/* Copyright (C) 2020 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef INCLUDED_SIMULATION2
#define INCLUDED_SIMULATION2

#include "lib/file/vfs/vfs_path.h"
#include "simulation2/helpers/SimulationCommand.h"
#include "simulation2/system/CmpPtr.h"
#include "simulation2/system/Components.h"

#include <unordered_map>
#include <map>

class CFrustum;
class CMessage;
class CSimContext;
class CSimulation2Impl;
class CTerrain;
class CUnitManager;
class IComponent;
class SceneCollector;
class ScriptInterface;
class ScriptContext;

/**
 * Public API for simulation system.
 * Most code should interact with the simulation only through this API.
 */
class CSimulation2
{
	NONCOPYABLE(CSimulation2);

public:
	// TODO: CUnitManager should probably be handled automatically by this
	// module, but for now we'll have it passed in externally instead
	CSimulation2(CUnitManager* unitManager, shared_ptr<ScriptContext> cx, CTerrain* terrain);
	~CSimulation2();

	void EnableSerializationTest();
	void EnableRejoinTest(int rejoinTestTurn);
	void EnableOOSLog();

	/**
	 * Load all scripts in the specified directory (non-recursively),
	 * so they can register new component types and functions. This
	 * should be called immediately after constructing the CSimulation2 object.
	 * @return false on failure
	 */
	bool LoadScripts(const VfsPath& path);

	/**
	 * Call LoadScripts for each of the game's standard simulation script paths.
	 * @return false on failure
	 */
	bool LoadDefaultScripts();

	/**
	 * Loads the player settings script (called before map is loaded)
	 * @param newPlayers will delete all the existing player entities (if any) and create new ones
	 *	(needed for loading maps, but Atlas might want to update existing player data)
	 */
	void LoadPlayerSettings(bool newPlayers);

	/**
	 * Loads the map settings script (called after map is loaded)
	 */
	void LoadMapSettings();

	/**
	 * Set a startup script, which will get executed before the first turn.
	 */
	void SetStartupScript(const std::string& script);

	/**
	 * Get the current startup script.
	 */
	const std::string& GetStartupScript();

	/**
	 * Set the attributes identifying the scenario/RMS used to initialise this
	 * simulation.
	 */
	void SetInitAttributes(JS::HandleValue settings);

	/**
	 * Get the data passed to SetInitAttributes.
	 */
	JS::Value GetInitAttributes();
	void GetInitAttributes(JS::MutableHandleValue ret);

	/**
	 * Set the initial map settings (as a UTF-8-encoded JSON string),
	 * which will be used to set up the simulation state.
	 * Called from atlas.
	 */
	void SetMapSettings(const std::string& settings);

	/**
	 * Set the initial map settings, which will be used
	 * to set up the simulation state.
	 * Called from MapReader (for all map-types).
	 */
	void SetMapSettings(JS::HandleValue settings);

	/**
	 * Get the current map settings as a UTF-8 JSON string.
	 */
	std::string GetMapSettingsString();

	/**
	 * Get the current map settings.
	 */
	void GetMapSettings(JS::MutableHandleValue ret);

	/**
	 * RegMemFun incremental loader function.
	 */
	int ProgressiveLoad();

	/**
	 * Reload any scripts that were loaded from the given filename.
	 * (This is used to implement hotloading.)
	 */
	Status ReloadChangedFile(const VfsPath& path);

	/**
	 * Initialise (or re-initialise) the complete simulation state.
	 * Must be called after LoadScripts, and must be called
	 * before any methods that depend on the simulation state.
	 * @param skipScriptedComponents don't load the scripted system components
	 *   (this is intended for use by test cases that don't mount all of VFS)
	 * @param skipAI don't initialise the AI system
	 *   (this is intended for use by test cases that don't want all entity
	 *   templates loaded automatically)
	 */
	void ResetState(bool skipScriptedComponents = false, bool skipAI = false);

	/**
	 * Replace/destroy some entities (e.g. skirmish replacers)
	 * Called right before InitGame, on CGame instantiation.
	 * (This mustn't be used when e.g. loading saved games, only when starting new ones.)
	 * This calls the PreInitGame function defined in helpers/InitGame.js.
	 */
	void PreInitGame();

	/**
	 * Initialise a new game, based on some script data. (Called on CGame instantiation)
	 * (This mustn't be used when e.g. loading saved games, only when starting new ones.)
	 * This calls the InitGame function defined in helpers/InitGame.js.
	 */
	void InitGame();

	void Update(int turnLength);
	void Update(int turnLength, const std::vector<SimulationCommand>& commands);
	void Interpolate(float simFrameLength, float frameOffset, float realFrameLength);
	void RenderSubmit(SceneCollector& collector, const CFrustum& frustum, bool culling);

	/**
	 * Returns the last frame offset passed to Interpolate(), i.e. the offset corresponding
	 * to the currently-rendered scene.
	 */
	float GetLastFrameOffset() const;

	/**
	 * Construct a new entity and add it to the world.
	 * @param templateName see ICmpTemplateManager for syntax
	 * @return the new entity ID, or INVALID_ENTITY on error
	 */
	entity_id_t AddEntity(const std::wstring& templateName);
	entity_id_t AddEntity(const std::wstring& templateName, entity_id_t preferredId);
	entity_id_t AddLocalEntity(const std::wstring& templateName);

	/**
	 * Destroys the specified entity, once FlushDestroyedEntities is called.
	 * Has no effect if the entity does not exist, or has already been added to the destruction queue.
	 */
	void DestroyEntity(entity_id_t ent);

	/**
	 * Does the actual destruction of entities from DestroyEntity.
	 * This is called automatically by Update, but should also be called at other
	 * times when an entity might have been deleted and should be removed from
	 * any further processing (e.g. after editor UI message processing)
	 */
	void FlushDestroyedEntities();

	IComponent* QueryInterface(entity_id_t ent, int iid) const;
	void PostMessage(entity_id_t ent, const CMessage& msg) const;
	void BroadcastMessage(const CMessage& msg) const;

	using InterfaceList =
		std::vector<std::pair<entity_id_t, IComponent*> >;

	using InterfaceListUnordered =
		std::unordered_map<entity_id_t, IComponent*>;

	/**
	 * Returns a list of components implementing the given interface, and their
	 * associated entities, sorted by entity ID.
	 */
	InterfaceList GetEntitiesWithInterface(int iid);

	/**
	 * Returns a list of components implementing the given interface, and their
	 * associated entities, as an unordered map.
	 */
	const InterfaceListUnordered& GetEntitiesWithInterfaceUnordered(int iid);

	const CSimContext& GetSimContext() const;
	ScriptInterface& GetScriptInterface() const;

	bool ComputeStateHash(std::string& outHash, bool quick);
	bool DumpDebugState(std::ostream& stream);
	bool SerializeState(std::ostream& stream);
	bool DeserializeState(std::istream& stream);

	/**
	 * Activate the rejoin-test feature for turn @param turn.
	 */
	void ActivateRejoinTest(int turn);

	std::string GenerateSchema();

	/////////////////////////////////////////////////////////////////////////////
	// Some functions for Atlas UI to be able to access VFS data

	/**
	 * Get random map script data
	 *
	 * @return vector of strings containing JSON format data
	 */
	std::vector<std::string> GetRMSData();

	/**
	 * Get civilization data
	 *
	 * @return vector of strings containing JSON format data
	 */
	std::vector<std::string> GetCivData();

	/**
	 * Get victory condition data
	 *
	 * @return vector of strings containing JSON format data
	 */
	std::vector<std::string> GetVictoryConditiondData();

	/**
	 * Get player default data
	 *
	 * @return string containing JSON format data
	 */
	std::string GetPlayerDefaults();

	/**
	 * Get map sizes data
	 *
	 * @return string containing JSON format data
	 */
	std::string GetMapSizes();

	/**
	 * Get AI data
	 *
	 * @return string containing JSON format data
	 */
	std::string GetAIData();

private:
	CSimulation2Impl* m;
};

#endif // INCLUDED_SIMULATION2