/**
 * TODO file description
 *
 * Created on 2021/11/21.
 */

#ifndef FORTH_FH_INPUT_H
#define FORTH_FH_INPUT_H

struct fh_thread_s;
struct fh_input_spec_s;

/** Refill the input buffer, returns false on failure / EOF */
typedef bool (*fh_input_refill_t)(struct fh_thread_s *fh, struct fh_input_spec_s *spec);
/** Spec free func */
typedef void (*fh_input_free_t)(void *spec);

typedef void (*fh_input_void_method_t)(struct fh_thread_s *fh, struct fh_input_spec_s *spec);

typedef enum fh_error (*fh_input_error_method_t)(struct fh_thread_s *fh, struct fh_input_spec_s *spec);

struct fh_input_spec_s {
  struct fh_input_spec_s *previous;
  fh_input_refill_t refill_input_buffer;
  fh_input_void_method_t start;
  fh_input_free_t free_self;
  fh_input_void_method_t push_prepare;
  fh_input_void_method_t pop_restore;
  fh_input_error_method_t save_input;
  fh_input_error_method_t restore_input;
  uint32_t linenum;
  int32_t source_id;
  char *cwd; // CWD of the input, used for relative includes. malloc'd (strdup)

  // saved values, filled when pushing
  uint32_t saved_inputaddr;
  uint32_t saved_inputptr;
  uint32_t saved_inputlen;
  uint32_t saved_execptr;
  enum fh_state saved_state;
};

/**
 * Push current input spec and state, replace with new one
 */
enum fh_error fh_push_input(struct fh_thread_s *fh, struct fh_input_spec_s *newinput);

/**
 * Discard current input spec, restore previous.
 * fh->input will be NULL if this was the topmost one
 */
enum fh_error fh_pop_input(struct fh_thread_s *fh);

struct fh_input_spec_s *fh_create_input_from_filename(char *path);
struct fh_input_spec_s *fh_create_input_from_filestruct(FILE *f, const char *path);
struct fh_input_spec_s *fh_create_input_from_string(char *str, size_t len, const char *cwd); // cwd is strduped.
void fh_input_teardown(struct fh_thread_s *fh);

#endif //FORTH_FH_INPUT_H