from django import forms
from yaksh.models import (
    get_model_class, Profile, Quiz, Question, Course, QuestionPaper, Lesson,
    LearningModule
)
from django.contrib.auth import authenticate
from django.contrib.auth.models import User
from django.conf import settings
from django.utils import timezone
from textwrap import dedent
try:
    from string import letters
except ImportError:
    from string import ascii_letters as letters
from string import punctuation, digits
import pytz
from .send_emails import generate_activation_key

languages = (
    ("select", "Select Language"),
    ("python", "Python"),
    ("bash", "Bash"),
    ("c", "C Language"),
    ("cpp", "C++ Language"),
    ("java", "Java Language"),
    ("scilab", "Scilab"),
)

question_types = (
    ("select", "Select Question Type"),
    ("mcq", "Multiple Choice"),
    ("mcc", "Multiple Correct Choices"),
    ("code", "Code"),
    ("upload", "Assignment Upload"),
    ("integer", "Answer in Integer"),
    ("string", "Answer in String"),
    ("float", "Answer in Float"),
)

test_case_types = (
    ("standardtestcase", "Standard Testcase"),
    ("stdiobasedtestcase", "StdIO Based Testcase"),
    ("mcqtestcase", "MCQ Testcase"),
    ("hooktestcase", "Hook Testcase"),
    ("integertestcase", "Integer Testcase"),
    ("stringtestcase", "String Testcase"),
    ("floattestcase", "Float Testcase"),
)

UNAME_CHARS = letters + "._" + digits
PWD_CHARS = letters + punctuation + digits

attempts = [(i, i) for i in range(1, 6)]
attempts.append((-1, 'Infinite'))
days_between_attempts = ((j, j) for j in range(401))


def get_object_form(model, exclude_fields=None):
    model_class = get_model_class(model)

    class _ObjectForm(forms.ModelForm):
        class Meta:
            model = model_class
            exclude = exclude_fields
    return _ObjectForm


class UserRegisterForm(forms.Form):
    """A Class to create new form for User's Registration.
    It has the various fields and functions required to register
    a new user to the system"""

    username = forms.CharField(max_length=30, help_text='Letters, digits,\
                period and underscores only.')
    email = forms.EmailField()
    password = forms.CharField(max_length=30, widget=forms.PasswordInput())
    confirm_password = forms.CharField(
        max_length=30, widget=forms.PasswordInput())
    first_name = forms.CharField(max_length=30)
    last_name = forms.CharField(max_length=30)
    roll_number = forms.CharField(
        max_length=30, help_text="Use a dummy if you don't have one.")
    institute = forms.CharField(
        max_length=128, help_text='Institute/Organization')
    department = forms.CharField(
        max_length=64, help_text='Department you work/study at')
    position = forms.CharField(
        max_length=64,
        help_text='Student/Faculty/Researcher/Industry/Fellowship/etc.')
    timezone = forms.ChoiceField(
        choices=[(tz, tz) for tz in pytz.common_timezones],
        help_text='Course timings are shown based on the selected timezone',
        initial=pytz.country_timezones['IN'][0])

    def clean_username(self):
        u_name = self.cleaned_data["username"]
        if u_name.strip(UNAME_CHARS):
            msg = "Only letters, digits, period and underscore characters are"\
                  " allowed in username"
            raise forms.ValidationError(msg)
        try:
            User.objects.get(username__exact=u_name)
            raise forms.ValidationError("Username already exists.")
        except User.DoesNotExist:
            return u_name

    def clean_password(self):
        pwd = self.cleaned_data['password']
        if pwd.strip(PWD_CHARS):
            raise forms.ValidationError("Only letters, digits and punctuation\
                                        are allowed in password")
        return pwd

    def clean_confirm_password(self):
        c_pwd = self.cleaned_data['confirm_password']
        pwd = self.data['password']
        if c_pwd != pwd:
            raise forms.ValidationError("Passwords do not match")

        return c_pwd

    def clean_email(self):
        user_email = self.cleaned_data['email']
        if User.objects.filter(email=user_email).exists():
            raise forms.ValidationError("This email already exists")
        return user_email

    def save(self):
        u_name = self.cleaned_data["username"]
        u_name = u_name.lower()
        pwd = self.cleaned_data["password"]
        email = self.cleaned_data['email']
        new_user = User.objects.create_user(u_name, email, pwd)

        new_user.first_name = self.cleaned_data["first_name"]
        new_user.last_name = self.cleaned_data["last_name"]
        new_user.save()

        cleaned_data = self.cleaned_data
        new_profile = Profile(user=new_user)
        new_profile.roll_number = cleaned_data["roll_number"]
        new_profile.institute = cleaned_data["institute"]
        new_profile.department = cleaned_data["department"]
        new_profile.position = cleaned_data["position"]
        new_profile.timezone = cleaned_data["timezone"]
        if settings.IS_DEVELOPMENT:
            new_profile.is_email_verified = True
        else:
            new_profile.activation_key = generate_activation_key(
                new_user.username)
            new_profile.key_expiry_time = timezone.now() + timezone.timedelta(
                minutes=20)
        new_profile.save()
        return u_name, pwd, new_user.email, new_profile.activation_key


class UserLoginForm(forms.Form):
    """Creates a form which will allow the user to log into the system."""

    username = forms.CharField(max_length=30)
    password = forms.CharField(max_length=30, widget=forms.PasswordInput())

    def clean(self):
        super(UserLoginForm, self).clean()
        try:
            u_name, pwd = self.cleaned_data["username"],\
                          self.cleaned_data["password"]
            user = authenticate(username=u_name, password=pwd)
        except Exception:
            raise forms.ValidationError(
                "Username and/or Password is not entered"
            )
        if not user:
            raise forms.ValidationError("Invalid username/password")
        return user


class ExerciseForm(forms.ModelForm):
    class Meta:
        model = Quiz
        fields = ['description', 'view_answerpaper', 'active']


class QuizForm(forms.ModelForm):
    """Creates a form to add or edit a Quiz.
    It has the related fields and functions required."""

    def __init__(self, *args, **kwargs):
        super(QuizForm, self).__init__(*args, **kwargs)

        self.fields["instructions"].initial = dedent("""\
            <p>
            This examination system has been developed with the intention of
            making you learn programming and be assessed in an interactive and
            fun manner.You will be presented with a series of programming
            questions and problems that you will answer online and get
            immediate feedback for.
            </p><p>Here are some important instructions and rules that you
            should understand carefully.</p>
            <ul><li>For any programming questions, you can submit solutions as
            many times as you want without a penalty. You may skip questions
            and solve them later.</li><li> You <strong>may</strong>
            use your computer's Python/IPython shell or an editor to solve the
            problem and cut/paste the solution to the web interface.
            </li><li> <strong>You are not allowed to use any internet resources
            i.e. no google etc.</strong>
            </li>
            <li> Do not copy or share the questions or answers with anyone
            until the exam is complete <strong>for everyone</strong>.
            </li><li> <strong>All</strong> your attempts at the questions are
            logged. Do not try to outsmart and break the testing system.
            If you do, we know who you are and we will expel you from the
            course. You have been warned.
            </li></ul>
            <p>We hope you enjoy taking this exam !!!</p>
        """)

    class Meta:
        model = Quiz
        exclude = ["is_trial", "creator", "is_exercise"]


class QuestionForm(forms.ModelForm):
    """Creates a form to add or edit a Question.
    It has the related fields and functions required."""

    class Meta:
        model = Question
        exclude = ['user', 'active']


class FileForm(forms.Form):
    file_field = forms.FileField(widget=forms.ClearableFileInput(
                                attrs={'multiple': True}),
                                required=False)


class RandomQuestionForm(forms.Form):
    question_type = forms.CharField(
        max_length=8, widget=forms.Select(choices=question_types)
    )
    marks = forms.CharField(
        max_length=8, widget=forms.Select(
            choices=(('select', 'Select Marks'),))
    )
    shuffle_questions = forms.BooleanField(required=False)


class QuestionFilterForm(forms.Form):
    def __init__(self, *args, **kwargs):
        user = kwargs.pop("user")
        super(QuestionFilterForm, self).__init__(*args, **kwargs)
        questions = Question.objects.filter(user_id=user.id)
        points_list = questions.values_list('points', flat=True).distinct()
        points_options = [(None, 'Select Marks')]
        points_options.extend([(point, point) for point in points_list])
        self.fields['marks'] = forms.FloatField(
            widget=forms.Select(choices=points_options)
        )
    language = forms.CharField(
        max_length=8, widget=forms.Select(choices=languages))
    question_type = forms.CharField(
        max_length=8, widget=forms.Select(choices=question_types)
    )


class CourseForm(forms.ModelForm):
    """ course form for moderators """

    def save(self, commit=True, *args, **kwargs):
        instance = super(CourseForm, self).save(commit=False)
        if instance.code:
            instance.hidden = True
        else:
            instance.hidden = False

        if commit:
            instance.save()
        return instance

    class Meta:
        model = Course
        fields = ['name', 'enrollment', 'active', 'code', 'instructions',
                  'start_enroll_time', 'end_enroll_time', 'grading_system']


class ProfileForm(forms.ModelForm):
    """ profile form for students and moderators """

    class Meta:
        model = Profile
        fields = ['first_name', 'last_name', 'institute',
                  'department', 'roll_number', 'position', 'timezone']

    first_name = forms.CharField(max_length=30)
    last_name = forms.CharField(max_length=30)

    def __init__(self, *args, **kwargs):
        if 'user' in kwargs:
            user = kwargs.pop('user')
        super(ProfileForm, self).__init__(*args, **kwargs)
        self.fields['first_name'].initial = user.first_name
        self.fields['last_name'].initial = user.last_name


class UploadFileForm(forms.Form):
    file = forms.FileField()


class QuestionPaperForm(forms.ModelForm):
    class Meta:
        model = QuestionPaper
        fields = ['shuffle_questions', 'shuffle_testcases']


class LessonForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(LessonForm, self).__init__(*args, **kwargs)
        des_msg = "Enter Lesson Description as Markdown text"
        name_msg = "Enter Lesson Name"
        self.fields['description'].widget.attrs['placeholder'] = des_msg
        self.fields['name'].widget.attrs['placeholder'] = name_msg

    class Meta:
        model = Lesson
        exclude = ['completed_lessons', 'creator', 'html_data']


class LessonFileForm(forms.Form):
    Lesson_files = forms.FileField(widget=forms.ClearableFileInput(
                                attrs={'multiple': True}),
                                required=False)


class LearningModuleForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(LearningModuleForm, self).__init__(*args, **kwargs)
        name_msg = "Enter Learning Module Name"
        self.fields['name'].widget.attrs['placeholder'] = name_msg
        self.fields['name'].widget.attrs['size'] = 30

    class Meta:
        model = LearningModule
        fields = ['name', 'description', 'active']