import subprocess, tempfile, shutil, traceback, importlib.util
import concurrent.futures
import os

class CodeExecutor:
    def __init__(self):
        self.temp_dir = tempfile.TemporaryDirectory()
        self.executor = concurrent.futures.ThreadPoolExecutor(max_workers=1)

    def _install_packages(self, packages):
        for package in packages:
            package = package.strip()
            if not package:
                continue
            try:
                spec = importlib.util.find_spec(package)
                if spec is None:
                    subprocess.check_call(["pip", "install", package], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, timeout=15)
            except subprocess.CalledProcessError as e:
                raise Exception(f"❌ Error installing package {package}: {e}")
            except subprocess.TimeoutExpired:
                raise Exception(f"⏰ Timed out installing package {package}")

    def _execute_code(self, code, inputs):
        temp_file = f"{self.temp_dir.name}/user_code.py"
        output_file = f"{self.temp_dir.name}/stdout.txt"
        error_file = f"{self.temp_dir.name}/stderr.txt"

        with open(temp_file, "w") as f:
            f.write(code)

        with open(output_file, "w") as out, open(error_file, "w") as err:
            try:
                process = subprocess.Popen(
                    ["python", temp_file],
                    stdin=subprocess.PIPE,
                    stdout=out,
                    stderr=err,
                    text=True
                )
                if inputs:
                    for line in inputs:
                        process.stdin.write(line + "\n")
                process.stdin.close()
                process.wait(timeout=15)
            except subprocess.TimeoutExpired:
                process.kill()
                err.write("⏰ Execution timed out.\n")
            except Exception:
                err.write(traceback.format_exc())

        with open(output_file, "r") as out, open(error_file, "r") as err:
            output_text = out.read().strip()
            error_text = err.read().strip()

            if error_text:
                return f"⚠️ Error:\n{error_text}"
            return f"✅ Output:\n{output_text}"

    def execute(self, code, inputs, packages):
        if packages:
            self._install_packages(packages.split(","))
        future = self.executor.submit(self._execute_code, code, inputs)
        try:
            return future.result(timeout=20)
        except concurrent.futures.TimeoutError:
            return "⏳ Code execution exceeded time limit."
        except Exception as e:
            return f"❌ Execution Error: {e}"

    def __del__(self):
        self.executor.shutdown(wait=False)
        shutil.rmtree(self.temp_dir.name)