#!/usr/bin/env python3

# cdates - Simple terminal calendar with events
# Copyright (c) 2025 640kb.neocities.org
# 
# This project is licensed under the Blue Oak Model License 1.0.0.
# Full text available at: https://blueoakcouncil.org/license/1.0.0

# Version 1.0 : initial release (07jun2025)
# cdates : a simple calendar that uses an events file (caldates)

# This is a simple personal use calendar that I just wanted to toss out there.
# It lists a max of 12 events per monthly calendar display.

# install:   chmod +x cdates && sudo install cdates caldates /usr/local/bin
# uninstall: sudo rm /usr/local/bin/{cdates,caldates}

import calendar
import os
import sys
from datetime import datetime

def show_help():
    help_text = """
cdates - a simple calendar with events

Usage: cdates [option]

Options: -h, --help, /?   (this help)
         -edit            (sudo editorName /usr/local/bin/caldates)

Install:    sudo install cdates caldates /usr/local/bin/
Uninstall:  sudo rm /usr/local/bin/cdates /usr/local/bin/caldates

Description:
    Shows the current month's calendar with events from a local 'caldates'
    file. Days with events or current day are marked with an '*'. Includes
    this month and the first week of next month. Max 12 events displayed.

caldates file format: <Month> <Day> <Description> (per line)

    Example: Jun 15 Birthday Party
             Jul 1 Rent Due
             Dec 25 Christmas Day
             # this is a comment and ignored.
"""
    print(help_text)

def read_events():
    """Read events from cdates file in the same directory as the script"""
    events = {}
    
    # Get the directory where the script is located
    script_dir = os.path.dirname(os.path.realpath(__file__))
    file_path = os.path.join(script_dir, "caldates")
    
    try:
        with open(file_path, 'r') as f:
            for line in f:
                line = line.strip()
                if line and not line.startswith("#"):
                    parts = line.split(maxsplit=2)
                    if len(parts) >= 3:
                        month_name, day, desc = parts
                        month = datetime.strptime(month_name, "%b").month
                        events[(month, int(day))] = desc
    except FileNotFoundError:
        pass
            
    return events

def generate_calendar():
    calendar.setfirstweekday(calendar.SUNDAY)
    now = datetime.now()
    month_name = now.strftime("%b")
    year = now.year
    today = now.day
    events = read_events()
    
    # Calendar grid setup
    cal = calendar.monthcalendar(year, now.month)
    border = "+-----+-----+-----+-----+-----+-----+-----+"
    header_border = "+" + ("-" * (len(border)-2)) + "+"
    
    # Prepare events text
    current_month = now.month
    next_month = current_month % 12 + 1
    next_year = year + 1 if next_month == 1 else year
    
    event_lines = []
    for (month, day), desc in sorted(events.items()):
        if month == current_month or (month == next_month and day <= 7):
            month_abbr = datetime(year if month == current_month else next_year, 
                                month, 1).strftime("%b")
            event_lines.append(f"{month_abbr} {day:2}: {desc}")

    # Fixed column position for events
    EVENT_COLUMN = 45
    
    # Build calendar lines
    calendar_lines = []
    calendar_lines.append(header_border)
    calendar_lines.append(f"|{f' {month_name} {year} '.center(len(header_border)-2)}|")
    calendar_lines.append(border)
    calendar_lines.append("| Sun | Mon | Tue | Wed | Thu | Fri | Sat |")
    calendar_lines.append(border)
    
    # Calendar weeks
    for week in cal:
        week_str = "|"
        for day in week:
            if day == 0:
                week_str += "     |"
            else:
                day_str = f"{day:2}"
                if day == today:
                    day_str += "*"
                elif (now.month, day) in events:
                    day_str += "*"
                else:
                    day_str += " "
                week_str += f" {day_str} |"
        calendar_lines.append(week_str)
        calendar_lines.append(border)

    # Combine calendar and events side by side
    max_lines = max(len(calendar_lines), len(event_lines))
    output_lines = []
    event_start_line = 3  # Line with Sun-Sat headers
    
    for i in range(max_lines):
        if i < len(calendar_lines):
            line = calendar_lines[i]
        else:
            line = " " * len(border)
            
        if i >= event_start_line and (i - event_start_line) < len(event_lines):
            line = line.ljust(EVENT_COLUMN) + event_lines[i - event_start_line]
            
        output_lines.append(line)
    
    print("\n".join(output_lines))

if __name__ == "__main__":
    # Check for help arguments
    if len(sys.argv) > 1:
        arg = sys.argv[1]
        if arg in ('-h', '--help', '/?', '-?', '--h'):
            show_help()
        elif arg == '-edit':
            editor = "xed"  # Hardcoded editor
            os.execvp("sudo", ["sudo", editor, "/usr/local/bin/caldates"])
        else:
            print(f"Unknown option: {arg}")
            show_help()
    else:
        generate_calendar()