import Foundation

func makeCommand(method: String, param: Any, completionHandler: @escaping (Any?) -> Void) -> Void {

// 1. Build a URL
    
    let testnetRpcPort = "18332"
    let nodeIp = "127.0.0.1:\(testnetRpcPort)"
    let rpcusername = "oIjA53JC2u"
    let rpcpassword = "ebVCeSyyM0LurvgQyi0exWTqm4oU0rZU"
    let walletName = ""
    let walletUrl = "http://\(rpcusername):\(rpcpassword)@\(nodeIp)/\(walletName)"

    let url = URL(string: walletUrl)

// 2. Build a Request
    
    var request = URLRequest(url: url!)
    request.httpMethod = "POST"
    request.setValue("text/plain", forHTTPHeaderField: "Content-Type")
    request.httpBody = "{\"jsonrpc\":\"1.0\",\"id\":\"curltest\",\"method\":\"\(method)\",\"params\":[\(param)]}".data(using: .utf8)

// 3. Build a Session
    
    let session = URLSession(configuration: .default)
    let task = session.dataTask(with: request as URLRequest) { data, response, error in

        do {


            if error != nil {

                    //Handle the error
                    
            } else {
                    
                if let urlContent = data {
                        
                    do {
                            
                        let json = try JSONSerialization.jsonObject(with: urlContent, options: JSONSerialization.ReadingOptions.mutableLeaves) as! NSDictionary
                        if let errorCheck = json["error"] as? NSDictionary {
                                                                
                            if let errorMessage = errorCheck["message"] as? String {

                                print("FAILED")
                                print(errorMessage)

                            }
                                
                        } else {
                                
                            let result = json["result"]
                            completionHandler(result)
                            
                        }
                            
                    } catch {
                            
                            //Handle error here
                            
                    }
                        
                }
                    
            }
                
        }
            
    }

    task.resume()
    
}

// Test getblockchaininfo

var method = "getblockchaininfo"
var param = ""

makeCommand(method: method,param: param) { result in
    
    print(result!)
    let blockinfo = result as! NSDictionary
    let block = blockinfo["blocks"] as! NSNumber

    // Test getblockchash
    
    method = "getblockhash"
    makeCommand(method: method,param: block) { result in
        print("Blockhash for \(block) is \(result!)")
    }
    
}