// Copyright Epic Games, Inc. All Rights Reserved.

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Text;
using EpicGames.Core;
using Microsoft.Extensions.Logging;
using UnrealBuildBase;

namespace UnrealBuildTool
{
	/// <summary>
	/// Base class for platform-specific project generators
	/// </summary>
	class AndroidProjectGenerator : PlatformProjectGenerator
	{
		/// <summary>
		/// Whether Android Game Development Extension is installed in the system. See https://developer.android.com/games/agde for more details.
		/// May be disabled by using -noagde on commandline
		/// </summary>
		private bool AGDEInstalled = false;

		public AndroidProjectGenerator(CommandLineArguments Arguments, ILogger Logger)
			: base(Arguments, Logger)
		{
			AGDEInstalled = false;
			if (OperatingSystem.IsWindows() && !Arguments.HasOption("-noagde"))
			{
				AGDEInstalled = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(@"SOFTWARE\WOW6432Node\Google\AndroidGameDevelopmentExtension")?.ValueCount > 0;

				if (!AGDEInstalled)
				{
					try
					{
						string? programFiles86 = Environment.GetEnvironmentVariable("ProgramFiles(x86)");
						if (programFiles86 != null)
						{
							string vswhereExe = Path.Join(programFiles86, @"Microsoft Visual Studio\Installer\vswhere.exe");
							if (File.Exists(vswhereExe))
							{
								using (Process p = new Process())
								{
									ProcessStartInfo info = new ProcessStartInfo
									{
										FileName = vswhereExe,
										Arguments = @"-find Common7\IDE\Extensions\*\Google.VisualStudio.Android.dll",
										RedirectStandardOutput = true,
										UseShellExecute = false
									};
									p.StartInfo = info;
									p.Start();
									AGDEInstalled = p.StandardOutput.ReadToEnd().Contains("Google.VisualStudio.Android.dll");
								}
							}
						}
					}
					catch (Exception ex)
					{
						Logger.LogInformation("Failed to identify AGDE installation status: {Message}", ex.Message);
					}
				}
			}
		}

		/// <summary>
		/// Enumerate all the platforms that this generator supports
		/// </summary>
		public override IEnumerable<UnrealTargetPlatform> GetPlatforms()
		{
			yield return UnrealTargetPlatform.Android;
		}

		/// <inheritdoc/>
		public override bool HasVisualStudioSupport(VSSettings InVSSettings)
		{
			// Debugging, etc. are dependent on the TADP being installed
			return AGDEInstalled;
		}

		/// <inheritdoc/>
		public override string GetVisualStudioPlatformName(VSSettings InVSSettings)
		{
			string PlatformName = InVSSettings.Platform.ToString();

			if (InVSSettings.Platform == UnrealTargetPlatform.Android && AGDEInstalled)
			{
				string longAbi = GetLongAbi(InVSSettings);
				PlatformName = $"Android-{longAbi}";
			}

			return PlatformName;
		}

		/// <inheritdoc/>
		public override void GetAdditionalVisualStudioPropertyGroups(VSSettings InVSSettings, StringBuilder ProjectFileBuilder)
		{
			if (AGDEInstalled)
			{
				base.GetAdditionalVisualStudioPropertyGroups(InVSSettings, ProjectFileBuilder);
			}
		}

		private string GetShortAbi(VSSettings InVSSettings)
		{
			if (InVSSettings.Architecture == null)
			{
				throw new BuildException("Architecture cannot be null");
			}
			else if (InVSSettings.Architecture == UnrealArch.Arm64)
			{
				return "arm64";
			}
			else if (InVSSettings.Architecture == UnrealArch.X64)
			{
				return "x64";
			}
			else
			{
				throw new BuildException($"Unexpected architecture: {InVSSettings.Architecture}");
			}
		}

		private string GetLongAbi(VSSettings InVSSettings)
		{
			if (InVSSettings.Architecture == null)
			{
				throw new BuildException("Architecture cannot be null");
			}
			else if (InVSSettings.Architecture == UnrealArch.Arm64)
			{
				return "arm64-v8a";
			}
			else if (InVSSettings.Architecture == UnrealArch.X64)
			{
				return "x86_64";
			}
			else
			{
				throw new BuildException($"Unexpected architecture: {InVSSettings.Architecture}");
			}
		}

		/// <inheritdoc/>
		public override void GetVisualStudioPathsEntries(VSSettings InVSSettings, TargetType TargetType, FileReference TargetRulesPath, FileReference ProjectFilePath, FileReference NMakeOutputPath, StringBuilder ProjectFileBuilder)
		{
			if (AGDEInstalled)
			{
				string shortAbi = GetShortAbi(InVSSettings);
				string longAbi = GetLongAbi(InVSSettings);

				string apkLocation = Path.Combine(
					Path.GetDirectoryName(NMakeOutputPath.FullName)!,
					Path.GetFileNameWithoutExtension(NMakeOutputPath.FullName) + $"-{shortAbi}.apk");

				ProjectFileBuilder.AppendLine($"    <AndroidApkLocation>{apkLocation}</AndroidApkLocation>");
				string intermediateRootPath = Path.GetFullPath(Path.GetDirectoryName(NMakeOutputPath.FullName) + @"\..\..\Intermediate\Android\");
				List<string> symbolLocations = new List<string>
				{
					Path.Combine(intermediateRootPath, shortAbi, "jni", longAbi),
					Path.Combine(intermediateRootPath, shortAbi, "libs", longAbi),
					Path.Combine(intermediateRootPath, "LLDBSymbolsLibs", shortAbi) // support bDontBundleLibrariesInAPK
				};
				ProjectFileBuilder.AppendLine($"    <AndroidSymbolDirectories>{String.Join(";", symbolLocations)}</AndroidSymbolDirectories>");
			}
			else
			{
				base.GetVisualStudioPathsEntries(InVSSettings, TargetType, TargetRulesPath, ProjectFilePath, NMakeOutputPath, ProjectFileBuilder);
			}
		}

		public override string GetExtraBuildArguments(VSSettings InVSSettings)
		{
			if (AGDEInstalled)
			{
				// do not need to check InPlatform since it will always be UnrealTargetPlatform.Android
				return $" -ForceAPKGeneration" + base.GetExtraBuildArguments(InVSSettings);
			}
			else
			{
				return base.GetExtraBuildArguments(InVSSettings);
			}
		}

		public override string GetVisualStudioUserFileStrings(VisualStudioUserFileSettings VCUserFileSettings, VSSettings InVSSettings, string InConditionString, TargetRules InTargetRules, FileReference TargetRulesPath, FileReference ProjectFilePath, FileReference? NMakeOutputPath, string ProjectName, string? ForeignUProjectPath)
		{
			if (AGDEInstalled
				&& (InVSSettings.Platform == UnrealTargetPlatform.Android)
				&& ((InTargetRules.Type == TargetRules.TargetType.Client) || (InTargetRules.Type == TargetRules.TargetType.Game)))
			{
				StringBuilder Out = new StringBuilder();
				Out.AppendLine("  <PropertyGroup " + InConditionString + ">");

				string LldbFormatterImport = $"command script import \"" + Path.Combine(Unreal.EngineDirectory.FullName, "Extras", "LLDBDataFormatters", "UEDataFormatters_2ByteChars.py") + "\"";
				Out.AppendLine($"    <AndroidLldbStartupCommands>{LldbFormatterImport};$(AndroidLldbStartupCommands)</AndroidLldbStartupCommands>");
				VCUserFileSettings.PatchProperty("AndroidLldbStartupCommands");

				if (NMakeOutputPath != null)
				{
					// It's critical to have AndroidDebugTarget here and for it to be before properties that use it (e.g. AndroidPostApkInstallCommands), otherwise MSBuild will evaluate it to empty string.
					Out.AppendLine("    <AndroidDebugTarget></AndroidDebugTarget>");

					// At this stage we don't know if bDontBundleLibrariesInAPK is enabled or not, so make a fail-safe check.
					string shortAbi = GetShortAbi(InVSSettings);
					string PushSOScript = Path.Combine(
						Path.GetDirectoryName(NMakeOutputPath.FullName)!,
						"Push_" + Path.GetFileNameWithoutExtension(NMakeOutputPath.FullName) + $"-{shortAbi}_so.bat");

					// AGDE specifies current debug target in AndroidDebugTarget property in a form of "model:serial:arch".
					// AndroidDebugTarget is a special property and needs to be evaluated in-line. And the push script needs the device serial as first argument to push to the correct device. 
					// MSBuild Property Functions allow to invoke limited C# expression from with-in MSBuild, see https://learn.microsoft.com/en-us/visualstudio/msbuild/property-functions?view=vs-2022
					// They lack conditional statements, so this expression makes a branch-less variant by always appending "::" to AndroidDebugTarget,
					// so regardless of what value it has, Split(':')[1] will never throw an exception.
					string GetTargetDeviceSerial = "$([System.String]::Concat($(AndroidDebugTarget), \"::\").Split(':')[1])";
					Out.AppendLine(
						$"    <AndroidPostApkInstallCommands>IF EXIST {PushSOScript} {PushSOScript} {GetTargetDeviceSerial};$(AndroidPostApkInstallCommands)</AndroidPostApkInstallCommands>");

					// Ensure the following properties are up to date even if .vcxproj.user already exists and are in correct order between each other.
					VCUserFileSettings.PatchProperty("AndroidDebugTarget", true);
					VCUserFileSettings.PatchProperty("AndroidPostApkInstallCommands");
				}

				Out.AppendLine("  </PropertyGroup>");
				return Out.ToString();
			}

			return String.Empty;
		}
	}
}