todo.py

#!/usr/bin/env python3
"""
todo — Dead-simple CLI task manager. File-backed, zero deps.

3 commands to learn. Tasks stored in .todo.json in current directory.
Perfect for per-project task tracking from the terminal.

Usage:
    py todo.py add "Fix the login bug"
    py todo.py add "Review PR #42" -p high
    py todo.py add "Write tests" -t backend,urgent
    py todo.py list                              # Show pending tasks
    py todo.py list --all                        # Include completed
    py todo.py done 1                            # Complete task #1
    py todo.py done 1 3 5                        # Complete multiple
    py todo.py edit 2 "Updated description"      # Edit task text
    py todo.py rm 3                              # Delete task
    py todo.py clear                             # Remove completed tasks
    py todo.py search "login"                    # Search tasks
    py todo.py stats                             # Summary statistics
"""

import argparse
import json
import sys
import os
from datetime import datetime
from pathlib import Path

TODO_FILE = ".todo.json"


def load_todos() -> list[dict]:
    """Load tasks from .todo.json"""
    path = Path(TODO_FILE)
    if not path.exists():
        return []
    try:
        return json.loads(path.read_text(encoding="utf-8"))
    except (json.JSONDecodeError, Exception):
        return []


def save_todos(todos: list[dict]):
    """Save tasks to .todo.json"""
    Path(TODO_FILE).write_text(
        json.dumps(todos, indent=2, default=str) + "\n",
        encoding="utf-8"
    )


def next_id(todos: list[dict]) -> int:
    """Get next available ID."""
    if not todos:
        return 1
    return max(t.get("id", 0) for t in todos) + 1


def cmd_add(args):
    """Add a new task."""
    todos = load_todos()
    task = {
        "id": next_id(todos),
        "text": " ".join(args.text),
        "done": False,
        "priority": args.priority or "normal",
        "tags": [t.strip() for t in args.tags.split(",")] if args.tags else [],
        "created": datetime.now().isoformat(),
        "completed": None,
    }
    todos.append(task)
    save_todos(todos)
    icon = {"high": "!", "normal": " ", "low": "."}
    print(f"  [{icon.get(task['priority'], ' ')}] #{task['id']} {task['text']}")


def cmd_list(args):
    """List tasks."""
    todos = load_todos()
    if not todos:
        print("  No tasks. Add one: py todo.py add \"Your task here\"")
        return

    # Filter
    if not args.all:
        shown = [t for t in todos if not t.get("done")]
    else:
        shown = todos

    if args.tag:
        shown = [t for t in shown if args.tag in t.get("tags", [])]

    if not shown:
        print("  All tasks completed!" if not args.all else "  No matching tasks.")
        return

    # Sort: priority (high first), then by id
    priority_order = {"high": 0, "normal": 1, "low": 2}
    shown.sort(key=lambda t: (priority_order.get(t.get("priority", "normal"), 1), t.get("id", 0)))

    # Display
    pending = sum(1 for t in todos if not t.get("done"))
    done = sum(1 for t in todos if t.get("done"))
    print(f"\n  Tasks ({pending} pending, {done} done)\n")

    for t in shown:
        check = "x" if t.get("done") else " "
        pri = {"high": "!", "normal": " ", "low": "."}
        icon = pri.get(t.get("priority", "normal"), " ")
        tags = ""
        if t.get("tags"):
            tags = " [" + ", ".join(t["tags"]) + "]"
        text = t.get("text", "")
        # Strikethrough for done tasks (terminal-safe)
        if t.get("done"):
            text = f"({text})"
        print(f"  [{check}] {icon} #{t['id']:<3} {text}{tags}")

    print()


def cmd_done(args):
    """Mark tasks as completed."""
    todos = load_todos()
    ids = set(args.ids)
    count = 0
    for t in todos:
        if t["id"] in ids and not t.get("done"):
            t["done"] = True
            t["completed"] = datetime.now().isoformat()
            print(f"  Done: #{t['id']} {t['text']}")
            count += 1
    if count == 0:
        print("  No matching pending tasks found.")
    save_todos(todos)


def cmd_edit(args):
    """Edit task text."""
    todos = load_todos()
    for t in todos:
        if t["id"] == args.id:
            old = t["text"]
            t["text"] = " ".join(args.text)
            save_todos(todos)
            print(f"  Updated #{args.id}: {old} -> {t['text']}")
            return
    print(f"  Task #{args.id} not found.")


def cmd_rm(args):
    """Delete a task."""
    todos = load_todos()
    new_todos = [t for t in todos if t["id"] not in args.ids]
    removed = len(todos) - len(new_todos)
    save_todos(new_todos)
    print(f"  Removed {removed} task(s).")


def cmd_clear(args):
    """Remove all completed tasks."""
    todos = load_todos()
    pending = [t for t in todos if not t.get("done")]
    removed = len(todos) - len(pending)
    save_todos(pending)
    print(f"  Cleared {removed} completed task(s). {len(pending)} remaining.")


def cmd_search(args):
    """Search tasks by text."""
    todos = load_todos()
    query = args.query.lower()
    matches = [t for t in todos if query in t.get("text", "").lower()
               or query in " ".join(t.get("tags", [])).lower()]

    if not matches:
        print(f"  No tasks matching '{args.query}'")
        return

    print(f"\n  Search results for '{args.query}':\n")
    for t in matches:
        check = "x" if t.get("done") else " "
        print(f"  [{check}] #{t['id']} {t['text']}")
    print()


def cmd_stats(args):
    """Show task statistics."""
    todos = load_todos()
    if not todos:
        print("  No tasks.")
        return

    total = len(todos)
    done = sum(1 for t in todos if t.get("done"))
    pending = total - done
    high = sum(1 for t in todos if not t.get("done") and t.get("priority") == "high")

    # Tag frequency
    all_tags = []
    for t in todos:
        all_tags.extend(t.get("tags", []))
    tag_counts = {}
    for tag in all_tags:
        tag_counts[tag] = tag_counts.get(tag, 0) + 1

    print(f"\n  Task Statistics")
    print(f"  Total:    {total}")
    print(f"  Pending:  {pending}")
    print(f"  Done:     {done}")
    print(f"  High-pri: {high}")
    if total > 0:
        print(f"  Progress: {done/total*100:.0f}%")
    if tag_counts:
        print(f"  Tags:     {', '.join(f'{k}({v})' for k, v in sorted(tag_counts.items(), key=lambda x: -x[1]))}")
    print()


def main():
    parser = argparse.ArgumentParser(description="todo -- dead-simple CLI task manager")
    sub = parser.add_subparsers(dest="command")

    # add
    p = sub.add_parser("add", help="Add a task")
    p.add_argument("text", nargs="+", help="Task description")
    p.add_argument("-p", "--priority", choices=["high", "normal", "low"], help="Priority level")
    p.add_argument("-t", "--tags", help="Comma-separated tags")

    # list
    p = sub.add_parser("list", aliases=["ls"], help="List tasks")
    p.add_argument("--all", "-a", action="store_true", help="Include completed tasks")
    p.add_argument("--tag", help="Filter by tag")

    # done
    p = sub.add_parser("done", help="Mark task(s) as completed")
    p.add_argument("ids", nargs="+", type=int, help="Task ID(s)")

    # edit
    p = sub.add_parser("edit", help="Edit task text")
    p.add_argument("id", type=int, help="Task ID")
    p.add_argument("text", nargs="+", help="New text")

    # rm
    p = sub.add_parser("rm", help="Delete task(s)")
    p.add_argument("ids", nargs="+", type=int, help="Task ID(s)")

    # clear
    sub.add_parser("clear", help="Remove completed tasks")

    # search
    p = sub.add_parser("search", help="Search tasks")
    p.add_argument("query", help="Search text")

    # stats
    sub.add_parser("stats", help="Show statistics")

    args = parser.parse_args()
    commands = {
        "add": cmd_add, "list": cmd_list, "ls": cmd_list,
        "done": cmd_done, "edit": cmd_edit, "rm": cmd_rm,
        "clear": cmd_clear, "search": cmd_search, "stats": cmd_stats,
    }

    if args.command in commands:
        commands[args.command](args)
    else:
        # Default: show list
        args.all = False
        args.tag = None
        cmd_list(args)


if __name__ == "__main__":
    main()