/*
 * This source file is part of RmlUi, the HTML/CSS Interface Middleware
 *
 * For the latest information, see http://github.com/mikke89/RmlUi
 *
 * Copyright (c) 2008-2010 CodePoint Ltd, Shift Technology Ltd
 * Copyright (c) 2019 The RmlUi Team, and contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */


#include "precompiled.h"
#include "DecoratorTiled.h"
#include "../../Include/RmlUi/Core.h"

namespace Rml {
namespace Core {

DecoratorTiled::DecoratorTiled()
{
}

DecoratorTiled::~DecoratorTiled()
{
}

static const Vector2f oriented_texcoords[6][2] = {{Vector2f(0, 0), Vector2f(1, 1)},
													   {Vector2f(0, 1), Vector2f(1, 0)},
													   {Vector2f(1, 1), Vector2f(0, 0)},
													   {Vector2f(1, 0), Vector2f(0, 1)},
													   {Vector2f(1, 0), Vector2f(0, 1)},
													   {Vector2f(0, 1), Vector2f(1, 0)}};

DecoratorTiled::Tile::Tile() : position(0, 0), size(1, 1)
{
	texture_index = -1;
	repeat_mode = STRETCH;
	fit_mode = FILL;
	orientation = ROTATE_0;

	position_absolute[0] = false;
	position_absolute[1] = false;
	size_absolute[0] = false;
	size_absolute[1] = false;
}


// Calculates the tile's dimensions from the texture and texture coordinates.
void DecoratorTiled::Tile::CalculateDimensions(Element* element, const Texture& texture) const
{
	RenderInterface* render_interface = element->GetRenderInterface();
	auto data_iterator = data.find(render_interface);
	if (data_iterator == data.end())
	{
		TileData new_data;
		const Vector2i texture_dimensions_i = texture.GetDimensions(render_interface);
		const Vector2f texture_dimensions((float)texture_dimensions_i.x, (float)texture_dimensions_i.y);

		if (texture_dimensions.x == 0 || texture_dimensions.y == 0)
		{
			new_data.size = Vector2f(0, 0);
			new_data.texcoords[0] = Vector2f(0, 0);
			new_data.texcoords[1] = Vector2f(0, 0);
		}
		else
		{
			// Need to scale the coordinates to normalized units and 'size' to absolute size (pixels)
			for(int i = 0; i < 2; i++)
			{
				float size_relative = size[i];
				new_data.size[i] = Math::AbsoluteValue(size[i]);

				if (size_absolute[i])
					size_relative /= texture_dimensions[i];
				else
					new_data.size[i] *= texture_dimensions[i];
				
				new_data.texcoords[0][i] = position[i];
				if (position_absolute[i])
					new_data.texcoords[0][i] /= texture_dimensions[i];

				new_data.texcoords[1][i] = size_relative + new_data.texcoords[0][i];
			}
		}

		data.emplace( render_interface, new_data );
	}
}

// Get this tile's dimensions.
Vector2f DecoratorTiled::Tile::GetDimensions(Element* element) const
{
	RenderInterface* render_interface = element->GetRenderInterface();
	auto data_iterator = data.find(render_interface);
	if (data_iterator == data.end())
		return Vector2f(0, 0);

	return data_iterator->second.size;
}

// Generates geometry to render this tile across a surface.
void DecoratorTiled::Tile::GenerateGeometry(std::vector< Vertex >& vertices, std::vector< int >& indices, Element* element, const Vector2f& surface_origin, const Vector2f& surface_dimensions, const Vector2f& tile_dimensions) const
{
	if (surface_dimensions.x <= 0 || surface_dimensions.y <= 0)
		return;

	RenderInterface* render_interface = element->GetRenderInterface();
	const auto& computed = element->GetComputedValues();

	float opacity = computed.opacity;
	Colourb quad_colour = computed.image_color;

    // Apply opacity
    quad_colour.alpha = (byte)(opacity * (float)quad_colour.alpha);

	auto data_iterator = data.find(render_interface);
	if (data_iterator == data.end())
		return;

	const TileData& data = data_iterator->second;

	int num_tiles[2] = { 0, 0 };
	Vector2f final_tile_dimensions( 0, 0 );

	// Generate the oriented texture coordinates for the tiles.
	Vector2f scaled_texcoords[3];
	for (int i = 0; i < 2; i++)
	{
		scaled_texcoords[i] = data.texcoords[0] + oriented_texcoords[orientation][i] * (data.texcoords[1] - data.texcoords[0]);
	}
	scaled_texcoords[2] = scaled_texcoords[1];

	// Resize the dimensions (if necessary) to fit this tile's repeat mode.
	for (int i = 0; i < 2; i++)
	{
		switch (repeat_mode)
		{
		case STRETCH:
		{
			// If the tile is stretched, we only need one quad.
			num_tiles[i] = 1;
			final_tile_dimensions[i] = surface_dimensions[i];
		}
		break;

		case CLAMP_STRETCH:
		case CLAMP_TRUNCATE:
		{
			// If the tile is clamped, we only need one quad if the surface is smaller than the tile, or two if it's larger (to take the last stretched pixel).
			num_tiles[i] = surface_dimensions[i] > tile_dimensions[i] ? 2 : 1;
			if (num_tiles[i] == 1)
			{
				final_tile_dimensions[i] = surface_dimensions[i];
				if (repeat_mode == CLAMP_TRUNCATE)
					scaled_texcoords[1][i] -= (scaled_texcoords[1][i] - scaled_texcoords[0][i]) * (1.0f - (final_tile_dimensions[i] / tile_dimensions[i]));
			}
			else
				final_tile_dimensions[i] = surface_dimensions[i] - tile_dimensions[i];
		}
		break;

		case REPEAT_STRETCH:
		case REPEAT_TRUNCATE:
		{
			num_tiles[i] = Math::RealToInteger((surface_dimensions[i] + (tile_dimensions[i] - 1)) / tile_dimensions[i]);
			num_tiles[i] = Math::Max(0, num_tiles[i]);

			final_tile_dimensions[i] = surface_dimensions[i] - (num_tiles[i] - 1) * tile_dimensions[i];
			if (final_tile_dimensions[i] <= 0)
				final_tile_dimensions[i] = tile_dimensions[i];

			if (repeat_mode == REPEAT_TRUNCATE)
				scaled_texcoords[2][i] -= (scaled_texcoords[1][i] - scaled_texcoords[0][i]) * (1.0f - (final_tile_dimensions[i] / tile_dimensions[i]));
		}
		break;
		}
	}


	// For now, we assume that fit mode and repeat mode cannot both be set on a single tile. The two code paths won't work well together.
	RMLUI_ASSERT(repeat_mode == STRETCH || fit_mode == FILL);

	bool offset_and_clip_tile = false;

	switch (fit_mode)
	{
	case FILL:
		// Do nothing, use results from above.
	break;
	case CONTAIN:
	{
		Vector2f scale_factor = surface_dimensions / tile_dimensions;
		float min_factor = std::min(scale_factor.x, scale_factor.y);
		final_tile_dimensions = tile_dimensions * min_factor;

		offset_and_clip_tile = true;
	}
	break;
	case COVER:
	{
		Vector2f scale_factor = surface_dimensions / tile_dimensions;
		float max_factor = std::max(scale_factor.x, scale_factor.y);
		final_tile_dimensions = tile_dimensions * max_factor;

		offset_and_clip_tile = true;
	}
	break;
	case SCALE_NONE:
	{
		final_tile_dimensions = tile_dimensions;
		
		offset_and_clip_tile = true;
	}
	break;
	case SCALE_DOWN:
	{
		Vector2f scale_factor = surface_dimensions / tile_dimensions;
		float min_factor = std::min(scale_factor.x, scale_factor.y);
		if (min_factor < 1.0f)
			final_tile_dimensions = tile_dimensions * min_factor;
		else
			final_tile_dimensions = tile_dimensions;

		offset_and_clip_tile = true;
	}
	break;
	}


	Vector2f tile_offset(0, 0);

	if (offset_and_clip_tile)
	{
		// Offset tile along each dimension.
		for(int i = 0; i < 2; i++)
		{
			switch (align[i].type) {
			case Style::LengthPercentage::Length:      tile_offset[i] = align[i].value;  break;
			case Style::LengthPercentage::Percentage:  tile_offset[i] = (surface_dimensions[i] - final_tile_dimensions[i]) * align[i].value * 0.01f;  break;
			}
		}
		tile_offset = tile_offset.Round();

		// Clip tile. See if our tile extends outside the boundary at either side, along each dimension.
		for(int i = 0; i < 2; i++)
		{
			// Left/right acts as top/bottom during the second iteration.
			float overshoot_left = std::max(-tile_offset[i], 0.0f);
			float overshoot_right = std::max(tile_offset[i] + final_tile_dimensions[i] - surface_dimensions[i], 0.0f);

			if(overshoot_left > 0.f || overshoot_right > 0.f)
			{
				float& left = scaled_texcoords[0][i];
				float& right = scaled_texcoords[1][i];
				float width = right - left;

				left += overshoot_left / final_tile_dimensions[i] * width;
				right -= overshoot_right / final_tile_dimensions[i] * width;

				final_tile_dimensions[i] -= overshoot_left + overshoot_right;
				tile_offset[i] += overshoot_left;
			}
		}

		scaled_texcoords[2] = scaled_texcoords[1];
	}

	// If any of the axes are zero or below, then we have a zero surface area and nothing to render.
	if (num_tiles[0] <= 0 || num_tiles[1] <= 0)
		return;

	// Resize the vertex and index arrays to fit the new geometry.
	int index_offset = (int) vertices.size();
	vertices.resize(vertices.size() + num_tiles[0] * num_tiles[1] * 4);
	Vertex* new_vertices = &vertices[0] + index_offset;

	size_t num_indices = indices.size();
	indices.resize(indices.size() + num_tiles[0] * num_tiles[1] * 6);
	int* new_indices = &indices[0] + num_indices;

	// Generate the vertices for the tiled surface.
	for (int y = 0; y < num_tiles[1]; y++)
	{
		Vector2f tile_position;
		tile_position.y = surface_origin.y + (float) tile_dimensions.y * y;

		Vector2f tile_size;
		tile_size.y = (float) (y < num_tiles[1] - 1 ? data.size.y : final_tile_dimensions.y);

		// Squish the texture coordinates in the y if we're clamping and this is the last in a double-tile.
		Vector2f tile_texcoords[2];
		if (num_tiles[1] == 2 &&
			y == 1 &&
			(repeat_mode == CLAMP_STRETCH ||
			 repeat_mode == CLAMP_TRUNCATE))
		{
			tile_texcoords[0].y = scaled_texcoords[1].y;
			tile_texcoords[1].y = scaled_texcoords[1].y;
		}
		else
		{
			tile_texcoords[0].y = scaled_texcoords[0].y;
			// The last tile might have truncated texture coords
			if (y == num_tiles[1] - 1)
				tile_texcoords[1].y = scaled_texcoords[2].y;
			else
				tile_texcoords[1].y = scaled_texcoords[1].y;
		}

		for (int x = 0; x < num_tiles[0]; x++)
		{
			// Squish the texture coordinates in the x if we're clamping and this is the last in a double-tile.
			if (num_tiles[0] == 2 &&
				x == 1 &&
				(repeat_mode == CLAMP_STRETCH ||
				 repeat_mode == CLAMP_TRUNCATE))
			{
				tile_texcoords[0].x = scaled_texcoords[1].x;
				tile_texcoords[1].x = scaled_texcoords[1].x;
			}
			else
			{
				tile_texcoords[0].x = scaled_texcoords[0].x;
				// The last tile might have truncated texture coords
				if (x == num_tiles[0] - 1)
					tile_texcoords[1].x = scaled_texcoords[2].x;
				else
					tile_texcoords[1].x = scaled_texcoords[1].x;
			}

			tile_position.x = surface_origin.x + (float) tile_dimensions.x * x;
			tile_size.x = (float) (x < num_tiles[0] - 1 ? tile_dimensions.x : final_tile_dimensions.x);

			tile_position = (tile_position + tile_offset).Round();
			tile_size = tile_size.Round();

			GeometryUtilities::GenerateQuad(new_vertices, new_indices, tile_position, tile_size, quad_colour, tile_texcoords[0], tile_texcoords[1], index_offset);
			new_vertices += 4;
			new_indices += 6;
			index_offset += 4;
		}
	}
}

// Scales a tile dimensions by a fixed value along one axis.
void DecoratorTiled::ScaleTileDimensions(Vector2f& tile_dimensions, float axis_value, int axis) const
{
	if (tile_dimensions[axis] != axis_value)
	{
		tile_dimensions[1 - axis] = tile_dimensions[1 - axis] * (axis_value / tile_dimensions[axis]);
		tile_dimensions[axis] = axis_value;
	}
}

}
}