from __future__ import annotations

import subprocess
from dataclasses import dataclass
from pathlib import Path
from typing import Any

from scripts.video_analysis.error_types import ErrorInfo, make_error


@dataclass
class _Ok:
 value: Any

 def is_ok(self) -> bool:
  return True

 def is_err(self) -> bool:
  return False


@dataclass
class _Err:
 err: ErrorInfo

 def is_ok(self) -> bool:
  return False

 def is_err(self) -> bool:
  return True


def ok(value: Any) -> _Ok:
 return _Ok(value)


def err(error: ErrorInfo) -> _Err:
 return _Err(error)


def validate_output_path(path: Path) -> _Ok | _Err:
 if path.exists() and path.is_dir():
  return err(make_error("OutputIsDirectory", "validate_output_path", str(path)))
 path.parent.mkdir(parents=True, exist_ok=True)
 return ok(path)


def build_ydl_args(url: str, output: Path) -> list[str]:
 return [
  "yt-dlp",
  "--format", "bestvideo[ext=mp4]/best",
  "--output", str(output),
  "--no-warnings",
  "--quiet",
  url,
 ]


def download_video(url: str, output: Path) -> _Ok | _Err:
 validated = validate_output_path(output)
 if validated.is_err():
  return validated
 completed = subprocess.run(
  build_ydl_args(url, output),
  capture_output=True,
  text=True,
 )
 log_path = output.with_suffix(".log")
 log_path.write_text(
  f"# yt-dlp log\n# url: {url}\n# output: {output}\n# returncode: {completed.returncode}\n\nstdout:\n{completed.stdout}\n\nstderr:\n{completed.stderr}\n",
  encoding="utf-8",
 )
 if completed.returncode != 0:
  return err(make_error("YtdlpError", "download_video", completed.stderr[:500]))
 return ok({"output": str(output), "log": str(log_path), "returncode": completed.returncode})