#ifndef MODXML_SAX_PROCESSOR_HH
#define MODXML_SAX_PROCESSOR_HH

#include <memory>
#include <span>

namespace modxml {
namespace sax {

class Delegate;

/**
 * The XML processor, or parser if you like that term better.
 * Feed it data and the processor will give the delegate calls with events or
 * possibly errors.
 */
class Processor {
 public:
  virtual ~Processor() = default;

  /**
   * Construct a Processor. Same as creating a ProcessorBuilder
   * and not changing any options and just calling build.
   */
  static std::unique_ptr<Processor> create(std::shared_ptr<Delegate> delegate);

  /**
   * Process (consume) input data.
   * Returns bytes consumed, can be zero.
   */
  virtual std::size_t process(std::span<uint8_t const> data,
                              std::size_t offset = 0) = 0;

  /**
   * When called from delegate, points to the start of the element that
   * triggered the callback.
   * When called otherwise, points to the last element that was processed.
   * Lines start at 1.
   * Columns start at 0.
   */
  virtual uint64_t line() const = 0;
  virtual uint64_t column() const = 0;

 protected:
  Processor() = default;

 private:
  Processor(Processor const&) = delete;
  Processor& operator=(Processor const&) = delete;
};

}  // namespace sax
}  // namespace modxml

#endif  // MODXML_SAX_PROCESSOR_HH