use std::ops::{Index, IndexMut};

pub struct Edge {
    pub vertex1_index: usize,
    pub vertex2_index: usize,
    pub length: f64,
    pub ferment_intensity: f64,
}

enum EdgeCell {
    Free { next_free_cell_id: Option<usize> },
    Value { data: Edge },
}

pub struct EdgesVec {
    storage: Vec<EdgeCell>,
}

impl EdgesVec {
    pub fn new() -> Self {
        return Self {
            storage: Vec::new(),
        };
    }
}

impl Index<usize> for EdgesVec {
    type Output = Edge;

    fn index(&self, index: usize) -> &Self::Output {
        match self.storage.get(index).expect("Edge index out of bounds") {
            EdgeCell::Free { .. } => panic!("Referenced edge doesn't exists"),
            EdgeCell::Value { data } => return data,
        }
    }
}

impl IndexMut<usize> for EdgesVec {
    fn index_mut(&mut self, index: usize) -> &mut Self::Output {
        match self
            .storage
            .get_mut(index)
            .expect("Edge index out of bounds")
        {
            EdgeCell::Free { .. } => panic!("Referenced edge doesn't exists"),
            EdgeCell::Value { data } => return data,
        }
    }
}