#ifndef CKIWI_H_
#define CKIWI_H_

#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

#define KIWI_REF_ISNULL(ref) ((ref).impl_ == NULL)

// LuaJIT start
enum KiwiErrKind {
   KiwiErrNone,
   KiwiErrUnsatisfiableConstraint = 1,
   KiwiErrUnknownConstraint,
   KiwiErrDuplicateConstraint,
   KiwiErrUnknownEditVariable,
   KiwiErrDuplicateEditVariable,
   KiwiErrBadRequiredStrength,
   KiwiErrInternalSolverError,
   KiwiErrAlloc,
   KiwiErrUnknown,
};

enum KiwiRelOp { KIWI_OP_LE, KIWI_OP_GE, KIWI_OP_EQ };

typedef struct {
   void* private_;
} KiwiVarRef;

typedef struct {
   KiwiVarRef var;
   double coefficient;
} KiwiTerm;

typedef struct {
   double constant;
   int term_count;
   KiwiTerm terms[1];
} KiwiExpression;

typedef struct {
   void* private_;
} KiwiConstraintRef;

typedef struct {
   enum KiwiErrKind kind;
   char message[64];
} KiwiErr;

typedef struct {
   void* impl_;
} KiwiSolverRef;

KiwiVarRef kiwi_var_new(const char* name);
void kiwi_var_del(KiwiVarRef var);

const char* kiwi_var_name(KiwiVarRef var);

void kiwi_var_set_name(KiwiVarRef var, const char* name);

double kiwi_var_value(KiwiVarRef var);

void kiwi_var_set_value(KiwiVarRef var, double value);

int kiwi_var_eq(KiwiVarRef var, KiwiVarRef other);

KiwiConstraintRef
kiwi_constraint_new(const KiwiExpression* expression, enum KiwiRelOp op, double strength);
void kiwi_constraint_del(KiwiConstraintRef constraint);

double kiwi_constraint_strength(KiwiConstraintRef constraint);

enum KiwiRelOp kiwi_constraint_op(KiwiConstraintRef constraint);

int kiwi_constraint_violated(KiwiConstraintRef constraint);

int kiwi_constraint_expression(
    KiwiConstraintRef constraint,
    KiwiExpression* out,
    int out_size
);

KiwiErr kiwi_solver_add_constraint(KiwiSolverRef s, KiwiConstraintRef constraint);

KiwiErr kiwi_solver_remove_constraint(KiwiSolverRef s, KiwiConstraintRef constraint);

int kiwi_solver_has_constraint(KiwiSolverRef s, KiwiConstraintRef constraint);

KiwiErr kiwi_solver_add_edit_var(KiwiSolverRef s, KiwiVarRef var, double strength);

KiwiErr kiwi_solver_remove_edit_var(KiwiSolverRef s, KiwiVarRef var);

int kiwi_solver_has_edit_var(KiwiSolverRef s, KiwiVarRef var);

KiwiErr kiwi_solver_suggest_value(KiwiSolverRef s, KiwiVarRef var, double value);

void kiwi_solver_update_vars(KiwiSolverRef s);

void kiwi_solver_reset(KiwiSolverRef s);

void kiwi_solver_dump(KiwiSolverRef s);

char* kiwi_solver_dumps(KiwiSolverRef s, void* (*alloc)(size_t));

KiwiSolverRef kiwi_solver_new();
void kiwi_solver_del(KiwiSolverRef s);
// LuaJIT end

#ifdef __cplusplus
}
#endif

// Local Variables:
// mode: c++
// End:
#endif  // CKIWI_H_