// Copyright (c) Umbraco.
// See LICENSE for more details.

using System;
using System.IO;
using System.Reflection;

namespace Umbraco.Extensions
{
    public static class AssemblyExtensions
    {
        private static string _rootDir = "";

        /// <summary>
        /// Utility method that returns the path to the root of the application, by getting the path to where the assembly where this
        /// method is included is present, then traversing until it's past the /bin directory. Ie. this makes it work
        /// even if the assembly is in a /bin/debug or /bin/release folder
        /// </summary>
        /// <returns></returns>
        public static string GetRootDirectorySafe(this Assembly executingAssembly)
        {
            if (string.IsNullOrEmpty(_rootDir) == false)
            {
                return _rootDir;
            }
            var codeBase = executingAssembly.Location;
            var uri = new Uri(codeBase);
            var path = uri.LocalPath;
            var baseDirectory = Path.GetDirectoryName(path);
            if (string.IsNullOrEmpty(baseDirectory))
                throw new Exception("No root directory could be resolved. Please ensure that your Umbraco solution is correctly configured.");

            _rootDir = baseDirectory.Contains("bin")
                ? baseDirectory.Substring(0, baseDirectory.LastIndexOf("bin", StringComparison.OrdinalIgnoreCase) - 1)
                : baseDirectory;

            return _rootDir;
        }

        /// <summary>
        /// Returns the file used to load the assembly
        /// </summary>
        /// <param name="assembly"></param>
        /// <returns></returns>
        public static FileInfo GetAssemblyFile(this Assembly assembly)
        {
            var codeBase = assembly.Location;
            var uri = new Uri(codeBase);
            var path = uri.LocalPath;
            return new FileInfo(path);
        }

        /// <summary>
        /// Returns true if the assembly is the App_Code assembly
        /// </summary>
        /// <param name="assembly"></param>
        /// <returns></returns>
        public static bool IsAppCodeAssembly(this Assembly assembly)
        {
            if (assembly.FullName!.StartsWith("App_Code"))
            {
                try
                {
                    Assembly.Load("App_Code");
                    return true;
                }
                catch (FileNotFoundException)
                {
                    //this will occur if it cannot load the assembly
                    return false;
                }
            }
            return false;
        }

        /// <summary>
        /// Returns true if the assembly is the compiled global asax.
        /// </summary>
        /// <param name="assembly"></param>
        /// <returns></returns>
        public static bool IsGlobalAsaxAssembly(this Assembly assembly)
        {
            //only way I can figure out how to test is by the name
            return assembly.FullName!.StartsWith("App_global.asax");
        }

        /// <summary>
        ///  Returns the file used to load the assembly
        /// </summary>
        /// <param name="assemblyName"></param>
        /// <returns></returns>
        public static FileInfo? GetAssemblyFile(this AssemblyName assemblyName)
        {
            var codeBase = assemblyName.CodeBase;
            if (!string.IsNullOrEmpty(codeBase))
            {
                var uri = new Uri(codeBase);
                var path = uri.LocalPath;
                return new FileInfo(path);
            }

            return null;
        }

    }
}