#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# Script to ...
#
# Minimally tested.  Seems to work.  Use at your own risk.
#
# By James Eagan <james.eagan@telecom-paris.fr>
# https://james.eagan.fr

import pandas as pd
import re

skipCols = ['SID', 'Email', 'Submission ID', 'Submission Time', 
            'Lateness (H:M:S)', 'View Count', 'Submission Count',
           ]

def readCSV(fileName):
    cols = list(pd.read_csv(fileName, nrows=1))
    keepCols = [col for col in cols if col not in skipCols]
    
    df = pd.read_csv(fileName, usecols=keepCols)
    df = df.sort_values(by='Nom')
    return df

pattern = re.compile(r'(\d+\.?\d*): (.+) \((\d+\.\d*) pts\)')
def massageHeaders(df, args):
    multiHeaders = [[], [], []]

    for header in df.columns:
        match = pattern.match(header)
        if match:
            # Question in the form: '11.4: types d'attributs (variables) (1.0 pts)'
            multiHeaders[0].append('Q' + match.group(1)) # Q1, Q2, Q3.1, Q3.2, etc
            multiHeaders[1].append(match.group(2)) # Question label
            multiHeaders[2].append(float(match.group(3))) # Question points (e.g. 1, 2, 1.5)
        else:
            multiHeaders[0].append('')
            multiHeaders[1].append('')
            multiHeaders[2].append(header)

    df.columns = pd.MultiIndex.from_arrays(multiHeaders)
    return df

def writeExcel(df, fileName):
    with pd.ExcelWriter(fileName) as writer:
        df.to_excel(writer)
#     with open(basename + "-out.csv", 'w') as writer:
#         writer.write(df.to_csv())

if __name__ == '__main__':
    import argparse
    import sys
    
    def parse_args():
        parser = argparse.ArgumentParser(description="Massage Gradescope data")
        parser.add_argument("csv", help="csv file as exported from Gradescope")
        parser.add_argument("-o", "--out", help="file to write output")
        group = parser.add_mutually_exclusive_group()
        group.add_argument("-,", "--commas", help="use commas for decimal separator", action="store_true")
        group.add_argument("-.", "--dots", help="use dots for decimal separator", action="store_true")
        group.add_argument("-d", "--decimal-separator", help="decimal separator for real numbers", default=",")
        parser.add_argument("-s", "--sep", help="csv column separator (default: ',' when decimal separator is '.' and ';' for ',')")

        args = parser.parse_args()
        if args.commas:
            args.decimal_separator = ","
        elif args.dots:
            args.decimal_separator = "."
        
        if not args.sep:
            args.sep = ';' if args.decimal_separator == ',' else ','
            
        return args
    
    def writeOutput(df, args):
        if args.out:
            writeExcel(df, args.out)
        else :
            df.to_csv(sys.stdout, sep=args.sep, decimal=args.decimal_separator)
    
    def nowDoIt():
        args = parse_args()
        df = readCSV(args.csv)
        massageHeaders(df, args)
        writeOutput(df, args)

    nowDoIt()