Very simple worklog script for CLI usage

worklog.py

#!/usr/bin/env python3

import sys
import datetime
import click
import appdirs
import io
import subprocess

from pathlib import Path

from typing import Sequence

dirs = appdirs.AppDirs("worklog")

class WorkLogException(Exception):
    pass

# https://stackoverflow.com/questions/2301789/how-to-read-a-file-in-reverse-order
def reverse_readline(filename, buf_size=8192):
    """A generator that returns the lines of a file in reverse order"""
    with open(filename, 'rb') as fh:
        segment = None
        offset = 0
        fh.seek(0, io.SEEK_END)
        file_size = remaining_size = fh.tell()
        while remaining_size > 0:
            offset = min(file_size, offset + buf_size)
            fh.seek(file_size - offset)
            buffer = fh.read(min(remaining_size, buf_size))
            # remove file's last "\n" if it exists, only for the first buffer
            if remaining_size == file_size and buffer[-1] == ord('\n'):
                buffer = buffer[:-1]
            remaining_size -= buf_size
            lines = buffer.split('\n'.encode())
            # append last chunk's segment to this chunk's last line
            if segment is not None:
                lines[-1] += segment
            segment = lines[0]
            lines = lines[1:]
            # yield lines in this chunk except the segment
            for line in reversed(lines):
                # only decode on a parsed line, to avoid utf-8 decode error
                yield line.decode()
        # Don't yield None if the file was empty
        if segment is not None:
            yield segment.decode()

class Data():
    def __init__(self, data_dir: Path, dt=None):
        if dt is None:
            dt = datetime.datetime.now()
        self.date = dt
        self.data_dir = data_dir
        self.todays_ts = dt.strftime("%Y-%m-%d")
        self.todays_file = self.data_dir / Path(f"worklog-{self.todays_ts}.md")
        self.todays_header = f"## Work Log: {self.todays_ts}"

    def exists(self):
        return self.todays_file.exists()

@click.group("worklog")
@click.pass_context
def cli_worklog(ctx):
    """Simplified Work Tracking Tool"""
    data_dir = Path(dirs.user_data_dir)
    data_dir.mkdir(parents=True, exist_ok=True)
    
    ctx.obj = Data(data_dir=data_dir)

@cli_worklog.command("task")
@click.argument("task", nargs=-1)
@click.pass_obj
def cli_task(obj: Data, task: Sequence[str]):
    """Add a task bullet point"""

    if not obj.todays_file.exists():
        obj.todays_file.write_text(obj.todays_header + "\n")

    # Ensure a newline at the end of the file before adding a new task
    with obj.todays_file.open("r+") as f:
        f.seek(0, io.SEEK_END)
        eof = f.tell()
        if eof != 0:
            f.seek(f.tell()-1, io.SEEK_SET)
            if f.read(1) != "\n":
                f.write("\n")
        else:
            f.write("\n")

    # Append the newline
    with obj.todays_file.open("at") as f:
        f.write(f"* {' '.join(task)}\n")

@cli_worklog.command("open")
@click.pass_obj
def cli_open(obj: Data):
    """Open todays worklog"""
    subprocess.call(["xdg-open", obj.todays_file.as_posix()])

@cli_worklog.command("summary")
@click.pass_obj
def cli_summary(obj: Data):
    """Summarize bullet points from today/yesterday"""
    yesterday = obj.date - datetime.timedelta(days=1)
    last_worklog = Data(data_dir=obj.data_dir, dt=yesterday)
    if last_worklog.exists():
        sys.stdout.write("# Yesterday\n")
        with last_worklog.todays_file.open("rt") as f:
            for line in f.readlines():
                if line.strip() == last_worklog.todays_header:
                    continue
                sys.stdout.write(line)
        sys.stdout.write("\n")
    else:
        # Check last 7 days
        while not last_worklog.exists() and (datetime.datetime.now() - last_worklog.date).days < 7:
            yesterday = last_worklog.date - datetime.timedelta(days=1)
            last_worklog = Data(data_dir=obj.data_dir, dt=yesterday)
        
        if last_worklog.exists():
            sys.stdout.write(f"# {last_worklog.date.strftime('%A')}\n")
            with last_worklog.todays_file.open("rt") as f:
                for line in f.readlines():
                    if line.strip() == last_worklog.todays_header:
                        continue
                    sys.stdout.write(line)
            sys.stdout.write("\n")


    if obj.todays_file.exists():
        with obj.todays_file.open("rt") as f:
            sys.stdout.write(f"# Today\n")
            for line in f.readlines():
                if line.strip() == obj.todays_header:
                    continue
                sys.stdout.write(line)

if __name__ == "__main__":
    cli_worklog(auto_envvar_prefix="WORKLOG")