using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

using Xamarin.MacDev;
using Xamarin.Utils;

namespace Xamarin.Bundler
{
	public abstract class ProcessTask : BuildTask
	{
		public ProcessStartInfo ProcessStartInfo;
		protected StringBuilder Output;

		protected string Command {
			get {
				var result = new StringBuilder ();
				if (ProcessStartInfo.EnvironmentVariables.ContainsKey ("MONO_PATH")) {
					result.Append ("MONO_PATH=");
					result.Append (StringUtils.Quote (ProcessStartInfo.EnvironmentVariables ["MONO_PATH"]));
					result.Append (' ');
				}
				result.Append (ProcessStartInfo.FileName);
				result.Append (' ');
				result.Append (ProcessStartInfo.Arguments);
				return result.ToString ();
			}
		}

		protected Task<int> StartAsync ()
		{
			return Task.Run (() => Start ());
		}

		protected int Start ()
		{
			if (Driver.Verbosity > 0)
				Console.WriteLine (Command);

			var info = ProcessStartInfo;
			var stdout_completed = new ManualResetEvent (false);
			var stderr_completed = new ManualResetEvent (false);

			Output = new StringBuilder ();

			using (var p = Process.Start (info)) {
				p.OutputDataReceived += (sender, e) =>
				{
					if (e.Data != null) {
						lock (Output)
							Output.AppendLine (e.Data);
					} else {
						stdout_completed.Set ();
					}
				};

				p.ErrorDataReceived += (sender, e) =>
				{
					if (e.Data != null) {
						lock (Output)
							Output.AppendLine (e.Data);
					} else {
						stderr_completed.Set ();
					}
				};

				p.BeginOutputReadLine ();
				p.BeginErrorReadLine ();

				p.WaitForExit ();

				stderr_completed.WaitOne (TimeSpan.FromSeconds (1));
				stdout_completed.WaitOne (TimeSpan.FromSeconds (1));

				GC.Collect (); // Workaround for: https://bugzilla.xamarin.com/show_bug.cgi?id=43462#c14

				if (Driver.Verbosity >= 2 && Output.Length > 0)
					Console.Error.WriteLine (Output.ToString ());

				return p.ExitCode;
			}
		}
	}

	class GenerateMainTask : BuildTask
	{
		public Target Target;
		public Abi Abi;
		public string MainM;
		public IList<string> RegistrationMethods;

		public override IEnumerable<string> Inputs {
			get {
				foreach (var asm in Target.Assemblies)
					yield return asm.FullPath;
			}
		}

		public override IEnumerable<string> Outputs {
			get {
				yield return MainM;
			}
		}

		protected override void Execute ()
		{
			Driver.GenerateMain (Target, Target.Assemblies, Target.App.AssemblyName, Abi, MainM, RegistrationMethods);
		}
	}

	class CompileMainTask : CompileTask
	{
		protected override void CompilationFailed (int exitCode)
		{
			throw ErrorHelper.CreateError (5103, "Failed to compile the file(s) '{0}'. Please file a bug report at https://github.com/xamarin/xamarin-macios/issues/new", string.Join ("', '", CompilerFlags.SourceFiles.ToArray ()));
		}
	}

	class PinvokesTask : CompileTask
	{
		protected override void CompilationFailed (int exitCode)
		{
			throw ErrorHelper.CreateError (4002, "Failed to compile the generated code for P/Invoke methods. Please file a bug report at https://github.com/xamarin/xamarin-macios/issues/new");
		}
	}

	class RunRegistrarTask : BuildTask
	{
		public Target Target;
		public string RegistrarCodePath;
		public string RegistrarHeaderPath;

		public override IEnumerable<string> Inputs {
			get {
				foreach (var asm in Target.Assemblies)
					yield return asm.FullPath;
			}
		}

		public override IEnumerable<string> Outputs {
			get {
				yield return RegistrarHeaderPath;
				yield return RegistrarCodePath;
			}
		}

		protected override void Execute ()
		{
			Target.StaticRegistrar.Generate (Target.Assemblies.Select ((a) => a.AssemblyDefinition), RegistrarHeaderPath, RegistrarCodePath);
		}
	}

	class CompileRegistrarTask : CompileTask
	{
		public string RegistrarCodePath;
		public string RegistrarHeaderPath;

		public override IEnumerable<string> Inputs {
			get {
				yield return RegistrarHeaderPath;
				yield return RegistrarCodePath;
			}
		}

		protected override void CompilationFailed (int exitCode)
		{
			throw ErrorHelper.CreateError (4109, "Failed to compile the generated registrar code. Please file a bug report at https://github.com/xamarin/xamarin-macios/issues/new");
		}
	}

	public class AOTTask : ProcessTask
	{
		public Assembly Assembly;
		public string AssemblyName;
		public bool AddBitcodeMarkerSection;
		public string AssemblyPath; // path to the .s file.
		List<string> inputs;
		public AotInfo AotInfo;

		public override IEnumerable<string> Outputs {
			get {
				return AotInfo.AotDataFiles
							  .Union (AotInfo.AsmFiles)
							  .Union (AotInfo.BitcodeFiles)
							  .Union (AotInfo.ObjectFiles);
			}
		}

		public override IEnumerable<string> Inputs {
			get {
				yield return Assembly.FullPath;
			}
		}

		public override IEnumerable<string> FileDependencies {
			get {
				if (inputs == null) {
					inputs = new List<string> ();
					if (Assembly.HasDependencyMap)
						inputs.AddRange (Assembly.DependencyMap);
					inputs.Add (AssemblyName);
					inputs.Add (Driver.GetAotCompiler (Assembly.App, Assembly.Target.Is64Build));
					var mdb = Assembly.FullPath + ".mdb";
					if (File.Exists (mdb))
						inputs.Add (mdb);
					var pdb = Path.ChangeExtension (Assembly.FullPath, ".pdb");
					if (File.Exists (pdb))
						inputs.Add (pdb);
					var config = Assembly.FullPath + ".config";
					if (File.Exists (config))
						inputs.Add (config);
				}
				return inputs;
			}
		}

		public override bool IsUptodate {
			get {
				// We can only check dependencies if we know the assemblies this assembly depend on (otherwise always rebuild).
				return Assembly.HasDependencyMap && base.IsUptodate;
			}
		}

		protected async override Task ExecuteAsync ()
		{
			var exit_code = await StartAsync ();

			if (exit_code == 0) {
				if (AddBitcodeMarkerSection)
					File.AppendAllText (AssemblyPath, @"
.section __LLVM, __bitcode
.byte 0
.section __LLVM, __cmdline
.byte 0
");
				return;
			}

			Console.Error.WriteLine ("AOT Compilation exited with code {0}, command:\n{1}{2}", exit_code, Command, Output.Length > 0 ? ("\n" + Output.ToString ()) : string.Empty);
			if (Output.Length > 0) {
				List<Exception> exceptions = new List<Exception> ();
				foreach (var line in Output.ToString ().Split ('\n')) {
					if (line.StartsWith ("AOT restriction: Method '", StringComparison.Ordinal) && line.Contains ("must be static since it is decorated with [MonoPInvokeCallback]")) {
						exceptions.Add (new MonoTouchException (3002, true, line));
					}
				}
				if (exceptions.Count > 0)
					throw new AggregateException (exceptions.ToArray ());
			}

			throw new MonoTouchException (3001, true, "Could not AOT the assembly '{0}'", AssemblyName);
		}

		public override string ToString ()
		{
			return Path.GetFileName (AssemblyName);
		}
	}

	public class NativeLinkTask : BuildTask
	{
		public Target Target;
		public string OutputFile;
		public CompilerFlags CompilerFlags;

		public override IEnumerable<string> Inputs {
			get {
				CompilerFlags.PopulateInputs ();
				return CompilerFlags.Inputs;
			}
		}

		public override IEnumerable<string> Outputs {
			get {
				yield return OutputFile;
			}
		}

		protected override async Task ExecuteAsync ()
		{
			// always show the native linker warnings since many of them turn out to be very important
			// and very hard to diagnose otherwise when hidden from the build output. Ref: bug #2430
			var linker_errors = new List<Exception> ();
			var output = new StringBuilder ();
			var code = await Driver.RunCommandAsync (Target.App.CompilerPath, CompilerFlags.ToString (), null, output);

			Application.ProcessNativeLinkerOutput (Target, output.ToString (), CompilerFlags.AllLibraries, linker_errors, code != 0);

			if (code != 0) {
				// if the build failed - it could be because of missing frameworks / libraries we identified earlier
				foreach (var assembly in Target.Assemblies) {
					if (assembly.UnresolvedModuleReferences == null)
						continue;

					foreach (var mr in assembly.UnresolvedModuleReferences) {
						// TODO: add more diagnose information on the warnings
						var name = Path.GetFileNameWithoutExtension (mr.Name);
						linker_errors.Add (new MonoTouchException (5215, false, "References to '{0}' might require additional -framework=XXX or -lXXX instructions to the native linker", name));
					}
				}
				// mtouch does not validate extra parameters given to GCC when linking (--gcc_flags)
				if (!String.IsNullOrEmpty (Target.App.UserGccFlags))
					linker_errors.Add (new MonoTouchException (5201, true, "Native linking failed. Please review the build log and the user flags provided to gcc: {0}", Target.App.UserGccFlags));
				linker_errors.Add (new MonoTouchException (5202, true, "Native linking failed. Please review the build log.", Target.App.UserGccFlags));

				if (code == 255) {
					// check command length
					// getconf ARG_MAX
					StringBuilder getconf_output = new StringBuilder ();
					if (Driver.RunCommand ("getconf", "ARG_MAX", output: getconf_output, suppressPrintOnErrors: true) == 0) {
						int arg_max;
						if (int.TryParse (getconf_output.ToString ().Trim (' ', '\t', '\n', '\r'), out arg_max)) {
							var cmd_length = Target.App.CompilerPath.Length + 1 + CompilerFlags.ToString ().Length;
							if (cmd_length > arg_max) {
								linker_errors.Add (ErrorHelper.CreateWarning (5217, $"Native linking possibly failed because the linker command line was too long ({cmd_length} characters)."));
							} else {
								Driver.Log (3, $"Linker failure is probably not due to command-line length (actual: {cmd_length} limit: {arg_max}");
							}
						} else {
							Driver.Log (3, "Failed to parse 'getconf ARG_MAX' output: {0}", getconf_output);
						}
					} else {
						Driver.Log (3, "Failed to execute 'getconf ARG_MAX'\n{0}", getconf_output);
					}
				}
			}
			ErrorHelper.Show (linker_errors);

			// the native linker can prefer private (and existing) over public (but non-existing) framework when weak_framework are used
			// on an iOS target version where the framework does not exists, e.g. targeting iOS6 for JavaScriptCore added in iOS7 results in
			// /System/Library/PrivateFrameworks/JavaScriptCore.framework/JavaScriptCore instead of
			// /System/Library/Frameworks/JavaScriptCore.framework/JavaScriptCore
			// more details in https://bugzilla.xamarin.com/show_bug.cgi?id=31036
			if (CompilerFlags.WeakFrameworks.Count > 0)
				Target.AdjustDylibs (OutputFile);
			Driver.Watch ("Native Link", 1);
		}

		public override string ToString ()
		{
			return Path.GetFileName (OutputFile);
		}
	}

	public class LinkTask : CompileTask
	{
		protected override async Task ExecuteAsync ()
		{
			await base.ExecuteAsync ();
			// we can't trust the native linker to pick the right (non private) framework when an older TargetVersion is used
			if (CompilerFlags.WeakFrameworks.Count > 0)
				Target.AdjustDylibs (OutputFile);
		}

		protected override void CompilationFailed (int exitCode)
		{
			throw ErrorHelper.CreateError (5216, "Native linking failed for '{0}'. Please file a bug report at https://github.com/xamarin/xamarin-macios/issues/new", OutputFile);
		}
	}

	public class CompileTask : BuildTask
	{
		public Target Target;
		public Application App { get { return Target.App; } }
		public bool SharedLibrary;
		public string OutputFile;
		public Abi Abi;
		public string InstallName;
		public string Language;

		public override IEnumerable<string> Inputs {
			get {
				CompilerFlags.PopulateInputs ();
				return CompilerFlags.Inputs;
			}
		}

		public override IEnumerable<string> Outputs {
			get {
				yield return OutputFile;
			}
		}

		public bool IsAssembler {
			get {
				return Language == "assembler";
			}
		}

		public string InputFile {
			set {
				// This is an accumulative setter-only property,
				// to make it possible add dependencies using object initializers.
				CompilerFlags.AddSourceFile (value);
			}
		}

		CompilerFlags compiler_flags;
		public CompilerFlags CompilerFlags {
			get { return compiler_flags ?? (compiler_flags = new CompilerFlags (Target)); }
			set { compiler_flags = value; }
		}

		public static void GetArchFlags (CompilerFlags flags, params Abi [] abis)
		{
			GetArchFlags (flags, (IEnumerable<Abi>) abis);
		}

		public static void GetArchFlags (CompilerFlags flags, IEnumerable<Abi> abis)
		{
			bool enable_thumb = false;

			foreach (var abi in abis) {
				var arch = abi.AsArchString ();
				flags.AddOtherFlag ($"-arch {arch}");

				enable_thumb |= (abi & Abi.Thumb) != 0;
			}

			if (enable_thumb)
				flags.AddOtherFlag ("-mthumb");
		}

		public static void GetCompilerFlags (Application app, CompilerFlags flags, bool is_assembler, string language = null)
		{
			if (!is_assembler)
				flags.AddOtherFlag ("-gdwarf-2");

			if (!is_assembler) {
				if (string.IsNullOrEmpty (language) || !language.Contains ("++")) {
					// error: invalid argument '-std=c99' not allowed with 'C++/ObjC++'
					flags.AddOtherFlag ("-std=c99");
				}
				flags.AddOtherFlag ($"-I{StringUtils.Quote (Path.Combine (Driver.GetProductSdkDirectory (app), "usr", "include"))}");
			}
			flags.AddOtherFlag ($"-isysroot {StringUtils.Quote (Driver.GetFrameworkDirectory (app))}");
			flags.AddOtherFlag ("-Qunused-arguments"); // don't complain about unused arguments (clang reports -std=c99 and -Isomething as unused).
		}

		public static void GetSimulatorCompilerFlags (CompilerFlags flags, bool is_assembler, Application app, string language = null)
		{
			GetCompilerFlags (app, flags, is_assembler, language);

			string sim_platform = Driver.GetPlatformDirectory (app);
			string plist = Path.Combine (sim_platform, "Info.plist");

			var dict = Driver.FromPList (plist);
			var dp = dict.Get<PDictionary> ("DefaultProperties");
			if (dp.GetString ("GCC_OBJC_LEGACY_DISPATCH") == "YES")
				flags.AddOtherFlag ("-fobjc-legacy-dispatch");
			string objc_abi = dp.GetString ("OBJC_ABI_VERSION");
			if (!String.IsNullOrWhiteSpace (objc_abi))
				flags.AddOtherFlag ($"-fobjc-abi-version={objc_abi}");

			plist = Path.Combine (Driver.GetFrameworkDirectory (app), "SDKSettings.plist");
			string min_prefix = app.CompilerPath.Contains ("clang") ? Driver.GetTargetMinSdkName (app) : "iphoneos";
			dict = Driver.FromPList (plist);
			dp = dict.Get<PDictionary> ("DefaultProperties");
			if (app.DeploymentTarget == new Version ()) {
				string target = dp.GetString ("IPHONEOS_DEPLOYMENT_TARGET");
				if (!String.IsNullOrWhiteSpace (target))
					flags.AddOtherFlag ($"-m{min_prefix}-version-min={target}");
			} else {
				flags.AddOtherFlag ($"-m{min_prefix}-version-min={app.DeploymentTarget}");
			}
			string defines = dp.GetString ("GCC_PRODUCT_TYPE_PREPROCESSOR_DEFINITIONS");
			if (!String.IsNullOrWhiteSpace (defines))
				flags.AddDefine (defines.Replace (" ", String.Empty));
		}

		void GetDeviceCompilerFlags (CompilerFlags flags, bool is_assembler)
		{
			GetCompilerFlags (App, flags, is_assembler, Language);

			flags.AddOtherFlag ($"-m{Driver.GetTargetMinSdkName (App)}-version-min={App.DeploymentTarget.ToString ()}");
		}

		void GetSharedCompilerFlags (CompilerFlags flags, string install_name)
		{
			if (string.IsNullOrEmpty (install_name))
				throw new ArgumentNullException (nameof (install_name));

			flags.AddOtherFlag ("-shared");
			if (!App.EnableBitCode && !Target.Is64Build)
				flags.AddOtherFlag ("-read_only_relocs suppress");
			if (App.EnableBitCode)
				flags.AddOtherFlag ("-lc++");
			flags.LinkWithMono ();
			flags.AddOtherFlag ("-install_name " + StringUtils.Quote (install_name));
			flags.AddOtherFlag ("-fapplication-extension"); // fixes this: warning MT5203: Native linking warning: warning: linking against dylib not safe for use in application extensions: [..]/actionextension.dll.arm64.dylib
		}

		void GetStaticCompilerFlags (CompilerFlags flags)
		{
			flags.AddOtherFlag ("-c");
		}

		void GetBitcodeCompilerFlags (CompilerFlags flags)
		{
			flags.AddOtherFlag (App.EnableMarkerOnlyBitCode ? "-fembed-bitcode-marker" : "-fembed-bitcode");
		}

		protected override async Task ExecuteAsync ()
		{
			int exitCode = await CompileAsync ();
			if (exitCode != 0)
				CompilationFailed (exitCode);
		}

		protected virtual void CompilationFailed (int exitCode)
		{
			throw ErrorHelper.CreateError (5106, "Could not compile the file(s) '{0}'. Please file a bug report at https://github.com/xamarin/xamarin-macios/issues/new", string.Join ("', '", CompilerFlags.SourceFiles.ToArray ()));
		}

		protected async Task<int> CompileAsync ()
		{
			if (App.IsDeviceBuild) {
				GetDeviceCompilerFlags (CompilerFlags, IsAssembler);
			} else {
				GetSimulatorCompilerFlags (CompilerFlags, IsAssembler, App, Language);
			}

			if (App.EnableBitCode)
				GetBitcodeCompilerFlags (CompilerFlags);
			GetArchFlags (CompilerFlags, Abi);

			if (SharedLibrary) {
				GetSharedCompilerFlags (CompilerFlags, InstallName);
			} else {
				GetStaticCompilerFlags (CompilerFlags);
			}

			if (App.EnableDebug)
				CompilerFlags.AddDefine ("DEBUG");

			CompilerFlags.AddOtherFlag ($"-o {StringUtils.Quote (OutputFile)}");

			if (!string.IsNullOrEmpty (Language))
				CompilerFlags.AddOtherFlag ($"-x {Language}");

			Directory.CreateDirectory (Path.GetDirectoryName (OutputFile));

			var rv = await Driver.RunCommandAsync (App.CompilerPath, CompilerFlags.ToString (), null, null);

			return rv;
		}

		public override string ToString ()
		{
			if (compiler_flags == null || compiler_flags.SourceFiles == null)
				return Path.GetFileName (OutputFile);
			return string.Join (", ", compiler_flags.SourceFiles.Select ((arg) => Path.GetFileName (arg)).ToArray ());
		}
	}

	public class BitCodeifyTask : BuildTask
	{
		public string Input { get; set; }
		public string OutputFile { get; set; }
		public ApplePlatform Platform { get; set; }
		public Abi Abi { get; set; }
		public Version DeploymentTarget { get; set; }

		public override IEnumerable<string> Inputs {
			get {
				yield return Input;
			}
		}

		public override IEnumerable<string> Outputs {
			get {
				yield return OutputFile;
			}
		}

		protected override void Execute ()
		{
			new BitcodeConverter (Input, OutputFile, Platform, Abi, DeploymentTarget).Convert ();
		}

		public override string ToString ()
		{
			return Path.GetFileName (Input);
		}
	}

	public class LipoTask : BuildTask
	{
		public IEnumerable<string> InputFiles { get; set; }
		public string OutputFile { get; set; }

		public override IEnumerable<string> Inputs {
			get {
				return InputFiles;
			}
		}

		public override IEnumerable<string> Outputs {
			get {
				yield return OutputFile;
			}
		}

		protected override void Execute ()
		{
			Application.Lipo (OutputFile, InputFiles.ToArray ());
		}

		public override string ToString ()
		{
			return Path.GetFileName (string.Join (",", InputFiles));
		}
	}


	public class FileCopyTask : BuildTask
	{
		public string InputFile { get; set; }
		public string OutputFile { get; set; }

		public override IEnumerable<string> Inputs {
			get {
				yield return InputFile;
			}
		}

		public override IEnumerable<string> Outputs {
			get {
				yield return OutputFile;
			}
		}

		protected override void Execute ()
		{
			Application.UpdateFile (InputFile, OutputFile);
		}

		public override string ToString ()
		{
			return $"cp {InputFile} {OutputFile}";
		}
	}
}