#pragma once

#include "GLFunctions.hpp"

#include <glm/glm.hpp>
#include <string>

namespace planetarium {

// -----------------------------------------------------------------------
// Shader
//
// Thin RAII wrapper around a linked OpenGL program object, compiled from
// a vertex + fragment shader pair loaded from disk.
// -----------------------------------------------------------------------
class Shader {
public:
    Shader() = default;
    ~Shader();

    Shader(const Shader&) = delete;
    Shader& operator=(const Shader&) = delete;
    Shader(Shader&& other) noexcept;
    Shader& operator=(Shader&& other) noexcept;

    // Compiles and links the program. Returns false (and logs to stderr)
    // on failure; the shader remains unusable but the caller can continue
    // running with a null program.
    bool loadFromFiles(const std::string& vertexPath, const std::string& fragmentPath);

    void use() const;
    GLuint id() const { return program_; }

    void setMat4(const std::string& name, const glm::mat4& m) const;
    void setVec3(const std::string& name, const glm::vec3& v) const;
    void setVec4(const std::string& name, const glm::vec4& v) const;
    void setFloat(const std::string& name, float f) const;
    void setInt(const std::string& name, int i) const;

private:
    GLuint program_ = 0;
    GLint locationOf(const std::string& name) const;
};

}  // namespace planetarium