#pragma region Copyright (c) 2014-2016 OpenRCT2 Developers
/*****************************************************************************
 * OpenRCT2, an open source clone of Roller Coaster Tycoon 2.
 *
 * OpenRCT2 is the work of many authors, a full list can be found in contributors.md
 * For more information, visit https://github.com/OpenRCT2/OpenRCT2
 *
 * OpenRCT2 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.
 *
 * A full copy of the GNU General Public License can be found in licence.txt
 *****************************************************************************/
#pragma endregion

#ifndef DISABLE_OPENGL

#include <vector>
#include <stdexcept>
#include "../../../core/Memory.hpp"
#include "TextureCache.h"

extern "C"
{
    #include "../../drawing.h"
}

TextureCache::TextureCache()
{
}

TextureCache::~TextureCache()
{
    FreeTextures();
}

void TextureCache::SetPalette(const SDL_Color * palette)
{
    Memory::CopyArray(_palette, palette, 256);
}

void TextureCache::InvalidateImage(uint32 image)
{
    auto kvp = _imageTextureMap.find(image);
    if (kvp != _imageTextureMap.end())
    {
        _atlases[kvp->second.index].Free(kvp->second);
        _imageTextureMap.erase(kvp);
    }
}

CachedTextureInfo TextureCache::GetOrLoadImageTexture(uint32 image)
{
    auto kvp = _imageTextureMap.find(image & 0x7FFFF);
    if (kvp != _imageTextureMap.end())
    {
        return kvp->second;
    }

    auto cacheInfo = LoadImageTexture(image);
    _imageTextureMap[image & 0x7FFFF] = cacheInfo;

    return cacheInfo;
}

CachedTextureInfo TextureCache::GetOrLoadGlyphTexture(uint32 image, uint8 * palette)
{
    GlyphId glyphId;
    glyphId.Image = image;
    Memory::Copy<void>(&glyphId.Palette, palette, sizeof(glyphId.Palette));

    auto kvp = _glyphTextureMap.find(glyphId);
    if (kvp != _glyphTextureMap.end())
    {
        return kvp->second;
    }

    auto cacheInfo = LoadGlyphTexture(image, palette);
    _glyphTextureMap[glyphId] = cacheInfo;

    return cacheInfo;
}

void TextureCache::CreateAtlasesTexture()
{
    if (!_atlasesTextureInitialised)
    {
        // Determine width and height to use for texture atlases
        glGetIntegerv(GL_MAX_TEXTURE_SIZE, &_atlasesTextureDimensions);
        if (_atlasesTextureDimensions > TEXTURE_CACHE_MAX_ATLAS_SIZE) {
            _atlasesTextureDimensions = TEXTURE_CACHE_MAX_ATLAS_SIZE;
        }

        // Determine maximum number of atlases (minimum of size and array limit)
        glGetIntegerv(GL_MAX_ARRAY_TEXTURE_LAYERS, &_atlasesTextureIndicesLimit);
        if (_atlasesTextureDimensions < _atlasesTextureIndicesLimit) _atlasesTextureIndicesLimit = _atlasesTextureDimensions;

        // Create an array texture to hold all of the atlases
        glGenTextures(1, &_atlasesTexture);
        glBindTexture(GL_TEXTURE_2D_ARRAY, _atlasesTexture);
        glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

        _atlasesTextureInitialised = true;
        _atlasesTextureIndices = 0;
    }
}

void TextureCache::EnlargeAtlasesTexture(GLuint newEntries)
{
    CreateAtlasesTexture();

    GLuint newIndices = _atlasesTextureIndices + newEntries;

    // Retrieve current array data
    auto oldPixels = std::vector<char>(_atlasesTextureDimensions * _atlasesTextureDimensions * _atlasesTextureIndices);
    glGetTexImage(GL_TEXTURE_2D_ARRAY, 0, GL_RED_INTEGER, GL_UNSIGNED_BYTE, oldPixels.data());

    // Reallocate array
    glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_R8UI, _atlasesTextureDimensions, _atlasesTextureDimensions, newIndices, 0, GL_RED_INTEGER, GL_UNSIGNED_BYTE, nullptr);

    // Restore old data
    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0, _atlasesTextureDimensions, _atlasesTextureDimensions, _atlasesTextureIndices, GL_RED_INTEGER, GL_UNSIGNED_BYTE, oldPixels.data());
    
    _atlasesTextureIndices = newIndices;
}

CachedTextureInfo TextureCache::LoadImageTexture(uint32 image)
{
    rct_drawpixelinfo * dpi = GetImageAsDPI(image, 0);
    
    auto cacheInfo = AllocateImage(dpi->width, dpi->height);

    glBindTexture(GL_TEXTURE_2D_ARRAY, _atlasesTexture);
    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, cacheInfo.bounds.x, cacheInfo.bounds.y, cacheInfo.index, dpi->width, dpi->height, 1, GL_RED_INTEGER, GL_UNSIGNED_BYTE, dpi->bits);

    DeleteDPI(dpi);

    return cacheInfo;
}

CachedTextureInfo TextureCache::LoadGlyphTexture(uint32 image, uint8 * palette)
{
    rct_drawpixelinfo * dpi = GetGlyphAsDPI(image, palette);

    auto cacheInfo = AllocateImage(dpi->width, dpi->height);

    glBindTexture(GL_TEXTURE_2D_ARRAY, _atlasesTexture);
    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, cacheInfo.bounds.x, cacheInfo.bounds.y, cacheInfo.index, dpi->width, dpi->height, 1, GL_RED_INTEGER, GL_UNSIGNED_BYTE, dpi->bits);

    DeleteDPI(dpi);

    return cacheInfo;
}

void * TextureCache::GetImageAsARGB(uint32 image, uint32 tertiaryColour, uint32 * outWidth, uint32 * outHeight)
{
    rct_g1_element * g1Element = gfx_get_g1_element(image & 0x7FFFF);
    sint32 width = g1Element->width;
    sint32 height = g1Element->height;

    rct_drawpixelinfo * dpi = CreateDPI(width, height);
    gfx_draw_sprite_software(dpi, image, -g1Element->x_offset, -g1Element->y_offset, tertiaryColour);
    void * pixels32 = ConvertDPIto32bpp(dpi);
    DeleteDPI(dpi);

    *outWidth = width;
    *outHeight = height;
    return pixels32;
}

CachedTextureInfo TextureCache::AllocateImage(int imageWidth, int imageHeight)
{
    CreateAtlasesTexture();

    // Find an atlas that fits this image
    for (Atlas& atlas : _atlases)
    {
        if (atlas.GetFreeSlots() > 0 && atlas.IsImageSuitable(imageWidth, imageHeight))
        {
            return atlas.Allocate(imageWidth, imageHeight);
        }
    }

    // If there is no such atlas, then create a new one
    if ((int) _atlases.size() >= _atlasesTextureIndicesLimit)
    {
        throw std::runtime_error("more texture atlases required, but device limit reached!");
    }

    int atlasIndex = (int) _atlases.size();
    int atlasSize = (int) powf(2, (float) Atlas::CalculateImageSizeOrder(imageWidth, imageHeight));

#ifdef DEBUG
    log_verbose("new texture atlas #%d (size %d) allocated\n", atlasIndex, atlasSize);
#endif

    _atlases.push_back(std::move(Atlas(atlasIndex, atlasSize)));
    _atlases.back().Initialise(_atlasesTextureDimensions, _atlasesTextureDimensions);

    // Enlarge texture array to support new atlas
    EnlargeAtlasesTexture(1);

    // And allocate from the new atlas
    return _atlases.back().Allocate(imageWidth, imageHeight);
}

rct_drawpixelinfo * TextureCache::GetImageAsDPI(uint32 image, uint32 tertiaryColour)
{
    rct_g1_element * g1Element = gfx_get_g1_element(image & 0x7FFFF);
    sint32 width = g1Element->width;
    sint32 height = g1Element->height;
    
    rct_drawpixelinfo * dpi = CreateDPI(width, height);
    gfx_draw_sprite_software(dpi, image, -g1Element->x_offset, -g1Element->y_offset, tertiaryColour);
    return dpi;
}

void * TextureCache::GetGlyphAsARGB(uint32 image, uint8 * palette, uint32 * outWidth, uint32 * outHeight)
{
    rct_g1_element * g1Element = gfx_get_g1_element(image & 0x7FFFF);
    sint32 width = g1Element->width;
    sint32 height = g1Element->height;

    rct_drawpixelinfo * dpi = CreateDPI(width, height);
    gfx_draw_sprite_palette_set_software(dpi, image, -g1Element->x_offset, -g1Element->y_offset, palette, nullptr);
    void * pixels32 = ConvertDPIto32bpp(dpi);
    DeleteDPI(dpi);

    *outWidth = width;
    *outHeight = height;
    return pixels32;
}

rct_drawpixelinfo * TextureCache::GetGlyphAsDPI(uint32 image, uint8 * palette)
{
    rct_g1_element * g1Element = gfx_get_g1_element(image & 0x7FFFF);
    sint32 width = g1Element->width;
    sint32 height = g1Element->height;
    
    rct_drawpixelinfo * dpi = CreateDPI(width, height);
    gfx_draw_sprite_palette_set_software(dpi, image, -g1Element->x_offset, -g1Element->y_offset, palette, nullptr);
    return dpi;
}

void * TextureCache::ConvertDPIto32bpp(const rct_drawpixelinfo * dpi)
{
    size_t numPixels = dpi->width * dpi->height;
    uint8 * pixels32 = Memory::Allocate<uint8>(numPixels * 4);
    uint8 * src = dpi->bits;
    uint8 * dst = pixels32;
    for (size_t i = 0; i < numPixels; i++)
    {
        uint8 paletteIndex = *src++;
        if (paletteIndex == 0)
        {
            // Transparent
            *dst++ = 0;
            *dst++ = 0;
            *dst++ = 0;
            *dst++ = 0;
        }
        else
        {
            SDL_Color colour = _palette[paletteIndex];
            *dst++ = colour.r;
            *dst++ = colour.g;
            *dst++ = colour.b;
            *dst++ = colour.a;
        }
    }
    return pixels32;
}

void TextureCache::FreeTextures()
{
    // Free array texture
    glDeleteTextures(1, &_atlasesTexture);
}

rct_drawpixelinfo * TextureCache::CreateDPI(sint32 width, sint32 height)
{
    size_t numPixels = width * height;
    uint8 * pixels8 = Memory::Allocate<uint8>(numPixels);
    Memory::Set(pixels8, 0, numPixels);

    rct_drawpixelinfo * dpi = new rct_drawpixelinfo();
    dpi->bits = pixels8;
    dpi->pitch = 0;
    dpi->x = 0;
    dpi->y = 0;
    dpi->width = width;
    dpi->height = height;
    dpi->zoom_level = 0;
    return dpi;
}

void TextureCache::DeleteDPI(rct_drawpixelinfo* dpi)
{
    Memory::Free(dpi->bits);
    delete dpi;
}

GLuint TextureCache::GetAtlasesTexture()
{
    return _atlasesTexture;
}

#endif /* DISABLE_OPENGL */