#!/usr/bin/env python3
# A todo.txt-cli add-on for recurring tasks
# Copyright 2021 Owen T. Heisler. GNU General Public License, version 3.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
#
"""Mark task(s) as done, adding new task(s) if required for recurrence."""

import argparse
import calendar
import datetime
import os
import re
import subprocess
import sys
import shutil
import logging
import pdb

# Configure logging
logging.basicConfig(filename='debug.log', level=logging.DEBUG, format='%(asctime)s %(message)s')

# Replace these paths with your actual paths
file_to_read = os.path.expanduser("~/Todo/todo.txt")
source_folder = os.path.expanduser("~/Todo/notes")
archive_folder = os.path.expanduser("~/Todo/notes/archive")


def move_files_with_note_prefix(file_path, source_folder, archive_folder, task):
    task_line = get_line(task)
    
    if task_line.strip().startswith("note:"):
        note_string = task_line.strip().split(':', 1)[1].strip()
        source_file = os.path.join(source_folder, note_string)
        archive_file = os.path.join(archive_folder, note_string)
        
        if os.path.exists(source_file):
            if os.path.exists(archive_file):
                print("Archive file already exists.")
            else:
                try:
                    shutil.move(source_file, archive_file)
                    print("Moved {} to {}".format(source_file, archive_file))
                except Exception as e:
                    print("Error moving file:", e)
        else:
            print("Source file not found.")


def add_new_task(line):
    """Add a new task by running todo-txt *add*."""
    subprocess.run(
        [os.environ['TODO_FULL_SH'], 'command', 'add', line],
        check=True,
        stdout=sys.stdout,
        stderr=sys.stderr,
    )


def adjust_date(date, adjust):
    """Return adjusted date, ignoring the `+` prefix if it exists.

    If the date is None, return None.

    >>> adjust_date(datetime.date(1970, 1, 1), '1')
    datetime.date(1970, 1, 2)
    >>> adjust_date(datetime.date(1970, 1, 1), '+1')
    datetime.date(1970, 1, 2)
    >>> adjust_date(datetime.date(1970, 1, 1), '1d')
    datetime.date(1970, 1, 2)
    >>> adjust_date(datetime.date(1970, 1, 1), '1b')
    datetime.date(1970, 1, 2)
    >>> adjust_date(datetime.date(1970, 1, 1), '2b')
    datetime.date(1970, 1, 5)
    >>> adjust_date(datetime.date(1970, 1, 1), '2w')
    datetime.date(1970, 1, 15)
    >>> adjust_date(datetime.date(1970, 1, 1), '3m')
    datetime.date(1970, 4, 1)
    >>> adjust_date(datetime.date(1970, 1, 31), '2m')
    datetime.date(1970, 3, 31)
    >>> adjust_date(datetime.date(1970, 1, 31), '1m')
    datetime.date(1970, 2, 28)
    >>> adjust_date(datetime.date(1970, 1, 1), '4y')
    datetime.date(1974, 1, 1)

    """
    if date is None:
        return None
    m = re.fullmatch(r'(\+?)(\d+)([dbwmy]?)', adjust)
    if not m:
        raise Exception('Malformed `rec:` value')
    num = int(m.group(2))
    unit = m.group(3)
    if unit in ['', 'd']:
        # Add days
        return date + datetime.timedelta(days=num)
    elif unit == 'b':
        # Add business days
        while num > 0:
            date += datetime.timedelta(days=1)
            weekday = date.weekday()
            if weekday >= 5:
                continue
            num -= 1
        return date
    elif unit == 'w':
        # Add weeks
        return date + datetime.timedelta(weeks=num)
    elif unit == 'm':
        # Add months
        month = date.month - 1 + num
        year = date.year + month // 12
        month = month % 12 + 1
        day = min(date.day, calendar.monthrange(year, month)[1])
        return datetime.date(year, month, day)
    elif unit == 'y':
        # Add years
        return date.replace(year=(date.year + num))


def get_date(line, key):
    """Return the date given in the specified key.

    Return None if the key does not exist.

    >>> get_date('Test task t:1970-01-01', 't')
    datetime.date(1970, 1, 1)
    >>> get_date('Test task', 't')
    >>> get_date('Test task t:malformed', 't')
    Traceback (most recent call last):
        ...
    Exception: Malformed `t:` date
    >>> get_date('Test task due:1970-01-01', 'due')
    datetime.date(1970, 1, 1)
    >>> get_date('Test task', 'due')
    >>> get_date('Test task due:malformed', 'due')
    Traceback (most recent call last):
        ...
    Exception: Malformed `due:` date

    """
    value = get_key_value(line, key)
    if value is None:
        return None
    else:
        try:
            return datetime.date.fromisoformat(value)
        except ValueError:
            raise Exception('Malformed `{}:` date'.format(key))


def get_key_value(line, key):
    """Return the value of key as a string, or None if it does not exist.

    Raise an Exception if the key is specified more than once.

    >>> get_key_value('Test task', 'key')
    >>> get_key_value('Test task key:val', 'key')
    'val'
    >>> get_key_value('key:val Test task', 'key')
    'val'
    >>> get_key_value('Test task key:val1 key:val2', 'key')
    Traceback (most recent call last):
        ...
    Exception: Task has multiple `key:` keys
    >>> get_key_value('Test task rec:1', 'rec')
    '1'
    >>> get_key_value('(A) Test task rec:3d', 'rec')
    '3d'

    """
    matches = re.findall(r'(?:^| ){}:([^ ]*)'.format(key), line)
    count = len(matches)
    if count == 1:
        return matches[0].lstrip(' ')
    elif count == 0:
        return None
    else:
        raise Exception('Task has multiple `{}:` keys'.format(key))


def get_line(item_number):
    """Get task by number and return as string."""
    with open(os.environ['TODO_FILE']) as f:
        for i, line in enumerate(f):
            if i+1 == item_number:
                return line.rstrip('\n')
    raise Exception('Task {} does not exist'.format(item_number))


def make_new_task(line, now=datetime.date.today()):
    """Replace dates in line and return new line.

    >>> now = datetime.date(1970, 1, 3)
    >>> make_new_task('Test task', now)
    >>> make_new_task('Test task rec:3d', now)
    'Test task rec:3d'
    >>> make_new_task('1970-01-01 Test task rec:3d', now)
    'Test task rec:3d'
    >>> make_new_task('(A) 1970-01-01 Test task rec:3d', now)
    '(A) Test task rec:3d'
    >>> make_new_task('(A) 1970 Test task rec:3d', now)
    '(A) 1970 Test task rec:3d'
    >>> make_new_task('(A) Test task with 1970-01-01 in it rec:3d', now)
    '(A) Test task with 1970-01-01 in it rec:3d'
    >>> make_new_task('Test task rec:+3d', now)
    'Test task rec:+3d'
    >>> make_new_task('Test task t:1970-01-01 rec:3d', now)
    'Test task t:1970-01-06 rec:3d'
    >>> make_new_task('Test task t:1970-01-01 rec:+3d', now)
    'Test task t:1970-01-04 rec:+3d'
    >>> make_new_task('Test task due:1970-01-01 rec:3d', now)
    'Test task due:1970-01-06 rec:3d'
    >>> make_new_task('Test task due:1970-01-01 rec:+3d', now)
    'Test task due:1970-01-04 rec:+3d'
    >>> make_new_task('Test task t:1970-01-01 due:1970-01-05 rec:3d', now)
    'Test task t:1970-01-06 due:1970-01-10 rec:3d'
    >>> make_new_task('Test task t:1970-01-01 due:1970-01-05 rec:+3d', now)
    'Test task t:1970-01-04 due:1970-01-08 rec:+3d'
    >>> make_new_task('Test task rec:1 rec:2', now)
    Traceback (most recent call last):
        ...
    Exception: Task has multiple `rec:` keys
    >>> make_new_task('Test task t:1970-01-01 t:1970-01-02, rec:1m', now)
    Traceback (most recent call last):
        ...
    Exception: Task has multiple `t:` keys
    >>> make_new_task('Test task due:1970-01-01 due:1970-01-02 rec:1', now)
    Traceback (most recent call last):
        ...
    Exception: Task has multiple `due:` keys

    # README examples
    >>> make_new_task('Fix lamp')
    >>> make_new_task('Meet friend for tea rec:1')
    'Meet friend for tea rec:1'
    >>> now = datetime.date(2021, 1, 2)
    >>> make_new_task('Water flowers t:2021-01-01 rec:5d', now)
    'Water flowers t:2021-01-07 rec:5d'
    >>> make_new_task('Send birthday greeting to friend t:2021-04-04 rec:+1y')
    'Send birthday greeting to friend t:2022-04-04 rec:+1y'
    >>> make_new_task('Pay rent t:2021-01-28 due:2021-02-01 rec:+1m')
    'Pay rent t:2021-02-28 due:2021-03-01 rec:+1m'
    >>> now = datetime.date(2021, 1, 3)
    >>> old_task = 'Do offline backup t:2021-01-01 due:2021-01-08 rec:2w'
    >>> make_new_task(old_task, now)
    'Do offline backup t:2021-01-17 due:2021-01-24 rec:2w'
    >>> now = datetime.date(2021, 1, 31)
    >>> make_new_task('Get groceries t:2021-01-14 rec:1m', now)
    'Get groceries t:2021-02-28 rec:1m'
    >>> make_new_task('Pay rent t:2021-01-31 due:2021-02-01 rec:+1m')
    'Pay rent t:2021-02-28 due:2021-03-01 rec:+1m'

    """
    adjustment = get_key_value(line, 'rec')
    if adjustment is None:
        return None
    start_date = get_date(line, 't')
    due_date = get_date(line, 'due')

    # Remove optional creation date
    line = re.sub("^(?P<pri>\([A-Z]\) )?\d{4}-(0[1-9]|1[0-2])-(0[1-9]|[12][0-9]|3[01]) ", "\g<pri>", line)

    # Remove notes: and min:
    # line = re.sub("^(?P<pri>\([A-Z]\) )?\d{4}-(0[1-9]|1[0-2])-(0[1-9]|[12][0-9]|3[01]) ", "\g<pri>", line)

    if not start_date and not due_date:
        # Neither date is specified
        return line
    elif start_date and due_date:
        if adjustment.startswith('+'):
            # Both dates are specified, with strict recurrence
            # Original + adjustment for both dates
            start_date = adjust_date(start_date, adjustment)
            due_date = adjust_date(due_date, adjustment)
        else:
            # Both dates are specified, with normal recurrence
            offset = due_date - start_date
            # Today + adjustment for start date
            start_date = adjust_date(now, adjustment)
            # Today + offset for due date
            due_date = start_date + offset
    elif adjustment.startswith('+'):
        # Only one date is specified, with strict recurrence.
        # Original + adjustment for whichever date is specified
        start_date = adjust_date(start_date, adjustment)
        due_date = adjust_date(due_date, adjustment)
    else:
        # Only one date is specified, with normal recurrence.
        # Today + adjustment for whichever date is specified
        if start_date:
            start_date = adjust_date(now, adjustment)
        if due_date:
            due_date = adjust_date(now, adjustment)
    # Apply date changes
    if start_date:
        line = set_key_value(line, 't', start_date.isoformat())
    if due_date:
        line = set_key_value(line, 'due', due_date.isoformat())
    return line


def mark_done(item_number):
    """Mark task as complete by executing todo-txt *do* action."""
    subprocess.run(
        [os.environ['TODO_FULL_SH'], 'command', 'do', str(item_number)],
        check=True,
        stdout=sys.stdout,
        stderr=sys.stderr,
    )


def parse_args():
    p = argparse.ArgumentParser(
        add_help=False,
        description=globals()['__doc__'],
        formatter_class=argparse.RawDescriptionHelpFormatter)
    subp = p.add_subparsers(title='actions', dest='action', required=True)
    usage = subp.add_parser('usage')
    usage = subp.add_parser('test')
    do = subp.add_parser('do')
    do.add_argument('item', type=int, nargs='+', metavar='ITEM#',
                    help='The task number')
    return p.parse_args()


def set_key_value(line, key, value):
    """Set value of key and return new line.

    A value of None deletes the key and its value.

    This does not check for duplicate keys; that is done by
    get_key_value().

    >>> set_key_value('Test task', 'key', 'val')
    'Test task key:val'
    >>> set_key_value('Test task key:val1 b key2:val2', 'key', 'val')
    'Test task key:val b key2:val2'
    >>> set_key_value('Test task key:val', 'key', None)
    'Test task'

    """
    if value is None:
        space = ''
        replacement = ''
    else:
        space = r'\1'
        replacement = '{}:{}'.format(key, value)
    line, repl_count = re.subn(r'(^| ){}:[^ ]*'.format(key),
                               space + replacement, line)
    if repl_count == 0:
        line += ' ' + replacement
    return line


def usage():
    """Return usage text suitable for todo-txt."""
    text = """
    do ITEM#[, ITEM#, ITEM#, ...]
      Mark ITEM# as complete. If `rec:` is set, add a new task, updating
      any start/due dates based on the value of `rec:`.
"""
    return text.strip('\n') + '\n'


if __name__ == '__main__':
    args = parse_args()
    if args.action == 'usage':
        print(usage())
        quit()
    elif args.action == 'test':
        import doctest
        doctest.testmod()
    elif args.action == 'do':
        for task in args.item:
            old_task = get_line(task)
            if re.match(r'^x ', old_task):
                print('Task {} is already marked as done!'.format(task))
                sys.exit(1)
            new_task = make_new_task(old_task)
            mark_done(task)
            # Archive old_task notes file after marking tasks as done
            move_files_with_note_prefix(file_to_read, source_folder,archive_folder, task)

            if new_task:
                add_new_task(new_task)