/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "ultima/ultima4/core/config.h"
#include "ultima/ultima4/core/settings.h"
#include "ultima/ultima4/gfx/image.h"
#include "ultima/ultima4/gfx/imagemgr.h"
#include "ultima/ultima4/gfx/screen.h"
#include "ultima/ultima4/map/tileanim.h"
#include "ultima/ultima4/map/tileset.h"
#include "ultima/ultima4/views/dungeonview.h"
#include "ultima/ultima4/ultima4.h"

namespace Ultima {
namespace Ultima4 {

DungeonView *DungeonView::_instance = nullptr;

DungeonView::DungeonView(int x, int y, int columns, int rows) : TileView(x, y, rows, columns)
	, _screen3dDungeonViewEnabled(true) {
}

DungeonView *DungeonView::getInstance() {
	if (!_instance) {
		_instance = new DungeonView(BORDER_WIDTH, BORDER_HEIGHT, VIEWPORT_W, VIEWPORT_H);
	}
	return _instance;
}

void DungeonView::display(Context *c, TileView *view) {
	int x, y;

	// 1st-person perspective
	if (_screen3dDungeonViewEnabled) {
		// Note: This shouldn't go above 4, unless we check opaque tiles each step of the way.
		const int farthest_non_wall_tile_visibility = 4;

		Std::vector<MapTile> tiles;

		g_screen->screenEraseMapArea();
		if (c->_party->getTorchDuration() > 0) {
			for (y = 3; y >= 0; y--) {
				DungeonGraphicType type;

				// FIXME: Maybe this should be in a loop
				tiles = getTiles(y, -1);
				type = tilesToGraphic(tiles);
				drawWall(-1, y, (Direction)g_ultima->_saveGame->_orientation, type);

				tiles = getTiles(y, 1);
				type = tilesToGraphic(tiles);
				drawWall(1, y, (Direction)g_ultima->_saveGame->_orientation, type);

				tiles = getTiles(y, 0);
				type = tilesToGraphic(tiles);
				drawWall(0, y, (Direction)g_ultima->_saveGame->_orientation, type);

				// This only checks that the tile at y==3 is opaque
				if (y == 3 && !tiles.front().getTileType()->isOpaque()) {
					for (int y_obj = farthest_non_wall_tile_visibility; y_obj > y; y_obj--) {
						Std::vector<MapTile> distant_tiles = getTiles(y_obj     , 0);
						DungeonGraphicType distant_type = tilesToGraphic(distant_tiles);

						if ((distant_type == DNGGRAPHIC_DNGTILE) || (distant_type == DNGGRAPHIC_BASETILE))
							drawTile(c->_location->_map->_tileSet->get(distant_tiles.front().getId()), 0, y_obj, Direction(g_ultima->_saveGame->_orientation));
					}
				}
				if ((type == DNGGRAPHIC_DNGTILE) || (type == DNGGRAPHIC_BASETILE))
					drawTile(c->_location->_map->_tileSet->get(tiles.front().getId()), 0, y, Direction(g_ultima->_saveGame->_orientation));
			}
		}
	}

	// 3rd-person perspective
	else {
		Std::vector<MapTile> tiles;

		static MapTile black = c->_location->_map->_tileSet->getByName("black")->getId();
		static MapTile avatar = c->_location->_map->_tileSet->getByName("avatar")->getId();

		for (y = 0; y < VIEWPORT_H; y++) {
			for (x = 0; x < VIEWPORT_W; x++) {
				tiles = getTiles((VIEWPORT_H / 2) - y, x - (VIEWPORT_W / 2));

				// Only show blackness if there is no light
				if (c->_party->getTorchDuration() <= 0)
					view->drawTile(black, false, x, y);
				else if (x == VIEWPORT_W / 2 && y == VIEWPORT_H / 2)
					view->drawTile(avatar, false, x, y);
				else
					view->drawTile(tiles, false, x, y);
			}
		}
	}
}

void DungeonView::drawInDungeon(Tile *tile, int x_offset, int distance, Direction orientation, bool tiledWall) {
	Image *scaled;

	const static int nscale_vga[] = { 12, 8, 4, 2, 1};
	const static int nscale_ega[] = { 8, 4, 2, 1, 0};

	const int lscale_vga[] = { 22, 18, 10, 4, 1};
	const int lscale_ega[] = { 22, 14, 6, 3, 1};

	const int *lscale;
	const int *nscale;
	int offset_multiplier = 0;
	int offset_adj = 0;
	if (settings._videoType != "EGA") {
		lscale = & lscale_vga[0];
		nscale = & nscale_vga[0];
		offset_multiplier = 1;
		offset_adj = 2;
	} else {
		lscale = & lscale_ega[0];
		nscale = & nscale_ega[0];
		offset_adj = 1;
		offset_multiplier = 4;
	}

	const int *dscale = tiledWall ? lscale : nscale;

	// Clear scratchpad and set a background color
	_animated->initializeToBackgroundColor();
	// Put tile on animated scratchpad
	if (tile->getAnim()) {
		MapTile mt = tile->getId();
		tile->getAnim()->draw(_animated, tile, mt, orientation);
	} else {
		tile->getImage()->drawOn(_animated, 0, 0);
	}
	_animated->makeBackgroundColorTransparent();
	// This process involving the background color is only required for drawing in the dungeon.
	// It will not play well with semi-transparent graphics.

	/* scale is based on distance; 1 means half size, 2 regular, 4 means scale by 2x, etc. */
	if (dscale[distance] == 0)
		return;
	else if (dscale[distance] == 1)
		scaled = g_screen->screenScaleDown(_animated, 2);
	else {
		scaled = g_screen->screenScale(_animated, dscale[distance] / 2, 1, 0);
	}

	if (tiledWall) {
		int i_x = SCALED((VIEWPORT_W * _tileWidth  / 2) + _bounds.left) - (scaled->width() / 2);
		int i_y = SCALED((VIEWPORT_H * _tileHeight / 2) + _bounds.top) - (scaled->height() / 2);
		int f_x = i_x + scaled->width();
		int f_y = i_y + scaled->height();
		int d_x = _animated->width();
		int d_y = _animated->height();

		for (int x = i_x; x < f_x; x += d_x)
			for (int y = i_y; y < f_y; y += d_y)
				_animated->drawSubRectOn(this->_screen,
					x, y, 0, 0, f_x - x, f_y - y);
	} else {
		int y_offset = MAX(0, (dscale[distance] - offset_adj) * offset_multiplier);
		int x = SCALED((VIEWPORT_W * _tileWidth / 2) + _bounds.left) - (scaled->width() / 2);
		int y = SCALED((VIEWPORT_H * _tileHeight / 2) + _bounds.top + y_offset) - (scaled->height() / 8);

		scaled->drawSubRectOn(this->_screen, x, y, 0, 0,
			SCALED(_tileWidth * VIEWPORT_W + _bounds.left) - x,
			SCALED(_tileHeight * VIEWPORT_H + _bounds.top) - y);
	}

	delete scaled;
}

int DungeonView::graphicIndex(int xoffset, int distance, Direction orientation, DungeonGraphicType type) {
	int index;

	index = 0;

	if (type == DNGGRAPHIC_LADDERUP && xoffset == 0)
		return 48 +
		       (distance * 2) +
		       (DIR_IN_MASK(orientation, MASK_DIR_SOUTH | MASK_DIR_NORTH) ? 1 : 0);

	if (type == DNGGRAPHIC_LADDERDOWN && xoffset == 0)
		return 56 +
		       (distance * 2) +
		       (DIR_IN_MASK(orientation, MASK_DIR_SOUTH | MASK_DIR_NORTH) ? 1 : 0);

	if (type == DNGGRAPHIC_LADDERUPDOWN && xoffset == 0)
		return 64 +
		       (distance * 2) +
		       (DIR_IN_MASK(orientation, MASK_DIR_SOUTH | MASK_DIR_NORTH) ? 1 : 0);

	// FIXME
	if (type != DNGGRAPHIC_WALL && type != DNGGRAPHIC_DOOR)
		return -1;

	if (type == DNGGRAPHIC_DOOR)
		index += 24;

	index += (xoffset + 1) * 2;

	index += distance * 6;

	if (DIR_IN_MASK(orientation, MASK_DIR_SOUTH | MASK_DIR_NORTH))
		index++;

	return index;
}

void DungeonView::drawTile(Tile *tile, int x_offset, int distance, Direction orientation) {
	// Draw the tile to the screen
	DungeonViewer.drawInDungeon(tile, x_offset, distance, orientation, tile->isTiledInDungeon());
}

Std::vector<MapTile> DungeonView::getTiles(int fwd, int side) {
	MapCoords coords = g_context->_location->_coords;

	switch (g_ultima->_saveGame->_orientation) {
	case DIR_WEST:
		coords.x -= fwd;
		coords.y -= side;
		break;

	case DIR_NORTH:
		coords.x += side;
		coords.y -= fwd;
		break;

	case DIR_EAST:
		coords.x += fwd;
		coords.y += side;
		break;

	case DIR_SOUTH:
		coords.x -= side;
		coords.y += fwd;
		break;

	case DIR_ADVANCE:
	case DIR_RETREAT:
	default:
		error("Invalid dungeon orientation");
	}

	// Wrap the coordinates if necessary
	coords.wrap(g_context->_location->_map);

	bool focus;
	return g_context->_location->tilesAt(coords, focus);
}

DungeonGraphicType DungeonView::tilesToGraphic(const Std::vector<MapTile> &tiles) {
	MapTile tile = tiles.front();

	if (!_tiles._loaded) {
		_tiles._corridor = g_context->_location->_map->_tileSet->getByName("brick_floor")->getId();
		_tiles._upLadder = g_context->_location->_map->_tileSet->getByName("up_ladder")->getId();
		_tiles._downLadder = g_context->_location->_map->_tileSet->getByName("down_ladder")->getId();
		_tiles._upDownLadder = g_context->_location->_map->_tileSet->getByName("up_down_ladder")->getId();
		_tiles._loaded = true;
	}


	/*
	 * check if the dungeon tile has an annotation or object on top
	 * (always displayed as a tile, unless a ladder)
	 */
	if (tiles.size() > 1) {
		if (tile._id == _tiles._upLadder._id)
			return DNGGRAPHIC_LADDERUP;
		else if (tile._id == _tiles._downLadder._id)
			return DNGGRAPHIC_LADDERDOWN;
		else if (tile._id == _tiles._upDownLadder._id)
			return DNGGRAPHIC_LADDERUPDOWN;
		else if (tile._id == _tiles._corridor._id)
			return DNGGRAPHIC_NONE;
		else
			return DNGGRAPHIC_BASETILE;
	}

	/*
	 * if not an annotation or object, then the tile is a dungeon
	 * token
	 */
	Dungeon *dungeon = dynamic_cast<Dungeon *>(g_context->_location->_map);
	assert(dungeon);
	DungeonToken token = dungeon->tokenForTile(tile);

	switch (token) {
	case DUNGEON_TRAP:
	case DUNGEON_CORRIDOR:
		return DNGGRAPHIC_NONE;
	case DUNGEON_WALL:
	case DUNGEON_SECRET_DOOR:
		return DNGGRAPHIC_WALL;
	case DUNGEON_ROOM:
	case DUNGEON_DOOR:
		return DNGGRAPHIC_DOOR;
	case DUNGEON_LADDER_UP:
		return DNGGRAPHIC_LADDERUP;
	case DUNGEON_LADDER_DOWN:
		return DNGGRAPHIC_LADDERDOWN;
	case DUNGEON_LADDER_UPDOWN:
		return DNGGRAPHIC_LADDERUPDOWN;

	default:
		return DNGGRAPHIC_DNGTILE;
	}
}

const struct {
	const char *subimage;
	int ega_x2, ega_y2;
	int vga_x2, vga_y2;
	const char *subimage2;
} DNG_GRAPHIC_INFO[] = {
	{ "dung0_lft_ew", -1, -1, -1, -1, nullptr },
	{ "dung0_lft_ns", -1, -1, -1, -1, nullptr },
	{ "dung0_mid_ew", -1, -1, -1, -1, nullptr },
	{ "dung0_mid_ns", -1, -1, -1, -1, nullptr },
	{ "dung0_rgt_ew", -1, -1, -1, -1, nullptr },
	{ "dung0_rgt_ns", -1, -1, -1, -1, nullptr },

	{ "dung1_lft_ew", 0, 32, 0, 8, "dung1_xxx_ew" },
	{ "dung1_lft_ns", 0, 32, 0, 8, "dung1_xxx_ns" },
	{ "dung1_mid_ew", -1, -1, -1, -1, nullptr },
	{ "dung1_mid_ns", -1, -1, -1, -1, nullptr },
	{ "dung1_rgt_ew", 144, 32, 160, 8, "dung1_xxx_ew" },
	{ "dung1_rgt_ns", 144, 32, 160, 8, "dung1_xxx_ns" },

	{ "dung2_lft_ew", 0, 64, 0, 48, "dung2_xxx_ew" },
	{ "dung2_lft_ns", 0, 64, 0, 48, "dung2_xxx_ns" },
	{ "dung2_mid_ew", -1, -1, -1, -1, nullptr },
	{ "dung2_mid_ns", -1, -1, -1, -1, nullptr },
	{ "dung2_rgt_ew", 112, 64, 128, 48, "dung2_xxx_ew" },
	{ "dung2_rgt_ns", 112, 64, 128, 48, "dung2_xxx_ns" },

	{ "dung3_lft_ew", 0, 80, 48, 72, "dung3_xxx_ew" },
	{ "dung3_lft_ns", 0, 80, 48, 72, "dung3_xxx_ns" },
	{ "dung3_mid_ew", -1, -1, -1, -1, nullptr },
	{ "dung3_mid_ns", -1, -1, -1, -1, nullptr },
	{ "dung3_rgt_ew", 96, 80, 104, 72, "dung3_xxx_ew" },
	{ "dung3_rgt_ns", 96, 80, 104, 72, "dung3_xxx_ns" },

	{ "dung0_lft_ew_door", -1, -1, -1, -1, nullptr },
	{ "dung0_lft_ns_door", -1, -1, -1, -1, nullptr },
	{ "dung0_mid_ew_door", -1, -1, -1, -1, nullptr },
	{ "dung0_mid_ns_door", -1, -1, -1, -1, nullptr },
	{ "dung0_rgt_ew_door", -1, -1, -1, -1, nullptr },
	{ "dung0_rgt_ns_door", -1, -1, -1, -1, nullptr },

	{ "dung1_lft_ew_door", 0, 32, 0, 8, "dung1_xxx_ew" },
	{ "dung1_lft_ns_door", 0, 32, 0, 8, "dung1_xxx_ns" },
	{ "dung1_mid_ew_door", -1, -1, -1, -1, nullptr },
	{ "dung1_mid_ns_door", -1, -1, -1, -1, nullptr },
	{ "dung1_rgt_ew_door", 144, 32, 160, 8, "dung1_xxx_ew" },
	{ "dung1_rgt_ns_door", 144, 32, 160, 8, "dung1_xxx_ns" },

	{ "dung2_lft_ew_door", 0, 64, 0, 48, "dung2_xxx_ew" },
	{ "dung2_lft_ns_door", 0, 64, 0, 48, "dung2_xxx_ns" },
	{ "dung2_mid_ew_door", -1, -1, -1, -1, nullptr },
	{ "dung2_mid_ns_door", -1, -1, -1, -1, nullptr },
	{ "dung2_rgt_ew_door", 112, 64, 128, 48, "dung2_xxx_ew" },
	{ "dung2_rgt_ns_door", 112, 64, 128, 48, "dung2_xxx_ns" },

	{ "dung3_lft_ew_door", 0, 80, 48, 72, "dung3_xxx_ew" },
	{ "dung3_lft_ns_door", 0, 80, 48, 72, "dung3_xxx_ns" },
	{ "dung3_mid_ew_door", -1, -1, -1, -1, nullptr },
	{ "dung3_mid_ns_door", -1, -1, -1, -1, nullptr },
	{ "dung3_rgt_ew_door", 96, 80, 104, 72, "dung3_xxx_ew" },
	{ "dung3_rgt_ns_door", 96, 80, 104, 72, "dung3_xxx_ns" },

	{ "dung0_ladderup", -1, -1, -1, -1, nullptr },
	{ "dung0_ladderup_side", -1, -1, -1, -1, nullptr },
	{ "dung1_ladderup", -1, -1, -1, -1, nullptr },
	{ "dung1_ladderup_side", -1, -1, -1, -1, nullptr },
	{ "dung2_ladderup", -1, -1, -1, -1, nullptr },
	{ "dung2_ladderup_side", -1, -1, -1, -1, nullptr },
	{ "dung3_ladderup", -1, -1, -1, -1, nullptr },
	{ "dung3_ladderup_side", -1, -1, -1, -1, nullptr },

	{ "dung0_ladderdown", -1, -1, -1, -1, nullptr },
	{ "dung0_ladderdown_side", -1, -1, -1, -1, nullptr },
	{ "dung1_ladderdown", -1, -1, -1, -1, nullptr },
	{ "dung1_ladderdown_side", -1, -1, -1, -1, nullptr },
	{ "dung2_ladderdown", -1, -1, -1, -1, nullptr },
	{ "dung2_ladderdown_side", -1, -1, -1, -1, nullptr },
	{ "dung3_ladderdown", -1, -1, -1, -1, nullptr },
	{ "dung3_ladderdown_side", -1, -1, -1, -1, nullptr },

	{ "dung0_ladderupdown", -1, -1, -1, -1, nullptr },
	{ "dung0_ladderupdown_side", -1, -1, -1, -1, nullptr },
	{ "dung1_ladderupdown", -1, -1, -1, -1, nullptr },
	{ "dung1_ladderupdown_side", -1, -1, -1, -1, nullptr },
	{ "dung2_ladderupdown", -1, -1, -1, -1, nullptr },
	{ "dung2_ladderupdown_side", -1, -1, -1, -1, nullptr },
	{ "dung3_ladderupdown", -1, -1, -1, -1, nullptr },
	{ "dung3_ladderupdown_side", -1, -1, -1, -1, nullptr },
};

void DungeonView::drawWall(int xoffset, int distance, Direction orientation, DungeonGraphicType type) {
	int index;

	index = graphicIndex(xoffset, distance, orientation, type);
	if (index == -1 || distance >= 4)
		return;

	int x = 0, y = 0;
	SubImage *subimage = imageMgr->getSubImage(DNG_GRAPHIC_INFO[index].subimage);
	if (subimage) {
		x = subimage->left;
		y = subimage->top;
	}

	g_screen->screenDrawImage(DNG_GRAPHIC_INFO[index].subimage, (BORDER_WIDTH + x) * settings._scale,
	                (BORDER_HEIGHT + y) * settings._scale);

	if (DNG_GRAPHIC_INFO[index].subimage2 != nullptr) {
		// FIXME: subimage2 is a horrible hack, needs to be cleaned up
		if (settings._videoType == "EGA")
			g_screen->screenDrawImage(DNG_GRAPHIC_INFO[index].subimage2,
				(8 + DNG_GRAPHIC_INFO[index].ega_x2) * settings._scale,
				(8 + DNG_GRAPHIC_INFO[index].ega_y2) * settings._scale);
		else
			g_screen->screenDrawImage(DNG_GRAPHIC_INFO[index].subimage2,
			    (8 + DNG_GRAPHIC_INFO[index].vga_x2) * settings._scale,
			    (8 + DNG_GRAPHIC_INFO[index].vga_y2) * settings._scale);
	}
}

} // End of namespace Ultima4
} // End of namespace Ultima