use itertools::Itertools;

struct MyRow {
    name: String,
    value: i32,
}

struct Column<'call, R> {
    _name: String,
    value_fn: &'call Fn(&R) -> String,
}


pub trait RenderColumn<R> {
    fn name(&self) -> String;
    fn get_value(&self, row: &R) -> String;
}

impl<'call, R> RenderColumn<R> for Column<'call, R> {
    fn name(&self) -> String {
        self._name.clone()
    }

    fn get_value(&self, row: &R) -> String {
        let fun = self.value_fn;
        fun(row)
    }
}

pub trait AsTable<R>  {
    fn as_table<C: RenderColumn<R>>(&self, columns: &[C]) -> String;
}

impl<T> AsTable<T> for Vec<T> {
    fn as_table<RowSpec>(&self, columns: &[RowSpec]) -> String
        where RowSpec: RenderColumn<T>
    {
        let headings = columns.iter().map(|c| c.name()).join(", ");

        let rows = self.iter().map(|row|
            columns.iter().map(|column| column.get_value(&row))
            .join(", ")
        );
        std::iter::once(headings).chain(rows).join("\n")
    }
}

fn main() {

    let data = vec![
        MyRow { name: "foo".to_owned(), value: 123 },
        MyRow { name: "bar".to_owned(), value: 465 },
        MyRow { name: "baz".to_owned(), value: 890 },
    ];


    let table = data.as_table(&vec![
        Column{ _name: "first".to_owned(), value_fn: &(|row: &MyRow| row.name.clone()) },
        Column{ _name: "second".to_owned(), value_fn: &(|row: &MyRow| format!("{}", row.value)) }
    ]);

    println!("{}", table);

}