delete_ghost_triangles.jl

"""
    delete_ghost_triangles!(tri::Triangulation)

Deletes all the ghost triangles from `tri`.

!!! warning "Ghost vertices"

    Ghost vertices are still used in the `keys` of the [`Adjacent2Vertex`](@ref)
    of `tri`, and are still present in the [`Graph`](@ref). If you want to delete the
    ghost vertex `keys` from the [`Adjacent2Vertex`](@ref), you need to use
    [`delete_adjacent2vertex!`](@ref). For deleting the ghost vertices from the
    [`Graph`](@ref), you need [`delete_ghost_vertices_from_graph!`](@ref). Additionally,
    edges in [`Adjacent`](@ref) can still map to ghost vertices. If you also want to delete
    those, you need to filter through the `values` of the [`Adjacent`](@ref) map
    that are ghost vertices, and use [`delete_adjacent!`](@ref).
"""
function delete_ghost_triangles!(tri::Triangulation)
    T = get_triangles(tri)
    for g in each_ghost_vertex(tri)
        for uv in (each_edge ∘ get_adjacent2vertex)(tri, g)
            u, v = edge_vertices(uv)
            delete_adjacent!(tri, v, g)
            delete_adjacent!(tri, g, u)
            delete_adjacent2vertex!(tri, u, v, g)
            delete_adjacent2vertex!(tri, v, g, u)
            delete_triangle!(T, u, v, g)
        end
    end
    empty!(get_boundary_vertex_to_ghost(tri))
    set_has_ghosts!(tri, false)
    return tri
end