using PrivaPub.ClientModels.Resources;
using PrivaPub.ClientModels.User;

using System.ComponentModel.DataAnnotations;

namespace decePubClient.Models
{
	public class PageSettings
	{
		[Required(ErrorMessageResourceName = "Required", ErrorMessageResourceType = typeof(ErrorsResource)),
		 Display(Name = "LanguageId", ResourceType = typeof(FieldsNameResource))]
		public string CurrentLanguageCode { get; set; } = "en";
		[Range(0, 359, ErrorMessageResourceName = nameof(Range), ErrorMessageResourceType = typeof(ErrorsResource))]
		public short LightThemeIndexColour { get; set; } = 25;
		[Range(0, 359, ErrorMessageResourceName = nameof(Range), ErrorMessageResourceType = typeof(ErrorsResource))]
		public short DarkThemeIndexColour { get; set; } = 215;

		public bool PreferSystemTheming { get; set; } = true;
		public bool ThemeIsDarkMode { get; set; } = false;
		public bool ThemeIsLightGray { get; set; } = true;
		public bool ThemeIsDarkGray { get; set; } = false;
		// before publishing pictures without a description, the composer asks once
		public bool RemindAltText { get; set; } = true;
		// the theme is the login's (PrivaPub's user settings): taken at sign-in, saved there whenever it changes here
		public bool SyncWithLogin { get; set; } = true;

		// How the theme flags combine is in wwwroot/js/theme.js: with PreferSystemTheming the OS picks light or dark;
		// otherwise ThemeIsDarkGray, then ThemeIsLightGray, then ThemeIsDarkMode decide; either grey flag drops the
		// colour. These keep the flags consistent when the UI changes one aspect.

		public const short DefaultLightThemeIndexColour = 25;
		public const short DefaultDarkThemeIndexColour = 215;

		public bool IsGray() => ThemeIsLightGray || ThemeIsDarkGray;

		/// <summary>Leaves system theming and shows the light or dark variant, grey or coloured as before.</summary>
		public void SetDarkMode(bool isDark)
		{
			PreferSystemTheming = false;
			ThemeIsDarkMode = isDark;
			if (IsGray())
				SetGray(true, isDark);
		}

		/// <summary>Switches grey on or off for the variant currently shown.</summary>
		public void SetGray(bool isGray, bool isDark)
		{
			ThemeIsDarkGray = isGray && isDark;
			ThemeIsLightGray = isGray && !isDark;
		}

		/// <summary>Sets the hue of the light or dark variant; picking a hue means colour, so grey goes off.</summary>
		public void SetHue(bool isDark, short hue)
		{
			if (isDark)
				DarkThemeIndexColour = hue;
			else
				LightThemeIndexColour = hue;
			SetGray(false, isDark);
		}

		/// <summary>
		/// These settings as the login keeps them: the language as the two letters of the culture the app runs in
		/// (ExtensionMethods.ToCulture: "it" is it-IT, anything else en-GB), the icons' hue at its default, since the client
		/// has no such setting.
		/// </summary>
		public ViewUserSettings ToLoginSettings() => new()
		{
			LanguageCode = CurrentLanguageCode is "it" ? "it" : "en",
			LightThemeIndexColour = LightThemeIndexColour,
			DarkThemeIndexColour = DarkThemeIndexColour,
			IconsThemeIndexColour = DefaultLightThemeIndexColour,
			PreferSystemTheming = PreferSystemTheming,
			ThemeIsDarkMode = ThemeIsDarkMode,
			ThemeIsLightGray = ThemeIsLightGray,
			ThemeIsDarkGray = ThemeIsDarkGray
		};

		/// <summary>Takes the login's theme; its language stays this device's, since changing it reloads the app.</summary>
		public void TakeLoginTheme(ViewUserSettings settings)
		{
			LightThemeIndexColour = Math.Clamp(settings.LightThemeIndexColour, (short)0, (short)359);
			DarkThemeIndexColour = Math.Clamp(settings.DarkThemeIndexColour, (short)0, (short)359);
			PreferSystemTheming = settings.PreferSystemTheming;
			ThemeIsDarkMode = settings.ThemeIsDarkMode;
			ThemeIsLightGray = settings.ThemeIsLightGray;
			ThemeIsDarkGray = settings.ThemeIsDarkGray;
		}
	}
}