//! This module contains the FaceVertex struct.

use std::fmt;

#[derive(Copy, Clone, PartialEq)]
/// The indices needed for each vertex of a face.
pub struct FaceVertex {

    /// The index of the vertex.
    pub vertex: usize,

    /// The index of the texture coordinate, None if there is no texture coordinate.
    pub texture_coordinate: Option<usize>,

    /// The index of the normal, None if there is no normal.
    pub normal: Option<usize>,
}

impl FaceVertex {

    /// Creates a new face vertex from its attributes.
    pub fn new(vertex: usize, texture_coordinate: Option<usize>, normal: Option<usize>) -> FaceVertex {
        FaceVertex {
            vertex: vertex,
            texture_coordinate: texture_coordinate,
            normal: normal,
        }
    }

}

impl fmt::Debug for FaceVertex {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {

        let texture_coordinate = if let Some(tc) = self.texture_coordinate {
            tc.to_string()
        } else {
            "".to_owned()
        };

        let normal = if let Some(n) = self.normal {
            n.to_string()
        } else {
            "".to_owned()
        };

        write!(formatter, "{}/{}/{}", self.vertex, texture_coordinate, normal)
    }
}