import json
import secrets
from datetime import datetime, timezone
from pathlib import Path

SETTINGS_PATH = Path(__file__).parent.parent / "settings.json"


def _now():
    return datetime.now(timezone.utc).isoformat().replace("+00:00", "Z")


def _read():
    if not SETTINGS_PATH.exists():
        return {"openai_api_key": "", "presets": []}
    return json.loads(SETTINGS_PATH.read_text(encoding="utf-8"))


def _write(data):
    tmp = SETTINGS_PATH.with_suffix(".tmp")
    tmp.write_text(json.dumps(data, indent=2), encoding="utf-8")
    tmp.replace(SETTINGS_PATH)


def list_presets():
    return _read()["presets"]


def create_preset(name, description, template, variables):
    data = _read()
    preset = {
        "id": secrets.token_hex(4),
        "name": name,
        "description": description,
        "template": template,
        "variables": variables,
        "created_at": _now(),
        "updated_at": _now(),
    }
    data["presets"].append(preset)
    _write(data)
    return preset


def update_preset(preset_id, fields):
    data = _read()
    for p in data["presets"]:
        if p["id"] == preset_id:
            p.update(fields)
            p["updated_at"] = _now()
            _write(data)
            return p
    return None


def delete_preset(preset_id):
    data = _read()
    before = len(data["presets"])
    data["presets"] = [p for p in data["presets"] if p["id"] != preset_id]
    if len(data["presets"]) == before:
        return False
    _write(data)
    return True


def get_openai_key():
    return _read().get("openai_api_key", "")


def set_openai_key(key: str):
    data = _read()
    data["openai_api_key"] = key
    _write(data)