#ifndef KIWI_CKIWI_H_
#define KIWI_CKIWI_H_

#ifdef __cplusplus
extern "C" {
#else
   #include <stdbool.h>
#endif

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

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

enum KiwiRelOp { KIWI_OP_LE, KIWI_OP_GE, KIWI_OP_EQ };

typedef struct KiwiVarRefType* KiwiVarRef;
typedef struct KiwiConstraintRefType* KiwiConstraintRef;

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

typedef struct KiwiExpression {
   double constant;
   int term_count;
   KiwiTerm terms[1];  // LuaJIT: struct KiwiTerm terms_[?];
} KiwiExpression;

typedef struct KiwiErr {
   enum KiwiErrKind kind;
   const char* message;
   bool must_free;
} KiwiErr;

typedef struct KiwiSolver KiwiSolver;

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

void kiwi_expression_del_vars(KiwiExpression* expr);

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

double kiwi_constraint_strength(KiwiConstraintRef constraint);
enum KiwiRelOp kiwi_constraint_op(KiwiConstraintRef constraint);
bool kiwi_constraint_violated(KiwiConstraintRef constraint);
int kiwi_constraint_expression(KiwiConstraintRef constraint, KiwiExpression* out, int out_size);

KiwiSolver* kiwi_solver_new();
void kiwi_solver_del(KiwiSolver* sp);

const KiwiErr* kiwi_solver_add_constraint(KiwiSolver* sp, KiwiConstraintRef constraint);
const KiwiErr* kiwi_solver_remove_constraint(KiwiSolver* sp, KiwiConstraintRef constraint);
bool kiwi_solver_has_constraint(const KiwiSolver* sp, KiwiConstraintRef constraint);
const KiwiErr* kiwi_solver_add_edit_var(KiwiSolver* sp, KiwiVarRef var, double strength);
const KiwiErr* kiwi_solver_remove_edit_var(KiwiSolver* sp, KiwiVarRef var);
bool kiwi_solver_has_edit_var(const KiwiSolver* sp, KiwiVarRef var);
const KiwiErr* kiwi_solver_suggest_value(KiwiSolver* sp, KiwiVarRef var, double value);
void kiwi_solver_update_vars(KiwiSolver* sp);
void kiwi_solver_reset(KiwiSolver* sp);
void kiwi_solver_dump(const KiwiSolver* sp);
char* kiwi_solver_dumps(const KiwiSolver* sp);

// LuaJIT end

#ifdef __cplusplus
}
#endif

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