using System.Globalization;
using Connected.Globalization.Languages;

namespace Connected.Globalization;

/// <summary>
/// The service used for globalization related purposes.
/// </summary>
public interface IGlobalizationService
{
	/// <summary>
	/// Converts an UTC date to a local one base on the current identity and timezone.
	/// </summary>
	/// <param name="value">The <see cref="DateTime"/> value to be converted.</param>
	/// <returns>a <see cref="DateTime"/> value converted to local time.</returns>
	DateTime FromUtc(DateTime value);
	/// <summary>
	/// Converts a local date to an UTC one base on the current identity and timezone.
	/// </summary>
	/// <param name="value">The <see cref="DateTime"/> value to be converted.</param>
	/// <returns>a <see cref="DateTime"/> value converted to UTC time.</returns>
	DateTime ToUtc(DateTime value);
	/// <summary>
	/// Converts an UTC date to a local one base on the current identity and timezone.
	/// </summary>
	/// <param name="value">The <see cref="DateTimeOffset"/> value to be converted.</param>
	/// <returns>a <see cref="DateTimeOffset"/> value converted to local time.</returns>
	DateTimeOffset FromUtc(DateTimeOffset value);
	/// <summary>
	/// Converts a local date to an UTC one base on the current identity and timezone.
	/// </summary>
	/// <param name="value">The <see cref="DateTimeOffset"/> value to be converted.</param>
	/// <returns>a <see cref="DateTimeOffset"/> value converted to UTC time.</returns>
	DateTimeOffset ToUtc(DateTimeOffset value);
	/// <summary>
	/// Returns currently used timezone which is based on the current identity.
	/// </summary>
	TimeZoneInfo TimeZone { get; }
	/// <summary>
	/// Returns the converted <see cref="DateTime.UtcNow"/> value to a currently set <see cref="TimeZone"/>.
	/// </summary>
	DateTimeOffset Now { get; }
	/// <summary>
	/// Returns the currently active language based on a user identity.
	/// </summary>
	/// <returns>The <see cref="ILanguage"/> if user has a language set, <code>null</code> otherwise.</returns>
	Task<ILanguage?> GetCurrentLanguage();
	/// <summary>
	/// Returns the currently active <see cref="System.Globalization.CultureInfo"/> based on a user identity.
	/// </summary>
	/// <returns>The <see cref="System.Globalization.CultureInfo"/> if user has a language set, 
	/// <see cref="System.Globalization.CultureInfo.InvariantCulture"/> otherwise.</returns>
	Task<CultureInfo> GetCurrentCulture();
}