import praw
import config
import json

ignored_subreddits = ["legaladvice",
                      "bestoflegaladvice",
                      "legaladviceofftopic"]


class load(object):
    def __init__(self, filename):
        self.filename = filename

        with open(self.filename, 'r') as f:
            self.data = json.load(f)

    def __enter__(self):
        return self.data

    def __exit__(self, type, value, tb):
        with open(self.filename, 'w') as f:
            json.dump(self.data, f, indent=4)


class URLError(Exception):
    pass


def login():
    """
    Returns a reddit instance using your bot login information in config.py
    Usage example: r = login()
    """
    return praw.Reddit(username=config.username,
                       password=config.password,
                       client_id=config.client_id,
                       client_secret=config.client_secret,
                       user_agent=config.user_agent)


def is_comment(thread, title, url):
    final_element = url[-1].split("_")[0]
    return final_element != str(thread) and final_element not in title.lower()


def post_comment_thread(reddit_instance, title, submission_obj):
    print("Comment thread!")


def post_thread(reddit_instance, title, submission_obj):
    body = submission_obj.selftext
    print("Title: " + title)
    print("Body: " + body)


def add_thread(thread):
    """
    Takes a submissionID and adds it to list of completed threads (set in config).
    """
    with load(config.filename) as subreddit_data:
        if thread not in subreddit_data["ThreadID"]:
            subreddit_data["ThreadID"].append(thread)


def url_splitter(url):
    """
    :param url: Reddit URL
    :return: Subreddit as string
             Target post as string
             Comment_thread as a boolean: True if comment thread
    """
    print(url)
    if "reddit" not in url:
        raise URLError("URL passed into function not from reddit.")

    # Split's URL on slashes, breaking the URL into its components.
    split_url = url.split("/")

    # Removes underscores
    split_url = list(filter(lambda x: x != '_', split_url))

    # Removes empty values
    url_components = list(filter(None, split_url))

    # Removes last element where it's a query - not useful for parsing data.
    while '?' in url_components[-1]:
        url_components.pop()

    return url_components


def clear_json():
    with load(config.filename) as jsondata:
        print("Are you sure you want to clear all previously worked threads?")
        print("WARNING: THIS COULD POST TWICE ON THE SAME COMMENT, WHICH BREAKS REDDIT TOS")
        if input("Please type 'I understand.': ") == "I understand.":
            jsondata["ThreadID"] = []
            print("Threads reset.")
        else:
            print("Threads not reset.")


def work_thread(submission, reddit_instance):
    url = url_splitter(submission.url)

    # The subreddit name is always immediately following /r/ in a reddit URL.
    subreddit = url[url.index("r")+1].lower()
    if subreddit not in ignored_subreddits:
        target_thread = url[url.index("comments")+1]
        target_thread_obj = reddit_instance.submission(target_thread)
        title = target_thread_obj.title

        if is_comment(target_thread, title, url):
            post_comment_thread(reddit_instance, title, target_thread_obj)
        else:
            post_thread(reddit_instance, title, target_thread_obj)


def main(reddit_instance):
    bola = reddit_instance.subreddit("bestoflegaladvice")
    for submission in bola.stream.submissions():
        threadID = str(submission)

        with open(config.filename, 'r') as f:
            jsondata = json.load(f)
            # Checks to see if thread has already been worked. If it has, skips.
            if threadID not in jsondata["ThreadID"]:
                add_thread(str(submission))
                try:
                    work_thread(submission, reddit_instance)
                except URLError:
                    pass


clear_json()
if __name__ == "__main__":
    main(login())