from django.contrib.auth.models import User
from django.http import HttpResponseRedirect
from django.contrib.auth.decorators import login_required
from django.contrib.auth.validators import UnicodeUsernameValidator
from django.contrib.auth import authenticate, login, logout
from django.contrib.auth.password_validation import validate_password
from django.shortcuts import render, redirect
from django.views.decorators.csrf import csrf_exempt
from django.db import connection
from django.core.exceptions import ValidationError

from notes.models import Note

@login_required()
def index(request):
    user = request.user

    notes = Note.objects.filter(owner=user)
    notes_list = [ { 'time' : note.time, 'body' : note.body, 'id' : note.id } for note in notes ]
    notes_list.sort(key=lambda note: note['time'])

    return render(request, 'index.html', { 'notes' : notes_list})


@login_required()
def add(request):
    if request.method == 'POST':
        user = request.user
        body = request.POST.get('body')

        Note.objects.create(owner=user, body=body)

    return redirect("index")


@login_required()
def remove(request, note_id):
    if request.method == 'POST':
        note = Note.objects.get(pk=note_id)
# FLAW 1:
# Adding an ownership check would fix the problem
#        user = request.user
#        if user == note.owner:
        note.delete()

    return HttpResponseRedirect(request.META.get('HTTP_REFERER', 'index'))


@login_required()
def search(request):
    if request.method == 'GET':
        user = request.user
        keyword = request.GET.get('keyword')

        notes = Note.objects.filter(owner=user, body__icontains=keyword)
        notes_list = [ { 'time' : note.time, 'body' : note.body, 'id' : note.id } for note in notes ]
        notes_list.sort(key=lambda note: note['time'])

        return render(request, 'search.html', { 'notes' : notes_list, 'keyword' : keyword})

    return redirect("index")


def login_view(request):
    if request.method == 'GET':
        return render(request, 'login.html')
    elif request.method == 'POST':
        username = request.POST.get('username')
        password = request.POST.get('password')

        user = authenticate(username=username, password=password)

        if user is not None:
            login(request, user)
            return redirect("index")
        else:
            return render(request, 'login.html', { 'login_failed' : True })

    return redirect("index")


def register_view(request):
    if request.method == 'POST':
        errors = []
        username = request.POST.get('username')
        password1 = request.POST.get('password1')
        password2 = request.POST.get('password2')

        # Username validation
        if User.objects.filter(username=username).first() != None:
            errors.append("Username in use.")
        try:
            username_validator = UnicodeUsernameValidator()
            username_validator(username)
        except ValidationError as error:
            for message in error.messages:
                errors.append(message)

        # Password validation
        if password1 != password2:
            errors.append("Passwords don't match.")
# FLAW 4:
# Adding some sensible password validation would fix the problem
#        try:
#            validate_password(password1)
#        except ValidationError as error:
#            for message in error.messages:
#                errors.append(message)

        if not errors:
            user = User.objects.create_user(username=username, password=password1)
            login(request, user)
            return redirect("index")
        else:
            return render(request, 'login.html', { 'registration_errors' : errors })

    return redirect("index")


def logout_view(request):
    if request.method == 'POST':
        logout(request)

    return redirect("index")