/*
 * CMapEditManager.h, part of VCMI engine
 *
 * Authors: listed in file AUTHORS in main folder
 *
 * License: GNU General Public License v2.0 or later
 * Full text of license available in license.txt file, in main folder
 *
 */

#pragma once

#include "../CRandomGenerator.h"
#include "CMap.h"

class CGObjectInstance;
class CTerrainViewPatternConfig;
struct TerrainViewPattern;

/// Represents a map rectangle.
struct DLL_LINKAGE MapRect
{
	MapRect();
	MapRect(int3 pos, si32 width, si32 height);
	si32 x, y, z;
	si32 width, height;

	si32 left() const;
	si32 right() const;
	si32 top() const;
	si32 bottom() const;

	int3 topLeft() const; /// Top left corner of this rect.
	int3 topRight() const; /// Top right corner of this rect.
	int3 bottomLeft() const; /// Bottom left corner of this rect.
	int3 bottomRight() const; /// Bottom right corner of this rect.

	/// Returns a MapRect of the intersection of this rectangle and the given one.
	MapRect operator&(const MapRect & rect) const;

	template<typename Func>
	void forEach(Func f) const
	{
		for(int j = y; j < bottom(); ++j)
		{
			for(int i = x; i < right(); ++i)
			{
				f(int3(i, j, z));
			}
		}
	}
};

/// Generic selection class to select any type
template<typename T>
class DLL_LINKAGE CMapSelection
{
public:
	explicit CMapSelection(CMap * map) : map(map) { }
	virtual ~CMapSelection() { };
	void select(const T & item)
	{
		selectedItems.insert(item);
	}
	void deselect(const T & item)
	{
		selectedItems.erase(item);
	}
	std::set<T> getSelectedItems()
	{
		return selectedItems;
	}
	CMap * getMap() { return map; }
	virtual void selectRange(const MapRect & rect) { }
	virtual void deselectRange(const MapRect & rect) { }
	virtual void selectAll() { }
	virtual void clearSelection() { }

private:
	std::set<T> selectedItems;
	CMap * map;
};

/// Selection class to select terrain.
class DLL_LINKAGE CTerrainSelection : public CMapSelection<int3>
{
public:
	explicit CTerrainSelection(CMap * map);
	void selectRange(const MapRect & rect) override;
	void deselectRange(const MapRect & rect) override;
	void selectAll() override;
	void clearSelection() override;
};

/// Selection class to select objects.
class DLL_LINKAGE CObjectSelection: public CMapSelection<CGObjectInstance *>
{
public:
	explicit CObjectSelection(CMap * map);
};

/// The abstract base class CMapOperation defines an operation that can be executed, undone and redone.
class DLL_LINKAGE CMapOperation : public boost::noncopyable
{
public:
	explicit CMapOperation(CMap * map);
	virtual ~CMapOperation() { };

	virtual void execute() = 0;
	virtual void undo() = 0;
	virtual void redo() = 0;
	virtual std::string getLabel() const = 0; /// Returns a display-able name of the operation.

protected:
	CMap * map;
};

/// The CMapUndoManager provides the functionality to save operations and undo/redo them.
class DLL_LINKAGE CMapUndoManager : boost::noncopyable
{
public:
	CMapUndoManager();

	void undo();
	void redo();
	void clearAll();

	/// The undo redo limit is a number which says how many undo/redo items can be saved. The default
	/// value is 10. If the value is 0, no undo/redo history will be maintained.
	int getUndoRedoLimit() const;
	void setUndoRedoLimit(int value);

	const CMapOperation * peekRedo() const;
	const CMapOperation * peekUndo() const;

	void addOperation(unique_ptr<CMapOperation> && operation); /// Client code does not need to call this method.

private:
	typedef std::list<unique_ptr<CMapOperation> > TStack;

	void doOperation(TStack & fromStack, TStack & toStack, bool doUndo);
	const CMapOperation * peek(const TStack & stack) const;

	TStack undoStack;
	TStack redoStack;
	int undoRedoLimit;
};

/// The map edit manager provides functionality for drawing terrain and placing
/// objects on the map.
class DLL_LINKAGE CMapEditManager : boost::noncopyable
{
public:
	CMapEditManager(CMap * map);
	CMap * getMap();

	/// Clears the terrain. The free level is filled with water and the underground level with rock.
	void clearTerrain(CRandomGenerator * gen = nullptr);

	/// Draws terrain at the current terrain selection. The selection will be cleared automatically.
	void drawTerrain(ETerrainType terType, CRandomGenerator * gen = nullptr);
	void insertObject(CGObjectInstance * obj, const int3 & pos);

	CTerrainSelection & getTerrainSelection();
	CObjectSelection & getObjectSelection();

	CMapUndoManager & getUndoManager();

private:
	void execute(unique_ptr<CMapOperation> && operation);

	CMap * map;
	CMapUndoManager undoManager;
	CRandomGenerator gen;
	CTerrainSelection terrainSel;
	CObjectSelection objectSel;
};

/* ---------------------------------------------------------------------------- */
/* Implementation/Detail classes, Private API */
/* ---------------------------------------------------------------------------- */

/// The CComposedOperation is an operation which consists of several operations.
class CComposedOperation : public CMapOperation
{
public:
	CComposedOperation(CMap * map);

	void execute() override;
	void undo() override;
	void redo() override;

	void addOperation(unique_ptr<CMapOperation> && operation);

private:
	std::list<unique_ptr<CMapOperation> > operations;
};

namespace ETerrainGroup
{
	enum ETerrainGroup
	{
		NORMAL,
		DIRT,
		SAND,
		WATER,
		ROCK
	};
}

/// The terrain view pattern describes a specific composition of terrain tiles
/// in a 3x3 matrix and notes which terrain view frame numbers can be used.
struct DLL_LINKAGE TerrainViewPattern
{
	struct WeightedRule
	{
		WeightedRule();
		/// Gets true if this rule is a standard rule which means that it has a value of one of the RULE_* constants.
		bool isStandardRule() const;

		/// The name of the rule. Can be any value of the RULE_* constants or a ID of a another pattern.
		std::string name;
		/// Optional. A rule can have points. Patterns may have a minimum count of points to reach to be successful.
		int points;
	};

	static const int PATTERN_DATA_SIZE = 9;
	/// Constant for the flip mode different images. Pattern will be flipped and different images will be used(mapping area is divided into 4 parts)
	static const std::string FLIP_MODE_DIFF_IMAGES;
	/// Constant for the rule dirt, meaning a dirty border is required.
	static const std::string RULE_DIRT;
	/// Constant for the rule sand, meaning a sandy border is required.
	static const std::string RULE_SAND;
	/// Constant for the rule transition, meaning a dirty OR sandy border is required.
	static const std::string RULE_TRANSITION;
	/// Constant for the rule native, meaning a native border is required.
	static const std::string RULE_NATIVE;
	/// Constant for the rule native strong, meaning a native type is required.
	static const std::string RULE_NATIVE_STRONG;
	/// Constant for the rule any, meaning a native type, dirty OR sandy border is required.
	static const std::string RULE_ANY;

	TerrainViewPattern();

	/// The pattern data can be visualized as a 3x3 matrix:
	/// [ ][ ][ ]
	/// [ ][ ][ ]
	/// [ ][ ][ ]
	///
	/// The box in the center belongs always to the native terrain type and
	/// is the point of origin. Depending on the terrain type different rules
	/// can be used. Their meaning differs also from type to type.
	///
	/// std::vector -> several rules can be used in one cell
	std::array<std::vector<WeightedRule>, PATTERN_DATA_SIZE> data;

	/// The identifier of the pattern, if it's referenced from a another pattern.
	std::string id;

	/// This describes the mapping between this pattern and the corresponding range of frames
	/// which should be used for the ter view.
	///
	/// std::vector -> size=1: typical, size=2: if this pattern should map to two different types of borders
	/// std::pair   -> 1st value: lower range, 2nd value: upper range
	std::vector<std::pair<int, int> > mapping;
	/// If diffImages is true, different images/frames are used to place a rotated terrain view. If it's false
	/// the same frame will be used and rotated.
	bool diffImages;
	/// The rotationTypesCount is only used if diffImages is true and holds the number how many rotation types(horizontal, etc...)
	/// are supported.
	int rotationTypesCount;

	/// The minimum and maximum points to reach to validate the pattern successfully.
	int minPoints, maxPoints;
};

/// The terrain view pattern config loads pattern data from the filesystem.
class DLL_LINKAGE CTerrainViewPatternConfig : public boost::noncopyable
{
public:
	CTerrainViewPatternConfig();
	~CTerrainViewPatternConfig();

	const std::vector<TerrainViewPattern> & getTerrainViewPatternsForGroup(ETerrainGroup::ETerrainGroup terGroup) const;
	boost::optional<const TerrainViewPattern &> getTerrainViewPatternById(ETerrainGroup::ETerrainGroup terGroup, const std::string & id) const;
	const TerrainViewPattern & getTerrainTypePatternById(const std::string & id) const;
	ETerrainGroup::ETerrainGroup getTerrainGroup(const std::string & terGroup) const;

private:
	std::map<ETerrainGroup::ETerrainGroup, std::vector<TerrainViewPattern> > terrainViewPatterns;
	std::map<std::string, TerrainViewPattern> terrainTypePatterns;
};

/// The CDrawTerrainOperation class draws a terrain area on the map.
class CDrawTerrainOperation : public CMapOperation
{
public:
	CDrawTerrainOperation(CMap * map, const CTerrainSelection & terrainSel, ETerrainType terType, CRandomGenerator * gen);

	void execute() override;
	void undo() override;
	void redo() override;
	std::string getLabel() const override;

private:
	struct ValidationResult
	{
		ValidationResult(bool result, const std::string & transitionReplacement = "");

		bool result;
		/// The replacement of a T rule, either D or S.
		std::string transitionReplacement;
		int flip;
	};

	struct InvalidTiles
	{
		std::set<int3> foreignTiles, nativeTiles;
	};

	void updateTerrainTypes();
	void invalidateTerrainViews(const int3 & centerPos);
	InvalidTiles getInvalidTiles(const int3 & centerPos) const;
	MapRect extendTileAround(const int3 & centerPos) const;
	MapRect extendTileAroundSafely(const int3 & centerPos) const; /// doesn't exceed map size

	void updateTerrainViews();
	ETerrainGroup::ETerrainGroup getTerrainGroup(ETerrainType terType) const;
	/// Validates the terrain view of the given position and with the given pattern. The first method wraps the
	/// second method to validate the terrain view with the given pattern in all four flip directions(horizontal, vertical).
	ValidationResult validateTerrainView(const int3 & pos, const TerrainViewPattern & pattern, int recDepth = 0) const;
	ValidationResult validateTerrainViewInner(const int3 & pos, const TerrainViewPattern & pattern, int recDepth = 0) const;
	/// Tests whether the given terrain type is a sand type. Sand types are: Water, Sand and Rock
	bool isSandType(ETerrainType terType) const;
	TerrainViewPattern getFlippedPattern(const TerrainViewPattern & pattern, int flip) const;

	static const int FLIP_PATTERN_HORIZONTAL = 1;
	static const int FLIP_PATTERN_VERTICAL = 2;
	static const int FLIP_PATTERN_BOTH = 3;

	CTerrainSelection terrainSel;
	ETerrainType terType;
	CRandomGenerator * gen;
	std::set<int3> invalidatedTerViews;
};

/// The CClearTerrainOperation clears+initializes the terrain.
class CClearTerrainOperation : public CComposedOperation
{
public:
	CClearTerrainOperation(CMap * map, CRandomGenerator * gen);

	std::string getLabel() const override;

private:

};

/// The CInsertObjectOperation class inserts an object to the map.
class CInsertObjectOperation : public CMapOperation
{
public:
	CInsertObjectOperation(CMap * map, CGObjectInstance * obj, const int3 & pos);

	void execute() override;
	void undo() override;
	void redo() override;
	std::string getLabel() const override;

private:
	int3 pos;
	CGObjectInstance * obj;
};