from __future__ import annotations

import json
from pathlib import Path
from datetime import datetime

from app.core.config import settings


def domain_root() -> Path:
    return Path(settings.domain_root)


def read_json(relative_path: str, default: dict | list | None = None):
    path = domain_root() / relative_path
    if not path.exists():
        return {} if default is None else default
    with path.open("r", encoding="utf-8") as handle:
        return json.load(handle)


def write_json(relative_path: str, payload) -> None:
    path = domain_root() / relative_path
    path.parent.mkdir(parents=True, exist_ok=True)
    with path.open("w", encoding="utf-8") as handle:
        json.dump(payload, handle, ensure_ascii=False, indent=2)


def tail_lines(relative_path: str, max_lines: int = 120) -> list[str]:
    path = domain_root() / relative_path
    if not path.exists():
        return []
    with path.open("r", encoding="utf-8", errors="replace") as handle:
        return handle.read().splitlines()[-max_lines:]


def runtime_root() -> Path:
    path = Path(__file__).resolve().parents[2] / "runtime"
    path.mkdir(parents=True, exist_ok=True)
    return path


def read_runtime_json(filename: str, default: dict | list | None = None):
    path = runtime_root() / filename
    if not path.exists():
        return {} if default is None else default
    with path.open("r", encoding="utf-8") as handle:
        return json.load(handle)


def write_runtime_json(filename: str, payload) -> None:
    path = runtime_root() / filename
    path.parent.mkdir(parents=True, exist_ok=True)
    with path.open("w", encoding="utf-8") as handle:
        json.dump(payload, handle, ensure_ascii=False, indent=2, default=str)


def exports_root() -> Path:
    path = runtime_root() / "exports"
    path.mkdir(parents=True, exist_ok=True)
    return path


def import_root() -> Path:
    path = runtime_root() / "imports"
    path.mkdir(parents=True, exist_ok=True)
    return path


def settings_backup_root() -> Path:
    path = runtime_root() / "settings_backups"
    path.mkdir(parents=True, exist_ok=True)
    return path


def load_export_records() -> list[dict]:
    path = runtime_root() / "export_tasks.json"
    if not path.exists():
        return []
    with path.open("r", encoding="utf-8") as handle:
        return json.load(handle)


def save_export_record(record: dict) -> None:
    records = load_export_records()
    records.insert(0, record)
    path = runtime_root() / "export_tasks.json"
    with path.open("w", encoding="utf-8") as handle:
        json.dump(records[:200], handle, ensure_ascii=False, indent=2, default=str)


def load_import_records() -> list[dict]:
    path = runtime_root() / "import_tasks.json"
    if not path.exists():
        return []
    with path.open("r", encoding="utf-8") as handle:
        return json.load(handle)


def save_import_records(records: list[dict]) -> None:
    path = runtime_root() / "import_tasks.json"
    with path.open("w", encoding="utf-8") as handle:
        json.dump(records[:200], handle, ensure_ascii=False, indent=2, default=str)


def timestamp_filename(prefix: str, ext: str) -> str:
    return f"{prefix}_{datetime.now().strftime('%Y%m%d_%H%M%S')}.{ext}"