using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;

using Mono.Cecil;
using MonoTouch.Tuner;
using XamCore.ObjCRuntime;

#if MONOTOUCH
using PlatformException = Xamarin.Bundler.MonoTouchException;
#else
using PlatformException = Xamarin.Bundler.MonoMacException;
#endif


namespace Xamarin.Bundler {
	public partial class Assembly
	{
		public Application App { get { return Target.App; } }

		string full_path;
		bool? is_framework_assembly;

		public AssemblyDefinition AssemblyDefinition;
		public Target Target;
		public bool IsFrameworkAssembly { get { return is_framework_assembly.Value; } }
		public string FullPath {
			get {
				return full_path;
			}
			set {
				full_path = value;
				if (!is_framework_assembly.HasValue)
					is_framework_assembly = full_path.StartsWith (Path.GetDirectoryName (Target.Resolver.FrameworkDirectory), StringComparison.Ordinal);
			}
		}
		public string FileName { get { return Path.GetFileName (FullPath); } }
		public bool EnableCxx;
		public bool NeedsGccExceptionHandling;
		public bool ForceLoad;
		public HashSet<string> Frameworks;
		public HashSet<string> WeakFrameworks;
		public List<string> LinkerFlags; // list of extra linker flags
		public List<string> LinkWith; // list of paths to native libraries to link with.
		public HashSet<ModuleReference> UnresolvedModuleReferences;

		bool? symbols_loaded;

		List<string> link_with_resources; // a list of resources that must be removed from the app

		public Assembly (Target target, string path)
		{
			this.Target = target;
			this.FullPath = path;
		}

		public Assembly (Target target, AssemblyDefinition definition)
		{
			this.Target = target;
			this.AssemblyDefinition = definition;
			this.FullPath = definition.MainModule.FullyQualifiedName;
		}

		public void LoadSymbols ()
		{	
			if (symbols_loaded.HasValue)
				return;

			symbols_loaded = false;
			try {
				if (File.Exists (FullPath + ".mdb")) {
					AssemblyDefinition.MainModule.ReadSymbols ();
					symbols_loaded = true;
				}
			}
			catch {
				// do not let stale file crash us
				Driver.Log (3, "Invalid debugging symbols for {0} ignored", FullPath);
			}
		}

		void AddResourceToBeRemoved (string resource)
		{
			if (link_with_resources == null)
				link_with_resources = new List<string> ();
			link_with_resources.Add (resource);
		}

		public void RemoveResources (bool remove_resources, string target_directory, string nores_directory)
		{
			var modified = false;

			if (link_with_resources != null && link_with_resources.Count != 0) {
				foreach (var r in link_with_resources)
					Application.RemoveResource (AssemblyDefinition.MainModule, r);
				modified = true;
			}

			if (remove_resources && RemoveMonoTouchResources.RemoveResources (AssemblyDefinition)) {
				Driver.Log (3, "Removing bundled resources from {0}", FullPath);
				modified = true;
			}

			// Note that we need to save the assembly even if no resources 
			// were removed, since this method is only called if the target assembly
			// is not up-to-date (which may happen for assemblies without resources).
			var target = Path.Combine (target_directory, FileName);
			if (modified) {
				if (!this.symbols_loaded.HasValue)
					LoadSymbols ();
				var nores_target = Path.Combine (nores_directory, FileName);
				Application.SaveAssembly (AssemblyDefinition, nores_target);
				CopyAssembly (nores_target, target);
			} else {
				// If no resources were removed we can just do a file copy.
				CopyAssembly (FullPath, target);
			}
			FullPath = target;
		}

		// Executed in parallel
		public void ExtractNativeLinkInfo ()
		{
			// ignore framework assemblies, they won't have any LinkWith attributes
			if (IsFrameworkAssembly)
				return;
			
			var assembly = AssemblyDefinition;
			if (!assembly.HasCustomAttributes)
				return;

			var exceptions = new List<Exception> ();
			string path;
			
			//
			// Tasks:
			// * Remove LinkWith attribute: this is done in the linker.
			// * Remove embedded resources related to LinkWith attribute from assembly: this is done at a later stage,
			//   here we just compile a list of resources to remove.
			// * Extract embedded resources related to LinkWith attribute to a file
			// * Modify the linker flags used to build/link the dylib (if fastdev) or the main binary (if !fastdev)
			// 

			for (int i = 0; i < assembly.CustomAttributes.Count; i++) {
				CustomAttribute attr = assembly.CustomAttributes[i];
				
				if (attr.Constructor == null)
					continue;
				
				TypeReference type = attr.Constructor.DeclaringType;
				if (!type.IsPlatformType ("ObjCRuntime", "LinkWithAttribute"))
					continue;
				
				// we know we'll modify this assembly, so load its symbols to keep them in sync
				LoadSymbols ();

				// Let the linker remove it the attribute from the assembly
				
				LinkWithAttribute linkWith = GetLinkWithAttribute (attr);
				string libraryName = linkWith.LibraryName;
				
				// Remove the resource from the assembly at a later stage.
				AddResourceToBeRemoved (libraryName);

				// We can't add -dead_strip if there are any LinkWith attributes where smart linking is disabled.
				if (!linkWith.SmartLink)
					App.DeadStrip = false;
				
				// Don't add -force_load if the binding's SmartLink value is set and the static registrar is being used.
				if (linkWith.ForceLoad && !(linkWith.SmartLink && App.Registrar == RegistrarMode.Static))
					ForceLoad = true;
				
				if (!string.IsNullOrEmpty (linkWith.LinkerFlags)) {
					if (LinkerFlags == null)
						LinkerFlags = new List<string> ();
					LinkerFlags.Add (linkWith.LinkerFlags);
				}
				
				if (!string.IsNullOrEmpty (linkWith.Frameworks)) {
					foreach (var f in linkWith.Frameworks.Split (new char[] { ' ' })) {
						if (Frameworks == null)
							Frameworks = new HashSet<string> ();
						Frameworks.Add (f);
					}
				}
				
				if (!string.IsNullOrEmpty (linkWith.WeakFrameworks)) {
					foreach (var f in linkWith.WeakFrameworks.Split (new char[] { ' ' })) {
						if (WeakFrameworks == null)
							WeakFrameworks = new HashSet<string> ();
						WeakFrameworks.Add (f);
					}
				}
				
				if (linkWith.NeedsGccExceptionHandling)
					NeedsGccExceptionHandling = true;
				
				if (linkWith.IsCxx)
					EnableCxx = true;

				path = Path.Combine (Cache.Location, libraryName);
				if (path.EndsWith (".framework")) {
#if MONOTOUCH
					if (App.DeploymentTarget.Major < 8) {
						throw ErrorHelper.CreateError (1305, "The binding library '{0}' contains a user framework ({0}), but embedded user frameworks require iOS 8.0 (the deployment target is {1}). Please set the deployment target in the Info.plist file to at least 8.0.",
							FileName, Path.GetFileName (path), App.DeploymentTarget);
					}
#endif
					var zipPath = path + ".zip";
					if (!Application.IsUptodate (FullPath, zipPath)) {
						Application.ExtractResource (assembly.MainModule, libraryName, zipPath, false);
						Driver.Log (3, "Extracted third-party framework '{0}' from '{1}' to '{2}'", libraryName, FullPath, zipPath);
					} else {
						Driver.Log (3, "Target '{0}' is up-to-date.", path);
					}

					if (!File.Exists (zipPath)) {
						ErrorHelper.Warning (1302, "Could not extract the native framework '{0}' from '{1}'. " +
							"Please ensure the native framework was properly embedded in the managed assembly " +
							"(if the assembly was built using a binding project, the native framework must be included in the project, and its Build Action must be 'ObjcBindingNativeFramework').",
							libraryName, zipPath);
					} else {
						if (!Directory.Exists (path))
							Directory.CreateDirectory (path);

						if (Driver.RunCommand ("/usr/bin/unzip", string.Format ("-u -o -d {0} {1}", Driver.Quote (path), Driver.Quote (zipPath))) != 0)
							throw ErrorHelper.CreateError (1303, "Could not decompress the native framework '{0}' from '{1}'. Please review the build log for more information from the native 'unzip' command.", libraryName, zipPath);
					}

					if (Frameworks == null)
						Frameworks = new HashSet<string> ();
					Frameworks.Add (path);
				} else {
					if (!Application.IsUptodate (FullPath, path)) {
						Application.ExtractResource (assembly.MainModule, libraryName, path, false);
						Driver.Log (3, "Extracted third-party binding '{0}' from '{1}' to '{2}'", libraryName, FullPath, path);
					} else {
						Driver.Log (3, "Target '{0}' is up-to-date.", path);
					}

					if (!File.Exists (path))
						ErrorHelper.Warning (1302, "Could not extract the native library '{0}' from '{1}'. " +
						"Please ensure the native library was properly embedded in the managed assembly " +
						"(if the assembly was built using a binding project, the native library must be included in the project, and its Build Action must be 'ObjcBindingNativeLibrary').",
							libraryName, path);

					if (LinkWith == null)
						LinkWith = new List<string> ();
					LinkWith.Add (path);
				}

			}

			if (exceptions != null && exceptions.Count > 0)
				throw new AggregateException (exceptions);

			// Make sure there are no duplicates between frameworks and weak frameworks.
			// Keep the weak ones.
			if (Frameworks != null && WeakFrameworks != null)
				Frameworks.ExceptWith (WeakFrameworks);

			if (NeedsGccExceptionHandling) {
				if (LinkerFlags == null)
					LinkerFlags = new List<string> ();
				LinkerFlags.Add ("-lgcc_eh");
			}

		}

		public static LinkWithAttribute GetLinkWithAttribute (CustomAttribute attr)
		{
			LinkWithAttribute linkWith;

			var cargs = attr.ConstructorArguments;
			switch (cargs.Count) {
			case 3: 
				linkWith = new LinkWithAttribute ((string) cargs [0].Value, (LinkTarget) cargs [1].Value, (string) cargs [2].Value); 
				break;
			case 2:
				linkWith = new LinkWithAttribute ((string) cargs [0].Value, (LinkTarget) cargs [1].Value); 
				break;
			default: 
			case 1: 
				linkWith = new LinkWithAttribute ((string) cargs [0].Value); 
				break;
			}

			foreach (var property in attr.Properties) {
				switch (property.Name) {
				case "NeedsGccExceptionHandling": 
					linkWith.NeedsGccExceptionHandling = (bool) property.Argument.Value; 
					break;
				case "WeakFrameworks": 
					linkWith.WeakFrameworks = (string) property.Argument.Value; 
					break;
				case "Frameworks": 
					linkWith.Frameworks = (string) property.Argument.Value; 
					break;
				case "LinkerFlags": 
					linkWith.LinkerFlags = (string) property.Argument.Value; 
					break;
				case "LinkTarget": 
					linkWith.LinkTarget = (LinkTarget) property.Argument.Value; 
					break;
				case "ForceLoad": 
					linkWith.ForceLoad = (bool) property.Argument.Value; 
					break;
				case "IsCxx": 
					linkWith.IsCxx = (bool) property.Argument.Value; 
					break;
				case "SmartLink":
					linkWith.SmartLink = (bool) property.Argument.Value;
					break;
				default: 
					break;
				}
			}
			
			return linkWith;
		}

		public void ComputeLinkerFlags ()
		{
			foreach (var m in AssemblyDefinition.Modules) {
				if (!m.HasModuleReferences)
					continue;
				
				foreach (var mr in m.ModuleReferences) {
					string name = mr.Name;
					string file = Path.GetFileNameWithoutExtension (name);
					switch (file) {
					// special case
					case "__Internal":
					// well known libs
					case "libc":
					case "libSystem":
					case "libobjc":
					case "libdyld":
					case "libsystem_kernel":
						break;
					case "libsqlite3":
						// remove lib prefix
						if (LinkWith == null)
							LinkWith = new List<string> ();
						LinkWith.Add ("-l" + file.Substring (3));
						Driver.Log (3, "Linking with {0} because it's referenced by a module reference in {1}", file, FileName);
					break;
					case "libGLES":
					case "libGLESv2":
						// special case for OpenGLES.framework
						if (Frameworks == null)
							Frameworks = new HashSet<string> ();
						if (!Frameworks.Contains ("OpenGLES")) {
							Frameworks.Add ("OpenGLES");
							Driver.Log (3, "Linking with the framework OpenGLES because {0} is referenced by a module reference in {1}", file, FileName);
						}
						break;
					case "vImage":
					case "vecLib":
						// sub-frameworks
						if (Frameworks == null)
							Frameworks = new HashSet<string> ();
						if (!Frameworks.Contains ("Accelerate")) {
							Frameworks.Add ("Accelerate");
							Driver.Log (3, "Linking with the framework Accelerate because {0} is referenced by a module reference in {1}", file, FileName);
						}
						break;
					case "CoreAudioKit":
					case "Metal":
					case "MetalKit":
					case "MetalPerformanceShaders":
						// some frameworks do not exists on simulators and will result in linker errors if we include them
#if MTOUCH
						if (!App.IsSimulatorBuild) {
#endif
							if (Frameworks == null)
								Frameworks = new HashSet<string> ();
							if (!Frameworks.Contains (file)) {
								Frameworks.Add (file);
								Driver.Log (3, "Linking with the framework {0} because it's referenced by a module reference in {1}", file, FileName);
							}
#if MTOUCH
						}
#endif
						break;
					case "openal32":
						if (Frameworks == null)
							Frameworks = new HashSet<string> ();
						Frameworks.Add ("OpenAL");
						break;
					default:
						// detect frameworks
						int f = name.IndexOf (".framework/", StringComparison.Ordinal);
						if (f > 0) {
							if (Frameworks == null)
								Frameworks = new HashSet<string> ();
							if (!Frameworks.Contains (file)) {
								Frameworks.Add (file);
								Driver.Log (3, "Linking with the framework {0} because it's referenced by a module reference in {1}", file, FileName);
							}
						} else {
							if (UnresolvedModuleReferences == null)
								UnresolvedModuleReferences = new HashSet<ModuleReference> ();
							UnresolvedModuleReferences.Add (mr);
							Driver.Log (3, "Could not resolve the module reference {0} in {1}", file, FileName);
						}
						break;
					}
				}
			}
		}

		public override string ToString ()
		{
			return FileName;
		}
	}
}