from __future__ import absolute_import
from __future__ import print_function
from __future__ import unicode_literals

import contextlib
import os.path
import sys
import traceback

import six

import pre_commit.constants as C
from pre_commit import five
from pre_commit import output
from pre_commit.store import Store


class FatalError(RuntimeError):
    pass


def _to_bytes(exc):
    try:
        return bytes(exc)
    except Exception:
        return six.text_type(exc).encode('UTF-8')


def _log_and_exit(msg, exc, formatted):
    error_msg = b''.join((
        five.to_bytes(msg), b': ',
        five.to_bytes(type(exc).__name__), b': ',
        _to_bytes(exc), b'\n',
    ))
    output.write(error_msg)
    store = Store()
    log_path = os.path.join(store.directory, 'pre-commit.log')
    output.write_line('Check the log at {}'.format(log_path))

    meta_info_msg = '### version information\n```\n'
    meta_info_msg += 'pre-commit.version: {}\n'.format(C.VERSION)
    meta_info_msg += 'sys.version: \n{}\n'.format(
        '\n'.join(
            [
                '\t{}'.format(line)
                for line in sys.version.splitlines()
            ],
        ),
    )
    meta_info_msg += 'sys.executable: {}\n'.format(sys.executable)
    meta_info_msg += 'os.name: {}\n'.format(os.name)
    meta_info_msg += 'sys.platform: {}\n```\n'.format(sys.platform)
    meta_info_msg += '### error information\n```\n'
    with open(log_path, 'wb') as log:
        output.write(meta_info_msg, stream=log)
        output.write(error_msg, stream=log)
        output.write_line(formatted, stream=log)
        output.write('\n```\n', stream=log)
    raise SystemExit(1)


@contextlib.contextmanager
def error_handler():
    try:
        yield
    except (Exception, KeyboardInterrupt) as e:
        if isinstance(e, FatalError):
            msg = 'An error has occurred'
        elif isinstance(e, KeyboardInterrupt):
            msg = 'Interrupted (^C)'
        else:
            msg = 'An unexpected error has occurred'
        _log_and_exit(msg, e, traceback.format_exc())