using System;
using System.Diagnostics;
using System.IO;
using NUnit.Framework;

using Debug = UnityEngine.Debug;

namespace Unity.SharpZipLib.Tests.TestSupport
{
    // Helper class for verifying zips with 7-zip
    internal static class SevenZipHelper
    {
        private static readonly string[] possible7zPaths = new[] {
            // Check in PATH
            "7z", "7za",
            // Check in default install location
            Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles), "7-Zip", "7z.exe"),
            Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86), "7-Zip", "7z.exe"),
        };
        private static bool TryGet7zBinPath(out string path7z)
        {
            var runTimeLimit = TimeSpan.FromSeconds(3);
            foreach (var testPath in possible7zPaths)
            {
                try
                {
                    var p = Process.Start(new ProcessStartInfo(testPath, "i")
                    {
                        RedirectStandardOutput = true,
                        UseShellExecute = false
                    });
                    while (!p.StandardOutput.EndOfStream && (DateTime.Now - p.StartTime) < runTimeLimit)
                    {
                        p.StandardOutput.DiscardBufferedData();
                    }
                    if (!p.HasExited)
                    {
                        p.Close();
                        Debug.LogWarning($"Timed out checking for 7z binary in \"{testPath}\"!");
                        continue;
                    }
                    if (p.ExitCode == 0)
                    {
                        path7z = testPath;
                        return true;
                    }
                }
                catch (Exception)
                {
                    continue;
                }
            }
            path7z = null;
            return false;
        }
        /// <summary>
        /// Helper function to verify the provided zip stream with 7Zip.
        /// </summary>
        /// <param name="zipStream">A stream containing the zip archive to test.</param>
        /// <param name="password">The password for the archive.</param>
        internal static void VerifyZipWith7Zip(Stream zipStream, string password)
        {
            if (TryGet7zBinPath(out string path7z))
            {
                Console.WriteLine($"Using 7z path: \"{path7z}\"");
                var fileName = Path.GetTempFileName();
                try
                {
                    using (var fs = File.OpenWrite(fileName))
                    {
                        zipStream.Seek(0, SeekOrigin.Begin);
                        zipStream.CopyTo(fs);
                    }
                    var p = Process.Start(new ProcessStartInfo(path7z, $"t -p{password} \"{fileName}\"")
                    {
                        RedirectStandardOutput = true,
                        RedirectStandardError = true,
                        UseShellExecute = false,
                    });

                    if (p == null)
                    {
                        Assert.Inconclusive("Failed to start 7z process. Skipping!");
                    }
                    if (!p.WaitForExit(2000))
                    {
                        Debug.LogWarning("Timed out verifying zip file!");
                    }
                    TestContext.Out.Write(p.StandardOutput.ReadToEnd());
                    var errors = p.StandardError.ReadToEnd();
                    Assert.IsEmpty(errors, "7z reported errors");
                    Assert.AreEqual(0, p.ExitCode, "Archive verification failed");
                }
                finally
                {
                    File.Delete(fileName);
                }
            }
            else
            {
                Debug.LogWarning("Skipping file verification since 7za is not in path");
            }
        }
    }
}