/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
 *                                                                                       *
 * Copyright (c) 2014-2017                                                               *
 *                                                                                       *
 * 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 <modules/globebrowsing/meshes/trianglesoup.h>

#include <ghoul/logging/logmanager.h>

namespace {
    const char* _loggerCat = "TriangleSoup";
}

namespace openspace::globebrowsing {

TriangleSoup::TriangleSoup(std::vector<unsigned int> elements, Positions usePositions,
                           TextureCoordinates useTextures, Normals useNormals)
    : _useVertexPositions(usePositions)
    , _useTextureCoordinates(useTextures)
    , _useVertexNormals(useNormals)
    , _vaoID(0)
    , _vertexBufferID(0)
    , _elementBufferID(0)
{
    setElements(elements);
}

TriangleSoup::~TriangleSoup() {
    glDeleteBuffers(1, &_vertexBufferID);
    glDeleteBuffers(1, &_elementBufferID);
    glDeleteVertexArrays(1, &_vaoID);
}

void TriangleSoup::setVertexPositions(std::vector<glm::vec4> positions) {
    _useVertexPositions = true;
    _gpuDataNeedUpdate = true;
    _vertexData.resize(positions.size());
    for (size_t i = 0; i < positions.size(); i++) {
        _vertexData[i].position[0] = static_cast<GLfloat>(positions[i].x);
        _vertexData[i].position[1] = static_cast<GLfloat>(positions[i].y);
        _vertexData[i].position[2] = static_cast<GLfloat>(positions[i].z);
        _vertexData[i].position[3] = static_cast<GLfloat>(positions[i].w);
    }
}

void TriangleSoup::setVertexTextureCoordinates(std::vector<glm::vec2> textures) {
    _useTextureCoordinates = true;
    _gpuDataNeedUpdate = true;
    _vertexData.resize(textures.size());
    for (size_t i = 0; i < textures.size(); i++) {
        _vertexData[i].texture[0] = static_cast<GLfloat>(textures[i].s);
        _vertexData[i].texture[1] = static_cast<GLfloat>(textures[i].t);
    }
}

void TriangleSoup::setVertexNormals(std::vector<glm::vec3> normals) {
    _useVertexNormals = true;
    _gpuDataNeedUpdate = true;
    _vertexData.resize(normals.size());
    for (size_t i = 0; i < normals.size(); i++) {
        _vertexData[i].normal[0] = static_cast<GLfloat>(normals[i].x);
        _vertexData[i].normal[1] = static_cast<GLfloat>(normals[i].y);
        _vertexData[i].normal[2] = static_cast<GLfloat>(normals[i].z);
    }
}

void TriangleSoup::setElements(std::vector<unsigned int> elements) {
    _elementData.resize(elements.size());
    _gpuDataNeedUpdate = true;
    for (size_t i = 0; i < elements.size(); i++) {
        _elementData[i] = static_cast<GLuint>(elements[i]);
    }
}

bool TriangleSoup::updateDataOnGPU() {
    // Create VAO
    if (_vaoID == 0) {
        glGenVertexArrays(1, &_vaoID);
    }

    // Create VBOs
    if (_vertexBufferID == 0 && _vertexData.size() > 0) {
        glGenBuffers(1, &_vertexBufferID);
        if (_vertexBufferID == 0) {
            LERROR("Could not create vertex buffer");
            return false;
        }
    }
    if (_elementBufferID == 0 && _elementData.size() > 0) {
        glGenBuffers(1, &_elementBufferID);
        if (_elementBufferID == 0) {
            LERROR("Could not create vertex element buffer");
            return false;
        }
    }

    // First VAO setup
    glBindVertexArray(_vaoID);

    // Vertex buffer
    glBindBuffer(GL_ARRAY_BUFFER, _vertexBufferID);
    glBufferData(
        GL_ARRAY_BUFFER,
        _vertexData.size() * sizeof(Vertex),
        &_vertexData[0],
        GL_STATIC_DRAW
    );

    // Positions at location 0
    if (_useVertexPositions) {
        glEnableVertexAttribArray(0);
        glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex),
            reinterpret_cast<const GLvoid*>(offsetof(Vertex, position)));
    }
    // Textures at location 1
    if (_useTextureCoordinates) {
        glEnableVertexAttribArray(1);
        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
            reinterpret_cast<const GLvoid*>(offsetof(Vertex, texture)));
    }
    // Normals at location 2
    if (_useVertexNormals) {
        glEnableVertexAttribArray(2);
        glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
            reinterpret_cast<const GLvoid*>(offsetof(Vertex, normal)));
    }

    // Element buffer
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _elementBufferID);
    glBufferData(
        GL_ELEMENT_ARRAY_BUFFER,
        _elementData.size() * sizeof(GLint),
        &_elementData[0],
        GL_STATIC_DRAW);

    glBindVertexArray(0);

    _gpuDataNeedUpdate = false;

    return true;
}

void TriangleSoup::drawUsingActiveProgram() {
    if (_gpuDataNeedUpdate) {
        updateDataOnGPU();
    }
    glBindVertexArray(_vaoID);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _elementBufferID);
    glDrawElements(
        GL_TRIANGLES,
        static_cast<GLsizei>(_elementData.size()),
        GL_UNSIGNED_INT,
        nullptr
    );
    glBindVertexArray(0);
}

} // namespace openspace::globebrowsing