#ifndef WORLD_LADDER_H
#define WORLD_LADDER_H

/*
 * The telescopic ladder.
 *
 * Carried in one hand at the side. It slides out for use and together for
 * carrying and storing. It leans against anything that would hold it: solid
 * (a wall, the car, a tree, not a bush), high enough, with level ground and
 * room for its feet. The top rests on the edge (the gutter of a roof); too
 * short for that, it leans against the face and you can't get off at the top.
 * A leaning ladder stands still; people climb it rung by rung. How steady it
 * stands (angle, ground, what it leans on) decides if it slips when climbed;
 * somebody holding it keeps it steady. Stood up on its own it falls over.
 */

#include "world/world.h"

/* Slides it out or together (it takes a moment). */
void        Ladder_slide(Object *ladder);
/* Slid out this far (0..1) right away: mesh and collider too. */
void        Ladder_setExtend(Object *ladder, float extend);
/* Eases the sliding along, rebuilding mesh and collider as it goes. */
void        Ladder_update(World *world, Object *ladder, float dt); /* (world: what it falls against; may be NULL) */

#define LADDER_FOLDING 1 /* variant: two sections on a hinge (unfolds); 0: telescopic (slides out) */
#define LADDER_STEP    2 /* variant: a step ladder (opens and stands on its own) */

enum { LEAN_NOTHING, LEAN_DONE, LEAN_NO };
/* Leans the ladder who carries against what's right in front. LEAN_NO sets why.
   fit: slides it out as far as it takes (over the edge a bit) first. */
int         Ladder_lean(World *world, Object *who, Object *ladder, bool fit, const char **why);
/* A leaning ladder who can get on: at its foot, or (from up there) at its top. */
Object     *Ladder_near(const World *world, const Object *who, bool *at_top);
/* Takes a leaning ladder down into a free hand. */
bool        Ladder_take(Object *who, Object *ladder);

/* Gets on at the bottom or at the top. */
void        Ladder_mount(Object *who, Object *ladder, bool at_top);
enum { CLIMB_ON, CLIMB_OFF_BOTTOM, CLIMB_AT_EDGE };
/* On it right away this far up (a game loaded): hands and feet straight onto the rungs. */
void        Ladder_mountAt(Object *who, Object *ladder, float at);
/* Climbing up (input > 0) or down. CLIMB_AT_EDGE: at the top, wanting over the edge. */
int         Ladder_climb(Object *who, float input, float dt);
/* Lets go of the ladder (on the ground at its foot, or handed over to a climb). */
void        Ladder_getOff(Object *who);
/* Where the top rests (on the edge), and the way over it (horizontal, away from the ladder). */
Vec3        Ladder_edge(const Object *ladder);

/* How steady it stands now (0..1): its own stability, or 1 with somebody holding it. */
float       Ladder_steadiness(const Object *ladder);
/* It falls over (away the way dir points, horizontal); anybody on it comes off. */
void        Ladder_topple(World *world, Object *ladder, Vec3 dir);
/* Holding it steady at its foot (both hands on the rails, a foot on the bottom rung), or not (NULL). */
void        Ladder_hold(Object *who, Object *ladder);
/* Where somebody stands to hold it (beside its foot, out of the climber's way), and which way they face. */
Vec3        Ladder_holdSpot(const Object *ladder, Vec3 *facing);

/* Climbing: hands on the rungs (after Hands_update) and feet on them (after Body_update);
   holding it: hands on the rails, a foot on the bottom rung. */
void        Ladder_poseHands(Object *who, float dt);
void        Ladder_poseFeet(Object *who, float dt);
/* Slid out and in hand: held near its foot, reaching up in front (steeper looking up). */
bool        Ladder_isRaised(const Object *ladder);
Vec3        Ladder_raisedGrip(const Object *ladder, float along);
/* Carried at the side, on edge; slid out, raised. */
void        Ladder_placeHeld(Object *who, int hand, Object *ladder);

#endif /* WORLD_LADDER_H */