from __future__ import annotations

import os
import subprocess
from dataclasses import dataclass
from pathlib import Path
from typing import Sequence

from .redaction import redact_text


class CommandExecutionError(RuntimeError):
    def __init__(self, message: str, *, output: str = ""):
        super().__init__(message)
        self.output = redact_text(output)


@dataclass(frozen=True, slots=True)
class CommandResult:
    returncode: int
    stdout: str
    stderr: str

    @property
    def output(self) -> str:
        return redact_text("\n".join(part for part in (self.stdout, self.stderr) if part))


class SubprocessRunner:
    """Injectable no-shell subprocess boundary."""

    def run(
        self,
        argv: Sequence[str],
        *,
        timeout: int,
        cwd: Path | None = None,
        input_text: str | None = None,
    ) -> CommandResult:
        if not argv or any(not isinstance(arg, str) or "\x00" in arg for arg in argv):
            raise CommandExecutionError("Refusing to execute invalid argv.")
        env = os.environ.copy()
        env.update({"PIP_NO_INPUT": "1", "PYTHONUNBUFFERED": "1"})
        try:
            completed = subprocess.run(
                list(argv),
                cwd=str(cwd) if cwd else None,
                env=env,
                shell=False,
                check=False,
                text=True,
                input=input_text,
                stdin=subprocess.DEVNULL if input_text is None else None,
                capture_output=True,
                timeout=timeout,
            )
        except subprocess.TimeoutExpired as exc:
            output = "\n".join(
                str(value) for value in (getattr(exc, "stdout", ""), getattr(exc, "stderr", "")) if value
            )
            raise CommandExecutionError("Command timed out.", output=output) from exc
        except OSError as exc:
            raise CommandExecutionError(f"Unable to start command: {type(exc).__name__}") from exc
        result = CommandResult(completed.returncode, completed.stdout or "", completed.stderr or "")
        if completed.returncode != 0:
            raise CommandExecutionError(
                f"Command failed with exit code {completed.returncode}.", output=result.output
            )
        return result