using System;
using System.Collections.Generic;
using System.Reflection;
using System.Threading;
using AspClassic.Scripting.Utils;

namespace AspClassic.Scripting.Runtime;

internal sealed class LanguageConfiguration
{
	private readonly AssemblyQualifiedTypeName _providerName;

	private readonly string _displayName;

	private readonly IDictionary<string, object> _options;

	private LanguageContext _context;

	public LanguageContext LanguageContext => _context;

	public AssemblyQualifiedTypeName ProviderName => _providerName;

	public string DisplayName => _displayName;

	public LanguageConfiguration(AssemblyQualifiedTypeName providerName, string displayName, IDictionary<string, object> options)
	{
		_providerName = providerName;
		_displayName = displayName;
		_options = options;
	}

	internal LanguageContext LoadLanguageContext(ScriptDomainManager domainManager, out bool alreadyLoaded)
	{
		if (_context == null)
		{
			Assembly assembly = domainManager.Platform.LoadAssembly(_providerName.AssemblyName.FullName);
			Type type = assembly.GetType(_providerName.TypeName);
			if (type == null)
			{
				throw new InvalidOperationException($"Failed to load language '{_displayName}': assembly '{assembly.Location}' does not contain type '{_providerName.TypeName}'");
			}
			if (!type.IsSubclassOf(typeof(LanguageContext)))
			{
				throw new InvalidOperationException($"Failed to load language '{_displayName}': type '{type}' is not a valid language provider because it does not inherit from LanguageContext");
			}
			LanguageContext value;
			try
			{
				value = (LanguageContext)Activator.CreateInstance(type, domainManager, _options);
			}
			catch (TargetInvocationException ex)
			{
				throw new TargetInvocationException($"Failed to load language '{_displayName}': {ex.InnerException.Message}", ex.InnerException);
			}
			catch (Exception ex2)
			{
				throw new InvalidImplementationException(Strings.InvalidCtorImplementation(type, ex2.Message), ex2);
			}
			alreadyLoaded = Interlocked.CompareExchange(ref _context, value, null) != null;
		}
		else
		{
			alreadyLoaded = true;
		}
		return _context;
	}
}