from functools import wraps
from flask import Flask, abort, render_template, flash, url_for, redirect, request, session, Response
from flaskext.sqlalchemy import SQLAlchemy
from wtforms import Form, TextField, TextAreaField, IntegerField, SelectField, validators

# INITIALISE FLASK
app = Flask(__name__)
app.config.from_pyfile('config.cfg')


# DEFINE MODEL(S)
db = SQLAlchemy(app)

class Page(db.Model):
    __tablename__ = 'pages'
    id          = db.Column(db.Integer, primary_key=True)
    title       = db.Column(db.String(100), nullable=False)
    content     = db.Column(db.Text, nullable=False)
    parent_id   = db.Column(db.Integer, db.ForeignKey("pages.id"), nullable=True)
    children    = db.relationship("Page", backref=db.backref("parent", remote_side=id))

    def __init__(self, title, content, parent_id=None):
        self.title = title
        self.content = content
        if parent_id:
            self.parent_id = parent_id

    def __repr__(self):
        return '<Page "%r">' % self.title


# DEFINE FORMS
class PageForm(Form):
    title   = TextField('Page Title', validators=[validators.Required()])
    content = TextAreaField('Page Content', validators=[validators.Required()])
    parent  = IntegerField('Parent Page ID (optional)', validators=[validators.optional()])
    #parent  = SelectField('Parent Page (Optional)', coerce=int)


# DISPLAY FUNCTIONS
@app.errorhandler(404)
def page_not_found(error):
    return render_template('404.html'), 404

@app.route('/')
def list_pages():
    '''Grab all top level pages and display them'''
    pages = Page.query.filter_by(parent_id=None)
    return render_template('list_pages.html', pages=pages)

@app.route('/<int:page_id>')
def display_page(page_id):
    '''Get the page content and it's children and
    display them
    '''
    page = Page.query.get(page_id)
    if not page:
        abort(404)
    title = page.title
    content = page.content
    sub_pages = Page.query.filter_by(parent_id=page_id)
    return render_template('page.html', title=title,
                           content=content, sub_pages=sub_pages)


# ADMIN HEPER FUNCTIONS
def check_auth(username, password):
    """This function is called to check if a username /
    password combination is valid.
    """
    return username == app.config['USERNAME'] and password == app.config['PASSWORD']

def authenticate():
    """Sends a 401 response that enables basic auth"""
    return Response(
    'Could not verify your access level for that URL.\n'
    'You have to login with proper credentials', 401,
    {'WWW-Authenticate': 'Basic realm="Login Required"'})

def requires_auth(f):
    @wraps(f)
    def decorated(*args, **kwargs):
        auth = request.authorization
        if not auth or not check_auth(auth.username, auth.password):
            return authenticate()
        return f(*args, **kwargs)
    return decorated


#ADMIN FUNCTIONS
@app.route('/admin/')
@requires_auth
def admin_page():
    '''Grab all pages and list so user can edit'''
    pages = Page.query.all()
    if not pages:
        return render_template('down.html')
    return render_template('admin_home.html', pages=pages)

@app.route('/admin/new/', methods=['GET','POST'])
@requires_auth
def new_page():
    '''Display edit form and add all data from submitted
    forms into the database'''
    form = PageForm(request.form)
    if request.method == 'POST' and form.validate():
        page = Page(form.title.data, form.content.data, form.parent.data)
        db.session.add(page)
        if db.session.commit():
            flash('Page was added successfully', 'success')
        else:
            flash('There was an error when inserting the page into the database',
                  'error')
        return redirect(url_for('list_pages'))
    return render_template('admin_new.html', form=form)

@app.route('/admin/edit/<int:page_id>', methods=['GET','POST'])
@requires_auth
def edit_page(page_id):
    '''Grab data for the specified page and insert into the
    form, then grab the submitted form and update the page
    '''
    page = Page.query.get(page_id)
    if not page:
        abort(404)
    form = PageForm(request.form)
    if request.method == 'POST' and form.validate():
        page = Page(form.title.data, form.content.data, form.parent.data)
        if db.session.commit():
            flash('Page was edited successfully', 'success')
        else:
            flash('There was an error when updating the page in the database',
                  'error')
        return redirect(url_for('list_pages'))
    form.title.data = page.title
    form.content.data = page.content
    form.parent.data = page.parent_id
    return render_template('admin_edit.html', form=form, page_edit_id=page_id)

# RUN APP
if __name__ == '__main__':
    app.run()