# Purpose: to compute course objective fulfillment percentage.
#
# Rationale: it is tedious to compute course objective fulfillment
#            percentage, which is a measurement of students'
#            performance in a course.
#
# Usage: python3 analyze.py
#
# Required files:
#
#   - students.txt: a plain text file where each row contains student number and student name, separated by a TAB#
#   - tasks.json: a plain text file in JSON format specifying the course objectives and tasks in this course.
#                 Each task is associated to at least one course objective (co). Each co in a task has an associated weight.
#                 Make sure that all weights across tasks sum to 100.
# Optional files:
#
#   - exclude.txt: a plain text file specifying a list of student numbers (one per line) which we do not want to include
#                  while computing the course objective fulfillment percentage.
#
#
#
# Limitations:
#
# For simplicity, I recommend associating one and only one co to each
# task, whether the task is an assignment, a quiz, a lab, or a test
# question.  In the case of having more than one co's in a task, a
# student's score in this task will be proportionally distributed
# among these co's according the co's weights.  This treatment is a
# simplification, since in reality two students with the same task
# score may have a different score distribution among different co's.
# For example, a task is associated to two course objectives, co1 and
# co2, with weights 2 and 2, respectively.  Student A achieved a score
# of 2 in this task, with 2 in co1 and 0 in co2.  Student B achieved a
# same score in this task, but with 0 in co1 and 2 in co2.  This
# software does not consider this difference.  It will assign 1 to co1
# and 1 to co2, for both student A and student B.  That is why I
# suggest using a single course objective for each task, to avoid this
# simplification.  Having more than one course objective in a task
# might indicate that this task's goal is not specific enough.  You
# could break down the task into several sub-tasks such that each
# sub-task corresponds to only one course objective.
#
# Copyright (C) 2019, 2020, 2021 Hui Lan
#
# Contact the author if you encounter any problems: Hui Lan <lanhui@zjnu.edu.cn>

import json
import os
import sys

# Solve UnicodeDecodeError - https://blog.csdn.net/blmoistawinde/article/details/87717065
import _locale
import codecs
_locale._getdefaultlocale = (lambda *args: ['zh_CN', 'utf8'])


def get_task_information(fname):
    with open(fname) as json_data:
        d = json.load(json_data)
    return d


def get_student_information(fname):
    result = []
    lineno = 1
    with open(fname) as f:
        for line in f:
            line = line.strip()
            lst = line.split('\t')
            if len(lst) == 2:
                result.append((lst[0], lst[1]))
            else:
                print('Warning: Line %d in file %s does not have two columns. Skipped!' % (lineno, fname))
            lineno += 1
    return result


def get_max_score(d):
    '''
    Return the maximum allowable score in a task.  The maximum score is the sum of all values across all
    course objectives.
    '''
    result = 0
    for k in d:
        result += int(d[k])
    return result


def get_student_number(fname):
    d = {}

    # If a file has BOM (Byte Order Marker) charater, stop.
    with open(fname, 'r+b') as f:
        s = f.read()
        if s.startswith(codecs.BOM_UTF8):
            print('\nERROR: The file %s contains BOM character.  Remove that first.' % (fname))
            sys.exit()

    f = open(fname)
    for line in f:
        line = line.strip()
        if not line.startswith('#'):
            lst = line.split('\t')
            sno = lst[0]    # student number
            d[sno] = lst[2]  # score
    f.close()
    return d


def make_individual_grade_files(grade_dir, task_dict, student_lst):
    if not os.path.exists(grade_dir):
        os.mkdir(grade_dir)
    for task in task_dict['tasks']:
        fname = task + '.txt'
        max_score = get_max_score(task_dict['tasks'][task])
        new_file = os.path.join(grade_dir, fname)
        if not os.path.exists(new_file):
            print('Create file %s. You need to fill out students\'s scores in this file.' % (new_file))
            f = open(new_file, 'w')
            f.write('#' + task + '\n')
            f.write('\t'.join(['#student.no', 'student.name', 'score']) + '\n')
            for student in student_lst:
                f.write('\t'.join([student[0], student[1], '0']) + '\n')
            f.close()
        else:
            inconsistency = 0
            d = get_student_number(new_file)
            # students.txt could be updated late ... an undesired event.  Check for this event.
            for student in student_lst:
                sno = student[0]
                if not sno in d:
                    inconsistency = 1
                    print('Warning: %s is in the new student file, but is not in the old grade file.' % (sno))
            student_numbers = [student[0] for student in student_lst]
            for sno in d:
                if not sno in student_numbers:
                    inconsistency = 1
                    print('Warning: %s is in the old grade file, but is not in the new student file.' % (sno))
            if inconsistency == 1:
                print('Warning: I am keeping the available scores.')

                f = open(new_file)
                s = f.read()
                f.close()

                f = open(new_file + '.old', 'w')
                f.write(s)
                f.close()

                f = open(new_file, 'w')
                f.write('#' + task + '\n')
                f.write('\t'.join(['#student.no', 'student.name', 'score']) + '\n')
                for student in student_lst:
                    if student[0] in d:
                        f.write('\t'.join([student[0], student[1], '%s' % d[student[0]]]) + '\n')
                    else:
                        f.write('\t'.join([student[0], student[1], '0']) + '\n')
                f.close()


def make_score_dict(fname):
    d = {}
    f = open(fname)
    lines = f.readlines()
    f.close()
    for line in lines:
        line = line.strip()
        if not line.startswith('#'):
            lst = line.split('\t')
            sno = lst[0]
            score = lst[2]
            d[sno] = score
    return d


def get_scores_for_each_student(grade_dir, task_dict):
    d = {}
    for task in task_dict['tasks']:
        fname = task + '.txt'
        max_score = get_max_score(task_dict['tasks'][task])
        new_file = os.path.join(grade_dir, fname)
        if os.path.exists(new_file):
            d[task] = make_score_dict(new_file)
        else:
            print('Warning: grade file %s not found.' % (new_file))

    return d


def get_objective_total(d):
    ''' For each objective, get its total by summing over all tasks.'''
    objective_lst = d['course.objectives']
    result = []
    check_sum = 0
    for o in objective_lst:
        total = 0
        for task in d['tasks']:
            for co in d['tasks'][task]:
                if co == o:
                    total += d['tasks'][task][co]
        check_sum += total
        result.append((o, total))
    if check_sum != 100:
        print('Objective total is not 100 (%d instead). Make sure you have divide the objective scores across tasks correctly.' % (check_sum))
        sys.exit()
    return result  # [(objective1, value1), (objective2, value2), ...]


def check_availability(fname):
    if not os.path.exists(fname):
        print('The required file %s does not exist.' % (fname))
        sys.exit()


def remove_a_student(student_lst, s):
    ''' student_lst is a list of tuples, each tuple in the form like (student_no, student_name).
    s is a student number. Effect: student_lst shortened.
    '''
    index = 0
    for x in student_lst:
        sno = x[0]
        if sno == s:
            student_lst.pop(index)
            return None
        index += 1


def all_gone(student_lst, lst):
    ''' Return True iff none of the student number in lst is in student_lst'''
    for x in student_lst:
        sno = x[0]
        if sno in lst:
            return False
    return True


# main
GRADE_DIR = 'grade'
TASK_FILE = 'tasks.json'  # required file containing course objectives and tasks.
check_availability(TASK_FILE)
STUDENT_FILE = 'students.txt'  # required file containing student numbers and student names.
check_availability(STUDENT_FILE)
EXCLUDE_FILE = 'exclude.txt'
GRADE_FILE = 'grade_file.xls'  # output
software_information = 'Course Objective Fulfillment Calculator\nCopyright (C) 2019,2020,2022 Lan Hui (lanhui@zjnu.edu.cn)'
n = max([len(s) for s in software_information.split('\n')])
banner = '%s\n%s\n%s' % ('-' * n, software_information, '-' * n)
print(banner)

task_dict = get_task_information(TASK_FILE)
student_lst = get_student_information(STUDENT_FILE)
make_individual_grade_files(GRADE_DIR, task_dict, student_lst)
print('Seen %d students.' % (len(student_lst)))

# output results to terminal and file
head_lst = ['student.no', 'student.name']
task_lst = sorted(task_dict['tasks'])
head_lst.extend(task_lst)

file_content = '\t'.join(head_lst) + '\tTotal\n'

score_dict = get_scores_for_each_student(GRADE_DIR, task_dict)

course_object_cumulative_score = {}
for co in task_dict['course.objectives']:
    course_object_cumulative_score[co] = 0

# Exclude some students from student list student_lst.  The excluded students are specified in a file called exclude.txt.
if os.path.exists(EXCLUDE_FILE):
    lst = []
    print('Read excluded students from %s.' % (EXCLUDE_FILE))
    with open(EXCLUDE_FILE) as f:
        for line in f:
            line = line.strip()
            sno = line.split('\t')[0]
            if sno != '':
                lst.append(sno)
        for s in lst:
            print('Ignore %s' % (s))
            remove_a_student(student_lst, s)
    assert all_gone(student_lst, lst) == True
    print('Still have %d students after excluding the undesired students specified in %s.' % (len(student_lst), EXCLUDE_FILE))


# Do statistics
for s in student_lst:
    sno = s[0]
    sname = s[1]
    result = '%s\t%s\n' % (sno, sname)
    file_content += '%s\t%s' % (sno, sname)
    total = 0
    for task in task_lst:
        score = score_dict[task][sno]
        total_score = get_max_score(task_dict['tasks'][task])
        if float(score) > total_score:
            print('Warning: student %s\'s score greater than maximum score in task %s' % (sno + '_' + sname, task))
            sys.exit()
        else:
            result += '    %s:%s\t' % (task, score)
            file_content += '\t%s' % (score)
            total += float(score)
            for co in task_dict['course.objectives']:
                if co in task_dict['tasks'][task]:
                    my_share = 1.0 * float(score) * task_dict['tasks'][task][co] / total_score
                    course_object_cumulative_score[co] += my_share
                    result += ' [%4.1f] ' % (my_share)
                else:
                    result += ' [%4.1f] ' % (0)
        result += '\n'
    result += '    ---\n    Total:%4.1f\n' % (total)
    file_content += '\t%4.1f\n' % (total)


f = open(GRADE_FILE, 'w')
f.write(file_content)
f.close()
print('Check spreadsheet %s.' % (GRADE_FILE))


objective_total = get_objective_total(task_dict)
num_student = len(student_lst)
for x in objective_total:
    co = x[0]  # name of the course objective
    value = x[1]  # the associated total value of that course objective
    try:
        percentage = 100 * course_object_cumulative_score[co] / (value * num_student)
        print('Course objective %s is %.0f%% satisfied.' % (co, percentage))
    except:
        print('Error: value = %4.1f, num_student = %4.1f' % (value, num_student))