using RemSox.Processing;
using RemSox.UI.GUI.Windows;

using System.Drawing;

using YesNt.Interpreter.Runtime;
using YesNt.Interpreter.Utilities;

namespace RemSox.Utils;

/// <summary>
/// Registers all YesNt statements that expose the WindowManager / UI element API.
///
/// Window management:
///   win_create "My Window" 320 240       creates a window, read back id with %win_last_id
///   win_close  ${myWinId}                closes/destroys a window by id
///   win_flush  ${myWinId}                forces a redraw of the window
///   win_title  ${myWinId} "New Title"    changes the window title
///   win_autoflush ${myWinId} true        enables/disables auto-flush
///   win_invalidate_all                   invalidates and redraws every window
///
/// UI element creation (read back id with %ui_last_id after each call):
///   ui_button   ${myWinId} 20 30 100 30 "Click Me"
///   ui_checkbox ${myWinId} 20 80 "Check Me" true
///   ui_label    ${myWinId} 20 10 "Hello World"
///   ui_textbox  ${myWinId} 20 50 160 24 "placeholder"
///   ui_line     ${myWinId} 20 130 180 130 255 0 0   (x1 y1 x2 y2 R G B)
///   ui_rect     ${myWinId} 20 20 100 60 0 128 255   (x y w h R G B)
///
/// Inline substitutions (use inside any line, like %read_line):
///   %win_last_id   expands to the id of the last created window
///   %ui_last_id    expands to the id of the last created UI element
/// </summary>
public static class YesNtWindowStatements
{
    // Maps script-visible integer ids to actual Window objects.
    private static readonly Dictionary<int, Window> s_windows = [];
    private static int s_nextWindowId = 1;
    private static int s_lastWindowId = 0;

    private static int s_nextUiId = 1;
    private static int s_lastUiId = 0;

    private static Process s_ownerProcess = null!;

    /// <summary>
    /// Call this from <see cref="YesNtInterpreterProcess.Start"/> to register
    /// every window-related statement with the given interpreter.
    /// </summary>
    /// <param name="interpreter">The live interpreter instance.</param>
    /// <param name="ownerProcess">
    ///   The <see cref="Process"/> that will own created windows
    ///   (usually the <see cref="YesNtInterpreterProcess"/> itself).
    /// </param>
    public static void Register(YesNtInterpreter interpreter, Process ownerProcess)
    {
        s_ownerProcess = ownerProcess;

        RegisterWindowStatements(interpreter);
        RegisterButtonStatement(interpreter);
        RegisterCheckBoxStatement(interpreter);
        RegisterLabelStatement(interpreter);
        RegisterTextBoxStatement(interpreter);
        RegisterLineStatement(interpreter);
        RegisterRectStatement(interpreter);
        RegisterLastIdSubstitutions(interpreter);
    }

    private static void RegisterWindowStatements(YesNtInterpreter interpreter)
    {
        // win_create "Title" width height
        // Sets %win_last_id to the new window's id.
        //
        //   win_create "Control Test" 320 240
        //   global winId = %win_last_id
        interpreter.AddStatement(
            new StatementInformation(
                "win_create",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string trimmed = args.Trim();
                if (!TryParseWindowArgs(trimmed, out string title, out int w, out int h))
                {
                    context.Exit($"[win_create] Invalid arguments: {trimmed}", false);
                    return;
                }

                Window win = WindowManager.CreateWindow(
                    s_ownerProcess,
                    title,
                    new Size(w, h));

                int id = s_lastWindowId = s_nextWindowId++;
                s_windows[id] = win;
            });

        // win_close <id>
        interpreter.AddStatement(
            new StatementInformation(
                "win_close",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string idStr = args.Trim();
                if (int.TryParse(idStr, out int id) && s_windows.TryGetValue(id, out Window? win))
                {
                    WindowManager.CloseWindow(win);
                    bool unused = s_windows.Remove(id);
                }
            });

        // win_flush <id>
        interpreter.AddStatement(
            new StatementInformation(
                "win_flush",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string idStr = args.Trim();
                if (int.TryParse(idStr, out int id) && s_windows.TryGetValue(id, out Window? win))
                {
                    win.Flush();
                }
            });

        // win_title <id> "New Title"
        interpreter.AddStatement(
            new StatementInformation(
                "win_title",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string rest = args.Trim();
                int spaceIdx = rest.IndexOf(' ');
                if (spaceIdx < 0) { return; }

                string idStr = rest[..spaceIdx].Trim();
                string newTitle = rest[(spaceIdx + 1)..].Trim().Trim('"');

                if (int.TryParse(idStr, out int id) && s_windows.TryGetValue(id, out Window? win))
                {
                    win.Title = newTitle;
                }
            });

        // win_autoflush <id> true|false
        interpreter.AddStatement(
            new StatementInformation(
                "win_autoflush",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string rest = args.Trim();
                string[] parts = rest.Split(' ', StringSplitOptions.RemoveEmptyEntries);
                if (parts.Length == 2
                    && int.TryParse(parts[0], out int id)
                    && bool.TryParse(parts[1], out bool enabled)
                    && s_windows.TryGetValue(id, out Window? win))
                {
                    win.AutoFlush = enabled;
                }
            });

        // win_invalidate_all
        interpreter.AddStatement(
            new StatementInformation(
                "win_invalidate_all",
                YesNt.Interpreter.Enums.SearchMode.Contains,
                YesNt.Interpreter.Enums.SpaceAround.None)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                WindowManager.InvalidateAll();
            });
    }

    // ui_button <winId> <x> <y> <w> <h> "Label" [R G B]
    //   ui_button ${winId} 20 30 100 30 "Click Me"
    //   ui_button ${winId} 20 30 100 30 "Click Me" 173 216 230
    private static void RegisterButtonStatement(YesNtInterpreter interpreter)
    {
        interpreter.AddStatement(
            new StatementInformation(
                "ui_button",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string rest = args.Trim();
                if (!TryParseUiArgs(rest, 5, out int winId, out int[] nums, out string label, out Color color))
                {
                    context.Exit($"[ui_button] Invalid arguments: {rest}", false);
                    return;
                }

                if (!s_windows.TryGetValue(winId, out Window? win))
                {
                    context.Exit($"[ui_button] No window with id {winId}", false);
                    return;
                }

                int uiId = s_lastUiId = s_nextUiId++;
                _ = win.CreateUIElement<UI.GUI.UIEelements.Controls.Button>(b =>
                {
                    b.Position = new Point(nums[0], nums[1]);
                    b.Size = new Size(nums[2], nums[3]);
                    b.Text = label;
                    if (color != Color.Empty)
                    {
                        b.BackgroundColor = color;
                    }
                });
            });
    }

    // ui_checkbox <winId> <x> <y> "Label" true|false
    //   ui_checkbox ${winId} 20 80 "Enable feature" false
    private static void RegisterCheckBoxStatement(YesNtInterpreter interpreter)
    {
        interpreter.AddStatement(
            new StatementInformation(
                "ui_checkbox",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string rest = args.Trim();
                if (!TryParseCheckboxArgs(rest, out int winId, out int x, out int y, out string label, out bool isChecked))
                {
                    context.Exit($"[ui_checkbox] Invalid arguments: {rest}", false);
                    return;
                }

                if (!s_windows.TryGetValue(winId, out Window? win))
                {
                    context.Exit($"[ui_checkbox] No window with id {winId}", false);
                    return;
                }

                int uiId = s_lastUiId = s_nextUiId++;
                _ = win.CreateUIElement<UI.GUI.UIEelements.Controls.CheckBox>(c =>
                {
                    c.Position = new Point(x, y);
                    c.Text = label;
                    c.IsChecked = isChecked;
                });
            });
    }

    // ui_label <winId> <x> <y> "Text"
    //   ui_label ${winId} 10 10 "Hello, World!"
    private static void RegisterLabelStatement(YesNtInterpreter interpreter)
    {
        interpreter.AddStatement(
            new StatementInformation(
                "ui_label",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string rest = args.Trim();
                if (!TryParseUiArgs(rest, 2, out int winId, out int[] nums, out string text, out _))
                {
                    context.Exit($"[ui_label] Invalid arguments: {rest}", false);
                    return;
                }

                if (!s_windows.TryGetValue(winId, out Window? win))
                {
                    context.Exit($"[ui_label] No window with id {winId}", false);
                    return;
                }

                //int uiId = s_lastUiId = s_nextUiId++;
                //_ = win.CreateUIElement<UI.GUI.UIEelements.Controls.Label>(l =>
                //{
                //    l.Position = new Point(nums[0], nums[1]);
                //    l.Text = text;
                //});
            });
    }

    // ui_textbox <winId> <x> <y> <w> <h> "Placeholder"
    //   ui_textbox ${winId} 20 50 160 24 "Enter name..."
    private static void RegisterTextBoxStatement(YesNtInterpreter interpreter)
    {
        interpreter.AddStatement(
            new StatementInformation(
                "ui_textbox",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string rest = args.Trim();
                if (!TryParseUiArgs(rest, 4, out int winId, out int[] nums, out string placeholder, out _))
                {
                    context.Exit($"[ui_textbox] Invalid arguments: {rest}", false);
                    return;
                }

                if (!s_windows.TryGetValue(winId, out Window? win))
                {
                    context.Exit($"[ui_textbox] No window with id {winId}", false);
                    return;
                }

                //int uiId = s_lastUiId = s_nextUiId++;
                //_ = win.CreateUIElement<UI.GUI.UIEelements.Controls.TextBox>(t =>
                //{
                //    t.Position = new Point(nums[0], nums[1]);
                //    t.Size = new Size(nums[2], nums[3]);
                //    t.PlaceholderText = placeholder;
                //});
            });
    }

    // ui_line <winId> <x1> <y1> <x2> <y2> <R> <G> <B>
    //   ui_line ${winId} 20 130 180 130 255 0 0
    private static void RegisterLineStatement(YesNtInterpreter interpreter)
    {
        interpreter.AddStatement(
            new StatementInformation(
                "ui_line",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string rest = args.Trim();
                string[] parts = rest.Split(' ', StringSplitOptions.RemoveEmptyEntries);
                if (parts.Length < 8
                    || !int.TryParse(parts[0], out int winId)
                    || !int.TryParse(parts[1], out int x1)
                    || !int.TryParse(parts[2], out int y1)
                    || !int.TryParse(parts[3], out int x2)
                    || !int.TryParse(parts[4], out int y2)
                    || !int.TryParse(parts[5], out int r)
                    || !int.TryParse(parts[6], out int g)
                    || !int.TryParse(parts[7], out int b))
                {
                    context.Exit($"[ui_line] Invalid arguments: {rest}", false);
                    return;
                }

                if (!s_windows.TryGetValue(winId, out Window? win))
                {
                    context.Exit($"[ui_line] No window with id {winId}", false);
                    return;
                }

                int uiId = s_lastUiId = s_nextUiId++;
                _ = win.CreateUIElement<UI.GUI.UIEelements.Shapes.Line>(l =>
                {
                    l.Position = new Point(x1, y1);
                    l.EndPosition = new Point(x2, y2);
                    l.Color = Color.FromArgb(r, g, b);
                });
            });
    }

    // ui_rect <winId> <x> <y> <w> <h> <R> <G> <B>
    //   ui_rect ${winId} 20 20 100 60 0 128 255
    private static void RegisterRectStatement(YesNtInterpreter interpreter)
    {
        interpreter.AddStatement(
            new StatementInformation(
                "ui_rect",
                YesNt.Interpreter.Enums.SearchMode.StartOfLine,
                YesNt.Interpreter.Enums.SpaceAround.End)
            {
                Priority = YesNt.Interpreter.Enums.Priority.Normal
            },
            (args, context) =>
            {
                string rest = args.Trim();
                string[] parts = rest.Split(' ', StringSplitOptions.RemoveEmptyEntries);
                if (parts.Length < 8
                    || !int.TryParse(parts[0], out int winId)
                    || !int.TryParse(parts[1], out int x)
                    || !int.TryParse(parts[2], out int y)
                    || !int.TryParse(parts[3], out int w)
                    || !int.TryParse(parts[4], out int h)
                    || !int.TryParse(parts[5], out int r)
                    || !int.TryParse(parts[6], out int g)
                    || !int.TryParse(parts[7], out int b))
                {
                    context.Exit($"[ui_rect] Invalid arguments: {rest}", false);
                    return;
                }

                if (!s_windows.TryGetValue(winId, out Window? win))
                {
                    context.Exit($"[ui_rect] No window with id {winId}", false);
                    return;
                }

                int uiId = s_lastUiId = s_nextUiId++;
                _ = win.CreateUIElement<UI.GUI.UIEelements.Shapes.Rectangle>(rect =>
                {
                    rect.Position = new Point(x, y);
                    rect.Size = new Size(w, h);
                    rect.Color = Color.FromArgb(r, g, b);
                });
            });
    }

    private static void RegisterLastIdSubstitutions(YesNtInterpreter interpreter)
    {
        // %win_last_id → replaced with the id of the last created window
        interpreter.AddStatement(
            new StatementInformation(
                "%win_last_id",
                YesNt.Interpreter.Enums.SearchMode.Contains,
                YesNt.Interpreter.Enums.SpaceAround.None)
            {
                KeepStatementInArgs = true,
                Priority = YesNt.Interpreter.Enums.Priority.PreProcessing
            },
            (args, context) =>
            {
                context.CurrentLine = TemplateProcessor.ProcessSimplePlaceholders(
                    args, "%win_last_id", s_lastWindowId.ToString());
            });

        // %ui_last_id → replaced with the id of the last created UI element
        interpreter.AddStatement(
            new StatementInformation(
                "%ui_last_id",
                YesNt.Interpreter.Enums.SearchMode.Contains,
                YesNt.Interpreter.Enums.SpaceAround.None)
            {
                KeepStatementInArgs = true,
                Priority = YesNt.Interpreter.Enums.Priority.PreProcessing
            },
            (args, context) =>
            {
                context.CurrentLine = TemplateProcessor.ProcessSimplePlaceholders(
                    args, "%ui_last_id", s_lastUiId.ToString());
            });
    }

    /// <summary>
    /// Parses: "Title" width height
    /// The title may be quoted or unquoted.
    /// </summary>
    private static bool TryParseWindowArgs(string input, out string title, out int w, out int h)
    {
        title = string.Empty; w = 0; h = 0;

        input = input.Trim();
        string remaining;

        if (input.StartsWith('"'))
        {
            int end = input.IndexOf('"', 1);
            if (end < 0)
            {
                return false;
            }

            title = input[1..end];
            remaining = input[(end + 1)..].Trim();
        }
        else
        {
            int space = input.IndexOf(' ');
            if (space < 0)
            {
                return false;
            }

            title = input[..space];
            remaining = input[(space + 1)..].Trim();
        }

        string[] nums = remaining.Split(' ', StringSplitOptions.RemoveEmptyEntries);
        return nums.Length >= 2
            && int.TryParse(nums[0], out w)
            && int.TryParse(nums[1], out h);
    }

    /// <summary>
    /// Generic UI arg parser.
    /// Input format: winId n0 n1 ... n{numCount-1} "Label" [R G B]
    /// </summary>
    private static bool TryParseUiArgs(
        string input,
        int numCount,
        out int winId,
        out int[] nums,
        out string label,
        out Color color)
    {
        winId = 0; nums = Array.Empty<int>(); label = string.Empty; color = Color.Empty;

        string[] parts = input.Split(' ', numCount + 2, StringSplitOptions.RemoveEmptyEntries);
        if (parts.Length < numCount + 1)
        {
            return false;
        }

        if (!int.TryParse(parts[0], out winId))
        {
            return false;
        }

        nums = new int[numCount];
        for (int i = 0; i < numCount; i++)
        {
            if (!int.TryParse(parts[i + 1], out nums[i]))
            {
                return false;
            }
        }

        string rest = string.Join(" ", parts[(numCount + 1)..]).Trim();

        if (rest.StartsWith('"'))
        {
            int end = rest.IndexOf('"', 1);
            if (end < 0)
            {
                return false;
            }

            label = rest[1..end];
            rest = rest[(end + 1)..].Trim();
        }
        else
        {
            int sp = rest.IndexOf(' ');
            label = sp < 0 ? rest : rest[..sp];
            rest = sp < 0 ? string.Empty : rest[(sp + 1)..].Trim();
        }

        if (!string.IsNullOrWhiteSpace(rest))
        {
            string[] rgb = rest.Trim().Split(' ', StringSplitOptions.RemoveEmptyEntries);
            if (rgb.Length >= 3
                && int.TryParse(rgb[0], out int r)
                && int.TryParse(rgb[1], out int g)
                && int.TryParse(rgb[2], out int b))
            {
                color = Color.FromArgb(r, g, b);
            }
        }

        return true;
    }

    /// <summary>Parses: winId x y "Label" true|false</summary>
    private static bool TryParseCheckboxArgs(
        string input,
        out int winId,
        out int x, out int y,
        out string label,
        out bool isChecked)
    {
        winId = 0; x = 0; y = 0; label = string.Empty; isChecked = false;

        string[] parts = input.Split(' ', 4, StringSplitOptions.RemoveEmptyEntries);
        if (parts.Length < 4)
        {
            return false;
        }

        if (!int.TryParse(parts[0], out winId)
            || !int.TryParse(parts[1], out x)
            || !int.TryParse(parts[2], out y))
        {
            return false;
        }

        string rest = parts[3].Trim();
        if (rest.StartsWith('"'))
        {
            int end = rest.IndexOf('"', 1);
            if (end < 0)
            {
                return false;
            }

            label = rest[1..end];
            rest = rest[(end + 1)..].Trim();
        }
        else
        {
            int sp = rest.IndexOf(' ');
            if (sp < 0) { label = rest; rest = "false"; }
            else { label = rest[..sp]; rest = rest[(sp + 1)..].Trim(); }
        }

        _ = bool.TryParse(rest, out isChecked);
        return true;
    }
}