#!/usr/bin/env python3

"""
A script to run a lambda function locally, accepting event JSON and
importing the lambda_function from a specified directory.
"""

import sys
import json
import logging
from pathlib import Path
import importlib.util

import argh
from argh import arg

__version__ = "0.1.1"

logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.INFO)


class BinaryEncoder(json.JSONEncoder):
    """JSON encoder that handles bytes by decoding them to UTF-8 strings."""
    def default(self, obj):
        if isinstance(obj, bytes):
            return obj.decode("utf-8", errors="replace")
        return super().default(obj)


@arg("directory", help="directory containing lambda_function.py")
def run_lambda(directory: str) -> None:
    """
    Run a lambda function locally, accepting event JSON from stdin and
    importing the lambda_function from a specified directory.
    """
    sys.path.insert(0, directory)
    import lambda_function

    # Load the event JSON from STDIN
    event = json.loads(sys.stdin.read())

    # Run lambda function
    response = lambda_function.lambda_handler(event, None)

    if response.get("statusCode") == 200 and "body" in response:
        if isinstance(response["body"], bytes):
            response["body"] = response["body"].decode("utf-8")
        print(json.dumps(response["body"], indent=2, cls=BinaryEncoder))
    else:
        print(json.dumps(response, indent=2, cls=BinaryEncoder))
        sys.exit(1)


if __name__ == "__main__":
    argh.dispatch_command(run_lambda)