extern crate calamine;
extern crate lazy_static;
extern crate rustler;

use calamine::Error as CaError;
use calamine::{open_workbook_auto, Reader};

rustler::init!("Elixir.Xler.Native");
mod atoms {
    rustler::atoms! {
        ok,
        error,

        // Posix
        enoent, // File does not exist
        eacces, // Permission denied
        epipe,  // Broken pipe
        eexist, // File exists
    }
}

type Sheet = Vec<Vec<String>>;
type SheetName = String;
type Worksheets = Vec<SheetName>;

fn io_error_to_term(err: &CaError) -> String {
    let error = match err {
        _ => format!("{}", err),
    };

    error
}

#[rustler::nif(schedule = "DirtyCpu")]
fn worksheets(filename: String) -> Result<Worksheets, String> {
    match open_workbook_auto(&filename) {
        Err(ref error) => Err(io_error_to_term(error)),
        Ok(ref inner) => Ok(inner.sheet_names().to_owned()),
    }
}

#[rustler::nif(schedule = "DirtyCpu")]
fn parse(filename: String, sheetname: SheetName) -> Result<Sheet, String> {
    let mut excel = match open_workbook_auto(&filename) {
        Err(ref error) => return Err(io_error_to_term(error)),
        Ok(inner) => inner,
    };

    if let Ok(range) = excel.worksheet_range(&sheetname) {
        let row: Sheet = range
            .rows()
            .into_iter()
            .enumerate()
            .map(|(_i, col)| col.iter().map(|c| c.to_string()).collect::<Vec<_>>())
            .collect::<Vec<_>>();

        Ok(row)
    } else {
        Err("Couldnt find the worksheet".to_string())
    }
}