#!./venv/bin/python3

import bleach
import bottle
import configparser
import functools
import importlib
import json
import markdown
import timeago
import urllib3
import yaml
from datetime import datetime, timezone
from bottle import abort, get, jinja2_template as template, post, redirect, request, response, static_file
from urllib.parse import urlparse

# This is used to export the bottle object for a WSGI server
# See passenger_wsgi.py
application = bottle.app ()

# Load user settings for this app
with open ('settings.yaml', encoding='UTF-8') as file:
    settings = yaml.load (file)

# Directories to search for app templates
bottle.TEMPLATE_PATH = [ './freepost/templates' ]

# Custom settings and functions for templates
template = functools.partial (
    template,
    template_settings = {
        'filters': {
            'ago': lambda date: timeago.format (date),
            'datetime': lambda date: date.strftime ('%b %-d, %Y - %H:%M%p%z%Z'),
            'title': lambda date: date.strftime ('%b %-d, %Y - %H:%M%z%Z'),
            # Convert markdown to html
            'md2html': lambda text: bleach.clean (markdown.markdown (
                                        text,
                                        # https://python-markdown.github.io/extensions/
                                        extensions=[ 'extra', 'admonition', 'nl2br', 'smarty' ],
                                        output_format='html5')),
            # Get the domain part of a URL
            'netloc': lambda url: urlparse (url).netloc
        },
        'globals': {
            'new_messages': lambda user_id: database.count_unread_messages (user_id),
            'now': lambda: datetime.now (timezone.utc),
            'url': application.get_url,
            'session_user': lambda: session.user ()
        },
        'autoescape': True
    })

# "bleach" library is used to sanitize the HTML output of jinja2's "md2html"
# filter. The library has only a very restrictive list of white-listed
# tags, so we add some more here.
bleach.sanitizer.ALLOWED_TAGS += [ 'p', 'pre', 'img' ]
bleach.sanitizer.ALLOWED_ATTRIBUTES.update ({
    'img': [ 'src' ]
})

from freepost import database, session

# Decorator.
# Make sure user is logged in
def requires_login (controller):
    def wrapper ():
        session_token = request.get_cookie (
            key    = settings['session']['name'],
            secret = settings['cookies']['secret'])
        
        if database.is_valid_session (session_token):
            return controller ()
        else:
            redirect (application.get_url ('login'))
    
    return wrapper

# Decorator.
# Make sure user is logged out
def requires_logout (controller):
    def wrapper ():
        session_token = request.get_cookie (
            key    = settings['session']['name'],
            secret = settings['cookies']['secret'])
        
        if database.is_valid_session (session_token):
            redirect (application.get_url ('user'))
        else:
            return controller ()
    
    return wrapper

# Routes

@get ('/', name='homepage')
def homepage ():
    # Page number
    page = int (request.query.page or 0)
    
    if page < 0:
        redirect (application.get_url ('homepage'))
    
    user = session.user ()
    posts = database.get_hot_posts (page, user['id'] if user else None)
    
    return template (
        'homepage.html',
        page_number=page,
        posts=posts,
        sorting='hot')

@get ('/new', name='new')
def new ():
    # Page number
    page = int (request.query.page or 0)
    
    if page < 0:
        redirect (application.get_url ('homepage'))
    
    user = session.user ()
    posts = database.get_new_posts (page, user['id'] if user else None)
    
    return template (
        'homepage.html',
        page_number=page,
        posts=posts,
        sorting='new')

@get ('/about', name='about')
def about ():
    return template ('about.html')

@get ('/login', name='login')
@requires_logout
def login ():
    return template ('login.html')

@post ('/login')
@requires_logout
def login_check ():
    username = request.forms.get ('username')
    password = request.forms.get ('password')
    remember = 'remember' in request.forms
    
    if not username or not password:
        return template (
            'login.html',
            flash = 'Bad login!')
    
    # Check if user exists
    user = database.check_user_credentials (username, password)
    
    # Username/Password not working
    if not user:
        return template (
            'login.html',
            flash = 'Bad login!')
    
    session.start (user['id'], remember)
    
    redirect (application.get_url ('homepage'))

@get ('/register', name='register')
@requires_logout
def register ():
    return template ('register.html')

@post ('/register')
@requires_logout
def register_new_account ():
    username = request.forms.get ('username')
    password = request.forms.get ('password')
    
    # Normalize username
    username = username.strip ()
    
    if len (username) == 0 or database.username_exists (username):
        return template (
            'register.html',
            flash='Name taken, please choose another.')
    
    # Password too short?
    if len (password) < 8:
        return template (
            'register.html',
            flash = 'Password too short')
    
    # Username OK, Password OK: create new user
    database.new_user (username, password)
    
    # Retrieve user (check if it was created)
    user = database.check_user_credentials (username, password)
    
    # Something bad happened...
    if user is None:
        return template (
            'register.html',
            flash = 'An error has occurred, please try again.')
    
    # Start session...
    session.start (user['id'])
    
    # ... and go to the homepage of the new user
    redirect (application.get_url ('user'))

@get ('/logout', name='logout')
@requires_login
def logout ():
    session.close ()
    
    redirect (application.get_url ('homepage'))

@get ('/user', name='user')
@requires_login
def user_private_homepage ():
    return template ('user_private_homepage.html')

@post ('/user')
@requires_login
def update_user ():
    user = session.user ()
    
    about = request.forms.get ('about')
    email = request.forms.get ('email')
    
    if about is None or email is None:
        redirect (application.get_url ('user'))
    
    database.update_user (user['id'], about, email, False)
    
    redirect (application.get_url ('user'))

@get ('/user_activity/posts')
@requires_login
def user_posts ():
    user = session.user ()
    posts = database.get_user_posts (user['id'])
    
    return template ('user_posts.html', posts=posts)

@get ('/user_activity/comments')
@requires_login
def user_comments ():
    user = session.user ()
    comments = database.get_user_comments (user['id'])
    
    return template ('user_comments.html', comments=comments)

@get ('/user_activity/replies')
@requires_login
def user_replies ():
    user = session.user ()
    replies = database.get_user_replies (user['id'])
    
    database.set_replies_as_read (user['id'])
    
    return template ('user_replies.html', replies=replies)

@get ('/user/<username>', name='user_public')
def user_public_homepage (username):
    account = database.get_user_by_username (username)
    
    if account is None:
        redirect (application.get_url ('user'))
    
    return template ('user_public_homepage.html', account=account)

@get ('/post/<hash_id>', name='post')
def post_thread (hash_id):
    user = session.user ()
    post = database.get_post (hash_id, user['id'] if user else None)
    comments = database.get_post_comments (post['id'], user['id'] if user else None)
    
    # Group comments by parent
    comments_tree = {}
    
    for comment in comments:
        if comment['parentId'] is None:
            if 0 not in comments_tree:
                comments_tree[0] = []
            
            comments_tree[0].append (comment)
        else:
            if comment['parentId'] not in comments_tree:
                comments_tree[comment['parentId']] = []
            
            comments_tree[comment['parentId']].append (comment)
    
    # Build ordered list of comments (recourse tree)
    def children (parent_id = 0, depth = 0):
        temp_comments = []
        
        if parent_id in comments_tree:
            for comment in comments_tree[parent_id]:
                comment['depth'] = depth
                temp_comments.append (comment)
                
                temp_comments.extend (children (comment['id'], depth + 1))
        
        return temp_comments
    
    comments = children ()
    
    return template (
        'post.html',
        post=post,
        comments=comments,
        votes = {
            'post': {},
            'comment': {}
        })

@requires_login
@post ('/post/<hash_id>')
def new_comment (hash_id):
    user = session.user ()
    
    # The comment text
    comment = request.forms.get ('new_comment').strip ()
    
    # Empty comment
    if len (comment) == 0:
        redirect (application.get_url ('post', hash_id=hash_id))
    
    comment_hash_id = database.new_comment (comment, hash_id, user['id'])
    
    # Retrieve new comment
    comment = database.get_comment (comment_hash_id)
    
    # Automatically add an upvote for the original poster
    database.vote_comment (comment['id'], user['id'], +1)
    
    redirect (application.get_url ('post', hash_id=hash_id))

@requires_login
@get ('/edit/post/<hash_id>', name='edit_post')
def edit_post (hash_id):
    user = session.user ()
    post = database.get_post (hash_id, user['id'])
    
    # Make sure the session user is the actual poster/commenter
    if post['userId'] != user['id']:
        redirect (application.get_url ('post', hash_id=hash_id))
    
    return template ('edit_post.html', post=post)

@requires_login
@post ('/edit/post/<hash_id>')
def edit_post_check (hash_id):
    user = session.user ()
    post = database.get_post (hash_id, user['id'])
    
    # Make sure the session user is the actual poster/commenter
    if post['userId'] != user['id']:
        redirect (application.get_url ('homepage'))
    
    # MUST have a title. If empty, use original title
    title = request.forms.get ('title').strip ()
    if len (title) == 0: title = post['title']
    link  = request.forms.get ('link').strip () if 'link' in request.forms else ''
    text  = request.forms.get ('text').strip () if 'text' in request.forms else ''
    
    # If there is a URL, make sure it has a "scheme"
    if len (link) > 0 and urlparse (link).scheme == '':
        link = 'http://' + link
    
    # Update post
    database.update_post (title, link, text, hash_id, user['id'])
    
    redirect (application.get_url ('post', hash_id=hash_id))

@requires_login
@get ('/edit/comment/<hash_id>', name='edit_comment')
def edit_comment (hash_id):
    user = session.user ()
    comment = database.get_comment (hash_id, user['id'])
    
    # Make sure the session user is the actual poster/commenter
    if comment['userId'] != user['id']:
        redirect (application.get_url ('post', hash_id=comment['postHashId']))
    
    return template ('edit_comment.html', comment=comment)

@requires_login
@post ('/edit/comment/<hash_id>')
def edit_comment_check (hash_id):
    user = session.user ()
    comment = database.get_comment (hash_id, user['id'])
    
    # Make sure the session user is the actual poster/commenter
    if comment['userId'] != user['id']:
        redirect (application.get_url ('homepage'))
    
    text = request.forms.get ('text').strip () if 'text' in request.forms else ''
    
    # Only update if the text is not empty
    if len (text) > 0:
        database.update_comment (text, hash_id, user['id'])
    
    redirect (application.get_url ('post', hash_id=comment['postHashId']) + '#comment-' + hash_id)

@get ('/submit')
@requires_login
def submit ():
    return template ('submit.html')

@post ('/submit')
@requires_login
def submit_check ():
    # Somebody sent a <form> without a title???
    if 'title' not in request.forms or \
       'link'  not in request.forms or \
       'text'  not in request.forms:
        abort ()
    
    user = session.user ()
    
    # Retrieve title
    title = request.forms.get ('title').strip ()
    
    # Bad title?
    if len (title) == 0:
        return template ('submit.html', flash='Title is missing.')
    
    # Retrieve link
    link = request.forms.get ('link').strip ()
    
    # If there is a URL, make sure it has a "scheme"
    if len (link) > 0 and urlparse (link).scheme == '':
        link = 'http://' + link
    
    # Retrieve text
    text = request.forms.get ('text')
    
    # Add the new post
    post_hash_id = database.new_post (title, link, text, user['id'])
    
    # Retrieve new post
    post = database.get_post (post_hash_id)
    
    # Automatically add an upvote for the original poster
    database.vote_post (post['id'], user['id'], +1)
    
    # Posted. Now go the new post's page
    redirect (application.get_url ('post', hash_id=post_hash_id))

@requires_login
@get ('/reply/<hash_id>', name='reply')
def reply (hash_id):
    user = session.user ()
    
    # The comment to reply to
    comment = database.get_comment (hash_id)
    
    # Does the comment exist?
    if not comment:
        redirect (application.get_url ('homepage'))
    
    return template ('reply.html', comment=comment)

@requires_login
@post ('/reply/<hash_id>')
def reply_check (hash_id):
    user = session.user ()
    
    # The comment to reply to
    comment = database.get_comment (hash_id)
    
    # The text of the reply
    text = request.forms.get ('text').strip ()
    
    # Empty comment. Redirect to parent post
    if len (text) == 0:
        redirect (application.get_url ('post', hash_id=comment['postHashId']))
    
    # We have a text, add the reply and redirect to the new reply
    reply_hash_id = database.new_comment (text, comment['postHashId'], user['id'], comment['id'])
    
    # TODO upvote comment
    # TODO Increase comments count for post
    
    redirect (application.get_url ('post', hash_id=comment['postHashId']) + '#comment-' + reply_hash_id)

@requires_login
@post ('/vote', name='vote')
def vote ():
    user = session.user ()
    
    # Vote a post
    if request.forms.get ('target') == 'post':
        # Retrieve the post
        post = database.get_post (request.forms.get ('post'), user['id'])
        
        if not post:
            return
        
        # If user clicked the "upvote" button...
        if request.forms.get ('updown') == 'up':
            # If user has upvoted this post before...
            if post['user_vote'] == 1:
                # Remove +1
                database.vote_post (post['id'], user['id'], -1)
            # If user has downvoted this post before...
            elif post['user_vote'] == -1:
                # Change vote from -1 to +1
                database.vote_post (post['id'], user['id'], +2)
            # If user hasn't voted this post...
            else:
                # Add +1
                database.vote_post (post['id'], user['id'], +1)
        
        # If user clicked the "downvote" button...
        if request.forms.get ('updown') == 'down':
            # If user has downvoted this post before...
            if post['user_vote'] == -1:
                # Remove -1
                database.vote_post (post['id'], user['id'], +1)
            # If user has upvoted this post before...
            elif post['user_vote'] == 1:
                # Change vote from +1 to -1
                database.vote_post (post['id'], user['id'], -2)
            # If user hasn't voted this post...
            else:
                # Add -1
                database.vote_post (post['id'], user['id'], -1)
    
    # Vote a comment
    if request.forms.get ('target') == 'comment':
        # Retrieve the comment
        comment = database.get_comment (request.forms.get ('comment'), user['id'])
        
        if not comment:
            return
        
        # If user clicked the "upvote" button...
        if request.forms.get ('updown') == 'up':
            # If user has upvoted this comment before...
            if comment['user_vote'] == 1:
                # Remove +1
                database.vote_comment (comment['id'], user['id'], -1)
            # If user has downvoted this comment before...
            elif comment['user_vote'] == -1:
                # Change vote from -1 to +1
                database.vote_comment (comment['id'], user['id'], +2)
            # If user hasn't voted this comment...
            else:
                # Add +1
                database.vote_comment (comment['id'], user['id'], +1)
        
        # If user clicked the "downvote" button...
        if request.forms.get ('updown') == 'down':
            # If user has downvoted this comment before...
            if comment['user_vote'] == -1:
                # Remove -1
                database.vote_comment (comment['id'], user['id'], +1)
            # If user has upvoted this comment before...
            elif comment['user_vote'] == 1:
                # Change vote from +1 to -1
                database.vote_comment (comment['id'], user['id'], -2)
            # If user hasn't voted this comment...
            else:
                # Add -1
                database.vote_comment (comment['id'], user['id'], -1)

@get ('/search')
def search ():
    # Get the search query
    query = request.query.get ('q')
    
    # Results order
    order = request.query.get ('order')
    if order not in [ 'newest', 'points' ]:
        order = 'newest'
    
    results = database.search (query, order=order)
    
    if not results:
        results = []
    
    return template ('search.html', results=results, query=query, order=order)

@get ('/rss')
def rss_default ():
    return redirect (application.get_url ('rss', sorting='hot'))

# TODO check if <description> is correctly displayed in RSS aggregators
@get ('/rss/<sorting>', name='rss')
def rss (sorting):
    posts = []
    
    # Retrieve the hostname from the HTTP request.
    # This is used to build absolute URLs in the RSS feed.
    base_url = request.urlparts.scheme + '://' + request.urlparts.netloc
    
    if sorting == 'new':
        posts = database.get_new_posts ()
    
    if sorting == 'hot':
        posts = database.get_hot_posts ()
    
    # Set correct Content-Type header for this RSS feed
    response.content_type = 'application/rss+xml; charset=UTF-8'
    
    return template ('rss.xml', base_url=base_url, posts=posts)

@get ('/<filename:path>')
def static (filename):
    return static_file (filename, root='freepost/static/')