        guard status == errSecSuccess else {
            throw KeychainWrapperError(status: status, type: .servicesError)
        }
    }

    func deleteGenericPasswordFor(account: String, service: String) throws {
        // 1
        let query: [String: Any] = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrAccount as String: account,
            kSecAttrService as String: service
        ]

        // 2
        let status = SecItemDelete(query as CFDictionary)
        guard status == errSecSuccess || status == errSecItemNotFound else {
            throw KeychainWrapperError(status: status, type: .servicesError)
        }
    }
}