use std::fmt;

use super::csc::CscMatrix;

/// COOrdinate format (aka IJV, triplet format)
#[derive(Clone, PartialEq, Eq)]
pub struct CooMatrix<T> {
    shape: (usize, usize),
    data: Vec<T>,
    row: Vec<usize>,        // COO format row index array of the matrix
    col: Vec<usize>         // COO format column index array of the matrix
}

impl<T: Copy> CooMatrix<T> {
    pub fn new(shape: (usize,usize), data: Vec<T>, ij: Vec<(usize,usize)>) -> Self {
        CooMatrix {
            shape: shape,
            data: data,
            row: ij.iter().map(|&(row,_col)| row).collect(),
            col: ij.iter().map(|&(_row,col)| col).collect()
        }
    }

    pub fn empty(shape: (usize,usize)) -> Self {
        CooMatrix {
            shape: shape,
            data: vec![],
            row: vec![],
            col: vec![]
        }
    }

    pub fn nnz(&self) -> usize {
        self.data.len()
    }

    pub fn shape(&self) -> (usize,usize) {
        self.shape
    }

    // converstion
    pub fn to_bsr(&self) -> () {
        unimplemented!()
    }

    pub fn to_coo(&self) -> Self {
        self.clone()
    }

    pub fn to_csc(&self) -> CscMatrix<T> {
        unimplemented!()
    }
}


impl<T: fmt::Display> fmt::Display for CooMatrix<T> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        for i in 0 .. self.data.len() {
            try!(writeln!(f, "  {:?}\t{}", (self.row[i], self.col[i]), self.data[i]));
        }
        Ok(())
    }
}

#[test]
fn test_coo() {

}