/**
 * Copyright (C) 2014-2016 Triumph LLC
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
"use strict";

/**
 * Object constraints API. Please note that these constraints are not the same
 * as those assigned in Blender.
 * @module constraints
 * @local StiffViewportPositioning
 */
b4w.module["constraints"] = function(exports, require) {

var m_cam      = require("__camera");
var m_cons     = require("__constraints");
var m_obj_util = require("__obj_util");
var m_phy      = require("__physics");
var m_print    = require("__print");
var m_trans    = require("__transform");

/**
 * An object that defines positioning for the stiff viewport constraint.
 * @typedef {Object} StiffViewportPositioning
 * @property {Number} [left] Offset from the left edge of the camera's viewport
 * @property {Number} [right] Offset from the right edge of the camera's viewport
 * @property {Number} [top] Offset from the top edge of the camera's viewport
 * @property {Number} [bottom] Offset from the bottom edge of the camera's viewport
 * @property {Number} distance Distance from the camera
 * @property {Quat} [rotation] Rotation offset
 * @property {String} [hor_units="widths"] Left/Right offset units: "heights" or "widths"
 * @property {String} [vert_units="heights"] Top/Bottom offset units: "heights" or "widths"
 * @cc_externs left right top bottom distance rotation hor_units vert_units
 */

/**
 * Attach the object to the other object or to the armature bone using a
 * stiff constraint. The child object will move, rotate and scale
 * together with its parent. Examples: a sword is parented to the
 * character's hand; the character is sitting in a vehicle.
 *
 * @method module:constraints.append_stiff
 * @param {Object3D} obj Constrained object
 * @param {(Object3D|Array)} target Target object or [Armature object, Bone Name]
 * @param {Vec3} offset Offset, in the parent's local space.
 * @param {Quat} [rotation_offset=null] Rotation offset, in the
 * parent's local space.
 * @param {Number} [scale_offset=1] Scale offset, in the parent's local space.
 */
exports.append_stiff = function(obj, target, offset, rotation_offset,
        scale_offset) {

    scale_offset = scale_offset || 1;

    if (target instanceof Array && target.length == 2)
        m_cons.append_stiff_bone(obj, target[0], target[1], offset,
                rotation_offset, scale_offset);
    else
        m_cons.append_stiff_obj(obj, target, offset, rotation_offset,
                scale_offset);

    m_trans.update_transform(obj);
    m_phy.sync_transform(obj);
}

/**
 * Attach the object to the other object using a
 * semi-stiff constraint. The child object will move and rotate together with
 * its parent, but it will be still possible to rotate it independently
 * in the parent's local space. Example: a tank turret.
 *
 * @method module:constraints.append_semi_stiff
 * @param {Object3D} obj Constrained object
 * @param {Object3D} target Target object
 * @param {Vec3} offset Offset, in the parent's local space
 * @param {Quat} [rotation_offset] Initial rotation offset, in the
 * parent's local space
 */
exports.append_semi_stiff = function(obj, target, offset, rotation_offset) {
    m_cons.append_semi_stiff_obj(obj, target, offset, rotation_offset);

    m_trans.update_transform(obj);
    m_phy.sync_transform(obj);
}

/**
 * Attach the EYE camera to the object using a
 * semi-stiff constraint. Also apply rotation limits to the camera.
 * The camera will move and rotate together with
 * its parent, but it will be still possible to rotate it independently
 * in the parent's local space. The camera's UP vector will be preserved.
 * Example: first-person vehicle view.
 *
 * @see https://www.blend4web.com/doc/en/camera.html#api
 * @method module:constraints.append_semi_stiff_cam
 * @param {Object3D} obj Constrained object
 * @param {Object3D} target Target object
 * @param {Vec3} offset Offset, in the parent's local space
 * @param {Quat} [rotation_offset] Initial rotation offset, in the
 * parent's local space
 * @param {Number} [clamp_left] Left camera rotation limit, in radians
 * @param {Number} [clamp_right] Right camera rotation limit, in radians
 * @param {Number} [clamp_up] Upward camera rotation limit, in radians
 * @param {Number} [clamp_down] Downward camera rotation limit, in radians
 */
exports.append_semi_stiff_cam = function(obj, target, offset, rotation_offset,
                                            clamp_left, clamp_right,
                                            clamp_up, clamp_down) {
    if (!m_cam.is_eye_camera(obj)) {
        m_print.error("append_semi_stiff_cam(): wrong object type, only EYE" +
            " camera objects can be parented.");
        return;
    }

    clamp_left  = clamp_left  || -Math.PI / 2;
    clamp_right = clamp_right ||  Math.PI / 2;
    clamp_up    = clamp_up    ||  Math.PI / 2;
    clamp_down  = clamp_down  || -Math.PI / 2;

    m_cons.append_semi_stiff_cam_obj(obj, target, offset, rotation_offset,
                                          clamp_left, clamp_right,
                                          clamp_up, clamp_down);
    m_trans.update_transform(obj);
    m_phy.sync_transform(obj);
}

/**
 * Attach the EYE camera to the object using a
 * semi-soft constraint. The camera will smoothly follow the object's rear.
 * Example: third-person character or vehicle views.
 *
 * @method module:constraints.append_semi_soft_cam
 * @param {Object3D} obj Constrained object
 * @param {Object3D} target Target object
 * @param {Vec3} offset Offset, in the parent's local space
 * @param {Number} [softness=0.25] Camera smoothness ratio
 */
exports.append_semi_soft_cam = function(obj, target, offset, softness) {

    if (!m_cam.is_eye_camera(obj)) {
        m_print.error("append_semi_soft_cam(): wrong object type, only EYE" +
            " camera objects can be parented.");
        return;
    }

    if (!softness || softness < 0)
        softness = 0.25;

    m_cons.append_semi_soft_cam_obj(obj, target, offset, softness);

    m_trans.update_transform(obj);
    m_phy.sync_transform(obj);
}

/**
 * Attach the object to the other object using a
 * stiff translation constraint. The child object will move together with
 * its parent, but will not rotate. It will be still possible to rotate it
 * independently from the parent.
 *
 * Example: attaching the camera to the physics character in order to
 * implement the first-person character view. Another example: the character
 * jumps in water and splashes' particle emitter is attached to the
 * first-person camera using this constraint - the bubbles will follow the
 * character but will not be rotated with the camera.
 *
 * @method module:constraints.append_stiff_trans
 * @param {Object3D} obj Constrained object
 * @param {Object3D} target Target object
 * @param {Vec3} offset Offset, in the parent's local space
 */
exports.append_stiff_trans = function(obj, target, offset) {
    m_cons.append_stiff_trans_obj(obj, target, offset);

    m_trans.update_transform(obj);
    m_phy.sync_transform(obj);
}

/**
 * Attach the object to the other object using a copy translation constraint.
 * The child object will move together with its parent, but will not rotate.
 * Note that the offset is specified in the world space.
 * Example: a light source attached to the character.
 *
 * @method module:constraints.append_copy_trans
 * @param {Object3D} obj Constrained object
 * @param {Object3D} target Target object
 * @param {Vec3} offset Offset, in the parent's world space
 */
exports.append_copy_trans = function(obj, target, offset) {
    m_cons.append_copy_trans_obj(obj, target, offset);

    m_trans.update_transform(obj);
    m_phy.sync_transform(obj);
}

/**
 * Attach the object to the other object using a
 * stiff translation/rotation constraint. The child object will move and rotate
 * together with its parent, but will not scale. It will be still possible to
 * scale it independently from the parent.
 *
 * Example: smoke emitter attached to the tractor pipe; exhaustion effects
 * are achieved by scaling the emitter.
 *
 * @method module:constraints.append_stiff_trans_rot
 * @param {Object3D} obj Constrained object
 * @param {Object3D} target Target object
 * @param {Vec3} offset Offset, in the parent's local space
 * @param {Quat} [rotation_offset] Rotation offset, in
 * the parent's local space
 */
exports.append_stiff_trans_rot = function(obj, target, offset, rotation_offset) {
    m_cons.append_stiff_trans_rot_obj(obj, target, offset, rotation_offset, 1.0);

    m_trans.update_transform(obj);
    m_phy.sync_transform(obj);
}

/**
 * Make the object "looking" at the target object or the position. The object's
 * facing direction is considered to be the -Z axis that is vertically
 * downwards.
 *
 * Example: a spot light which is tracking the character; both objects can be
 * moved via API or animated.
 *
 * @method module:constraints.append_track
 * @param {Object3D} obj Constrained object
 * @param {(Object3D|Vec3)} target Target object or position vector
 */
exports.append_track = function(obj, target) {
    if (target.length == 3)
        m_cons.append_track_point(obj, target);
    else
        m_cons.append_track_obj(obj, target);

    m_trans.update_transform(obj);
    m_phy.sync_transform(obj);
}

/**
 * Attach the object to the other object using a follow constraint. The child
 * object will track and follow its parent position.
 *
 * Example: a follow-style camera view for the character.
 *
 * @method module:constraints.append_follow
 * @param {Object3D} obj Constrained object
 * @param {(Object3D|Vec3)} target Target object or position vector
 * @param {Number} dist_min Minimum distance
 * @param {Number} dist_max Maximum distance
 */
exports.append_follow = function(obj, target, dist_min, dist_max) {

    if (target.length == 3)
        m_cons.append_follow_point(obj, target, dist_min, dist_max);
    else
        m_cons.append_follow_obj(obj, target, dist_min, dist_max);

    m_trans.update_transform(obj);
    m_phy.sync_transform(obj);
}

/**
 * Attach the object to the camera using a stiff vieport constraint, so
 * the child object will preserve its orientation in the camera viewport.
 * This constraint is used to create onscreen 2D/3D user interfaces.
 * @method module:constraints.append_stiff_viewport
 * @param {Object3D} obj Constrained object
 * @param {Object3D} camobj Camera object
 * @param {StiffViewportPositioning} positioning Positioning
 */
exports.append_stiff_viewport = function(obj, camobj, positioning) {
    m_cons.append_stiff_viewport(obj, camobj, positioning);

    m_trans.update_transform(obj);
    m_phy.sync_transform(obj);
}

/**
 * Remove the object's constraint (if any).
 * @method module:constraints.remove
 * @param {Object3D} obj Constrained object
 */
exports.remove = function(obj) {
    if (obj.constraint)
        m_cons.remove(obj);
}

/**
 * Get object's parent object.
 * @method module:constraints.get_parent
 * @param {Object3D} obj Object
 * @returns {?Object3D} Parent object
 * @deprecated use {@link module:objects.get_parent|objects.get_parent} instead.
 */
exports.get_parent = function(obj) {
    m_print.error_deprecated("constraints.get_parent", "objects.get_parent");
    return m_obj_util.get_parent(obj);
}

}