from __future__ import annotations

import json
import shutil
import subprocess
from datetime import datetime, timezone
from pathlib import Path
from typing import Any, Dict, Iterable, List, Optional

import yaml


UTC = timezone.utc


def now_utc() -> datetime:
    return datetime.now(tz=UTC)


def isoformat(dt: datetime) -> str:
    return dt.astimezone(UTC).replace(microsecond=0).isoformat()


def ensure_dir(path: Path) -> None:
    path.mkdir(parents=True, exist_ok=True)


def read_json(path: Path, default: Any = None) -> Any:
    if not path.exists():
        return default
    return json.loads(path.read_text(encoding="utf-8"))


def write_json(path: Path, data: Any) -> None:
    ensure_dir(path.parent)
    content = json.dumps(data, indent=2, ensure_ascii=True, sort_keys=False) + "\n"
    if path.exists() and path.read_text(encoding="utf-8") == content:
        return
    path.write_text(content, encoding="utf-8")


def read_yaml(path: Path, default: Any = None) -> Any:
    if not path.exists():
        return default
    with path.open("r", encoding="utf-8") as handle:
        return yaml.safe_load(handle)


def write_yaml(path: Path, data: Any) -> None:
    ensure_dir(path.parent)
    with path.open("w", encoding="utf-8") as handle:
        yaml.safe_dump(data, handle, allow_unicode=False, sort_keys=False)


def write_text(path: Path, content: str) -> None:
    ensure_dir(path.parent)
    rendered = content.rstrip() + "\n"
    if path.exists() and path.read_text(encoding="utf-8") == rendered:
        return
    path.write_text(rendered, encoding="utf-8")


def load_json_dir(path: Path) -> List[Dict[str, Any]]:
    if not path.exists():
        return []
    values: List[Dict[str, Any]] = []
    for file_path in sorted(path.glob("*.json")):
        content = read_json(file_path, default=None)
        if isinstance(content, dict):
            values.append(content)
    return values


def run(cmd: List[str], cwd: Optional[Path] = None, check: bool = False) -> subprocess.CompletedProcess:
    return subprocess.run(
        cmd,
        cwd=str(cwd) if cwd else None,
        text=True,
        capture_output=True,
        check=check,
    )


def command_available(name: str) -> bool:
    return shutil.which(name) is not None


def slugify(value: str) -> str:
    safe = []
    for ch in value.lower().strip():
        if ch.isalnum():
            safe.append(ch)
        else:
            safe.append("-")
    result = "".join(safe)
    while "--" in result:
        result = result.replace("--", "-")
    return result.strip("-") or "item"


def unique(values: Iterable[str]) -> List[str]:
    seen = set()
    result = []
    for value in values:
        if not value or value in seen:
            continue
        seen.add(value)
        result.append(value)
    return result