using Microsoft.DotNet.Cli.Build.Framework;
using Microsoft.Extensions.PlatformAbstractions;
using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;

using static Microsoft.DotNet.Cli.Build.FS;
using static Microsoft.DotNet.Cli.Build.Framework.BuildHelpers;

namespace Microsoft.DotNet.Cli.Build
{
    public class CompileTargets
    {
        public static readonly string CoreCLRVersion = "1.0.1-rc2-23811";
        public static readonly string AppDepSdkVersion = "1.0.6-prerelease-00001";

        public static readonly List<string> AssembliesToCrossGen = GetAssembliesToCrossGen();

        public static readonly string[] BinariesForCoreHost = new[]
        {
            "csi",
            "csc",
            "vbc"
        };

        public static readonly string[] ProjectsToPublish = new[]
        {
            "dotnet"
        };

        public static readonly string[] FilesToClean = new[]
        {
            "README.md",
            "Microsoft.DotNet.Runtime.exe",
            "Microsoft.DotNet.Runtime.dll",
            "Microsoft.DotNet.Runtime.deps",
            "Microsoft.DotNet.Runtime.pdb"
        };

        public static readonly string[] ProjectsToPack = new[]
        {
            "Microsoft.DotNet.Cli.Utils",
            "Microsoft.DotNet.ProjectModel",
            "Microsoft.DotNet.ProjectModel.Loader",
            "Microsoft.DotNet.ProjectModel.Workspaces",
            "Microsoft.Extensions.DependencyModel",
            "Microsoft.Extensions.Testing.Abstractions"
        };

        [Target(nameof(PrepareTargets.Init), nameof(CompileCoreHost), nameof(CompileStage1), nameof(CompileStage2))]
        public static BuildTargetResult Compile(BuildTargetContext c)
        {
            return c.Success();
        }

        [Target]
        public static BuildTargetResult CompileCoreHost(BuildTargetContext c)
        {
            // Generate build files
            var cmakeOut = Path.Combine(Dirs.Corehost, "cmake");

            Rmdir(cmakeOut);
            Mkdirp(cmakeOut);

            var configuration = (string)c.BuildContext["Configuration"];

            // Run the build
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
                // Why does Windows directly call cmake but Linux/Mac calls "build.sh" in the corehost dir?
                // See the comment in "src/corehost/build.sh" for details. It doesn't work for some reason.
                ExecIn(cmakeOut, "cmake",
                    Path.Combine(c.BuildContext.BuildDirectory, "src", "corehost"),
                    "-G",
                    "Visual Studio 14 2015 Win64");

                var pf32 = RuntimeInformation.OSArchitecture == Architecture.X64 ?
                    Environment.GetEnvironmentVariable("ProgramFiles(x86)") :
                    Environment.GetEnvironmentVariable("ProgramFiles");

                if (configuration.Equals("Release"))
                {
                    // Cmake calls it "RelWithDebInfo" in the generated MSBuild
                    configuration = "RelWithDebInfo";
                }

                Exec(Path.Combine(pf32, "MSBuild", "14.0", "Bin", "MSBuild.exe"),
                    Path.Combine(cmakeOut, "ALL_BUILD.vcxproj"),
                    $"/p:Configuration={configuration}");

                // Copy the output out
                File.Copy(Path.Combine(cmakeOut, "cli", "Debug", "corehost.exe"), Path.Combine(Dirs.Corehost, "corehost.exe"), overwrite: true);
                File.Copy(Path.Combine(cmakeOut, "cli", "Debug", "corehost.pdb"), Path.Combine(Dirs.Corehost, "corehost.pdb"), overwrite: true);
                File.Copy(Path.Combine(cmakeOut, "cli", "dll", "Debug", "hostpolicy.dll"), Path.Combine(Dirs.Corehost, "hostpolicy.dll"), overwrite: true);
                File.Copy(Path.Combine(cmakeOut, "cli", "dll", "Debug", "hostpolicy.pdb"), Path.Combine(Dirs.Corehost, "hostpolicy.pdb"), overwrite: true);
            }
            else
            {
                ExecIn(cmakeOut, Path.Combine(c.BuildContext.BuildDirectory, "src", "corehost", "build.sh"));

                // Copy the output out
                File.Copy(Path.Combine(cmakeOut, "cli", "corehost"), Path.Combine(Dirs.Corehost, "corehost"), overwrite: true);
                File.Copy(Path.Combine(cmakeOut, "cli", "dll", $"{Constants.DynamicLibPrefix}hostpolicy{Constants.DynamicLibSuffix}"), Path.Combine(Dirs.Corehost, $"{Constants.DynamicLibPrefix}hostpolicy{Constants.DynamicLibSuffix}"), overwrite: true);
            }

            return c.Success();
        }

        [Target]
        public static BuildTargetResult CompileStage1(BuildTargetContext c)
        {
            CleanBinObj(c, Path.Combine(c.BuildContext.BuildDirectory, "src"));
            CleanBinObj(c, Path.Combine(c.BuildContext.BuildDirectory, "test"));
            return CompileStage(c,
                dotnet: DotNetCli.Stage0,
                outputDir: Dirs.Stage1);
        }

        [Target]
        public static BuildTargetResult CompileStage2(BuildTargetContext c)
        {
            var configuration = (string)c.BuildContext["Configuration"];

            CleanBinObj(c, Path.Combine(c.BuildContext.BuildDirectory, "src"));
            CleanBinObj(c, Path.Combine(c.BuildContext.BuildDirectory, "test"));
            var result = CompileStage(c,
                dotnet: DotNetCli.Stage1,
                outputDir: Dirs.Stage2);
            if (!result.Success)
            {
                return result;
            }

            // Build projects that are packed in NuGet packages, but only on Windows
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
                var packagingOutputDir = Path.Combine(Dirs.Stage2Compilation, "forPackaging");
                Mkdirp(packagingOutputDir);
                foreach(var project in ProjectsToPack)
                {
                    // Just build them, we'll pack later
                    DotNetCli.Stage1.Build(
                        "--build-base-path",
                        packagingOutputDir,
                        "--configuration",
                        configuration,
                        Path.Combine(c.BuildContext.BuildDirectory, "src", project))
                        .Execute()
                        .EnsureSuccessful();
                }
            }

            return c.Success();
        }

        private static BuildTargetResult CompileStage(BuildTargetContext c, DotNetCli dotnet, string outputDir)
        {
            Rmdir(outputDir);

            dotnet.SetDotNetHome();

            var configuration = (string)c.BuildContext["Configuration"];
            var binDir = Path.Combine(outputDir, "bin");
            var runtimeOutputDir = Path.Combine(outputDir, "runtime", "coreclr");

            Mkdirp(binDir);
            Mkdirp(runtimeOutputDir);

            foreach (var project in ProjectsToPublish)
            {
                dotnet.Publish(
                    "--native-subdirectory",
                    "--output",
                    binDir,
                    "--configuration",
                    configuration,
                    Path.Combine(c.BuildContext.BuildDirectory, "src", project))
                    .Execute()
                    .EnsureSuccessful();
            }

            // Publish the runtime
            dotnet.Publish(
                "--output",
                runtimeOutputDir,
                "--configuration",
                configuration,
                Path.Combine(c.BuildContext.BuildDirectory, "src", "Microsoft.DotNet.Runtime"))
                .Execute()
                .EnsureSuccessful();

            // Clean bogus files
            foreach (var fileToClean in FilesToClean)
            {
                var pathToClean = Path.Combine(runtimeOutputDir, fileToClean);
                if (File.Exists(pathToClean))
                {
                    File.Delete(pathToClean);
                }
            }

            FixModeFlags(outputDir);

            // Copy the whole runtime local to the tools
            CopyRecursive(runtimeOutputDir, binDir);

            // Copy corehost
            File.Copy(Path.Combine(Dirs.Corehost, $"corehost{Constants.ExeSuffix}"), Path.Combine(binDir, $"corehost{Constants.ExeSuffix}"), overwrite: true);
            File.Copy(Path.Combine(Dirs.Corehost, $"{Constants.DynamicLibPrefix}hostpolicy{Constants.DynamicLibSuffix}"), Path.Combine(binDir, $"{Constants.DynamicLibPrefix}hostpolicy{Constants.DynamicLibSuffix}"), overwrite: true);

            // Corehostify binaries
            foreach(var binaryToCorehostify in BinariesForCoreHost)
            {
                try
                {
                    // Yes, it is .exe even on Linux. This is the managed exe we're working with
                    File.Copy(Path.Combine(binDir, $"{binaryToCorehostify}.exe"), Path.Combine(binDir, $"{binaryToCorehostify}.dll"));
                    File.Delete(Path.Combine(binDir, $"{binaryToCorehostify}.exe"));
                    File.Copy(Path.Combine(binDir, $"corehost{Constants.ExeSuffix}"), Path.Combine(binDir, binaryToCorehostify + Constants.ExeSuffix));
                }
                catch(Exception ex)
                {
                    return c.Failed($"Failed to corehostify '{binaryToCorehostify}': {ex.ToString()}");
                }
            }

            // Crossgen Roslyn
            var result = Crossgen(c, binDir);
            if (!result.Success)
            {
                return result;
            }

            // Copy AppDeps
            result = CopyAppDeps(c, binDir);
            if(!result.Success)
            {
                return result;
            }

            // Generate .version file
            var version = ((BuildVersion)c.BuildContext["BuildVersion"]).SimpleVersion;
            var content = $@"{c.BuildContext["CommitHash"]}{Environment.NewLine}{version}{Environment.NewLine}";
            File.WriteAllText(Path.Combine(outputDir, ".version"), content);

            return c.Success();
        }

        private static BuildTargetResult CopyAppDeps(BuildTargetContext c, string outputDir)
        {
            var appDepOutputDir = Path.Combine(outputDir, "appdepsdk");
            Rmdir(appDepOutputDir);
            Mkdirp(appDepOutputDir);

            // Find toolchain package
            string packageId;
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
                packageId = "toolchain.win7-x64.Microsoft.DotNet.AppDep";
            }
            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
            {
                var osname = PlatformServices.Default.Runtime.OperatingSystem;
                if (string.Equals(osname, "ubuntu", StringComparison.OrdinalIgnoreCase))
                {
                    packageId = "toolchain.ubuntu.14.04-x64.Microsoft.DotNet.AppDep";
                }
                else if (string.Equals(osname, "centos", StringComparison.OrdinalIgnoreCase))
                {
                    c.Warn("Native compilation is not yet working on CentOS");
                    return c.Success();
                }
                else
                {
                    return c.Failed($"Unknown Linux Distro: {osname}");
                }
            }
            else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
            {
                packageId = "toolchain.osx.10.10-x64.Microsoft.DotNet.AppDep";
            }
            else
            {
                return c.Failed("Unsupported OS Platform");
            }

            var appDepPath = Path.Combine(
                Dirs.NuGetPackages,
                packageId,
                AppDepSdkVersion);
            CopyRecursive(appDepPath, appDepOutputDir, overwrite: true);

            return c.Success();
        }

        private static BuildTargetResult Crossgen(BuildTargetContext c, string outputDir)
        {
            // Check if we need to skip crossgen
            if (string.Equals(Environment.GetEnvironmentVariable("DOTNET_BUILD_SKIP_CROSSGEN"), "1"))
            {
                c.Warn("Skipping crossgen because DOTNET_BUILD_SKIP_CROSSGEN is set");
                return c.Success();
            }

            // Find crossgen
            string packageId;
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
                packageId = "runtime.win7-x64.Microsoft.NETCore.Runtime.CoreCLR";
            }
            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
            {
                var osname = PlatformServices.Default.Runtime.OperatingSystem;
                if (string.Equals(osname, "ubuntu", StringComparison.OrdinalIgnoreCase))
                {
                    packageId = "runtime.ubuntu.14.04-x64.Microsoft.NETCore.Runtime.CoreCLR";
                }
                else if (string.Equals(osname, "centos", StringComparison.OrdinalIgnoreCase))
                {
                    // CentOS runtime is in the runtime.rhel.7-x64... package.
                    packageId = "runtime.rhel.7-x64.Microsoft.NETCore.Runtime.CoreCLR";
                }
                else
                {
                    return c.Failed($"Unknown Linux Distro: {osname}");
                }
            }
            else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
            {
                packageId = "runtime.osx.10.10-x64.Microsoft.NETCore.Runtime.CoreCLR";
            }
            else
            {
                return c.Failed("Unsupported OS Platform");
            }

            var crossGenExePath = Path.Combine(
                Dirs.NuGetPackages,
                packageId,
                CoreCLRVersion,
                "tools",
                $"crossgen{Constants.ExeSuffix}");

            // We have to copy crossgen next to mscorlib
            var crossgen = Path.Combine(outputDir, $"crossgen{Constants.ExeSuffix}");
            File.Copy(crossGenExePath, crossgen, overwrite: true);
            Chmod(crossgen, "a+x");

            // And if we have mscorlib.ni.dll, we need to rename it to mscorlib.dll
            if (File.Exists(Path.Combine(outputDir, "mscorlib.ni.dll")))
            {
                File.Copy(Path.Combine(outputDir, "mscorlib.ni.dll"), Path.Combine(outputDir, "mscorlib.dll"), overwrite: true);
            }

            foreach (var assemblyToCrossgen in AssembliesToCrossGen)
            {
                c.Info($"Crossgenning {assemblyToCrossgen}");
                ExecIn(outputDir, crossgen, "-nologo", "-platform_assemblies_paths", outputDir, assemblyToCrossgen);
            }

            c.Info("Crossgen complete");

            // Check if csc/vbc.ni.exe exists, and overwrite the dll with it just in case
            if (File.Exists(Path.Combine(outputDir, "csc.ni.exe")) && !File.Exists(Path.Combine(outputDir, "csc.ni.dll")))
            {
                File.Move(Path.Combine(outputDir, "csc.ni.exe"), Path.Combine(outputDir, "csc.ni.dll"));
            }

            if (File.Exists(Path.Combine(outputDir, "vbc.ni.exe")) && !File.Exists(Path.Combine(outputDir, "vbc.ni.dll")))
            {
                File.Move(Path.Combine(outputDir, "vbc.ni.exe"), Path.Combine(outputDir, "vbc.ni.dll"));
            }

            return c.Success();
        }

        private static List<string> GetAssembliesToCrossGen()
        {
            var list = new List<string>
            {
                "System.Collections.Immutable.dll",
                "System.Reflection.Metadata.dll",
                "Microsoft.CodeAnalysis.dll",
                "Microsoft.CodeAnalysis.CSharp.dll",
                "Microsoft.CodeAnalysis.VisualBasic.dll",
                "csc.dll",
                "vbc.dll"
            };

            // mscorlib is already crossgenned on Windows
            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
                // mscorlib has to be crossgenned first
                list.Insert(0, "mscorlib.dll");
            }

            return list;
        }
    }
}