import Foundation

class RNSecureStorageHelper {
    let appBundleName = Bundle.main.bundleIdentifier!
    enum KeychainError: Error {
        case keyRequired
    }
    /*
     Store an item in keychain.
     */
    func createKeychainValue(key: String, value: String, accessible:String) -> Bool {
        let keyData = appBundleName+"."+key
        let tag = keyData.data(using: .utf8)!
        let valData =  value.data(using: .utf8)
        let query:[String : Any] = [
            kSecClass as String: kSecClassKey,
            kSecAttrApplicationTag as String : tag,
            kSecValueData as String   : valData!,
            kSecAttrAccessible as String: self.accessibleValue(accessible: accessible)
        ]
        
        SecItemDelete(query as CFDictionary)
        
        let status = SecItemAdd(query as CFDictionary, nil)
        
        return status == errSecSuccess
        
    }
    
    /*
     Get value from keychain by key.
     */
    func getKeychainValue(key: String) -> Data?  {
        let keyData = appBundleName+"."+key
        let tag = keyData.data(using: .utf8)!
        
        let query: [String : Any] = [
            kSecClass as String: kSecClassKey,
            kSecAttrApplicationTag as String: tag,
            kSecReturnData as String:  kCFBooleanTrue!,
        ]
        var dataTypeRef: AnyObject? = nil
        
        let status: OSStatus = SecItemCopyMatching(query as CFDictionary, &dataTypeRef)
        
        if status == noErr {
            return dataTypeRef as! Data?
        } else {
            return nil
        }
        
    }
    /*
     Check if key exist in keychain.
     */
    func keychainValueExist(key: String) -> Bool  {
        let keyData = appBundleName+"."+key
        let tag = keyData.data(using: .utf8)!
        
        let query: [String : Any] = [
            kSecClass as String: kSecClassKey,
            kSecAttrApplicationTag as String: tag,
            kSecReturnData as String:  kCFBooleanTrue!,
        ]
        
        let status = SecItemCopyMatching(query as CFDictionary, nil)
        
        return status == errSecSuccess
        
    }
    
    /*
     Get all stored keys from keychain.
     */
    func getAllKeychainKeys()  -> [String] {
        var keys = [String]()
        let query: [String: Any] = [
            kSecClass as String : kSecClassKey,
            kSecReturnData as String  : kCFBooleanTrue!,
            kSecReturnAttributes as String : kCFBooleanTrue!,
            kSecMatchLimit as String: kSecMatchLimitAll
        ]
        
        var result: AnyObject? = nil
        
        let lastResultCode = withUnsafeMutablePointer(to: &result) {
            SecItemCopyMatching(query as CFDictionary, UnsafeMutablePointer($0))
        }
        
        if lastResultCode == noErr {
            let array = result as? Array<Dictionary<String, Any>>
            
            for item in array! {
                let key = item[kSecAttrApplicationTag as String]
                let replaceKey = String(data:key as! Data, encoding: .utf8)!
                let result = replaceKey.replacingOccurrences(of: appBundleName+".", with: "")
                keys.append(result)
            }
        }
        
        return keys
        
    }
    
    /*
     Set multiple values from keychain with keys
     */
    func multiSetKeychainValues(keyValuePairs: [String: String], accessible: String) -> Bool {
        var settedPairs = 0
        for (key, value) in keyValuePairs {
            let val = self.createKeychainValue(key: key, value: value, accessible: accessible)
            if val {
                settedPairs += 1
            }
        }
        return settedPairs == keyValuePairs.count
    }
    
    
    /*
     Get multiple values from keychain with keys
     */
    func multiGetKeychainValues(keys: [String]) throws -> [String: String?] {
        guard !keys.isEmpty else {
            throw RNSecureErrors.KEY_REQUIRED
        }
        
        var values = [String: String?]()
        for key in keys {
            if let val = self.getKeychainValue(key: key) {
                values[key] = String(data: val, encoding: .utf8)
            } else {
                values[key] = nil
            }
        }
        return values
    }
    
    
    /*
     Remove keychain item.
     */
    func removeKeychainValue(key: String) -> Bool {
        let keyData = appBundleName+"."+key
        let tag = keyData.data(using: .utf8)!
        
        let query: [String : Any] = [
            kSecClass as String: kSecClassKey,
            kSecAttrApplicationTag as String: tag,
            kSecReturnData as String:  kCFBooleanTrue!,
        ]
        
        return SecItemDelete(query as CFDictionary) == errSecSuccess
    }
    
    /*
     Multi remove keychain item.
     */
    func multiRemoveKeychainValue(keys: [String]) -> [String] {
        var unremovedKeys = [String]()
        for key in keys {
            let val = self.removeKeychainValue(key: key)
            if !val {
                unremovedKeys.append(key)
            }
        }
        return unremovedKeys
    }
    
    /*
     Clear all stored keys
     */
    func clearAllStoredValues() -> [String] {
        var keys = [String]()
        var unremovedKeys = [String]()
        let query: [String: Any] = [
            kSecClass as String : kSecClassKey,
            kSecReturnData as String  : kCFBooleanTrue!,
            kSecReturnAttributes as String : kCFBooleanTrue!,
            kSecMatchLimit as String: kSecMatchLimitAll
        ]
        
        var result: AnyObject? = nil
        
        let lastResultCode = withUnsafeMutablePointer(to: &result) {
            SecItemCopyMatching(query as CFDictionary, UnsafeMutablePointer($0))
        }
        
        if lastResultCode == noErr {
            let array = result as? Array<Dictionary<String, Any>>
            
            for item in array! {
                let key = item[kSecAttrApplicationTag as String]
                let replaceKey = String(data:key as! Data, encoding: .utf8)!
                let result = replaceKey.replacingOccurrences(of: appBundleName+".", with: "")
                keys.append(result)
            }
        }
        
        for key in keys {
            let status  = self.removeKeychainValue(key: key)
            if !status {
                unremovedKeys.append(key)
            }
        }
        return unremovedKeys
    }
    
    func accessibleValue(accessible: String) -> CFString {
        
        let list = [
            "AccessibleWhenUnlocked": kSecAttrAccessibleWhenUnlocked,
            "AccessibleAfterFirstUnlock": kSecAttrAccessibleAfterFirstUnlock,
            "AccessibleAlways": kSecAttrAccessibleAlways,
            "AccessibleWhenPasscodeSetThisDeviceOnly": kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly,
            "AccessibleWhenUnlockedThisDeviceOnly": kSecAttrAccessibleWhenUnlockedThisDeviceOnly,
            "AccessibleAfterFirstUnlockThisDeviceOnly": kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly,
            "AccessibleAlwaysThisDeviceOnly": kSecAttrAccessibleAlwaysThisDeviceOnly
        ]
        
        return list[accessible]!
        
    }
    
    
}