from __future__ import annotations

from pathlib import Path
from typing import Callable, Optional
import sys

import requests

from models import ProgressBar


def sanitize_filename(name: str, *, max_len: int = 150) -> str:
    text = str(name or "").strip()
    if not text:
        return "download"

    forbidden = set('<>:"/\\|?*')
    cleaned = "".join("_" if c in forbidden else c for c in text)
    cleaned = " ".join(cleaned.split()).strip().strip(".")
    if not cleaned:
        cleaned = "download"
    return cleaned[:max_len]


def download_file(
    url: str,
    output_path: Path,
    *,
    session: Optional[requests.Session] = None,
    timeout_s: float = 30.0,
    progress_callback: Optional[Callable[[int,
                                          Optional[int],
                                          str],
                                         None]] = None,
) -> bool:
    output_path = Path(output_path)
    output_path.parent.mkdir(parents=True, exist_ok=True)

    s = session or requests.Session()

    bar = ProgressBar() if progress_callback is None else None
    downloaded = 0
    total = None

    try:
        with s.get(url, stream=True, timeout=timeout_s) as resp:
            resp.raise_for_status()
            try:
                total_val = int(resp.headers.get("content-length") or 0)
                total = total_val if total_val > 0 else None
            except Exception:
                total = None

            label = str(output_path.name or "download")

            # Render once immediately so fast downloads still show something.
            try:
                if progress_callback is not None:
                    progress_callback(0, total, label)
                elif bar is not None:
                    bar.update(downloaded=0, total=total, label=label, file=sys.stderr)
            except Exception:
                pass

            with open(output_path, "wb") as f:
                for chunk in resp.iter_content(chunk_size=1024 * 256):
                    if chunk:
                        f.write(chunk)
                        downloaded += len(chunk)
                        try:
                            if progress_callback is not None:
                                progress_callback(downloaded, total, label)
                            elif bar is not None:
                                bar.update(
                                    downloaded=downloaded,
                                    total=total,
                                    label=label,
                                    file=sys.stderr
                                )
                        except Exception:
                            pass

        try:
            if bar is not None:
                bar.finish()
        except Exception:
            pass
        return output_path.exists() and output_path.stat().st_size > 0
    except Exception:
        try:
            if bar is not None:
                bar.finish()
        except Exception:
            pass
        try:
            if output_path.exists():
                output_path.unlink()
        except Exception:
            pass
        return False