using System.Collections.Generic;
using FarseerPhysics.Collision.Shapes;
using FarseerPhysics.Common;
using FarseerPhysics.Dynamics;
using Vortex.Drawing;

namespace FarseerPhysics.Factories
{
    public static class LinkFactory
    {
        /// <summary>
        /// Creates a chain.
        /// </summary>
        /// <param name="world">The world.</param>
        /// <param name="start">The start.</param>
        /// <param name="end">The end.</param>
        /// <param name="linkWidth">The width.</param>
        /// <param name="linkHeight">The height.</param>
        /// <param name="fixStart">if set to <c>true</c> [fix start].</param>
        /// <param name="fixEnd">if set to <c>true</c> [fix end].</param>
        /// <param name="numberOfLinks">The number of links.</param>
        /// <param name="linkDensity">The link density.</param>
        /// <returns></returns>
        public static Path CreateChain(World world, Vector2 start, Vector2 end, float linkWidth, float linkHeight, bool fixStart, bool fixEnd, int numberOfLinks, float linkDensity)
        {
            //Chain start / end
            Path path = new Path();
            path.Add(start);
            path.Add(end);

            //A single chainlink
            PolygonShape shape = new PolygonShape(PolygonTools.CreateRectangle(linkWidth, linkHeight));

            //Use PathManager to create all the chainlinks based on the chainlink created before.
            List<Body> chainLinks = PathManager.EvenlyDistibuteShapesAlongPath(world, path, shape, BodyType.Dynamic, numberOfLinks, linkDensity);

            if (fixStart)
            {
                //Fix the first chainlink to the world
                JointFactory.CreateFixedRevoluteJoint(world, chainLinks[0], new Vector2(0, -(linkHeight / 2)), chainLinks[0].Position);
            }

            if (fixEnd)
            {
                //Fix the last chainlink to the world
                JointFactory.CreateFixedRevoluteJoint(world, chainLinks[chainLinks.Count - 1], new Vector2(0, (linkHeight / 2)), chainLinks[chainLinks.Count - 1].Position);
            }

            //Attach all the chainlinks together with a revolute joint
            PathManager.AttachBodiesWithRevoluteJoint(world, chainLinks, new Vector2(0, -linkHeight), new Vector2(0, linkHeight),
                                                      false, false);

            return (path);
        }
    }
}