# ===------- file_same_as_stdout.py - File Same as stdout Directive -------===//
#
# Copyright 2019-2020 The IBM Research Authors.
#
# =============================================================================
#
# Verifies that a file is the same as stdout of some command execution.
#
# ===----------------------------------------------------------------------===//

import logging
import subprocess
import difflib
import sys

logger = logging.getLogger('doc-check')

from doc_parser import *
from utils import *


def handle(config, ctx):
    logger.debug(
        "Handling a file-same-as-stdout directive with config {}".format(
            config))

    # Read in file content.
    file = config["file"]
    with open(os.path.join(ctx.root_dir, file)) as f:
        file_content = f.read()

    # Execute command and retrieve output.
    cmd = config["cmd"]
    cmd_stdout = subprocess.run(cmd, stdout=subprocess.PIPE,
                                cwd=ctx.root_dir).stdout.decode('utf-8')

    # Compute diff.
    diff = difflib.unified_diff(file_content.splitlines(keepends=True),
                                cmd_stdout.splitlines(keepends=True),
                                fromfile=file,
                                tofile="$({})".format(" ".join(cmd)))
    diff = list(diff)

    # If diff is non-trivial, raise error and display diff.
    if len(diff):
        print("The folloing diff is detected:")
        sys.stdout.writelines(diff)
        raise ValueError("Check file-same-as-stdout failed")


ext_to_patterns = {'.dc': 'file-same-as-stdout\\(([^)]*)\\)'}