Canvas grading

grade.py

"""
An interactive CLI script for entering grades on Canvas (an LMS).
Python 3.6+

Usage:
1. Export the CSV file with Canvas
2. Modify the file with this script
3. Import the modified file to Canvas

Tip: use rlwrap.

Author: Linghan Zhang
Date: Feb 2018
"""

import sys
assert sys.version_info >= (3, 0)

import csv
import io
import bisect


class Grader(object):
    WELCOME = '##### Canvas Grader #####'
    TOP_MENU = '\n'.join([
        '(TOP)',
        'exit',
        'help',
        'load <fname>: load data from CSV file',
        'save <fname>: save data to CSV file',
        'print: print data',
        'cols: list columns',
        'list [<name>...]: filter and list students and their grades',
        'col [<num>]: get or set the current column',
        'grade: enter GRADE mode to set grades one by one',
        'selmake: enter SEL mode to make a selection of students',
        'sel: print the current selection',
        'selclear: clear the selection',
        'selset <grade>: set grade for all selected students'
    ])
    GRADE_MENU = '\n'.join([
        '(GRADE)',
        'exit',
        '<name>... <grade>: set grade for the given student'
    ])
    SEL_MENU = '\n'.join([
        '(SEL)',
        'exit',
        '<name>...: select/deselect the given student'
    ])

    def __init__(self):
        self.data = None  # list of rows
        self.col = 0  # current col index
        self.sel = []  # a selection of students as sorted row indices
        print(self.WELCOME)
        print(self.TOP_MENU)
        self.top()

    def top(self):
        """Top menu"""
        PROMPT = '>> '
        words = input(PROMPT).split()
        it = iter(words)
        
        try:
            s = next(it) 
            if s == 'exit':
                print('Bye')
                return
            elif s in ['help', 'h']:
                print(self.TOP_MENU)
            elif s == 'load':
                fname = next(it)
                try:
                    with open(fname, newline='') as f:
                        self.data = list(csv.reader(f))
                        print('{} rows loaded.'.format(len(self.data)))
                except Exception as e:
                    print(e)
            elif self.data:
                if s == 'save':
                    fname = next(it)
                    try:
                        with open(fname, 'w', newline='') as f:
                            csv.writer(f).writerows(self.data)
                            print('Data saved to file.')
                    except Exception as e:
                        print(e)
                elif s == 'print':
                    with io.StringIO() as f:
                        csv.writer(f).writerows(self.data)
                        print(f.getvalue())
                elif s == 'cols':
                    for j in range(len(self.data[0])):
                        self.print_col(j)
                elif s in ['list', 'ls']:
                    for i in self.find(list(it)):
                        self.print_row(i)
                elif s == 'col':
                    try:
                        j = int(next(it)) - 1 
                        # Set col
                        if 0 <= j < len(self.data[0]):
                            self.col = j 
                            self.print_col(j)
                        else:
                            raise ValueError()
                    except StopIteration:
                        # Get col
                        self.print_col(self.col)
                    except ValueError:
                        print('Wrong col number!')
                elif s == 'grade':
                    print(self.GRADE_MENU)
                    self.grade()
                elif s == 'selmake':
                    print(self.SEL_MENU)
                    self.selmake()
                elif s == 'sel':
                    print('{} students selected.'.format(len(self.sel)))
                    for i in self.sel:
                        self.print_row(i)
                elif s == 'selclear':
                    self.sel.clear()
                    print('Selection cleared.')
                elif s == 'selset':
                    v = next(it)
                    for i in self.sel:
                        self.data[i][self.col] = v
                    print('{} scores set to {}.'.format(len(self.sel), v))
                else:
                    print('Unrecognized command "{}"'.format(s))
            else:
                print('No data!')
        except StopIteration:
            if words:
                print('Argument(s) missing!')

        self.top()

    def print_col(self, j):
        print('[{:>2}] "{}"'.format(j + 1, self.data[0][j]))
    
    def print_row(self, i):
        print('[{:>3}] {:<30} {}'.format
                  (i + 1, self.data[i][0], self.data[i][self.col]))
    def find(self, names):
        """Find students with words."""
        names = [n.lower() for n in names]
        def match(i):
            n0 = self.data[i][0].lower()
            return all(n in n0 for n in names)
        return list(filter(match, range(len(self.data)))) 

    def choose_student(self, names):
        """
        Let the user choose one from the filtered students.
        Return: row index (-1 if fail)
        """
        FAIL = -1
        i_list = self.find(names)
        c = len(i_list)
        if not c:
            print('Name not found!')
            return FAIL
        if c == 1:
            return i_list[0]
        for i in i_list:
            self.print_row(i)
        try:
            i = int(input('Choose one: ')) - 1
            if i not in i_list:
                raise ValueError()
            return i
        except ValueError:
            print('Wrong number!')
            return FAIL

    def selmake(self):
        """SEL mode"""
        PROMPT = 'SEL>> '
        cmd = input(PROMPT)
        if cmd == 'exit':
            return
        names = cmd.split()
        if names:
            i = self.choose_student(names)
            if i >= 0:
                if i in self.sel:
                    self.sel.remove(i)
                    print('Deselected:')
                else:
                    bisect.insort(self.sel, i)
                    print('Selected:')
                self.print_row(i)
        self.selmake()

    def grade(self):
        """GRADE mode"""
        PROMPT = 'GRADE>> '
        cmd = input(PROMPT)
        if cmd == 'exit':
            return
        names = cmd.split()
        try:
            v = names.pop()
            if not names:
                raise ValueError()
        except IndexError:
            pass
        except ValueError:
            print('Wrong syntax!')
        else:
            i = self.choose_student(names)
            if i >= 0:
                self.data[i][self.col] = v
                self.print_row(i)
        self.grade()
        

def main():
    Grader()
    return 0


if __name__ == '__main__':
    sys.exit(main())