#include "Mesh.hpp"

namespace renderer {
Mesh::Mesh () : mVAO( 0 ), mVBO( 0 ), mEBO( 0 ), mVertexCount( 0 ), mIndexCount( 0 ), mMode( GL_TRIANGLES ) {}

Mesh::~Mesh () {
    if( mVBO ) {
        glDeleteBuffers( 1, &mVBO );
    }
    if( mEBO ) {
        glDeleteBuffers( 1, &mEBO );
    }
    if( mVAO ) {
        glDeleteVertexArrays( 1, &mVAO );
    }
}

bool Mesh::createFromPositions ( const std::vector<float>& positions, bool lines ) {
    if( positions.empty() ) {
        return false;
    }

    mMode        = lines ? GL_LINES : GL_TRIANGLES;
    mVertexCount = static_cast<GLsizei>( positions.size() / 3 );

    glGenVertexArrays( 1, &mVAO );
    glGenBuffers( 1, &mVBO );

    glBindVertexArray( mVAO );
    glBindBuffer( GL_ARRAY_BUFFER, mVBO );
    glBufferData( GL_ARRAY_BUFFER, positions.size() * sizeof( float ), positions.data(), GL_STATIC_DRAW );

    glEnableVertexAttribArray( 0 );
    glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof( float ), (void*)0 );

    glBindVertexArray( 0 );

    return true;
}

bool Mesh::createFromPosTex ( const std::vector<float>& data ) {
    if( data.empty() )
        return false;

    const size_t strideFloats = 5;
    mMode                     = GL_TRIANGLES;
    mVertexCount              = static_cast<GLsizei>( data.size() / strideFloats );

    glGenVertexArrays( 1, &mVAO );
    glGenBuffers( 1, &mVBO );

    glBindVertexArray( mVAO );
    glBindBuffer( GL_ARRAY_BUFFER, mVBO );
    glBufferData( GL_ARRAY_BUFFER, data.size() * sizeof( float ), data.data(), GL_STATIC_DRAW );

    glEnableVertexAttribArray( 0 );
    glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, strideFloats * sizeof( float ), (void*)0 );

    glEnableVertexAttribArray( 1 );
    glVertexAttribPointer( 1, 2, GL_FLOAT, GL_FALSE, strideFloats * sizeof( float ),
                           (void*)( 3 * sizeof( float ) ) );

    glBindVertexArray( 0 );
    return true;
}

bool Mesh::createFromPosTexNormal ( const std::vector<float>& data ) {
    if( data.empty() )
        return false;

    const size_t strideFloats = 8;
    mMode                     = GL_TRIANGLES;
    mVertexCount              = static_cast<GLsizei>( data.size() / strideFloats );

    glGenVertexArrays( 1, &mVAO );
    glGenBuffers( 1, &mVBO );

    glBindVertexArray( mVAO );
    glBindBuffer( GL_ARRAY_BUFFER, mVBO );
    glBufferData( GL_ARRAY_BUFFER, data.size() * sizeof( float ), data.data(), GL_STATIC_DRAW );

    glEnableVertexAttribArray( 0 );
    glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, strideFloats * sizeof( float ), (void*)0 );

    glEnableVertexAttribArray( 1 );
    glVertexAttribPointer( 1, 2, GL_FLOAT, GL_FALSE, strideFloats * sizeof( float ),
                           (void*)( 3 * sizeof( float ) ) );

    glEnableVertexAttribArray( 2 );
    glVertexAttribPointer( 2, 3, GL_FLOAT, GL_FALSE, strideFloats * sizeof( float ),
                           (void*)( 5 * sizeof( float ) ) );

    glBindVertexArray( 0 );
    return true;
}

bool Mesh::createFromPosTexNormalIndexed ( const std::vector<float>&        data,
                                           const std::vector<unsigned int>& indices ) {
    if( data.empty() || indices.empty() )
        return false;

    const size_t strideFloats = 8;
    mMode                     = GL_TRIANGLES;
    mVertexCount              = static_cast<GLsizei>( data.size() / strideFloats );
    mIndexCount               = static_cast<GLsizei>( indices.size() );

    glGenVertexArrays( 1, &mVAO );
    glGenBuffers( 1, &mVBO );
    glGenBuffers( 1, &mEBO );

    glBindVertexArray( mVAO );
    glBindBuffer( GL_ARRAY_BUFFER, mVBO );
    glBufferData( GL_ARRAY_BUFFER, data.size() * sizeof( float ), data.data(), GL_STATIC_DRAW );

    glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, mEBO );
    glBufferData( GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof( unsigned int ), indices.data(),
                  GL_STATIC_DRAW );

    glEnableVertexAttribArray( 0 );
    glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, strideFloats * sizeof( float ), (void*)0 );

    glEnableVertexAttribArray( 1 );
    glVertexAttribPointer( 1, 2, GL_FLOAT, GL_FALSE, strideFloats * sizeof( float ),
                           (void*)( 3 * sizeof( float ) ) );

    glEnableVertexAttribArray( 2 );
    glVertexAttribPointer( 2, 3, GL_FLOAT, GL_FALSE, strideFloats * sizeof( float ),
                           (void*)( 5 * sizeof( float ) ) );

    glBindVertexArray( 0 );
    return true;
}

void Mesh::draw () const {
    if( mVAO == 0 )
        return;

    glBindVertexArray( mVAO );
    if( mEBO && mIndexCount > 0 ) {
        glDrawElements( mMode, mIndexCount, GL_UNSIGNED_INT, 0 );
    } else {
        glDrawArrays( mMode, 0, mVertexCount );
    }
    glBindVertexArray( 0 );
}

}   // namespace renderer