/* $Id$ */

/*
 * 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 clear_cmd.cpp Commands related to clear tiles. */

#include "stdafx.h"
#include "clear_map.h"
#include "command_func.h"
#include "landscape.h"
#include "genworld.h"
#include "viewport_func.h"
#include "water.h"
#include "core/random_func.hpp"
#include "newgrf_generic.h"

#include "table/strings.h"
#include "table/sprites.h"
#include "table/clear_land.h"

#include "safeguards.h"

static CommandCost ClearTile_Clear(TileIndex tile, DoCommandFlag flags)
{
	static const Price clear_price_table[] = {
		PR_CLEAR_GRASS,
		PR_CLEAR_ROUGH,
		PR_CLEAR_ROCKS,
		PR_CLEAR_FIELDS,
		PR_CLEAR_ROUGH,
		PR_CLEAR_ROUGH,
	};
	CommandCost price(EXPENSES_CONSTRUCTION);

	if (!IsClearGround(tile, CLEAR_GRASS) || GetClearDensity(tile) != 0) {
		price.AddCost(_price[clear_price_table[GetClearGround(tile)]]);
	}

	if (flags & DC_EXEC) DoClearSquare(tile);

	return price;
}

void DrawClearLandTile(const TileInfo *ti, byte set)
{
	DrawGroundSprite(SPR_FLAT_BARE_LAND + SlopeToSpriteOffset(ti->tileh) + set * 19, PAL_NONE);
}

void DrawHillyLandTile(const TileInfo *ti)
{
	if (ti->tileh != SLOPE_FLAT) {
		DrawGroundSprite(SPR_FLAT_ROUGH_LAND + SlopeToSpriteOffset(ti->tileh), PAL_NONE);
	} else {
		DrawGroundSprite(_landscape_clear_sprites_rough[GB(TileHash(ti->x, ti->y), 0, 3)], PAL_NONE);
	}
}

static void DrawClearLandFence(const TileInfo *ti)
{
	/* combine fences into one sprite object */
	StartSpriteCombine();

	int maxz = GetSlopeMaxPixelZ(ti->tileh);

	uint fence_nw = GetFence(ti->tile, DIAGDIR_NW);
	if (fence_nw != 0) {
		int z = GetSlopePixelZInCorner(ti->tileh, CORNER_W);
		SpriteID sprite = _clear_land_fence_sprites[fence_nw - 1] + _fence_mod_by_tileh_nw[ti->tileh];
		AddSortableSpriteToDraw(sprite, PAL_NONE, ti->x, ti->y - 15, 16, 31, maxz - z + 4, ti->z + z, false, 0, 15, -z);
	}

	uint fence_ne = GetFence(ti->tile, DIAGDIR_NE);
	if (fence_ne != 0) {
		int z = GetSlopePixelZInCorner(ti->tileh, CORNER_E);
		SpriteID sprite = _clear_land_fence_sprites[fence_ne - 1] + _fence_mod_by_tileh_ne[ti->tileh];
		AddSortableSpriteToDraw(sprite, PAL_NONE, ti->x - 15, ti->y, 31, 16, maxz - z + 4, ti->z + z, false, 15, 0, -z);
	}

	uint fence_sw = GetFence(ti->tile, DIAGDIR_SW);
	uint fence_se = GetFence(ti->tile, DIAGDIR_SE);

	if (fence_sw != 0 || fence_se != 0) {
		int z = GetSlopePixelZInCorner(ti->tileh, CORNER_S);

		if (fence_sw != 0) {
			SpriteID sprite = _clear_land_fence_sprites[fence_sw - 1] + _fence_mod_by_tileh_sw[ti->tileh];
			AddSortableSpriteToDraw(sprite, PAL_NONE, ti->x, ti->y, 16, 16, maxz - z + 4, ti->z + z, false, 0, 0, -z);
		}

		if (fence_se != 0) {
			SpriteID sprite = _clear_land_fence_sprites[fence_se - 1] + _fence_mod_by_tileh_se[ti->tileh];
			AddSortableSpriteToDraw(sprite, PAL_NONE, ti->x, ti->y, 16, 16, maxz - z + 4, ti->z + z, false, 0, 0, -z);
		}
	}
	EndSpriteCombine();
}

static void DrawTile_Clear(TileInfo *ti)
{
	switch (GetClearGround(ti->tile)) {
		case CLEAR_GRASS:
			DrawClearLandTile(ti, GetClearDensity(ti->tile));
			break;

		case CLEAR_ROUGH:
			DrawHillyLandTile(ti);
			break;

		case CLEAR_ROCKS:
			DrawGroundSprite((HasGrfMiscBit(GMB_SECOND_ROCKY_TILE_SET) && (TileHash(ti->x, ti->y) & 1) ? SPR_FLAT_ROCKY_LAND_2 : SPR_FLAT_ROCKY_LAND_1) + SlopeToSpriteOffset(ti->tileh), PAL_NONE);
			break;

		case CLEAR_FIELDS:
			DrawGroundSprite(_clear_land_sprites_farmland[GetFieldType(ti->tile)] + SlopeToSpriteOffset(ti->tileh), PAL_NONE);
			DrawClearLandFence(ti);
			break;

		case CLEAR_SNOW:
		case CLEAR_DESERT:
			DrawGroundSprite(_clear_land_sprites_snow_desert[GetClearDensity(ti->tile)] + SlopeToSpriteOffset(ti->tileh), PAL_NONE);
			break;
	}

	DrawBridgeMiddle(ti);
}

static int GetSlopePixelZ_Clear(TileIndex tile, uint x, uint y)
{
	int z;
	Slope tileh = GetTilePixelSlope(tile, &z);

	return z + GetPartialPixelZ(x & 0xF, y & 0xF, tileh);
}

static Foundation GetFoundation_Clear(TileIndex tile, Slope tileh)
{
	return FOUNDATION_NONE;
}

static void UpdateFences(TileIndex tile)
{
	assert(IsTileType(tile, MP_CLEAR) && IsClearGround(tile, CLEAR_FIELDS));
	bool dirty = false;

	bool neighbour = (IsTileType(TILE_ADDXY(tile, 1, 0), MP_CLEAR) && IsClearGround(TILE_ADDXY(tile, 1, 0), CLEAR_FIELDS));
	if (!neighbour && GetFence(tile, DIAGDIR_SW) == 0) {
		SetFence(tile, DIAGDIR_SW, 3);
		dirty = true;
	}

	neighbour = (IsTileType(TILE_ADDXY(tile, 0, 1), MP_CLEAR) && IsClearGround(TILE_ADDXY(tile, 0, 1), CLEAR_FIELDS));
	if (!neighbour && GetFence(tile, DIAGDIR_SE) == 0) {
		SetFence(tile, DIAGDIR_SE, 3);
		dirty = true;
	}

	neighbour = (IsTileType(TILE_ADDXY(tile, -1, 0), MP_CLEAR) && IsClearGround(TILE_ADDXY(tile, -1, 0), CLEAR_FIELDS));
	if (!neighbour && GetFence(tile, DIAGDIR_NE) == 0) {
		SetFence(tile, DIAGDIR_NE, 3);
		dirty = true;
	}

	neighbour = (IsTileType(TILE_ADDXY(tile, 0, -1), MP_CLEAR) && IsClearGround(TILE_ADDXY(tile, 0, -1), CLEAR_FIELDS));
	if (!neighbour && GetFence(tile, DIAGDIR_NW) == 0) {
		SetFence(tile, DIAGDIR_NW, 3);
		dirty = true;
	}

	if (dirty) MarkTileDirtyByTile(tile);
}


/** Convert to or from snowy tiles. */
static void TileLoopClearAlps(TileIndex tile)
{
	int k = GetTileZ(tile) - GetSnowLine() + 1;

	if (k < 0) {
		/* Below the snow line, do nothing if no snow. */
		if (!IsSnowTile(tile)) return;
	} else {
		/* At or above the snow line, make snow tile if needed. */
		if (!IsSnowTile(tile)) {
			MakeSnow(tile);
			MarkTileDirtyByTile(tile);
			return;
		}
	}
	/* Update snow density. */
	uint current_density = GetClearDensity(tile);
	uint req_density = (k < 0) ? 0u : min((uint)k, 3);

	if (current_density < req_density) {
		AddClearDensity(tile, 1);
	} else if (current_density > req_density) {
		AddClearDensity(tile, -1);
	} else {
		/* Density at the required level. */
		if (k >= 0) return;
		ClearSnow(tile);
	}
	MarkTileDirtyByTile(tile);
}

/**
 * Tests if at least one surrounding tile is non-desert
 * @param tile tile to check
 * @return does this tile have at least one non-desert tile around?
 */
static inline bool NeighbourIsNormal(TileIndex tile)
{
	for (DiagDirection dir = DIAGDIR_BEGIN; dir < DIAGDIR_END; dir++) {
		TileIndex t = tile + TileOffsByDiagDir(dir);
		if (!IsValidTile(t)) continue;
		if (GetTropicZone(t) != TROPICZONE_DESERT) return true;
		if (HasTileWaterClass(t) && GetWaterClass(t) == WATER_CLASS_SEA) return true;
	}
	return false;
}

static void TileLoopClearDesert(TileIndex tile)
{
	/* Current desert level - 0 if it is not desert */
	uint current = 0;
	if (IsClearGround(tile, CLEAR_DESERT)) current = GetClearDensity(tile);

	/* Expected desert level - 0 if it shouldn't be desert */
	uint expected = 0;
	if (GetTropicZone(tile) == TROPICZONE_DESERT) {
		expected = NeighbourIsNormal(tile) ? 1 : 3;
	}

	if (current == expected) return;

	if (expected == 0) {
		SetClearGroundDensity(tile, CLEAR_GRASS, 3);
	} else {
		/* Transition from clear to desert is not smooth (after clearing desert tile) */
		SetClearGroundDensity(tile, CLEAR_DESERT, expected);
	}

	MarkTileDirtyByTile(tile);
}

static void TileLoop_Clear(TileIndex tile)
{
	/* If the tile is at any edge flood it to prevent maps without water. */
	if (_settings_game.construction.freeform_edges && DistanceFromEdge(tile) == 1) {
		int z;
		if (IsTileFlat(tile, &z) && z == 0) {
			DoFloodTile(tile);
			MarkTileDirtyByTile(tile);
			return;
		}
	}
	AmbientSoundEffect(tile);

	switch (_settings_game.game_creation.landscape) {
		case LT_TROPIC: TileLoopClearDesert(tile); break;
		case LT_ARCTIC: TileLoopClearAlps(tile);   break;
	}

	switch (GetClearGround(tile)) {
		case CLEAR_GRASS:
			if (GetClearDensity(tile) == 3) return;

			if (_game_mode != GM_EDITOR) {
				if (GetClearCounter(tile) < 7) {
					AddClearCounter(tile, 1);
					return;
				} else {
					SetClearCounter(tile, 0);
					AddClearDensity(tile, 1);
				}
			} else {
				SetClearGroundDensity(tile, GB(Random(), 0, 8) > 21 ? CLEAR_GRASS : CLEAR_ROUGH, 3);
			}
			break;

		case CLEAR_FIELDS:
			UpdateFences(tile);

			if (_game_mode == GM_EDITOR) return;

			if (GetClearCounter(tile) < 7) {
				AddClearCounter(tile, 1);
				return;
			} else {
				SetClearCounter(tile, 0);
			}

			if (GetIndustryIndexOfField(tile) == INVALID_INDUSTRY && GetFieldType(tile) >= 7) {
				/* This farmfield is no longer farmfield, so make it grass again */
				MakeClear(tile, CLEAR_GRASS, 2);
			} else {
				uint field_type = GetFieldType(tile);
				field_type = (field_type < 8) ? field_type + 1 : 0;
				SetFieldType(tile, field_type);
			}
			break;

		default:
			return;
	}

	MarkTileDirtyByTile(tile);
}

void GenerateClearTile()
{
	uint i, gi;
	TileIndex tile;

	/* add rough tiles */
	i = ScaleByMapSize(GB(Random(), 0, 10) + 0x400);
	gi = ScaleByMapSize(GB(Random(), 0, 7) + 0x80);

	SetGeneratingWorldProgress(GWP_ROUGH_ROCKY, gi + i);
	do {
		IncreaseGeneratingWorldProgress(GWP_ROUGH_ROCKY);
		tile = RandomTile();
		if (IsTileType(tile, MP_CLEAR) && !IsClearGround(tile, CLEAR_DESERT)) SetClearGroundDensity(tile, CLEAR_ROUGH, 3);
	} while (--i);

	/* add rocky tiles */
	i = gi;
	do {
		uint32 r = Random();
		tile = RandomTileSeed(r);

		IncreaseGeneratingWorldProgress(GWP_ROUGH_ROCKY);
		if (IsTileType(tile, MP_CLEAR) && !IsClearGround(tile, CLEAR_DESERT)) {
			uint j = GB(r, 16, 4) + 5;
			for (;;) {
				TileIndex tile_new;

				SetClearGroundDensity(tile, CLEAR_ROCKS, 3);
				do {
					if (--j == 0) goto get_out;
					tile_new = tile + TileOffsByDiagDir((DiagDirection)GB(Random(), 0, 2));
				} while (!IsTileType(tile_new, MP_CLEAR) || IsClearGround(tile_new, CLEAR_DESERT));
				tile = tile_new;
			}
get_out:;
		}
	} while (--i);
}

static TrackStatus GetTileTrackStatus_Clear(TileIndex tile, TransportType mode, uint sub_mode, DiagDirection side)
{
	return 0;
}

static const StringID _clear_land_str[] = {
	STR_LAI_CLEAR_DESCRIPTION_GRASS,
	STR_LAI_CLEAR_DESCRIPTION_ROUGH_LAND,
	STR_LAI_CLEAR_DESCRIPTION_ROCKS,
	STR_LAI_CLEAR_DESCRIPTION_FIELDS,
	STR_LAI_CLEAR_DESCRIPTION_SNOW_COVERED_LAND,
	STR_LAI_CLEAR_DESCRIPTION_DESERT
};

static void GetTileDesc_Clear(TileIndex tile, TileDesc *td)
{
	if (IsClearGround(tile, CLEAR_GRASS) && GetClearDensity(tile) == 0) {
		td->str = STR_LAI_CLEAR_DESCRIPTION_BARE_LAND;
	} else {
		td->str = _clear_land_str[GetClearGround(tile)];
	}
	td->owner[0] = GetTileOwner(tile);
}

static void ChangeTileOwner_Clear(TileIndex tile, Owner old_owner, Owner new_owner)
{
	return;
}

static CommandCost TerraformTile_Clear(TileIndex tile, DoCommandFlag flags, int z_new, Slope tileh_new)
{
	return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
}

extern const TileTypeProcs _tile_type_clear_procs = {
	DrawTile_Clear,           ///< draw_tile_proc
	GetSlopePixelZ_Clear,     ///< get_slope_z_proc
	ClearTile_Clear,          ///< clear_tile_proc
	nullptr,                     ///< add_accepted_cargo_proc
	GetTileDesc_Clear,        ///< get_tile_desc_proc
	GetTileTrackStatus_Clear, ///< get_tile_track_status_proc
	nullptr,                     ///< click_tile_proc
	nullptr,                     ///< animate_tile_proc
	TileLoop_Clear,           ///< tile_loop_proc
	ChangeTileOwner_Clear,    ///< change_tile_owner_proc
	nullptr,                     ///< add_produced_cargo_proc
	nullptr,                     ///< vehicle_enter_tile_proc
	GetFoundation_Clear,      ///< get_foundation_proc
	TerraformTile_Clear,      ///< terraform_tile_proc
};