using System.Diagnostics;
using DataModel.Database;
using Processor;
using UI_WinForms.Resources;

namespace UI_WinForms.Components;

public sealed partial class Setting : UserControl
{
    private readonly record struct SettingUIData(
        Bitmap Icon,
        Func<string> SettingName,
        Func<string> SettingExplanation,
        Func<(string URL, string TextPattern)> SettingExplanationLink,
        Func<Action, Control> SetupDataControl,
        bool ChangeNeedsRestart
    );
    
    private readonly SettingUIData data;
    private bool needRestart = false;
    
    public Setting()
    {
        this.InitializeComponent();
    }

    public bool NeedRestart => this.needRestart;
    
    private Setting(SettingUIData settingMetaData)
    {
        this.InitializeComponent();
        if(this.DesignMode)
            return;
        
        this.Dock = DockStyle.Top;
        this.data = settingMetaData;
        this.labelIcon.Image = settingMetaData.Icon;
        this.labelSettingName.Text = settingMetaData.SettingName();
        this.labelExplanation.Text = settingMetaData.SettingExplanation();

        //
        // Handle up to one link in the explanation:
        //
        var link = settingMetaData.SettingExplanationLink();
        var startIdx = this.labelExplanation.Text.IndexOf(link.TextPattern, StringComparison.InvariantCulture);
        this.labelExplanation.Links.Clear();
        if (!string.IsNullOrWhiteSpace(link.TextPattern) && !string.IsNullOrWhiteSpace(link.URL) && startIdx > -1)
            this.labelExplanation.Links.Add(startIdx, link.TextPattern.Length, link.URL);

        this.labelExplanation.LinkClicked += (_, args) =>
        {
            if(args.Link.LinkData is string url && !string.IsNullOrWhiteSpace(url) && url.ToLowerInvariant().StartsWith("https://", StringComparison.InvariantCulture))
                Process.Start(new ProcessStartInfo(url) { UseShellExecute = true });
        };

        var dataControl = settingMetaData.SetupDataControl(this.ChangeTrigger);
        this.tableLayout.Controls.Add(dataControl, 2, 0);
        
        // Ensure, that this data control is vertical centered by calculating the needed margin, considering the outer size of the table layout:
        var margin = (this.tableLayout.GetRowHeights().First() - dataControl.Height) / 2f;
        dataControl.Margin = new Padding(0, (int) margin, 0, (int)margin);
        
        // Calculate the needed height of the explanation label & centering of the data control when the parent window is resized:
        this.tableLayout.Resize += (sender, args) =>
        {
            // Adjust the height of the parent controls (table & user control):
            this.tableLayout.Height = Math.Max((int)this.labelExplanation.CreateGraphics().MeasureString(this.labelExplanation.Text, this.labelExplanation.Font, new SizeF(this.labelExplanation.Width, 1000)).Height, 66);
            this.Height = this.tableLayout.Height + this.tableLayout.Margin.Vertical;
            
            // Ensure, that this data control is vertical centered by calculating the needed margin, considering the outer size of the table layout:
            var margin = (this.tableLayout.GetRowHeights().First() - dataControl.Height) / 2f;
            dataControl.Margin = new Padding(0, (int) margin, 0, (int)margin);
        };
    }

    private void ChangeTrigger()
    {
        if(this.data.ChangeNeedsRestart)
            this.needRestart = true;
    }

    private void UpdateExplanation() => this.labelExplanation.Text = this.data.SettingExplanation();

    private static async Task<Setting> ShowDeepLModeSettingAsync()
    {
        var currentSetting = await AppSettings.GetDeepLMode();
        var settingData = new SettingUIData(
            Icon: Icons.deepl_logo_icon_170284,
            SettingName: () => "DeepL Service",
            ChangeNeedsRestart: true,
            SettingExplanation: () => "DeepL is a translation service that offers a wide range of translation services. This setting allows you to choose between the free and pro version of DeepL.",
            SettingExplanationLink: () => ("https://www.deepl.com/", "DeepL"),
            SetupDataControl: (changeTrigger) =>
            {
                var dropdown = new ComboBox();
                dropdown.Items.Add("Disabled");
                dropdown.Items.Add("Free version");
                dropdown.Items.Add("Pro version");
                dropdown.SelectedIndex = currentSetting switch
                {
                    SettingDeepLMode.DISABLED => 0,
                    SettingDeepLMode.USE_FREE_ACCOUNT => 1,
                    SettingDeepLMode.USE_PRO_ACCOUNT => 2,

                    _ => 0,
                };

                // Setup the change event handler:
                dropdown.SelectedValueChanged += async (sender, args) => await AppSettings.SetDeepLMode(dropdown.SelectedIndex switch
                {
                    0 => SettingDeepLMode.DISABLED,
                    1 => SettingDeepLMode.USE_FREE_ACCOUNT,
                    2 => SettingDeepLMode.USE_PRO_ACCOUNT,

                    _ => SettingDeepLMode.DISABLED,
                });
                
                // Fires the change trigger:
                dropdown.SelectedValueChanged += (sender, args) => changeTrigger();

                // Apply the desired layout:
                dropdown.Dock = DockStyle.Fill;
                dropdown.DropDownStyle = ComboBoxStyle.DropDownList;

                return dropdown;
            }
        );

        return new Setting(settingData);
    }
    
    private static async Task<Setting> ShowDeepLAPIKeySettingAsync()
    {
        var currentSetting = await AppSettings.GetDeepLAPIKey();
        var settingData = new SettingUIData(
            Icon: Icons.icons8_key_512,
            SettingName: () => "DeepL API Key",
            ChangeNeedsRestart: true,
            SettingExplanation: () => "The API key is required to use the DeepL translation service. You can find your API key on the DeepL website.",
            SettingExplanationLink: () => ("https://www.deepl.com/", "DeepL"),
            SetupDataControl: (changeTrigger) =>
            {
                var textbox = new TextBox();
                textbox.Text = currentSetting;
                textbox.TextChanged += async (sender, args) => await AppSettings.SetDeepLAPIKey(textbox.Text);
                textbox.TextChanged += (sender, args) => changeTrigger();
                textbox.Dock = DockStyle.Fill;
                return textbox;
            }
        );

        return new Setting(settingData);
    }
    
    private static async Task<Setting> ShowDeepLUsageSettingAsync()
    {
        var currentUsage = await Processor.DeepL.GetUsage();
        var percent = currentUsage.Enabled ? currentUsage.CharacterCount / (float)currentUsage.CharacterLimit : 0;
        
        // Local function to show & update the explanation text:
        string GetUsageText() => currentUsage.Enabled ?
            $"You used {currentUsage.CharacterCount:###,###,###,##0} characters out of {currentUsage.CharacterLimit:###,###,###,##0} ({percent:P2})." : currentUsage.AuthIssue ?
                "Was not able to authorize with DeepL. Please check your API key." :
                "DeepL is disabled or the API key is not set.";
        
        var settingData = new SettingUIData(
            Icon: Icons.icons8_increase_512,
            SettingName: () => "DeepL Usage",
            ChangeNeedsRestart: false,
            SettingExplanation: GetUsageText,
            SettingExplanationLink: () => (string.Empty, string.Empty),
            SetupDataControl: (changeTrigger) =>
            {
                var progressbar = new ProgressBar();
                progressbar.Maximum = 100;
                progressbar.Margin = new Padding(0, 16, 0, 16);
                progressbar.Dock = DockStyle.Fill;
                progressbar.Style = ProgressBarStyle.Continuous;
                progressbar.Value = percent switch
                {
                    < 0 => 0,
                    > 1 => 100,
                    
                    _ => (int)(percent * 100)
                };
                
                var reloadButton = new Button();
                reloadButton.Text = string.Empty;
                reloadButton.Image = Icons.icons8_reload_512;
                reloadButton.FlatStyle = FlatStyle.Flat;
                reloadButton.FlatAppearance.BorderSize = 0;
                reloadButton.BackColor = Color.Empty;
                reloadButton.UseVisualStyleBackColor = true;
                reloadButton.Size = new Size(60, 60);
                reloadButton.Click += async (sender, args) =>
                {
                    var usage = await Processor.DeepL.GetUsage();
                    
                    // Update the outer variables:
                    percent = usage.Enabled ? usage.CharacterCount / (float)usage.CharacterLimit : 0;
                    currentUsage = usage;
                    
                    // Update the progress bar:
                    progressbar.Value = percent switch
                    {
                        < 0 => 0,
                        > 1 => 100,
                    
                        _ => (int)(percent * 100)
                    };

                    // Update the explanation text. Therefore, we need to get the setting object through the chain of parents:
                    var setting = (Setting) ((Control) sender).Parent.Parent.Parent;
                    setting.UpdateExplanation();
                };
                
                // Setup the layout:
                var layout = new TableLayoutPanel();
                layout.ColumnCount = 2;
                layout.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100));
                layout.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 66));
                layout.RowCount = 1;
                layout.RowStyles.Add(new RowStyle(SizeType.Percent, 100));
                layout.Controls.Add(progressbar, 0, 0);
                layout.Controls.Add(reloadButton, 1, 0);
                layout.Dock = DockStyle.Fill;

                return layout;
            }
        );

        var setting = new Setting(settingData);
        return setting;
    }
    
    private static async Task<Setting> ShowDeepLActionSettingAsync()
    {
        var currentSetting = await AppSettings.GetDeepLAction();
        var settingData = new SettingUIData(
            Icon: Icons.icons8_play_512__2_,
            SettingName: () => "DeepL Operation",
            ChangeNeedsRestart: true,
            SettingExplanation: () => "Should the missing translations be automatically completed by DeepL? This can lead to higher costs. By default, DeepL is only applied manually.",
            SettingExplanationLink: () => ("https://www.deepl.com/", "DeepL"),
            SetupDataControl: (changeTrigger) =>
            {
                // We set up a combo box with the available actions:
                var dropdown = new ComboBox();
                dropdown.Items.Add("Manual");
                dropdown.Items.Add("Automatic");
                dropdown.SelectedIndex = currentSetting switch
                {
                    SettingDeepLAction.MANUAL => 0,
                    SettingDeepLAction.AUTOMATIC_ALL => 1,
                    
                    _ => 0,
                };
                
                // Setup the change event handler:
                dropdown.SelectedValueChanged += (sender, args) => changeTrigger();
                dropdown.SelectedValueChanged += async (sender, args) => await AppSettings.SetDeepLAction(dropdown.SelectedIndex switch
                {
                    0 => SettingDeepLAction.MANUAL,
                    1 => SettingDeepLAction.AUTOMATIC_ALL,
                    
                    _ => SettingDeepLAction.MANUAL,
                });
                
                // Apply the desired layout:
                dropdown.Dock = DockStyle.Fill;
                dropdown.DropDownStyle = ComboBoxStyle.DropDownList;

                return dropdown;
            }
        );

        return new Setting(settingData);
    }

    internal readonly record struct ComboBoxItem(string DisplayText, int CultureIndex)
    {
        public override string ToString() => this.DisplayText;
    }
    
    private static async Task<Setting> ShowDeepLSourceCultureSettingAsync()
    {
        var currentSourceCultureIndex = await AppSettings.GetDeepLSourceCultureIndex();
        
        // We load the corresponding culture for that index. As dropdown items, we show
        // all other available cultures:
        var allCultures = await AppSettings.GetCultureInfos();

        // Attention: We have to store the culture's index, because the index is not
        // continuous and can change when the user adds or removes a culture!
        var settingData = new SettingUIData(
            Icon: Icons.icons8_chat_bubble_512,
            SettingName: () => "DeepL Source Culture",
            ChangeNeedsRestart: true,
            SettingExplanation: () => "The source culture is used to translate the missing translations.",
            SettingExplanationLink: () => (string.Empty, string.Empty),
            SetupDataControl: (changeTrigger) =>
            {
                var dropdown = new ComboBox();
                var currentCultureDropdownIndex = 0;
                for (var n = 0; n < allCultures.Count; n++)
                {
                    var cultureInfo = allCultures[n];
                    if(cultureInfo.Index == currentSourceCultureIndex)
                        currentCultureDropdownIndex = n;

                    dropdown.Items.Add(new ComboBoxItem($"{cultureInfo.Index}.: {cultureInfo.Code}", cultureInfo.Index));
                }

                dropdown.SelectedIndex = currentCultureDropdownIndex;
                
                // Setup the change event handler:
                dropdown.SelectedValueChanged += (sender, args) => changeTrigger();
                dropdown.SelectedValueChanged += async (sender, args) =>
                {
                    if(dropdown.SelectedItem is ComboBoxItem selectedItem)
                        await AppSettings.SetDeepLSourceCultureIndex(selectedItem.CultureIndex);
                };
                
                // Apply the desired layout:
                dropdown.Dock = DockStyle.Fill;
                dropdown.DropDownStyle = ComboBoxStyle.DropDownList;
                
                return dropdown;
            }
        );
        
        return new Setting(settingData);
    }

    private static IEnumerable<Task<Setting>> ShowCultureSettingsAsync()
    {
        var isFirstCulture = true; // We need this flag to distinguish the first task from the others.
        var cultureIndices = new List<int>(new []{ -1 });
        while (cultureIndices.Count > 0)
        {
            var innerLoopIndex = cultureIndices.Last(); // needed to avoid closure issues.
            yield return Task.Run(async () =>
            {
                var localCultureIndex = innerLoopIndex;
                
                // Get a list of culture indices. Thus, we know the number of cultures. We cannot do this in the outer loop,
                // because we cannot await there. The AppSettings is caching the answer, though. The list of indices is ordered
                // ascending.
                var localCultureIndices = await AppSettings.GetCultureIndices();
                
                // Update the number of cultures in the outer loop for the first call:
                if(isFirstCulture)
                {
                    localCultureIndex = localCultureIndices.Last();
                    innerLoopIndex = localCultureIndices.Last();
                    
                    cultureIndices.Clear();
                    cultureIndices.AddRange(localCultureIndices);
                    isFirstCulture = false;
                }

                // Get the current culture code:
                var currentCultureCode = await AppSettings.GetCultureCode(localCultureIndex);
                
                // Construct the setting:
                return new Setting(new()
                {
                    Icon = Icons.icons8_chat_bubble_512,
                    SettingName = () => $"{localCultureIndex}. Culture",
                    ChangeNeedsRestart = true,
                    SettingExplanation = () => "The culture according to RFC 4646: First comes the ISO 639-1 language code in lower case, followed by a hyphen, followed by the ISO 3166-1 alpha-2 country code in upper case. Example: en-US for English in the USA, de-DE for German in Germany.",
                    SettingExplanationLink = () => ("https://lonewolfonline.net/list-net-culture-country-codes/", "according to RFC 4646"),
                    SetupDataControl = (changeTrigger) =>
                    {
                        var textbox = new TextBox();
                        textbox.Text = currentCultureCode;
                        textbox.TextChanged += async (sender, args) =>
                        {
                            await AppSettings.SetCultureCode(localCultureIndex, textbox.Text);
                            changeTrigger();
                        };
                        textbox.Dock = DockStyle.Fill;
                        return textbox;
                    }
                });
            });
            
            cultureIndices.Remove(innerLoopIndex);
        }
    }
    
    private static async Task<Setting> ShowGeneratorModeSettingAsync()
    {
        var currentSetting = await AppSettings.GetGeneratorMode();
        
        var settingData = new SettingUIData(
            Icon: Icons.icons8_code_512,
            SettingName: () => "Generator Mode",
            ChangeNeedsRestart: false,
            SettingExplanation: () => "The generator mode determines how the translation files are generated.",
            SettingExplanationLink: () => (string.Empty, string.Empty),
            SetupDataControl: (changeTrigger) =>
            {
                // We set up a combo box with the available actions:
                var dropdown = new ComboBox();
                dropdown.Items.Add("Automatic generation");
                dropdown.Items.Add("Manual generation");
                dropdown.SelectedIndex = currentSetting switch
                {
                    SettingGeneratorMode.AUTOMATIC => 0,
                    SettingGeneratorMode.MANUAL => 1,
                    
                    _ => 0,
                };
                
                // Setup the change event handler:
                dropdown.SelectedValueChanged += (sender, args) => changeTrigger();
                dropdown.SelectedValueChanged += async (sender, args) => await AppSettings.SetGeneratorMode(dropdown.SelectedIndex switch
                {
                    0 => SettingGeneratorMode.AUTOMATIC,
                    1 => SettingGeneratorMode.MANUAL,
                    
                    _ => SettingGeneratorMode.AUTOMATIC,
                });
                
                // Apply the desired layout:
                dropdown.Dock = DockStyle.Fill;
                dropdown.DropDownStyle = ComboBoxStyle.DropDownList;

                return dropdown;
            }
        );

        return new Setting(settingData);
    }

    private static async Task<Setting> ShowGeneratorDotnetEnabledSettingAsync()
    {
        var currentSetting = await AppSettings.GetGeneratorDotnetEnabled();
        
        var settingData = new SettingUIData(
            Icon: Icons.icons8_code_512,
            SettingName: () => "Generator: .NET",
            ChangeNeedsRestart: false,
            SettingExplanation: () => "When enabled, .NET translation files are generated. Requires a .NET 6 or newer project.",
            SettingExplanationLink: () => (string.Empty, string.Empty),
            SetupDataControl: (changeTrigger) =>
            {
                // Set up an checkbox:
                var checkbox = new CheckBox();
                checkbox.Checked = currentSetting;
                checkbox.CheckedChanged += (sender, args) => changeTrigger();
                checkbox.CheckedChanged += async (sender, args) => await AppSettings.SetGeneratorDotnetEnabled(checkbox.Checked);
                checkbox.Text = "Enable .NET Generator";

                // Apply the desired layout:
                checkbox.Dock = DockStyle.Fill;
                return checkbox;
            }
        );

        return new Setting(settingData);
    }

    private static async Task<Setting> ShowGeneratorDotnetDestinationPathSettingAsync()
    {
        var currentSetting = await AppSettings.GetGeneratorDotnetDestinationPath();
        
        var settingData = new SettingUIData(
            Icon: Icons.icons8_code_512,
            SettingName: () => "Generator: .NET Destination Path",
            ChangeNeedsRestart: false,
            SettingExplanation: () => "The destination path for the .NET translation files. You might use environment variables like %USERPROFILE%.",
            SettingExplanationLink: () => (string.Empty, string.Empty),
            SetupDataControl: (changeTrigger) =>
            {
                // Set up a horizontal layout:
                var layout = new TableLayoutPanel();
                layout.ColumnCount = 2;
                layout.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100F));
                layout.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 66F));
                layout.RowCount = 1;
                layout.RowStyles.Add(new RowStyle(SizeType.Percent, 100F));
                layout.Dock = DockStyle.Fill;

                // Set up a textbox:
                var textbox = new TextBox();
                textbox.Text = currentSetting;
                textbox.TextChanged += (sender, args) => changeTrigger();
                textbox.TextChanged += async (sender, args) => await AppSettings.SetGeneratorDotnetDestinationPath(textbox.Text);
                textbox.Dock = DockStyle.Fill;
                textbox.Margin = new Padding(0, 13, 0, 13);
                layout.Controls.Add(textbox, 0, 0);
                
                // Set up a button:
                var button = new Button();
                button.Text = string.Empty;
                button.Image = Icons.icons8_folder_tree_512;
                button.FlatStyle = FlatStyle.Flat;
                button.FlatAppearance.BorderSize = 0;
                button.BackColor = Color.Empty;
                button.UseVisualStyleBackColor = true;
                button.Size = new Size(60, 60);
                button.Click += (sender, args) =>
                {
                    var dialog = new FolderBrowserDialog();
                    dialog.SelectedPath = textbox.Text;
                    dialog.InitialDirectory = textbox.Text;
                    dialog.Description = "Select the destination path for the .NET translation files.";
                    dialog.ShowNewFolderButton = true;
                    if (dialog.ShowDialog() == DialogResult.OK)
                        textbox.Text = dialog.SelectedPath;
                };
                button.Dock = DockStyle.Fill;
                layout.Controls.Add(button, 1, 0);
                
                return layout;
            }
        );
        
        return new Setting(settingData);
    }

    public static IEnumerable<Task<Setting>> GetAllSettings()
    {
        yield return ShowGeneratorDotnetDestinationPathSettingAsync();
        yield return ShowGeneratorDotnetEnabledSettingAsync();
        yield return ShowGeneratorModeSettingAsync();
        yield return ShowDeepLSourceCultureSettingAsync();
        foreach (var setting in ShowCultureSettingsAsync())
        {
            yield return setting;
        }

        yield return ShowDeepLUsageSettingAsync();
        yield return ShowDeepLActionSettingAsync();
        yield return ShowDeepLAPIKeySettingAsync();
        yield return ShowDeepLModeSettingAsync();
    }
}