due_dict = {}
missing_ids = []

with open('CLIO_TASKS.csv', mode='r', newline='', encoding='utf-8') as CLIO_TASKS:
    for clio_line in CLIO_TASKS:
        clio_line = clio_line.split(",")
        task_id = clio_line[0][1:-1]
        due_date = clio_line[3]
        due_dict[task_id] = due_date
    CLIO_TASKS.close()
    print("dictionary created!\n")

dict_keys = due_dict.keys()


def find_due_date(orig_id):
    if orig_id in dict_keys:
        return due_dict[orig_id]
    else:
        missing_ids.append(orig_id)
        return "0"


out_date = ""

with open('MVS_TASKS.csv', mode='r', newline='',encoding='utf-8') as MVS_TASKS,\
     open('MVS_TASKS_JOINED.csv', mode='a', newline='', encoding='utf-8') as MVS_TASKS_JOINED:
    MVS_TASKS.readline()
    for line in MVS_TASKS:
        line_holder = line
        line = line.split(", ")
        engagement_id = line[0]
        out_date = find_due_date(engagement_id)
        print(out_date)
        MVS_TASKS_JOINED.write(line_holder.strip() + out_date.strip() + "\n")
MVS_TASKS_JOINED.close()
MVS_TASKS.close()

with open('MISSING.txt', mode='a') as MISSING:
    MISSING.write(''.join(missing_ids))
MISSING.close()