import os
import shutil
import re

from coalib.bears.GlobalBear import GlobalBear
from coalib.results.HiddenResult import HiddenResult
from coalib.results.Result import Result
from coala_utils.ContextManagers import change_directory
from coalib.misc.Shell import run_shell_command
from dependency_management.requirements.PipRequirement import PipRequirement


class CommitResult(HiddenResult):
    def run(self):
        yield HiddenResult(self, commit_info)

class VCSCommitBear(GlobalBear):
    LANGUAGES = {'Git'}
    REQUIREMENTS = {PipRequirement('nltk', '3.2')}
    AUTHORS = {'The coala developers'}
    AUTHORS_EMAILS = {'coala-devel@googlegroups.com'}
    LICENSE = 'AGPL-3.0'

    @classmethod
    def check_prerequisites(cls):
        if shutil.which('git') is None:
            return 'git is not installed.'
        else:
            return True

    def analyze_git_commit(self, stdout, commit_sha):
        commit_info = dict()

        commit_type = []
        if len(stdout) == 0:
            speciacommit_type.append('empty_commit')

        stdout = stdout.rstrip('\n')

        if stdout.startswith('Revert '):
            commit_type.append('revert_commit')

        if 'ci skip' in stdout or 'skip ci' in stdout:
            commit_type.append('ci_skip_commit')

        get_parent_commits = 'git log --pretty=%P -n 1 ' + commit_sha
        parent_commits, _ = run_shell_command(get_parent_commits)
        parent_commits_list = parent_commits.split('\n')

        if len(parent_commits_list) > 2:
            commit_type.append('merge_commit')

        get_modified_files = 'git show --pretty="" --name-only ' + commit_sha
        modified_files, _ = run_shell_command(get_modified_files)
        modified_files_list = modified_files.split('\n')

        commit_info['commit_sha'] = commit_sha
        commit_info['commit_type'] = commit_type
        commit_info['modified_files'] = modified_files_list

        return commit_info

    def run(self):
        with change_directory(self.get_config_dir() or os.getcwd()):
            stdout, stderr = run_shell_command('git log -1 --pretty=%B')

        if stderr:
            self.err('git:', repr(stderr))
            return

        commit_sha = run_shell_command('git rev-parse HEAD')[0].strip('\n')
        commit_info = self.analyze_git_commit(stdout, commit_sha)

        yield CommitResult(self, (commit_info,), "HEAD commit information")