from __future__ import annotations

from datetime import datetime
from pathlib import Path
from typing import Optional

from .storage import JsonStorage


STORE = JsonStorage(Path(__file__).resolve().parents[1] / "data" / "tasks.json", [])


def list_tasks() -> list[dict]:
    tasks = STORE.read()
    return sorted(tasks, key=lambda item: (item.get("completed", False), item.get("created_at", "")))


def add_task(text: str) -> dict:
    tasks = STORE.read()
    next_id = max((task["id"] for task in tasks), default=0) + 1
    task = {
        "id": next_id,
        "text": text.strip(),
        "completed": False,
        "created_at": datetime.now().isoformat(),
    }
    tasks.append(task)
    STORE.write(tasks)
    return task


def complete_task(task_id: int) -> Optional[dict]:
    tasks = STORE.read()
    updated = None
    for task in tasks:
        if task["id"] == task_id:
            task["completed"] = True
            task["completed_at"] = datetime.now().isoformat()
            updated = task
            break
    if updated:
        STORE.write(tasks)
    return updated


def delete_task(task_id: int) -> Optional[dict]:
    tasks = STORE.read()
    kept: list[dict] = []
    removed = None
    for task in tasks:
        if task["id"] == task_id:
            removed = task
            continue
        kept.append(task)
    if removed:
        STORE.write(kept)
    return removed