#ifndef GROUND_EXT_H
#define GROUND_EXT_H

#include "groundvm.h"

#ifdef __cplusplus
extern "C" {
#endif

// Macro for easily returning errors
#define ERROR(what, type) return createErrorGroundValue(createGroundError(what, type, NULL, NULL))

// Forward declaration of the scope structure used in interpreter
struct GroundScope;
typedef struct GroundScope GroundScope;

/*
 * Stores data associated with an error thrown during Ground execution.
 */
typedef struct GroundError {
    char* what;
    char* type;
    struct GroundInstruction* where;
    size_t line;
    bool hasLine;
} GroundError;

// Creates a GroundValue containing (in), with type ERROR.
GroundValue createErrorGroundValue(GroundError in);

// Creates a GroundError.
GroundError createGroundError(char* what, char* type, GroundInstruction* where, size_t* line);

/*
 * Function pointer type for native functions.
 * scope: The current execution scope (opaque).
 * args: A List of arguments passed to the function.
 */
typedef GroundValue (*NativeGroundFunction)(GroundScope* scope, List args);

/*
 * Registers a native function in the given scope.
 * 
 * scope: The scope to register the function in.
 * name: The name of the function in Ground.
 * fn: The C function to call.
 * returnType: The return type of the function.
 * argCount: The number of arguments the function expects.
 * ...: A sequence of (GroundValueType type, char* name) for each argument.
 */
void groundAddNativeFunction(GroundScope* scope, char* name, NativeGroundFunction fn, GroundValueType returnType, int argCount, ...);

#ifdef __cplusplus
}
#endif

#endif