#ifndef COMPONENTS_TERRAIN_STORAGE_H
#define COMPONENTS_TERRAIN_STORAGE_H

#include <OgreAxisAlignedBox.h>

#include <OgreHardwareVertexBuffer.h>

namespace Terrain
{

    struct LayerInfo
    {
        std::string mDiffuseMap;
        std::string mNormalMap;
        bool mParallax; // Height info in normal map alpha channel?
        bool mSpecular; // Specular info in diffuse map alpha channel?
    };

    /// We keep storage of terrain data abstract here since we need different implementations for game and editor
    class Storage
    {
    public:
        virtual ~Storage() {}

    public:
        /// Get bounds of the whole terrain in cell units
        virtual Ogre::AxisAlignedBox getBounds() = 0;

        /// Get the minimum and maximum heights of a terrain chunk.
        /// @note Should only be called for chunks <= 1 cell, i.e. leafs of the quad tree.
        ///        Larger chunks can simply merge AABB of children.
        /// @param size size of the chunk in cell units
        /// @param center center of the chunk in cell units
        /// @param min min height will be stored here
        /// @param max max height will be stored here
        /// @return true if there was data available for this terrain chunk
        virtual bool getMinMaxHeights (float size, const Ogre::Vector2& center, float& min, float& max) = 0;

        /// Fill vertex buffers for a terrain chunk.
        /// @param lodLevel LOD level, 0 = most detailed
        /// @param size size of the terrain chunk in cell units
        /// @param center center of the chunk in cell units
        /// @param vertexBuffer buffer to write vertices
        /// @param normalBuffer buffer to write vertex normals
        /// @param colourBuffer buffer to write vertex colours
        virtual void fillVertexBuffers (int lodLevel, float size, const Ogre::Vector2& center,
                                Ogre::HardwareVertexBufferSharedPtr vertexBuffer,
                                Ogre::HardwareVertexBufferSharedPtr normalBuffer,
                                Ogre::HardwareVertexBufferSharedPtr colourBuffer) = 0;

        /// Create textures holding layer blend values for a terrain chunk.
        /// @note The terrain chunk shouldn't be larger than one cell since otherwise we might
        ///       have to do a ridiculous amount of different layers. For larger chunks, composite maps should be used.
        /// @param chunkSize size of the terrain chunk in cell units
        /// @param chunkCenter center of the chunk in cell units
        /// @param pack Whether to pack blend values for up to 4 layers into one texture (one in each channel) -
        ///        otherwise, each texture contains blend values for one layer only. Shader-based rendering
        ///        can utilize packing, FFP can't.
        /// @param blendmaps created blendmaps will be written here
        /// @param layerList names of the layer textures used will be written here
        virtual void getBlendmaps (float chunkSize, const Ogre::Vector2& chunkCenter, bool pack,
                           std::vector<Ogre::TexturePtr>& blendmaps,
                           std::vector<LayerInfo>& layerList) = 0;

        virtual float getHeightAt (const Ogre::Vector3& worldPos) = 0;

        virtual LayerInfo getDefaultLayer() = 0;

        /// Get the transformation factor for mapping cell units to world units.
        virtual float getCellWorldSize() = 0;

        /// Get the number of vertices on one side for each cell. Should be (power of two)+1
        virtual int getCellVertices() = 0;
    };

}

#endif