#include "scriptmgr.h"
#include "gamemgr.h"
#include "gameobj.h"
#include <iostream>  // cout
#include <stdio.h>  // fopen, fclose
#include <string.h> // strcmp
#include <assert.h>
#include "../../../add_on/scriptstdstring/scriptstdstring.h"
#include "../../../add_on/scriptbuilder/scriptbuilder.h"
#include "../../../add_on/weakref/weakref.h"

using namespace std;

CScriptMgr::CScriptMgr()
{
	engine           = 0;
	hasCompileErrors = false;
}

CScriptMgr::~CScriptMgr()
{
	for( unsigned int n = 0; n < controllers.size(); n++ )
		delete controllers[n];

	for( unsigned int n = 0; n < contexts.size(); n++ )
		contexts[n]->Release();

	if( engine )
		engine->ShutDownAndRelease();
}

int CScriptMgr::Init()
{
	int r;

	engine = asCreateScriptEngine(ANGELSCRIPT_VERSION);

	// Set the message callback to print the human readable messages that the engine gives in case of errors
	r = engine->SetMessageCallback(asMETHOD(CScriptMgr, MessageCallback), this, asCALL_THISCALL); assert( r >= 0 );

	// Register the string type
	RegisterStdString(engine);

	// Register the generic handle type, called 'ref' in the script
	RegisterScriptHandle(engine);

	// Register the weak ref template type
	RegisterScriptWeakRef(engine);

	// Register the game object. The scripts cannot create these directly, so there is no factory function.
	r = engine->RegisterObjectType("CGameObj", 0, asOBJ_REF); assert( r >= 0 );
	r = engine->RegisterObjectBehaviour("CGameObj", asBEHAVE_ADDREF, "void f()", asMETHOD(CGameObj, AddRef), asCALL_THISCALL); assert( r >= 0 );
	r = engine->RegisterObjectBehaviour("CGameObj", asBEHAVE_RELEASE, "void f()", asMETHOD(CGameObj, Release), asCALL_THISCALL); assert( r >= 0 );
	r = engine->RegisterObjectBehaviour("CGameObj", asBEHAVE_GET_WEAKREF_FLAG, "int &f()", asMETHOD(CGameObj, GetWeakRefFlag), asCALL_THISCALL); assert( r >= 0 );

	// The object's position is read-only to the script. The position is updated with the Move method
	r = engine->RegisterObjectMethod("CGameObj", "int get_x() const", asMETHOD(CGameObj, GetX), asCALL_THISCALL); assert( r >= 0 );
	r = engine->RegisterObjectMethod("CGameObj", "int get_y() const", asMETHOD(CGameObj, GetY), asCALL_THISCALL); assert( r >= 0 );
	r = engine->RegisterObjectMethod("CGameObj", "bool Move(int dx, int dy)", asMETHOD(CGameObj, Move), asCALL_THISCALL); assert( r >= 0 );

	// The script can kill the owning object
	r = engine->RegisterObjectMethod("CGameObj", "void Kill()", asMETHOD(CGameObj, Kill), asCALL_THISCALL); assert( r >= 0 );
	
	// The script can send a message to the other object through this method
	// Observe the autohandle @+ to tell AngelScript to automatically release the handle after the call
	// The generic handle type is used to allow the script to pass any object to
	// the other script without the application having to know anything about it
	r = engine->RegisterObjectMethod("CGameObj", "void Send(ref msg, const CGameObj @+ to)", asMETHOD(CGameObj, Send), asCALL_THISCALL); assert( r >= 0 );



	// The game engine will determine the class that represents the controller
	// by checking if the class implements the IController interface. No methods
	// are registered for this interface, as the script shouldn't be required to
	// implement the methods. This will allow the game engine to avoid calling
	// methods that doesn't do anything, thus improving performance.
	r = engine->RegisterInterface("IController"); assert( r >= 0 );



	// Register the game manager as a singleton. The script will access it through the global property
	r = engine->RegisterObjectType("CGameMgr", 0, asOBJ_REF | asOBJ_NOHANDLE); assert( r >= 0 );

	// Register the game manager's methods
	r = engine->RegisterGlobalProperty("CGameMgr game", gameMgr); assert( r >= 0 );

	// The script can determine what the user wants to do through the actionStates
	r = engine->RegisterObjectMethod("CGameMgr", "bool get_actionState(int idx)", asMETHOD(CGameMgr, GetActionState), asCALL_THISCALL); assert( r >= 0 );

	// The script can call this method to end the game
	r = engine->RegisterObjectMethod("CGameMgr", "void EndGame(bool win)", asMETHOD(CGameMgr, EndGame), asCALL_THISCALL); assert( r >= 0 );
	
	// Register a method that will allow the script to find an object by its name.
	// This returns the object as const handle, as the script should only be 
	// allow to directly modify its owner object.
	// Observe the @+ that tells AngelScript to automatically increase the refcount
	r = engine->RegisterObjectMethod("CGameMgr", "const CGameObj @+ FindObjByName(const string &in name)", asMETHOD(CGameMgr, FindGameObjByName), asCALL_THISCALL); assert( r >= 0 );


	return 0;
}

void CScriptMgr::MessageCallback(const asSMessageInfo &msg)
{
	const char *type = "ERR ";
	if( msg.type == asMSGTYPE_WARNING ) 
		type = "WARN";
	else if( msg.type == asMSGTYPE_INFORMATION ) 
		type = "INFO";

	cout << msg.section << " (" << msg.row << ", " << msg.col << ") : " << type << " : " << msg.message << endl;

	if( msg.type == asMSGTYPE_ERROR )
		hasCompileErrors = true;
}

CScriptMgr::SController *CScriptMgr::GetControllerScript(const string &script)
{
	int r;

	// Find the cached controller
	for( unsigned int n = 0; n < controllers.size(); n++ )
	{
		if( controllers[n]->module == script )
			return controllers[n];
	}

	// No controller, check if the script has already been loaded
	asIScriptModule *mod = engine->GetModule(script.c_str(), asGM_ONLY_IF_EXISTS);
	if( mod )
	{
		// We've already attempted loading the script before, but there is no controller
		return 0;
	}

	// Compile the script into the module
	CScriptBuilder builder;
	r = builder.StartNewModule(engine, script.c_str());
	if( r < 0 )
		return 0;

	// If the script file doesn't exist, then there is no script controller for this type
	FILE *f;
	if( (f = fopen((script + ".as").c_str(), "r")) == 0 )
		return 0;
	fclose(f);

	// Let the builder load the script, and do the necessary pre-processing (include files, etc)
	r = builder.AddSectionFromFile((script + ".as").c_str());
	if( r < 0 )
		return 0;

	r = builder.BuildModule();
	if( r < 0 )
		return 0;

	// Cache the functions and methods that will be used
	SController *ctrl = new SController;
	controllers.push_back(ctrl);
	ctrl->module = script;

	// Find the class that implements the IController interface
	mod = engine->GetModule(script.c_str(), asGM_ONLY_IF_EXISTS);
	asIObjectType *type = 0;
	int tc = mod->GetObjectTypeCount();
	for( int n = 0; n < tc; n++ )
	{
		bool found = false;
		type = mod->GetObjectTypeByIndex(n);
		int ic = type->GetInterfaceCount();
		for( int i = 0; i < ic; i++ )
		{
			if( strcmp(type->GetInterface(i)->GetName(), "IController") == 0 )
			{
				found = true;
				break;
			}
		}

		if( found == true )
		{
			ctrl->type = type;
			break;
		}
	}

	if( ctrl->type == 0 )
	{
		cout << "Couldn't find the controller class for the type '" << script << "'" << endl;
		controllers.pop_back();
		delete ctrl;
		return 0;
	}

	// Find the factory function
	// The game engine will pass in the owning CGameObj to the controller for storage
	string s = string(type->GetName()) + "@ " + string(type->GetName()) + "(CGameObj @)";
	ctrl->factoryFunc = type->GetFactoryByDecl(s.c_str());
	if( ctrl->factoryFunc == 0 )
	{
		cout << "Couldn't find the appropriate factory for the type '" << script << "'" << endl;
		controllers.pop_back();
		delete ctrl;
		return 0;
	}
	
	// Find the optional event handlers
	ctrl->onThinkMethod     = type->GetMethodByDecl("void OnThink()");
	ctrl->onMessageMethod   = type->GetMethodByDecl("void OnMessage(ref @msg, const CGameObj @sender)");

	// Add the cache as user data to the type for quick access
	type->SetUserData(ctrl);

	return ctrl;
}

asIScriptObject *CScriptMgr::CreateController(const string &script, CGameObj *gameObj)
{
	int r;
	asIScriptObject *obj = 0;

	SController *ctrl = GetControllerScript(script);
	if( ctrl == 0 ) return 0;
		
	// Create the object using the factory function
	asIScriptContext *ctx = PrepareContextFromPool(ctrl->factoryFunc);

	// Pass the object pointer to the script function. With this call the 
	// context will automatically increase the reference count for the object.
	ctx->SetArgObject(0, gameObj);

	// Make the call and take care of any errors that may happen
	r = ExecuteCall(ctx);
	if( r == asEXECUTION_FINISHED )
	{
		// Get the newly created object
		obj = *((asIScriptObject**)ctx->GetAddressOfReturnValue());

		// Since a reference will be kept to this object 
		// it is necessary to increase the ref count
		obj->AddRef();
	}

	// Return the context to the pool so it can be reused
	ReturnContextToPool(ctx);
	
	return obj;
}

void CScriptMgr::CallOnThink(asIScriptObject *object)
{
	// Find the cached onThink method id 
	SController *ctrl = reinterpret_cast<SController*>(object->GetObjectType()->GetUserData());

	// Call the method using the shared context
	if( ctrl->onThinkMethod != 0 )
	{
		asIScriptContext *ctx = PrepareContextFromPool(ctrl->onThinkMethod);
		ctx->SetObject(object);
		ExecuteCall(ctx);
		ReturnContextToPool(ctx);
	}
}

void CScriptMgr::CallOnMessage(asIScriptObject *object, CScriptHandle &msg, CGameObj *caller)
{
	// Find the cached onMessage method id
	SController *ctrl = reinterpret_cast<SController*>(object->GetObjectType()->GetUserData());

	// Call the method using the shared context
	if( ctrl->onMessageMethod != 0 )
	{
		asIScriptContext *ctx = PrepareContextFromPool(ctrl->onMessageMethod);
		ctx->SetObject(object);
		ctx->SetArgObject(0, &msg);
		ctx->SetArgObject(1, caller);
		ExecuteCall(ctx);
		ReturnContextToPool(ctx);
	}
}

int CScriptMgr::ExecuteCall(asIScriptContext *ctx)
{
	int r = ctx->Execute();
	if( r != asEXECUTION_FINISHED )
	{
		if( r == asEXECUTION_EXCEPTION )
		{
			cout << "Exception: " << ctx->GetExceptionString() << endl;
			cout << "Function: " << ctx->GetExceptionFunction()->GetDeclaration() << endl;
			cout << "Line: " << ctx->GetExceptionLineNumber() << endl;

			// It is possible to print more information about the location of the 
			// exception, for example the call stack, values of variables, etc if 
			// that is of interest.
		}
	}

	return r;
}

asIScriptContext *CScriptMgr::PrepareContextFromPool(asIScriptFunction *func)
{
	asIScriptContext *ctx = 0;
	if( contexts.size() )
	{
		ctx = *contexts.rbegin();
		contexts.pop_back();
	}
	else
		ctx = engine->CreateContext();

	int r = ctx->Prepare(func); assert( r >= 0 );

	return ctx;
}

void CScriptMgr::ReturnContextToPool(asIScriptContext *ctx)
{
	contexts.push_back(ctx);

	// Unprepare the context to free any objects that might be held
	// as we don't know when the context will be used again.
	ctx->Unprepare();
}
