using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using static System.Windows.Forms.ListViewItem;

namespace Client
{
    /**
     * Progetto: creare un client che permetta l'esecuzione dei metodi HTTP CRUD (Get, Post, Put, Delete) su una web API utilizzando metodi Asincroni
     * e premettendo l'autenticazione e con una piccola gestione degli errori
     * L'app si può provare sui siti https://jsonplaceholder.typicode.com/ e https://dummy.restapiexample.com/
     */
    public partial class Form1 : Form
    {
        private ICredentials credentials = new NetworkCredential();

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private async void Get(string url)
        {
            using (var client = new WebClient())
            {
                client.Credentials = credentials;
                foreach (ListViewItem item in lstQuery.Items)
                {
                    client.QueryString.Add(item.SubItems[0].Text, item.SubItems[1].Text);
                }
                try
                {
                    var result = await client.DownloadStringTaskAsync(new Uri(url));
                    txtOutput.Text = result;
                }
                catch (WebException e)
                {
                    HandleException(e);
                }
            }
        }

        private async void ExecuteMethod(string method, string url)
        {
            var values = new NameValueCollection();
            using (var client = new WebClient())
            {
                client.Credentials = credentials;
                foreach (ListViewItem item in lstQuery.Items)
                {
                    values.Add(item.SubItems[0].Text, item.SubItems[1].Text);
                }
                try
                {
                    var response = await client.UploadValuesTaskAsync(url, method, values);
                    txtOutput.Text = Encoding.ASCII.GetString(response);
                }
                catch (WebException e)
                {
                    HandleException(e);
                }
            }
        }

        private void HandleException(WebException exception)
        {
            if (exception.Status == WebExceptionStatus.ProtocolError)
            {
                MessageBox.Show("Errore, status code: " + ((HttpWebResponse)exception.Response).StatusCode);
            }
            else if (exception.Status == WebExceptionStatus.Timeout)
                MessageBox.Show("Errore: timeout");
            else if (exception.Status == WebExceptionStatus.ConnectFailure)
                MessageBox.Show("Connessione fallita");
            else
                MessageBox.Show("Errore: " + exception.ToString());
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {
            var key = txtKey.Text;
            var value = txtValue.Text;
            lstQuery.Items.Add(new ListViewItem(new string[] { key, value }));
        }

        private void btnGet_Click(object sender, EventArgs e)
        {
            Get(txtUrl.Text);
        }

        private void btnPost_Click(object sender, EventArgs e)
        {
            ExecuteMethod("POST", txtUrl.Text);
        }

        private void btnPut_Click(object sender, EventArgs e)
        {
            ExecuteMethod("PUT", txtUrl.Text);
        }

        private void btnDelete_Click(object sender, EventArgs e)
        {
            ExecuteMethod("DELETE", txtUrl.Text);
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            txtOutput.Text = "";
        }

        private void btnGetSync_Click(object sender, EventArgs e)
        {
            using (var client = new WebClient())
            {
                foreach (ListViewItem item in lstQuery.Items)
                {
                    client.QueryString.Add(item.SubItems[0].Text, item.SubItems[1].Text);
                }
                try
                {
                    var result = client.DownloadString(txtUrl.Text);
                    txtOutput.Text = result;
                }
                catch (WebException exc)
                {
                    HandleException(exc);
                }
            }
        }

        private void btnSet_Click(object sender, EventArgs e)
        {
            this.credentials = new NetworkCredential(txtUsername.Text, txtPassword.Text);
        }
    }
}