/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD 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, version 2.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file newgrf_spritegroup.h Action 2 handling. */

#ifndef NEWGRF_SPRITEGROUP_H
#define NEWGRF_SPRITEGROUP_H

#include "town_type.h"
#include "engine_type.h"
#include "house_type.h"

#include "newgrf_callbacks.h"
#include "newgrf_generic.h"
#include "newgrf_storage.h"
#include "newgrf_commons.h"

/**
 * Gets the value of a so-called newgrf "register".
 * @param i index of the register
 * @pre i < 0x110
 * @return the value of the register
 */
static inline uint32 GetRegister(uint i)
{
	extern TemporaryStorageArray<int32, 0x110> _temp_store;
	return _temp_store.GetValue(i);
}

/**
 * Clears the value of a so-called newgrf "register".
 * @param i index of the register
 * @pre i < 0x110
 */
static inline void ClearRegister(uint i)
{
	extern TemporaryStorageArray<int32, 0x110> _temp_store;
	_temp_store.StoreValue(i, 0);
}

/* List of different sprite group types */
enum SpriteGroupType {
	SGT_REAL,
	SGT_DETERMINISTIC,
	SGT_RANDOMIZED,
	SGT_CALLBACK,
	SGT_RESULT,
	SGT_TILELAYOUT,
	SGT_INDUSTRY_PRODUCTION,
};

struct SpriteGroup;
typedef uint32 SpriteGroupID;
struct ResolverObject;

/* SPRITE_WIDTH is 24. ECS has roughly 30 sprite groups per real sprite.
 * Adding an 'extra' margin would be assuming 64 sprite groups per real
 * sprite. 64 = 2^6, so 2^30 should be enough (for now) */
typedef Pool<SpriteGroup, SpriteGroupID, 1024, 1 << 30, PT_DATA> SpriteGroupPool;
extern SpriteGroupPool _spritegroup_pool;

/* Common wrapper for all the different sprite group types */
struct SpriteGroup : SpriteGroupPool::PoolItem<&_spritegroup_pool> {
protected:
	SpriteGroup(SpriteGroupType type) : type(type) {}
	/** Base sprite group resolver */
	virtual const SpriteGroup *Resolve(ResolverObject &object) const { return this; };

public:
	virtual ~SpriteGroup() {}

	SpriteGroupType type;

	virtual SpriteID GetResult() const { return 0; }
	virtual byte GetNumResults() const { return 0; }
	virtual uint16 GetCallbackResult() const { return CALLBACK_FAILED; }

	/**
	 * ResolverObject (re)entry point.
	 * This cannot be made a call to a virtual function because virtual functions
	 * do not like NULL and checking for NULL *everywhere* is more cumbersome than
	 * this little helper function.
	 * @param group the group to resolve for
	 * @param object information needed to resolve the group
	 * @return the resolved group
	 */
	static const SpriteGroup *Resolve(const SpriteGroup *group, ResolverObject &object)
	{
		return group == NULL ? NULL : group->Resolve(object);
	}
};


/* 'Real' sprite groups contain a list of other result or callback sprite
 * groups. */
struct RealSpriteGroup : SpriteGroup {
	RealSpriteGroup() : SpriteGroup(SGT_REAL) {}
	~RealSpriteGroup();

	/* Loaded = in motion, loading = not moving
	 * Each group contains several spritesets, for various loading stages */

	/* XXX: For stations the meaning is different - loaded is for stations
	 * with small amount of cargo whilst loading is for stations with a lot
	 * of da stuff. */

	byte num_loaded;       ///< Number of loaded groups
	byte num_loading;      ///< Number of loading groups
	const SpriteGroup **loaded;  ///< List of loaded groups (can be SpriteIDs or Callback results)
	const SpriteGroup **loading; ///< List of loading groups (can be SpriteIDs or Callback results)

protected:
	const SpriteGroup *Resolve(ResolverObject &object) const;
};

/* Shared by deterministic and random groups. */
enum VarSpriteGroupScope {
	VSG_BEGIN,

	VSG_SCOPE_SELF = VSG_BEGIN, ///< Resolved object itself
	VSG_SCOPE_PARENT,           ///< Related object of the resolved one
	VSG_SCOPE_RELATIVE,         ///< Relative position (vehicles only)

	VSG_END
};
DECLARE_POSTFIX_INCREMENT(VarSpriteGroupScope)

enum DeterministicSpriteGroupSize {
	DSG_SIZE_BYTE,
	DSG_SIZE_WORD,
	DSG_SIZE_DWORD,
};

enum DeterministicSpriteGroupAdjustType {
	DSGA_TYPE_NONE,
	DSGA_TYPE_DIV,
	DSGA_TYPE_MOD,
};

enum DeterministicSpriteGroupAdjustOperation {
	DSGA_OP_ADD,  ///< a + b
	DSGA_OP_SUB,  ///< a - b
	DSGA_OP_SMIN, ///< (signed) min(a, b)
	DSGA_OP_SMAX, ///< (signed) max(a, b)
	DSGA_OP_UMIN, ///< (unsigned) min(a, b)
	DSGA_OP_UMAX, ///< (unsigned) max(a, b)
	DSGA_OP_SDIV, ///< (signed) a / b
	DSGA_OP_SMOD, ///< (signed) a % b
	DSGA_OP_UDIV, ///< (unsigned) a / b
	DSGA_OP_UMOD, ///< (unsigned) a & b
	DSGA_OP_MUL,  ///< a * b
	DSGA_OP_AND,  ///< a & b
	DSGA_OP_OR,   ///< a | b
	DSGA_OP_XOR,  ///< a ^ b
	DSGA_OP_STO,  ///< store a into temporary storage, indexed by b. return a
	DSGA_OP_RST,  ///< return b
	DSGA_OP_STOP, ///< store a into persistent storage, indexed by b, return a
	DSGA_OP_ROR,  ///< rotate a b positions to the right
	DSGA_OP_SCMP, ///< (signed) comparison (a < b -> 0, a == b = 1, a > b = 2)
	DSGA_OP_UCMP, ///< (unsigned) comparison (a < b -> 0, a == b = 1, a > b = 2)
	DSGA_OP_SHL,  ///< a << b
	DSGA_OP_SHR,  ///< (unsigned) a >> b
	DSGA_OP_SAR,  ///< (signed) a >> b
};


struct DeterministicSpriteGroupAdjust {
	DeterministicSpriteGroupAdjustOperation operation;
	DeterministicSpriteGroupAdjustType type;
	byte variable;
	byte parameter; ///< Used for variables between 0x60 and 0x7F inclusive.
	byte shift_num;
	uint32 and_mask;
	uint32 add_val;
	uint32 divmod_val;
	const SpriteGroup *subroutine;
};


struct DeterministicSpriteGroupRange {
	const SpriteGroup *group;
	uint32 low;
	uint32 high;
};


struct DeterministicSpriteGroup : SpriteGroup {
	DeterministicSpriteGroup() : SpriteGroup(SGT_DETERMINISTIC) {}
	~DeterministicSpriteGroup();

	VarSpriteGroupScope var_scope;
	DeterministicSpriteGroupSize size;
	uint num_adjusts;
	byte num_ranges;
	DeterministicSpriteGroupAdjust *adjusts;
	DeterministicSpriteGroupRange *ranges; // Dynamically allocated

	/* Dynamically allocated, this is the sole owner */
	const SpriteGroup *default_group;

protected:
	const SpriteGroup *Resolve(ResolverObject &object) const;
};

enum RandomizedSpriteGroupCompareMode {
	RSG_CMP_ANY,
	RSG_CMP_ALL,
};

struct RandomizedSpriteGroup : SpriteGroup {
	RandomizedSpriteGroup() : SpriteGroup(SGT_RANDOMIZED) {}
	~RandomizedSpriteGroup();

	VarSpriteGroupScope var_scope;  ///< Take this object:

	RandomizedSpriteGroupCompareMode cmp_mode; ///< Check for these triggers:
	byte triggers;
	byte count;

	byte lowest_randbit; ///< Look for this in the per-object randomized bitmask:
	byte num_groups; ///< must be power of 2

	const SpriteGroup **groups; ///< Take the group with appropriate index:

protected:
	const SpriteGroup *Resolve(ResolverObject &object) const;
};


/* This contains a callback result. A failed callback has a value of
 * CALLBACK_FAILED */
struct CallbackResultSpriteGroup : SpriteGroup {
	/**
	 * Creates a spritegroup representing a callback result
	 * @param value The value that was used to represent this callback result
	 * @param grf_version8 True, if we are dealing with a new NewGRF which uses GRF version >= 8.
	 */
	CallbackResultSpriteGroup(uint16 value, bool grf_version8) :
		SpriteGroup(SGT_CALLBACK),
		result(value)
	{
		/* Old style callback results (only valid for version < 8) have the highest byte 0xFF so signify it is a callback result.
		 * New style ones only have the highest bit set (allows 15-bit results, instead of just 8) */
		if (!grf_version8 && (this->result >> 8) == 0xFF) {
			this->result &= ~0xFF00;
		} else {
			this->result &= ~0x8000;
		}
	}

	uint16 result;
	uint16 GetCallbackResult() const { return this->result; }
};


/* A result sprite group returns the first SpriteID and the number of
 * sprites in the set */
struct ResultSpriteGroup : SpriteGroup {
	/**
	 * Creates a spritegroup representing a sprite number result.
	 * @param sprite The sprite number.
	 * @param num_sprites The number of sprites per set.
	 * @return A spritegroup representing the sprite number result.
	 */
	ResultSpriteGroup(SpriteID sprite, byte num_sprites) :
		SpriteGroup(SGT_RESULT),
		sprite(sprite),
		num_sprites(num_sprites)
	{
	}

	SpriteID sprite;
	byte num_sprites;
	SpriteID GetResult() const { return this->sprite; }
	byte GetNumResults() const { return this->num_sprites; }
};

/**
 * Action 2 sprite layout for houses, industry tiles, objects and airport tiles.
 */
struct TileLayoutSpriteGroup : SpriteGroup {
	TileLayoutSpriteGroup() : SpriteGroup(SGT_TILELAYOUT) {}
	~TileLayoutSpriteGroup() {}

	NewGRFSpriteLayout dts;

	const DrawTileSprites *ProcessRegisters(uint8 *stage) const;
};

struct IndustryProductionSpriteGroup : SpriteGroup {
	IndustryProductionSpriteGroup() : SpriteGroup(SGT_INDUSTRY_PRODUCTION) {}

	uint8 version;
	int16 subtract_input[3];  // signed
	uint16 add_output[2];     // unsigned
	uint8 again;
};

/**
 * Interface to query and set values specific to a single #VarSpriteGroupScope (action 2 scope).
 *
 * Multiple of these interfaces are combined into a #ResolverObject to allow access
 * to different game entities from a #SpriteGroup-chain (action 1-2-3 chain).
 */
struct ScopeResolver {
	ResolverObject &ro; ///< Surrounding resolver object.

	ScopeResolver(ResolverObject &ro);
	virtual ~ScopeResolver();

	virtual uint32 GetRandomBits() const;
	virtual uint32 GetTriggers() const;
	virtual void SetTriggers(int triggers) const;

	virtual uint32 GetVariable(byte variable, uint32 parameter, bool *available) const;
	virtual void StorePSA(uint reg, int32 value);
};

/**
 * Interface for #SpriteGroup-s to access the gamestate.
 *
 * Using this interface #SpriteGroup-chains (action 1-2-3 chains) can be resolved,
 * to get the results of callbacks, rerandomisations or normal sprite lookups.
 */
struct ResolverObject {
	ResolverObject(const GRFFile *grffile, CallbackID callback = CBID_NO_CALLBACK, uint32 callback_param1 = 0, uint32 callback_param2 = 0);
	virtual ~ResolverObject();

	ScopeResolver default_scope; ///< Default implementation of the grf scope.

	CallbackID callback;        ///< Callback being resolved.
	uint32 callback_param1;     ///< First parameter (var 10) of the callback.
	uint32 callback_param2;     ///< Second parameter (var 18) of the callback.

	byte trigger;

	uint32 last_value;          ///< Result of most recent DeterministicSpriteGroup (including procedure calls)
	uint32 reseed[VSG_END];     ///< Collects bits to rerandomise while triggering triggers.

	const GRFFile *grffile;     ///< GRFFile the resolved SpriteGroup belongs to

	virtual const SpriteGroup *ResolveReal(const RealSpriteGroup *group) const;

	virtual ScopeResolver *GetScope(VarSpriteGroupScope scope = VSG_SCOPE_SELF, byte relative = 0);

	/**
	 * Returns the OR-sum of all bits that need reseeding
	 * independent of the scope they were accessed with.
	 * @return OR-sum of the bits.
	 */
	uint32 GetReseedSum() const
	{
		uint32 sum = 0;
		for (VarSpriteGroupScope vsg = VSG_BEGIN; vsg < VSG_END; vsg++) {
			sum |= this->reseed[vsg];
		}
		return sum;
	}

	/**
	 * Resets the dynamic state of the resolver object.
	 * To be called before resolving an Action-1-2-3 chain.
	 */
	void ResetState()
	{
		this->last_value = 0;
		this->trigger    = 0;
		memset(this->reseed, 0, sizeof(this->reseed));
	}
};

#endif /* NEWGRF_SPRITEGROUP_H */