#!/usr/bin/env python
import os
import argparse
from collections import Counter

import ast
from nltk import pos_tag


DEFAULT_PATH = '.'
DEFAULT_STATS_SIZE = 10
DEFAULT_SCANNING_PROJECTS = (
    'django',
    'flask',
    'pyramid',
    'reddit',
    'requests',
    'sqlalchemy',
)


def get_console_or_default_args(default_path, default_stats_size):
    parser = argparse.ArgumentParser(description='Finds verbs in python code')
    parser.add_argument(
        '--path',
        '-p',
        default=default_path,
        help='a path of scanning directory'
    )
    parser.add_argument(
        '--projects',
        help='a comma separated list of projects we are going to scan'
    )
    parser.add_argument(
        '--stats_limit',
        '-l',
        default=default_stats_size,
        type=int,
        help='a limit of verbs in stats'
    )
    return parser.parse_args()


def seek_python_files(_path, limit_of_files_amount=None):
    paths_to_python_files = []
    for dir_name, _dirs, files in os.walk(_path, topdown=True):
        python_files = filter(lambda x: x.endswith('.py'), files)
        paths_to_python_files += map(lambda x, d=dir_name: os.path.join(d, x),
                                     python_files)
    return paths_to_python_files[:limit_of_files_amount]


def load_file_content(path_to_file):
    with open(path_to_file, encoding='utf-8') as file_handler:
        return file_handler.read()


def make_ast_trees_list(files_paths_list):
    trees = []
    for file_path in files_paths_list:
        try:
            trees.append(ast.parse(load_file_content(file_path)))
        except SyntaxError:
            pass
    return trees


def get_nodes_names_from_ast_trees(ast_trees):
    names_of_ast_nodes = []
    for ast_tree in ast_trees:
        names_of_ast_nodes += [node.name.lower() for node in ast.walk(ast_tree)
                               if isinstance(node, ast.FunctionDef)]
    return names_of_ast_nodes


def is_verb(word):
    if not word:
        return False
    index_of_tuple_tagged_word = 0
    tagged_as_verb = 'VB'
    word, nltk_tag = pos_tag([word])[index_of_tuple_tagged_word]
    return nltk_tag.startswith(tagged_as_verb)


def get_verbs_from_nodes_names(nodes_names_list):
    verbs = []
    for node_name in nodes_names_list:
        verbs += [word for word in node_name.split('_') if is_verb(word)]
    return verbs


def get_top_verbs(_verbs_list, _stats_size):
    return Counter(_verbs_list).most_common(_stats_size)


def print_project_stats(verbs_list, _project):
    if verbs_list:
        print('The stats of using verbs in function names of {} project:'.
              format(_project))
        for verb, count in verbs_list:
            print(' \'{}\' used {} times'.format(verb, count))
    else:
        print('There is no stats for \'{}\' project'.format(_project))
    print('\r')


def update_total_stats(_verbs_list, _verbs_dict):
    for verb, count in _verbs_list:
        _verbs_dict[verb] = _verbs_dict.get(verb, 0) + count
    return _verbs_dict


def print_total_stats(verb_dict):
    if verb_dict:
        print('Total stats:')
        for verb, count in sorted(verb_dict.items(), key=lambda x: x[1],
                                  reverse=True):
            print(' \'{}\' used {} times'.format(verb, count))


if __name__ == '__main__':
    args = get_console_or_default_args(DEFAULT_PATH, DEFAULT_STATS_SIZE)

    if args.projects:
        scanning_projects = args.projects.split(',')
    else:
        scanning_projects = DEFAULT_SCANNING_PROJECTS

    total_verbs_dict = {}

    for project in scanning_projects:
        scanning_path = os.path.join(args.path, project)
        list_of_python_files = seek_python_files(scanning_path)
        ast_trees_list = make_ast_trees_list(list_of_python_files)
        list_of_nodes_names = get_nodes_names_from_ast_trees(ast_trees_list)
        list_of_verbs = get_verbs_from_nodes_names(list_of_nodes_names)
        top_verbs_list = get_top_verbs(list_of_verbs, args.stats_limit)

        print_project_stats(top_verbs_list, project)
        total_verbs_dict = update_total_stats(top_verbs_list, total_verbs_dict)

    print_total_stats(total_verbs_dict)