import datetime as datetime
from urllib.parse import urlparse
import webbrowser
from emailtool.emailer import Emailer
from flask import Flask, render_template, request, redirect, url_for, session, send_file
from gevent.pywsgi import WSGIServer
import socket
import logging
from peewee import Model, CharField, DateTimeField, SqliteDatabase, BooleanField, fn
import hashlib
import os
import csv

db_name = 'app.db'
db = SqliteDatabase(db_name)


class User(Model):
    username = CharField()
    password = CharField()
    date_created = DateTimeField(default=datetime.datetime.now)
    logged_in = BooleanField(default=False)

    class Meta:
        database = db


class IlsUser(Model):
    username = CharField()
    email = CharField()
    reset_datetime = DateTimeField(default=datetime.datetime.now)

    class Meta:
        database = db


class Settings(Model):
    name = CharField()
    value = CharField()

    class Meta:
        database = db


class Schedule(Model):
    interval = CharField()

    class Meta:
        database = db


class Log(Model):
    date = DateTimeField(default=datetime.datetime.now)
    username = CharField()
    action = CharField()

    class Meta:
        database = db


class PasswordResetLog(Model):
    date = DateTimeField(default=datetime.datetime.now)
    username = CharField()

    class Meta:
        database = db


settings = Settings.select().execute()

debug_setting = Settings.get(Settings.name == 'Debug Mode')
debug = debug_setting.value

http_port_setting = Settings.get(Settings.name == 'HTTP Port')
http_port = http_port_setting.value

smtp_host_setting = Settings.get(Settings.name == 'SMTP Host')
smtp_host = smtp_host_setting.value

smtp_port_setting = Settings.get(Settings.name == 'SMTP Port')
smtp_port = smtp_port_setting.value

smtp_username_setting = Settings.get(Settings.name == 'SMTP Username')
smtp_username = smtp_username_setting.value

smtp_password_setting = Settings.get(Settings.name == 'SMTP Password')
smtp_password = smtp_password_setting.value

domain_name_setting = Settings.get(Settings.name == 'Domain Name')
domain_name = domain_name_setting.value

password_reset_url_setting = Settings.get(Settings.name == 'Password Reset URL')
password_reset_url = password_reset_url_setting.value

log = logging.getLogger('werkzeug')
log.setLevel(logging.INFO)

if debug.lower() == 'true':
    debug = True
else:
    debug = False


def send_email(to, subject, body):
    # Get settings from smtp_settings
    host = smtp_host
    port = smtp_port
    username = smtp_username
    password = smtp_password

    # Create an instance of the Emailer class
    emailer = Emailer(host, port, username, password)
    # Call the send_email method
    emailer.send_email(to, subject, body)


# Encrypt the password with SHA256
def encrypt_password(password):
    hash = hashlib.sha256(password.encode('utf-8')).hexdigest()
    return hash


def shutdown_session(exception=None):
    print('Stopping HTTP Service...')
    http_server.stop()


# Get the systems hostname
def get_hostname():
    return socket.gethostname()


# Get systems IP address
def get_ip_address():
    return socket.gethostbyname(socket.gethostname())


# Method to check if a URL is valid using regex
def is_valid_url(url):
    try:
        result = urlparse(url)
        if all([result.scheme, result.netloc]):
            url = '{uri.scheme}://{uri.netloc}/'.format(uri=result)
        else:
            url = False
        return url
    except:
        return False


def requires_auth():
    if 'username' in session:
        username = session['username']
        user = User.get(User.username == username)
        if user.logged_in is True:
            return True
        else:
            return False
    else:
        return False


# Check for DB tables and create if they don't exist
if db.table_exists('user') is False:
    db.create_tables([User, IlsUser])
    User.create(username='admin', password=encrypt_password('admin'),
                date_created=datetime.datetime.now(), logged_in=False).save()

if db.table_exists('ilsuser') is False:
    db.create_tables([IlsUser])

if db.table_exists('settings') is False:
    db.create_tables([Settings])
    Settings.create(name='Debug Mode', value=False).save()
    Settings.create(name='HTTP Port', value=5055).save()
    Settings.create(name='SMTP Host', value="").save()
    Settings.create(name='SMTP Port', value="587").save()
    Settings.create(name='SMTP Username', value="").save()
    Settings.create(name='SMTP Password', value="").save()
    Settings.create(name='Domain Name', value="lynx").save()
    Settings.create(name='Password Reset URL', value="https://terminal.idaho-lynx.org").save()

if db.table_exists('log') is False:
    db.create_tables([Log])

if db.table_exists('password_reset_log') is False:
    db.create_tables([PasswordResetLog])

if db.table_exists('schedule') is False:
    db.create_tables([Schedule])

db.close()

app = Flask(__name__)
app.secret_key = os.urandom(24)


def format_time_ago(timestamp):
    """Calculate the time passed since a datetime stamp and format it as a human-readable string."""
    now = datetime.datetime.utcnow()
    diff = now - timestamp

    if diff.days > 365:
        years = diff.days // 365
        return f"{years} year{'s' if years > 1 else ''} ago"

    if diff.days > 30:
        months = diff.days // 30
        return f"{months} month{'s' if months > 1 else ''} ago"

    if diff.days > 0:
        return f"{diff.days} day{'s' if diff.days > 1 else ''} ago"

    if diff.seconds > 3600:
        hours = diff.seconds // 3600
        return f"{hours} hour{'s' if hours > 1 else ''} ago"

    if diff.seconds > 60:
        minutes = diff.seconds // 60
        return f"{minutes} minute{'s' if minutes > 1 else ''} ago"

    return "just now"


app.jinja_env.filters['time_since'] = format_time_ago


@app.before_request
def before_request():
    db.connect()


@app.after_request
def after_request(response):
    db.close()
    return response


# Create a route for the home page
@app.route('/', methods=['GET', 'POST'])
def index():
    # send_email('aday@twinfallspubliclibrary.org', 'TEST', 'This is a test email')
    error = None
    reset = False
    reset_url = is_valid_url(password_reset_url)
    reset_url_error = False

    if reset_url is False:
        reset_url_error = True

    if request.method == 'POST':
        username = request.form.get('username')

        # Check for the username in the DB
        try:
            user = IlsUser.filter(IlsUser.username == username).first()
        except Exception as e:
            print(e)
            user = None

        if user:
            # Reset login datetime
            user.reset_datetime = datetime.datetime.now()
            PasswordResetLog.create(username=user.username, date_created=datetime.datetime.now()).save()
            user.save()

            # Open the reset URL in a new tab if the URL is valid
            if reset_url is not False:
                webbrowser.open_new_tab(str(reset_url))
                # Set reset to True to pass back to the view to display the correct content back to the user.
                reset = True
        else:
            error = 'Invalid username'

    context = {
        'domain': domain_name,
        'error': error,
        'reset': reset,
        'reset_url': reset_url,
        'reset_url_error': reset_url_error,
    }
    return render_template('index.html', context=context)


# Create a route for admin page
@app.route('/admin/')
def admin():
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))

    return render_template('admin.html')


@app.route('/admin/users/', methods=['GET', 'POST'])
def admin_users():
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))
    message = None
    if request.method == 'POST':
        username = request.form.get('username')
        password = request.form.get('password')
        confirm_password = request.form.get('confirm_password')

        # Check to see if username already exists
        try:
            user = User.filter(User.username == username).first()
        except Exception as e:
            print(e)
            user = None

        if user:
            message = 'Username already exists'
        else:
            if password == confirm_password:
                User.create(username=username, password=encrypt_password(password),
                            date_created=datetime.datetime.now(), logged_in=False).save()
                message = 'User created successfully'
                Log.create(username=session['username'], action='Created admin user: %s' % username, ).save()
            else:
                message = 'Passwords do not match'

    # Get all admin users from the DB
    users = User.select().execute()

    context = {
        'users': users,
        'message': message,
    }

    return render_template('admin_users.html', context=context)


@app.route('/admin/users/delete/<int:id>', methods=['GET', 'POST'])
def admin_users_delete(id):
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))

    # Get the user from the DB
    user = User.get(User.id == id)

    if user.username != 'admin':
        # Unset session variable if the user is deleting their own account
        if user.username == session['username']:
            session.pop('username', None)
        username = user.username
        user.delete_instance()
        Log.create(username=session['username'], action='Removed admin user: %s' % username, ).save()

    return redirect(url_for('admin_users'))


@app.route('/admin/users/ils', methods=['GET', 'POST'])
def admin_ils_users():
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))
    message = None
    if request.method == 'POST':
        username = request.form.get('username')
        email = request.form.get('email')

        # Check to see if username already exists
        try:
            user = IlsUser.filter(IlsUser.username == username).first()
        except Exception as e:
            print(e)
            user = None

        if user:
            message = 'Username already exists'
        else:

            IlsUser.create(username=username, email=email, reset_datetime=datetime.datetime.now()).save()
            message = 'ILS User: %s created successfully' % username
            Log.create(username=session['username'], action='Created ILS User: %s' % username, ).save()

    # Get all admin users from the DB
    users = IlsUser.select().execute()

    context = {
        'users': users,
        'message': message,
    }

    return render_template('admin_ils_users.html', context=context)


@app.route('/admin/users/ils/delete/<int:id>', methods=['GET', 'POST'])
def admin_ils_users_delete(id):
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))

    # Get the user from the DB
    user = IlsUser.get(IlsUser.id == id)
    username = user.username
    user.delete_instance()
    Log.create(username=session['username'], action='Removed ILS user: %s' % username, ).save()
    return redirect(url_for('admin_ils_users'))


# create a route for generating a CSV file for download
@app.route('/admin/users/ils/csv/download', methods=['GET', 'POST'])
def admin_ils_users_csv_download():
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))
    # Create a CSV file with the users and don't add a blank line between rows
    with open('users.csv', 'w', newline='') as f:
        writer = csv.writer(f)
        writer.writerow(['username', 'email'])
        users = IlsUser.select().execute()
        for user in users:
            writer.writerow([user.username, user.email])
    Log.create(username=session['username'], action='Downloaded ILS user CSV file.').save()
    # return the CSV file to the user
    return send_file('users.csv', as_attachment=True)


@app.route('/admin/users/ils/csv/import', methods=['GET', 'POST'])
def admin_ils_users_csv_import():
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))
    message = None
    if request.method == 'POST':
        csv_file = request.files['csv']
        if csv_file.filename != '':
            csv_file.save(os.path.join('uploads', csv_file.filename))
            with open(os.path.join('uploads', csv_file.filename), 'r') as f:
                reader = csv.reader(f)
                for row in reader:
                    username = row[0]
                    email = row[1]

                    # ignore the header row
                    if username == 'username':
                        continue

                    # ignore blank rows
                    if username == '':
                        continue

                    # Check if user already exists and if it does update the entry
                    try:
                        user = IlsUser.filter(IlsUser.username == username).first()
                    except Exception as e:
                        print(e)
                        user = None

                    if user:
                        user.email = email
                        user.reset_datetime = datetime.datetime.now()
                        user.save()
                    else:
                        IlsUser.create(username=username, email=email, reset_datetime=datetime.datetime.now()).save()
            # Delete the uploaded file
            os.remove(os.path.join('uploads', csv_file.filename))
            return redirect(url_for('admin_ils_users'))

    context = {
        'message': message,
    }

    return render_template('csv.html', context=context)


@app.route('/admin/settings', methods=['GET', 'POST'])
def settings():
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))

    message = None

    # Process form submission
    if request.method == 'POST':
        # Assign form values to variables
        id = request.form.get('id')
        value = request.form.get('value')

        # Check if the setting exists
        try:
            setting = Settings.get(Settings.id == id)
        except Exception as e:
            print(e)
            setting = None

        if setting:
            # Update the setting
            old_value = setting.value
            setting.value = value
            setting.save()
            Log.create(username=session['username'], action='Changed %s setting from "%s" to "%s"' % (setting.name,
                                                                                                      old_value,
                                                                                                      value)).save()
            message = '%s updated successfully' % setting.name

    # Get settings from DB
    all_settings = Settings.select().execute()

    context = {
        'settings': all_settings,
        'message': message,
    }

    return render_template('settings.html', context=context)


@app.route('/admin/schedule', methods=['GET', 'POST'])
def schedule():
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))

    message = None

    # add schedule
    if request.method == 'POST':
        # Assign form values to variables
        interval = request.form.get('interval')

        # Check if the schedule already exists
        try:
            schedule = Schedule.get(Schedule.interval == interval)
        except Exception as e:
            print(e)
            schedule = None

        if schedule:
            message = 'Schedule already exists'
        else:
            # Create the schedule
            Schedule.create(interval=interval).save()
            Log.create(username=session['username'], action='Created schedule for %s day interval.' % interval).save()
            message = 'Schedule: %s created successfully' % interval

    # Get all schedules from the DB
    schedules = Schedule.select().order_by(Schedule.interval.cast("INTEGER")).execute()

    context = {
        'schedules': schedules,
        'message': message,
    }

    return render_template('schedule.html', context=context)


# remove schedule
@app.route('/admin/schedule/remove/<int:id>', methods=['GET', 'POST'])
def schedule_remove(id):
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))

    # Get the schedule from the DB
    schedule = Schedule.get(Schedule.id == id)
    schedule.delete_instance()
    Log.create(username=session['username'], action='Removed schedule for a %s day reminder.' % schedule.interval).save()
    return redirect(url_for('schedule'))


@app.route('/admin/system/log')
def system_log():
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))

    # Get all logs from the DB
    logs = Log.select().order_by(Log.id.desc()).execute()

    context = {
        'logs': logs,
    }

    return render_template('system_log.html', context=context)


@app.route('/admin/system/log/password/resets')
def password_reset_log():
    # Check to see if user is logged in
    if not requires_auth():
        return redirect(url_for('login'))

    # Get all logs from the DB
    logs = PasswordResetLog.select().order_by(PasswordResetLog.id.desc()).execute()

    context = {
        'logs': logs,
    }

    return render_template('password_reset_log.html', context=context)


@app.route('/logout')
def logout():
    if 'username' in session:
        username = session['username']
        user = User.get(User.username == username)
        user.logged_in = False
        Log.create(username=session['username'], action='Logged out').save()
        user.save()
        session.pop('username', None)
    return redirect(url_for('login'))


@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        username = request.form.get('username')
        password = encrypt_password(request.form.get('password'))

        try:
            user = User.filter(User.username == username and User.password == password).first()
        except Exception as e:
            print(e)
            user = None
            session.pop('username', None)

        if user:
            # Login user
            session['username'] = request.form.get('username')
            user.logged_in = True
            Log.create(username=session['username'], action='Logged in').save()
            user.save()

            return redirect(url_for('admin'))
        else:
            error = 'Invalid Credentials. Please try again.'

        context = {
            'error': error
        }
        return render_template('login.html', context=context)

    context = {

    }
    return render_template('login.html', context=context)


# on exit of the program make sure the http server is stopped
# @app.teardown_appcontext


if __name__ == "__main__":
    print("------------------------- Start up -----------------------------")
    print("Starting HTTP Service on port %s..." % http_port)

    if debug is True:
        print("Debug mode is enabled.")
        http_server = WSGIServer(('0.0.0.0', int(http_port)), app)
    else:
        http_server = WSGIServer(('0.0.0.0', int(http_port)), app, log=log, error_log=log)
    print("HTTP Service Started.")
    print("--------------------- Application Details ---------------------")
    print("Application started at %s" % datetime.datetime.now())
    print("System IP Address: %s" % get_ip_address())
    print("System Hostname: %s" % get_hostname())
    print("Access the Dashboard using a web browser using any of the following:")
    print("http://%s:%s or http://%s:%s" % (get_hostname(), http_port, get_ip_address(), http_port))
    print("---------------------------------------------------------------")
    print("To stop the application close this window.")
    print("---------------------------------------------------------------")
    http_server.serve_forever()