#!/usr/bin/env python3
#
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from tempfile import TemporaryFile
import os
import subprocess
import sys

from style.repo import GitRepo
from style.verifiers import all_verifiers, all_regions
from style.style import StdioUI, check_ignores

import argparse

parser = argparse.ArgumentParser(
    description="gem5 git style checker hook")

parser.add_argument("--verbose", "-v", action="store_true",
                    help="Produce verbose output")

args = parser.parse_args()

git = GitRepo()

opts = {}
repo_base = git.repo_base()
ui = StdioUI()

os.chdir(repo_base)
failing_files = set()
staged_mismatch = set()

for status, fname in git.status(filter="MA", cached=True):
    if args.verbose:
        print("Checking {}...".format(fname))
    if check_ignores(fname):
        continue
    if status == "M":
        regions = git.staged_regions(fname)
    else:
        regions = all_regions

    # Show the appropriate object and dump it to a file
    try:
        status = git.file_from_index(fname)
    except UnicodeDecodeError:
        print("Decoding '" + fname
            + "' throws a UnicodeDecodeError.", file=sys.stderr)
        print("Please check '" + fname
            + "' exclusively uses utf-8 character encoding.", file=sys.stderr)
        sys.exit(1)

    f = TemporaryFile()
    f.write(status.encode('utf-8'))

    verifiers = [ v(ui, opts, base=repo_base) for v in all_verifiers ]
    for v in verifiers:
        f.seek(0)
        # It is prefered that the first check is silent as it is in the
        # staged file. If the check fails, then we will do it non-silently
        # on the current file, reporting meaningful shortcomings
        if not v.skip(fname) and v.check(fname, regions, fobj=f, silent=True):
            failing_files.add(fname)
            if not v.check(fname, regions):
                staged_mismatch.add(fname)
    f.close()

if failing_files:
    if len(failing_files) > len(staged_mismatch):
        print("\n", file=sys.stderr)
        print("Style checker failed for the following files:", file=sys.stderr)
        for f in failing_files:
            if f not in staged_mismatch:
                print("\t{}".format(f), file=sys.stderr)
        print("\n", file=sys.stderr)
        print(
            "Please run the style checker manually to fix "
            "the offending files.\n"
            "To check your modifications, run: util/style.py -m",
            file=sys.stderr)

    print("\n", file=sys.stderr)
    if staged_mismatch:
        print(
            "It looks like you have forgotten to stage your "
            "fixes for commit in\n"
            "the following files: ", file=sys.stderr)
        for f in staged_mismatch:
            print("\t{}".format(f), file=sys.stderr)
        print("Please `git --add' them", file=sys.stderr)
    sys.exit(1)
