using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
using Microsoft.Win32;
using Shadowsocks.Controller;
using Shadowsocks.Model;
using Shadowsocks.Properties;

namespace Shadowsocks.View
{
    public partial class ConfigForm : Form
    {
        private ShadowsocksController controller;
        private UpdateChecker updateChecker;

        // this is a copy of configuration that we are working on
        private Configuration _modifiedConfiguration;
        private int _oldSelectedIndex = -1;
        private bool _isFirstRun;

        public ConfigForm(ShadowsocksController controller)
        {
            InitializeComponent();
            this.Icon = Icon.FromHandle(Resources.ssw128.GetHicon());

            this.controller = controller;
            controller.ConfigChanged += controller_ConfigChanged;

            LoadCurrentConfiguration();
        }

        private void controller_ConfigChanged(object sender, EventArgs e)
        {
            LoadCurrentConfiguration();
        }

        void notifyIcon1_BalloonTipClicked(object sender, EventArgs e)
        {
            Process.Start(updateChecker.LatestVersionURL);
        }

        
        private void ShowWindow()
        {
            this.Opacity = 1;
            this.Show();
            IPTextBox.Focus();
        }

        private bool SaveOldSelectedServer()
        {
            try
            {
                if (_oldSelectedIndex == -1 || _oldSelectedIndex >= _modifiedConfiguration.configs.Count)
                {
                    return true;
                }
                Server server = new Server
                {
                    server = IPTextBox.Text,
                    server_port = int.Parse(ServerPortTextBox.Text),
                    password = PasswordTextBox.Text,
                    local_port = int.Parse(ProxyPortTextBox.Text),
                    method = EncryptionSelect.Text,
                    remarks = RemarksTextBox.Text
                };
                Configuration.CheckServer(server);
                _modifiedConfiguration.configs[_oldSelectedIndex] = server;
                
                return true;
            }
            catch (FormatException)
            {
                MessageBox.Show("illegal port number format");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            return false;
        }

        private void LoadSelectedServer()
        {
            if (ServersListBox.SelectedIndex >= 0 && ServersListBox.SelectedIndex < _modifiedConfiguration.configs.Count)
            {
                Server server = _modifiedConfiguration.configs[ServersListBox.SelectedIndex];

                IPTextBox.Text = server.server;
                ServerPortTextBox.Text = server.server_port.ToString();
                PasswordTextBox.Text = server.password;
                ProxyPortTextBox.Text = server.local_port.ToString();
                EncryptionSelect.Text = server.method ?? "aes-256-cfb";
                RemarksTextBox.Text = server.remarks;
                ServerGroupBox.Visible = true;
                //IPTextBox.Focus();
            }
            else
            {
                ServerGroupBox.Visible = false;
            }
        }

        private void LoadConfiguration(Configuration configuration)
        {
            ServersListBox.Items.Clear();
            foreach (Server server in _modifiedConfiguration.configs)
            {
                ServersListBox.Items.Add(string.IsNullOrEmpty(server.server) ? "New server" : string.IsNullOrEmpty(server.remarks)? server.server + ":" + server.server_port : server.server + ":" + server.server_port + " (" + server.remarks + ")");
            }
        }

        private void LoadCurrentConfiguration()
        {
            _modifiedConfiguration = controller.GetConfiguration();
            LoadConfiguration(_modifiedConfiguration);
            _oldSelectedIndex = _modifiedConfiguration.index;
            ServersListBox.SelectedIndex = _modifiedConfiguration.index;
            LoadSelectedServer();
        }

        private void ConfigForm_Load(object sender, EventArgs e)
        {

        }

        private void ServersListBox_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (_oldSelectedIndex == ServersListBox.SelectedIndex)
            {
                // we are moving back to oldSelectedIndex or doing a force move
                return;
            }
            if (!SaveOldSelectedServer())
            {
                // why this won't cause stack overflow?
                ServersListBox.SelectedIndex = _oldSelectedIndex;
                return;
            }
            LoadSelectedServer();
            _oldSelectedIndex = ServersListBox.SelectedIndex;
        }

        private void AddButton_Click(object sender, EventArgs e)
        {
            if (!SaveOldSelectedServer())
            {
                return;
            }
            Server server = Configuration.GetDefaultServer();
            _modifiedConfiguration.configs.Add(server);
            LoadConfiguration(_modifiedConfiguration);
            ServersListBox.SelectedIndex = _modifiedConfiguration.configs.Count - 1;
            _oldSelectedIndex = ServersListBox.SelectedIndex;
        }

        private void DeleteButton_Click(object sender, EventArgs e)
        {
            _oldSelectedIndex = ServersListBox.SelectedIndex;
            if (_oldSelectedIndex >= 0 && _oldSelectedIndex < _modifiedConfiguration.configs.Count)
            {
                _modifiedConfiguration.configs.RemoveAt(_oldSelectedIndex);
            }
            if (_oldSelectedIndex >= _modifiedConfiguration.configs.Count)
            {
                // can be -1
                _oldSelectedIndex = _modifiedConfiguration.configs.Count - 1;
            }
            ServersListBox.SelectedIndex = _oldSelectedIndex;
            LoadConfiguration(_modifiedConfiguration);
            ServersListBox.SelectedIndex = _oldSelectedIndex;
            LoadSelectedServer();
        }

        private void OKButton_Click(object sender, EventArgs e)
        {
            if (!SaveOldSelectedServer())
            {
                return;
            }
            if (_modifiedConfiguration.configs.Count == 0)
            {
                MessageBox.Show("Please add at least one server");
                return;
            }
            controller.SaveServers(_modifiedConfiguration.configs);
            this.Hide();
        }

        private void CancelButton_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void ConfigForm_Shown(object sender, EventArgs e)
        {
            IPTextBox.Focus();
        }

        private void ConfigForm_FormClosed(object sender, FormClosedEventArgs e)
        {
            controller.ConfigChanged -= controller_ConfigChanged;
        }

    }
}