using UnityEngine;
using System.Collections;

namespace Uniblocks {

public class FallingBlockEvents : DefaultVoxelEvents {


    public override void OnBlockPlace ( VoxelInfo voxelInfo ) {

        // if the block below is empty, make this block fall
        Index indexBelow = new Index (voxelInfo.index.x, voxelInfo.index.y-1, voxelInfo.index.z); // get index below

        if ( voxelInfo.chunk.GetVoxel(indexBelow) == 0 ) { // check if the block below is empty

            FallingBlockEvents fallCoroutine = Engine.EngineInstance.gameObject.AddComponent <FallingBlockEvents>(); // create a new object to run the coroutine
            fallCoroutine.DropBlock (voxelInfo); // run the coroutine on the new object

        }

    }

    public override void OnBlockDestroy ( VoxelInfo voxelInfo ) {

        // if the block above is a falling block, make it fall (because the currrent block below it is now empty)
        Index indexAbove = new Index (voxelInfo.index.x, voxelInfo.index.y+1, voxelInfo.index.z); // get index above
        ushort voxelAbove = voxelInfo.chunk.GetVoxel(indexAbove); // get voxel above

        if (Engine.GetVoxelGameObject(voxelAbove).GetComponent<FallingBlockEvents>() != null) { // if the block above has a FallingBlockEvents component

            VoxelInfo blockAbove = new VoxelInfo (indexAbove, voxelInfo.chunk); // create a VoxelInfo pointing to the block above
            FallingBlockEvents fallCoroutine = Engine.EngineInstance.gameObject.AddComponent <FallingBlockEvents>(); // create a new object to run the coroutine
            fallCoroutine.DropBlock (blockAbove); // run the coroutine on the new object
        }

    }


    public void DropBlock (VoxelInfo voxelInfo) {
        StartCoroutine (DoDropBlock (voxelInfo));
    }

    private IEnumerator DoDropBlock ( VoxelInfo voxelInfo ) {

        Index indexBelow = new Index (voxelInfo.index.x, voxelInfo.index.y-1, voxelInfo.index.z); // get index below
        VoxelInfo blockBelow = new VoxelInfo (indexBelow, voxelInfo.chunk); // create a VoxelInfo pointing to the block below

        yield return new WaitForSeconds (0.1f); // wait before falling

        Voxel.PlaceBlock (blockBelow, voxelInfo.GetVoxel()); // place the block below using PlaceBlock. This will trigger OnBlockPlace function again at the new position
        Voxel.DestroyBlock (voxelInfo); // destroy the block above. This will trigger OnBlockDestroy on the falling block to check if there is another falling block above.

        Destroy (this); // we only needed the object to run the coroutine, so we can get rid of it now

    }


}

}