// ----------------------------------------------------------------
// From Game Programming in C++ by Sanjay Madhav
// Copyright (C) 2017 Sanjay Madhav. All rights reserved.
// 
// Released under the BSD License
// See LICENSE in root directory for full details.
// ----------------------------------------------------------------

#include "Game.h"
#include <algorithm>
#include "Renderer.h"
#include "AudioSystem.h"
#include "PhysWorld.h"
#include "Actor.h"
#include "UIScreen.h"
#include "HUD.h"
#include "MeshComponent.h"
#include "FollowActor.h"
#include "PlaneActor.h"
#include "TargetActor.h"
#include "BallActor.h"
#include "PauseMenu.h"
#include <SDL/SDL.h>
#include <SDL/SDL_ttf.h>
#include "Font.h"
#include <rapidjson/document.h>
#include "Skeleton.h"
#include "Animation.h"
#include "PointLightComponent.h"
#include "LevelLoader.h"

Game::Game()
:mRenderer(nullptr)
,mAudioSystem(nullptr)
,mPhysWorld(nullptr)
,mGameState(EGameplay)
,mUpdatingActors(false)
{
	
}

bool Game::Initialize()
{
	if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO) != 0)
	{
		SDL_Log("Unable to initialize SDL: %s", SDL_GetError());
		return false;
	}

	// Create the renderer
	mRenderer = new Renderer(this);
	if (!mRenderer->Initialize(1024.0f, 768.0f))
	{
		SDL_Log("Failed to initialize renderer");
		delete mRenderer;
		mRenderer = nullptr;
		return false;
	}

	// Create the audio system
	mAudioSystem = new AudioSystem(this);
	if (!mAudioSystem->Initialize())
	{
		SDL_Log("Failed to initialize audio system");
		mAudioSystem->Shutdown();
		delete mAudioSystem;
		mAudioSystem = nullptr;
		return false;
	}

	// Create the physics world
	mPhysWorld = new PhysWorld(this);
	
	// Initialize SDL_ttf
	if (TTF_Init() != 0)
	{
		SDL_Log("Failed to initialize SDL_ttf");
		return false;
	}

	LoadData();

	mTicksCount = SDL_GetTicks();
	
	return true;
}

void Game::RunLoop()
{
	while (mGameState != EQuit)
	{
		ProcessInput();
		UpdateGame();
		GenerateOutput();
	}
}

void Game::ProcessInput()
{
	SDL_Event event;
	while (SDL_PollEvent(&event))
	{
		switch (event.type)
		{
			case SDL_QUIT:
				mGameState = EQuit;
				break;
			// This fires when a key's initially pressed
			case SDL_KEYDOWN:
				if (!event.key.repeat)
				{
					if (mGameState == EGameplay)
					{
						HandleKeyPress(event.key.keysym.sym);
					}
					else if (!mUIStack.empty())
					{
						mUIStack.back()->
							HandleKeyPress(event.key.keysym.sym);
					}
				}
				break;
			case SDL_MOUSEBUTTONDOWN:
				if (mGameState == EGameplay)
				{
					HandleKeyPress(event.button.button);
				}
				else if (!mUIStack.empty())
				{
					mUIStack.back()->
						HandleKeyPress(event.button.button);
				}
				break;
			default:
				break;
		}
	}
	
	const Uint8* state = SDL_GetKeyboardState(NULL);
	if (mGameState == EGameplay)
	{
		for (auto actor : mActors)
		{
			if (actor->GetState() == Actor::EActive)
			{
				actor->ProcessInput(state);
			}
		}
	}
	else if (!mUIStack.empty())
	{
		mUIStack.back()->ProcessInput(state);
	}
}

void Game::HandleKeyPress(int key)
{
	switch (key)
	{
	case SDLK_ESCAPE:
		// Create pause menu
		new PauseMenu(this);
		break;
	case '-':
	{
		// Reduce master volume
		float volume = mAudioSystem->GetBusVolume("bus:/");
		volume = Math::Max(0.0f, volume - 0.1f);
		mAudioSystem->SetBusVolume("bus:/", volume);
		break;
	}
	case '=':
	{
		// Increase master volume
		float volume = mAudioSystem->GetBusVolume("bus:/");
		volume = Math::Min(1.0f, volume + 0.1f);
		mAudioSystem->SetBusVolume("bus:/", volume);
		break;
	}
	case '1':
	{
		// Load English text
		LoadText("Assets/English.gptext");
		break;
	}
	case '2':
	{
		// Load Russian text
		LoadText("Assets/Russian.gptext");
		break;
	}
	case 'r':
	{
		// Save level
		LevelLoader::SaveLevel(this, "Assets/Saved.gplevel");
		break;
	}
	case SDL_BUTTON_LEFT:
	{
		break;
	}
	default:
		break;
	}
}

void Game::UpdateGame()
{
	// Compute delta time
	// Wait until 16ms has elapsed since last frame
	while (!SDL_TICKS_PASSED(SDL_GetTicks(), mTicksCount + 16))
		;

	float deltaTime = (SDL_GetTicks() - mTicksCount) / 1000.0f;
	if (deltaTime > 0.05f)
	{
		deltaTime = 0.05f;
	}
	mTicksCount = SDL_GetTicks();

	if (mGameState == EGameplay)
	{
		// Update all actors
		mUpdatingActors = true;
		for (auto actor : mActors)
		{
			actor->Update(deltaTime);
		}
		mUpdatingActors = false;

		// Move any pending actors to mActors
		for (auto pending : mPendingActors)
		{
			pending->ComputeWorldTransform();
			mActors.emplace_back(pending);
		}
		mPendingActors.clear();

		// Add any dead actors to a temp vector
		std::vector<Actor*> deadActors;
		for (auto actor : mActors)
		{
			if (actor->GetState() == Actor::EDead)
			{
				deadActors.emplace_back(actor);
			}
		}

		// Delete dead actors (which removes them from mActors)
		for (auto actor : deadActors)
		{
			delete actor;
		}
	}
	
	// Update audio system
	mAudioSystem->Update(deltaTime);
	
	// Update UI screens
	for (auto ui : mUIStack)
	{
		if (ui->GetState() == UIScreen::EActive)
		{
			ui->Update(deltaTime);
		}
	}
	// Delete any UIScreens that are closed
	auto iter = mUIStack.begin();
	while (iter != mUIStack.end())
	{
		if ((*iter)->GetState() == UIScreen::EClosing)
		{
			delete *iter;
			iter = mUIStack.erase(iter);
		}
		else
		{
			++iter;
		}
	}
}

void Game::GenerateOutput()
{
	mRenderer->Draw();
}

void Game::LoadData()
{
	// Load English text
	LoadText("Assets/English.gptext");
	// Create HUD
	mHUD = new HUD(this);

	// Load the level from file
	LevelLoader::LoadLevel(this, "Assets/Level3.gplevel");
	
	// Start music
	mMusicEvent = mAudioSystem->PlayEvent("event:/Music");

	// Enable relative mouse mode for camera look
	SDL_SetRelativeMouseMode(SDL_TRUE);
	// Make an initial call to get relative to clear out
	SDL_GetRelativeMouseState(nullptr, nullptr);
}

void Game::UnloadData()
{
	// Delete actors
	// Because ~Actor calls RemoveActor, have to use a different style loop
	while (!mActors.empty())
	{
		delete mActors.back();
	}

	// Clear the UI stack
	while (!mUIStack.empty())
	{
		delete mUIStack.back();
		mUIStack.pop_back();
	}

	if (mRenderer)
	{
		mRenderer->UnloadData();
	}

	// Unload fonts
	for (auto f : mFonts)
	{
		f.second->Unload();
		delete f.second;
	}

	// Unload skeletons
	for (auto s : mSkeletons)
	{
		delete s.second;
	}

	// Unload animations
	for (auto a : mAnims)
	{
		delete a.second;
	}
}

void Game::Shutdown()
{
	UnloadData();
	TTF_Quit();
	delete mPhysWorld;
	if (mRenderer)
	{
		mRenderer->Shutdown();
	}
	if (mAudioSystem)
	{
		mAudioSystem->Shutdown();
	}
	SDL_Quit();
}

void Game::AddActor(Actor* actor)
{
	// If we're updating actors, need to add to pending
	if (mUpdatingActors)
	{
		mPendingActors.emplace_back(actor);
	}
	else
	{
		mActors.emplace_back(actor);
	}
}

void Game::RemoveActor(Actor* actor)
{
	// Is it in pending actors?
	auto iter = std::find(mPendingActors.begin(), mPendingActors.end(), actor);
	if (iter != mPendingActors.end())
	{
		// Swap to end of vector and pop off (avoid erase copies)
		std::iter_swap(iter, mPendingActors.end() - 1);
		mPendingActors.pop_back();
	}

	// Is it in actors?
	iter = std::find(mActors.begin(), mActors.end(), actor);
	if (iter != mActors.end())
	{
		// Swap to end of vector and pop off (avoid erase copies)
		std::iter_swap(iter, mActors.end() - 1);
		mActors.pop_back();
	}
}

void Game::PushUI(UIScreen* screen)
{
	mUIStack.emplace_back(screen);
}

Font* Game::GetFont(const std::string& fileName)
{
	auto iter = mFonts.find(fileName);
	if (iter != mFonts.end())
	{
		return iter->second;
	}
	else
	{
		Font* font = new Font(this);
		if (font->Load(fileName))
		{
			mFonts.emplace(fileName, font);
		}
		else
		{
			font->Unload();
			delete font;
			font = nullptr;
		}
		return font;
	}
}

void Game::LoadText(const std::string& fileName)
{
	// Clear the existing map, if already loaded
	mText.clear();

	rapidjson::Document doc;
	if (!LevelLoader::LoadJSON(fileName, doc))
	{
		SDL_Log("Failed to load text file %s", fileName.c_str());
		return;
	}

	// Parse the text map
	const rapidjson::Value& actions = doc["TextMap"];
	for (rapidjson::Value::ConstMemberIterator itr = actions.MemberBegin();
		itr != actions.MemberEnd(); ++itr)
	{
		if (itr->name.IsString() && itr->value.IsString())
		{
			mText.emplace(itr->name.GetString(),
				itr->value.GetString());
		}
	}
}

const std::string& Game::GetText(const std::string& key)
{
	static std::string errorMsg("**KEY NOT FOUND**");
	// Find this text in the map, if it exists
	auto iter = mText.find(key);
	if (iter != mText.end())
	{
		return iter->second;
	}
	else
	{
		return errorMsg;
	}
}

Skeleton* Game::GetSkeleton(const std::string& fileName)
{
	auto iter = mSkeletons.find(fileName);
	if (iter != mSkeletons.end())
	{
		return iter->second;
	}
	else
	{
		Skeleton* sk = new Skeleton();
		if (sk->Load(fileName))
		{
			mSkeletons.emplace(fileName, sk);
		}
		else
		{
			delete sk;
			sk = nullptr;
		}
		return sk;
	}
}

Animation* Game::GetAnimation(const std::string& fileName)
{
	auto iter = mAnims.find(fileName);
	if (iter != mAnims.end())
	{
		return iter->second;
	}
	else
	{
		Animation* anim = new Animation();
		if (anim->Load(fileName))
		{
			mAnims.emplace(fileName, anim);
		}
		else
		{
			delete anim;
			anim = nullptr;
		}
		return anim;
	}
}