from __future__ import annotations

import json
import time
from dataclasses import dataclass
from pathlib import Path

from modules.display_control import set_brightness


ROOT = Path(__file__).resolve().parents[1]
SCHEDULE_PATH = ROOT / "data" / "brightness_schedule.json"


@dataclass(frozen=True, slots=True)
class ScheduleItem:
    at: str  # "HH:MM" 24h
    value: int


def _load_schedule() -> list[ScheduleItem]:
    if not SCHEDULE_PATH.exists():
        SCHEDULE_PATH.parent.mkdir(parents=True, exist_ok=True)
        SCHEDULE_PATH.write_text(
            json.dumps(
                {
                    "enabled": True,
                    "items": [
                        {"at": "07:00", "value": 80},
                        {"at": "22:00", "value": 30},
                    ],
                },
                indent=2,
            ),
            encoding="utf-8",
        )
    try:
        data = json.loads(SCHEDULE_PATH.read_text(encoding="utf-8"))
    except Exception:
        return []
    if not bool(data.get("enabled", True)):
        return []
    items = []
    for it in data.get("items", []):
        at = str(it.get("at", "")).strip()
        if not at or ":" not in at:
            continue
        try:
            v = int(it.get("value", 50))
        except Exception:
            v = 50
        items.append(ScheduleItem(at=at, value=max(0, min(100, v))))
    return sorted(items, key=lambda x: x.at)


def run_loop(poll_seconds: int = 20) -> None:
    """Background scheduler. Applies brightness at the matching minute boundary."""
    last_minute = ""
    while True:
        items = _load_schedule()
        if not items:
            time.sleep(max(5, int(poll_seconds)))
            continue
        now = time.localtime()
        minute = f"{now.tm_hour:02d}:{now.tm_min:02d}"
        if minute != last_minute:
            last_minute = minute
            for it in items:
                if it.at == minute:
                    set_brightness(it.value)
                    break
        time.sleep(max(5, int(poll_seconds)))