using System;
using System.Collections.Generic;
using System.Globalization;

namespace codelanguage;

/// <summary>
/// The single source of truth for how an interface control looks. Both the
/// interface window editor (design time) and the Craft++ Seeker (run time)
/// resolve appearance through <see cref="Resolve"/>, so a saved .cpf renders
/// identically in both. Pure and headless; InterfaceFidelityTests asserts the
/// editor and runtime paths agree for every control kind.
/// </summary>
public static class ControlVisualSpec
{
    /// <summary>Editor placeholder background, also the window fill.</summary>
    public const string DefaultWindowBackground = "#FFF5F5F5"; // WhiteSmoke
    public const string DefaultMapBackground = "#FF2F4F4F";    // DarkSlateGray
    /// <summary>Default fill for non-window controls (as authored in the editor).</summary>
    public const string DefaultControlBackground = "#FFF5F5F5";
    public const string DefaultOutputBackground = "#FFFFFFFF";
    public const string DefaultBorderColor = "#FF808080";   // Gray
    public const string DefaultTextColor = "#FF000000";

    /// <summary>Normalized appearance of one control.</summary>
    public sealed record Visual(
        string Type,
        string Background,
        string BorderColor,
        double BorderThickness,
        string Foreground,
        string FontFamily,
        double FontSize,
        double Padding,
        bool IsVisible);

    /// <summary>Canonical, ordered property fallbacks per control kind.</summary>
    private static readonly Dictionary<string, Dictionary<string, string>> Defaults =
        new(StringComparer.OrdinalIgnoreCase)
        {
            ["Window"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["background-color"] = DefaultWindowBackground,
                ["text-color"] = DefaultTextColor,
                ["font-family"] = "Arial",
                ["font-size"] = "12",
                ["is-visible"] = "true",
            },
            ["Map"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["background-color"] = DefaultMapBackground,
                ["is-default"] = "true",
                ["view-size"] = "15x15",
                ["zoom"] = "0",
                ["show-names"] = "false",
            },
            ["Output"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["background-color"] = DefaultOutputBackground,
                ["text-color"] = DefaultTextColor,
                ["max-lines"] = "1000",
                ["allow-html"] = "false",
                ["can-scroll"] = "true",
            },
            ["Input"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["background-color"] = DefaultControlBackground,
                ["text-color"] = DefaultTextColor,
                ["multi-line"] = "false",
                ["is-password"] = "false",
            },
            ["Button"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["button-type"] = "pushbutton",
                ["is-checked"] = "false",
            },
            ["Label"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["background-color"] = "",
                ["text-color"] = DefaultTextColor,
            },
            ["Bar"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["value"] = "0",
                ["is-slider"] = "false",
            },
            ["Tabs"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["tabs"] = "",
                ["current-tab"] = "",
            },
            ["Menu"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["items"] = "File>New|File>Open|Help>About",
            },
            ["Macro"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["bindings"] = "W=move_north|A=move_west|S=move_south|D=move_east",
            },
            ["Grid"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["cells"] = "4x4",
                ["cell-span"] = "1x1",
                ["is-list"] = "false",
            },
            ["Child"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["orientation"] = "horizontal",
                ["splitter"] = "50",
            },
            ["Browser"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["allow-html"] = "true",
                ["allow-navigation"] = "true",
                ["browser-zoom"] = "100",
            },
            ["Info"] = new(StringComparer.OrdinalIgnoreCase)
            {
                ["stat-panel"] = "true",
                ["verb-panel"] = "true",
            },
        };

    /// <summary>Applies the canonical defaults for <paramref name="type"/> then the authored properties.</summary>
    public static Dictionary<string, string> WithDefaults(string type, IEnumerable<KeyValuePair<string, string>>? authored)
    {
        var result = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
        if (Defaults.TryGetValue(type, out var defaults))
            foreach (var pair in defaults) result[pair.Key] = pair.Value;

        // Every control kind shares these appearance fallbacks.
        SetIfMissing(result, "text-color", DefaultTextColor);
        SetIfMissing(result, "font-family", "Arial");
        SetIfMissing(result, "font-size", "12");
        SetIfMissing(result, "is-visible", "true");

        if (authored != null)
            foreach (var pair in authored)
                result[pair.Key] = pair.Value;
        return result;
    }

    /// <summary>Resolves the normalized appearance both the editor and the Seeker render.</summary>
    public static Visual Resolve(string type, IEnumerable<KeyValuePair<string, string>>? authored)
        => Resolve(type, authored, null);

    /// <summary>
    /// Resolves appearance, preferring the control's explicit background field
    /// (where DmfInterfaceDocument.Parse stores an authored background-color)
    /// over any background-color inside the property string.
    /// </summary>
    public static Visual Resolve(string type, IEnumerable<KeyValuePair<string, string>>? authored, string? backgroundField)
    {
        var props = WithDefaults(type, authored);
        string normalized = NormalizeType(type);

        string background = !string.IsNullOrWhiteSpace(backgroundField)
            ? backgroundField
            : Get(props, "background-color", DefaultBackgroundFor(normalized));
        string border = Get(props, "border-color", DefaultBorderColor);
        // Windows draw no inner frame; every other control has a 1px outline in
        // both the editor and the Seeker.
        double borderThickness = normalized == "Window" ? 0 : 1;
        if (double.TryParse(Get(props, "border-thickness", null), NumberStyles.Float, CultureInfo.InvariantCulture, out double thickness))
            borderThickness = Math.Clamp(thickness, 0, 64);

        double fontSize = double.TryParse(Get(props, "font-size", "12"), NumberStyles.Float, CultureInfo.InvariantCulture, out double size)
            && double.IsFinite(size) && size is >= 1 and <= 512 ? size : 12;

        double padding = normalized == "Input" ? 4 : 0;
        if (double.TryParse(Get(props, "padding", null), NumberStyles.Float, CultureInfo.InvariantCulture, out double pad))
            padding = Math.Clamp(pad, 0, 256);

        bool visible = !string.Equals(Get(props, "is-visible", "true"), "false", StringComparison.OrdinalIgnoreCase);

        return new Visual(
            normalized,
            background,
            border,
            borderThickness,
            Get(props, "text-color", DefaultTextColor),
            Get(props, "font-family", "Arial"),
            fontSize,
            padding,
            visible);
    }

    /// <summary>Canonical control kind (matches DmfInterfaceDocument's names).</summary>
    public static string NormalizeType(string? type) => (type ?? "").Trim().ToLowerInvariant() switch
    {
        "window" or "mainwindow" => "Window",
        "subwindow" => "SubWindow",
        "map" => "Map",
        "output" => "Output",
        "input" => "Input",
        "button" or "checkbox" or "radio" => "Button",
        "label" => "Label",
        "bar" => "Bar",
        "tabs" or "tab" => "Tabs",
        "menu" => "Menu",
        "macro" => "Macro",
        "grid" => "Grid",
        "child" => "Child",
        "browser" => "Browser",
        "info" => "Info",
        "select" => "Select",
        "image" => "Image",
        "panel" => "Panel",
        _ => "Panel",
    };

    /// <summary>The background used when a control authors none.</summary>
    public static string DefaultBackgroundFor(string normalizedType) => normalizedType switch
    {
        "Window" or "Panel" or "Info" or "Child" or "Browser" or "Grid" or "Tabs" or "Menu" => DefaultWindowBackground,
        "Map" => DefaultMapBackground,
        "Output" => DefaultOutputBackground,
        "Label" => "",
        _ => DefaultControlBackground,
    };

    private static string Get(Dictionary<string, string> props, string key, string? fallback)
        => props.TryGetValue(key, out string? value) && !string.IsNullOrWhiteSpace(value) ? value : fallback ?? "";

    private static void SetIfMissing(Dictionary<string, string> props, string key, string value)
    {
        if (!props.ContainsKey(key)) props[key] = value;
    }
}