using System;
using System.IO;
using System.Reflection;
using System.Text;
using gaemstone.ECS;

namespace gaemstone.Client;

public static class Resources
{
	public static Stream GetStream(EntityPath path)
		{ var (ass, name) = GetAssemblyAndName(path); return GetStream(ass, name); }
	public static Stream GetStream(Assembly assembly, string name)
	{
		var assemblyName = assembly.GetName().Name;
		return assembly.GetManifestResourceStream($"{assemblyName}.Resources.{name}")
			?? throw new ArgumentException($"Could not find embedded resource '{name}' in assembly '{assemblyName}'");
	}

	public static string GetString(EntityPath path)
		{ var (ass, name) = GetAssemblyAndName(path); return GetString(ass, name); }
	public static string GetString(Assembly assembly, string name)
	{
		using var stream = GetStream(assembly, name);
		using var reader = new StreamReader(stream);
		return reader.ReadToEnd();
	}

	public static byte[] GetBytes(EntityPath path)
		{ var (ass, name) = GetAssemblyAndName(path); return GetBytes(ass, name); }
	public static byte[] GetBytes(Assembly assembly, string name)
	{
		using var stream = GetStream(assembly, name);
		using var memoryStream = new MemoryStream();
		stream.CopyTo(memoryStream);
		return memoryStream.ToArray();
	}

	private static (Assembly, string) GetAssemblyAndName(EntityPath path)
	{
		if (!path.IsAbsolute) throw new ArgumentException(
			$"Path '{path}' must be absolute", nameof(path));
		if ((path.Count < 3) || (path[1] != "Resources")) throw new ArgumentException(
			$"Path '{path}' must be in the format '/[domain]/Resources/...", nameof(path));

		var assembly = Assembly.Load(path[0]);
		var builder = new StringBuilder(path[2]);
		for (var i = 3; i < path.Count; i++)
			builder.Append('.').Append(path[i]);
		return (assembly, builder.ToString());
	}
}