# Copyright (C) 2020 by Animath
# SPDX-License-Identifier: GPL-3.0-or-later

import csv
from io import StringIO
import re
from typing import Iterable

from crispy_forms.bootstrap import InlineField
from crispy_forms.helper import FormHelper
from crispy_forms.layout import Div, Fieldset, Submit
from django import forms
from django.contrib.auth.models import User
from django.core.exceptions import ValidationError
from django.core.validators import FileExtensionValidator
from django.db.models import CharField, Value
from django.db.models.functions import Concat
from django.utils.translation import gettext_lazy as _
from pypdf import PdfReader

from .models import Note, Participation, Passage, Pool, Solution, Synthesis, Team, Tournament


class TeamForm(forms.ModelForm):
    """
    Form to create a team, with the name and the trigram,...
    """
    def clean_name(self):
        if "name" in self.cleaned_data:
            name = self.cleaned_data["name"]
            if Team.objects.filter(name=name).exclude(pk=self.instance.pk).exists():
                raise ValidationError(_("This name is already used."))
            return name

    def clean_trigram(self):
        if "trigram" in self.cleaned_data:
            trigram = self.cleaned_data["trigram"].upper()
            if not re.match("[A-Z]{3}", trigram):
                raise ValidationError(_("The trigram must be composed of three uppercase letters."))

            if Team.objects.filter(trigram=trigram).exclude(pk=self.instance.pk).exists():
                raise ValidationError(_("This trigram is already used."))
            return trigram

    class Meta:
        model = Team
        fields = ('name', 'trigram',)


class JoinTeamForm(forms.ModelForm):
    """
    Form to join a team by the access code.
    """
    def clean_access_code(self):
        access_code = self.cleaned_data["access_code"]
        if not Team.objects.filter(access_code=access_code).exists():
            raise ValidationError(_("No team was found with this access code."))
        return access_code

    def clean(self):
        cleaned_data = super().clean()
        if "access_code" in cleaned_data:
            team = Team.objects.get(access_code=cleaned_data["access_code"])
            self.instance = team
        return cleaned_data

    class Meta:
        model = Team
        fields = ('access_code',)


class ParticipationForm(forms.ModelForm):
    """
    Form to update the problem of a team participation.
    """
    class Meta:
        model = Participation
        fields = ('tournament', 'final',)


class MotivationLetterForm(forms.ModelForm):
    def clean_motivation_letter(self):
        if "motivation_letter" in self.files:
            file = self.files["motivation_letter"]
            if file.size > 2e6:
                raise ValidationError(_("The uploaded file size must be under 2 Mo."))
            if file.content_type not in ["application/pdf", "image/png", "image/jpeg"]:
                raise ValidationError(_("The uploaded file must be a PDF, PNG of JPEG file."))
            return self.cleaned_data["motivation_letter"]

    class Meta:
        model = Team
        fields = ('motivation_letter',)


class RequestValidationForm(forms.Form):
    """
    Form to ask about validation.
    """
    _form_type = forms.CharField(
        initial="RequestValidationForm",
        widget=forms.HiddenInput(),
    )

    engagement = forms.BooleanField(
        label=_("I engage myself to participate to the whole TFJM²."),
        required=True,
    )


class ValidateParticipationForm(forms.Form):
    """
    Form to let administrators to accept or refuse a team.
    """
    _form_type = forms.CharField(
        initial="ValidateParticipationForm",
        widget=forms.HiddenInput(),
    )

    message = forms.CharField(
        label=_("Message to address to the team:"),
        widget=forms.Textarea(),
    )


class TournamentForm(forms.ModelForm):
    class Meta:
        model = Tournament
        fields = '__all__'
        widgets = {
            'date_start': forms.DateInput(attrs={'type': 'date'}, format='%Y-%m-%d'),
            'date_end': forms.DateInput(attrs={'type': 'date'}, format='%Y-%m-%d'),
            'inscription_limit': forms.DateTimeInput(attrs={'type': 'datetime-local'}, format='%Y-%m-%d %H:%M'),
            'solution_limit': forms.DateTimeInput(attrs={'type': 'datetime-local'}, format='%Y-%m-%d %H:%M'),
            'solutions_draw': forms.DateTimeInput(attrs={'type': 'datetime-local'}, format='%Y-%m-%d %H:%M'),
            'syntheses_first_phase_limit': forms.DateTimeInput(attrs={'type': 'datetime-local'},
                                                               format='%Y-%m-%d %H:%M'),
            'solutions_available_second_phase': forms.DateTimeInput(attrs={'type': 'datetime-local'},
                                                                    format='%Y-%m-%d %H:%M'),
            'syntheses_second_phase_limit': forms.DateTimeInput(attrs={'type': 'datetime-local'},
                                                                format='%Y-%m-%d %H:%M'),
            'organizers': forms.SelectMultiple(attrs={
                'class': 'selectpicker',
                'data-live-search': 'true',
                'data-live-search-normalize': 'true',
                'data-width': 'fit',
            })
        }


class SolutionForm(forms.ModelForm):
    def clean_file(self):
        if "file" in self.files:
            file = self.files["file"]
            if file.size > 5e6:
                raise ValidationError(_("The uploaded file size must be under 5 Mo."))
            if file.content_type != "application/pdf":
                raise ValidationError(_("The uploaded file must be a PDF file."))
            pdf_reader = PdfReader(file)
            pages = len(pdf_reader.pages)
            if pages > 30:
                raise ValidationError(_("The PDF file must not have more than 30 pages."))
            return self.cleaned_data["file"]

    def save(self, commit=True):
        """
        Don't save a solution with this way. Use a view instead
        """

    class Meta:
        model = Solution
        fields = ('problem', 'file',)


class PoolForm(forms.ModelForm):
    class Meta:
        model = Pool
        fields = ('tournament', 'round', 'letter', 'bbb_url', 'results_available', 'juries',)
        widgets = {
            "juries": forms.SelectMultiple(attrs={
                'class': 'selectpicker',
                'data-live-search': 'true',
                'data-live-search-normalize': 'true',
            }),
        }


class PoolTeamsForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields["participations"].queryset = self.instance.tournament.participations.all()

    class Meta:
        model = Pool
        fields = ('participations',)
        widgets = {
            "participations": forms.SelectMultiple(attrs={
                'class': 'selectpicker',
                'data-live-search': 'true',
                'data-live-search-normalize': 'true',
                'data-width': 'fit',
            }),
        }


class AddJuryForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.helper = FormHelper()
        self.helper.form_class = 'form-inline'
        self.helper.layout = Div(
            Div(
                Div(
                    InlineField('first_name', autofocus="autofocus"),
                    css_class='col-md-3',
                ),
                Div(
                    InlineField('last_name'),
                    css_class='col-md-3',
                ),
                Div(
                    InlineField('email'),
                    css_class='col-md-5',
                ),
                Div(
                    Submit('submit', _("Add")),
                    css_class='col-md-1',
                ),
                css_class='row',
            )
        )

    def clean_email(self):
        """
        Ensure that the email address is unique.
        """
        email = self.data["email"]
        if User.objects.filter(email=email).exists():
            self.add_error("email", _("This email address is already used."))
        return email

    class Meta:
        model = User
        fields = ('first_name', 'last_name', 'email',)


class UploadNotesForm(forms.Form):
    file = forms.FileField(
        label=_("CSV file:"),
        validators=[FileExtensionValidator(allowed_extensions=["csv"])],
    )

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['file'].widget.attrs['accept'] = 'text/csv'

    def clean(self):
        cleaned_data = super().clean()

        if 'file' in cleaned_data:
            file = cleaned_data['file']
            with file:
                try:
                    data: bytes = file.read()
                    try:
                        content = data.decode()
                    except UnicodeDecodeError:
                        # This is not UTF-8, grrrr
                        content = data.decode('latin1')
                    csvfile = csv.reader(StringIO(content))
                    self.process(csvfile, cleaned_data)
                except UnicodeDecodeError:
                    self.add_error('file', _("This file contains non-UTF-8 and non-ISO-8859-1 content. "
                                             "Please send your sheet as a CSV file."))

        return cleaned_data

    def process(self, csvfile: Iterable[str], cleaned_data: dict):
        parsed_notes = {}
        valid_lengths = [1 + 6 * 3, 1 + 7 * 4, 1 + 6 * 5]  # Per pool sizes
        pool_size = 0
        line_length = 0
        for line in csvfile:
            line = [s.strip() for s in line if s]
            if line and line[0] == 'Problème':
                pool_size = len(line) - 1
                if pool_size < 3 or pool_size > 5:
                    self.add_error('file', _("Can't determine the pool size. Are you sure your file is correct?"))
                    return
                line_length = valid_lengths[pool_size - 3]
                continue

            if pool_size == 0 or len(line) < line_length:
                continue

            name = line[0]
            if name.lower() in ["rôle", "juré", "moyenne", "coefficient", "sous-total", "équipe", "equipe"]:
                continue
            notes = line[1:line_length]
            if not all(s.isnumeric() or s[0] == '-' and s[1:].isnumeric() for s in notes):
                continue
            notes = list(map(int, notes))

            max_notes = pool_size * ([20, 16, 9, 10, 9, 10] + ([4] if pool_size == 4 else []))
            for n, max_n in zip(notes, max_notes):
                if n > max_n:
                    self.add_error('file',
                                   _("The following note is higher of the maximum expected value:")
                                   + str(n) + " > " + str(max_n))

            # Search by "{first_name} {last_name}"
            jury = User.objects.annotate(full_name=Concat('first_name', Value(' '), 'last_name',
                                                          output_field=CharField())) \
                .filter(full_name=name.replace('’', '\''), registration__volunteerregistration__isnull=False)
            if jury.count() != 1:
                self.add_error('file', _("The following user was not found:") + " " + name)
                continue
            jury = jury.get()

            vr = jury.registration
            parsed_notes[vr] = notes

        cleaned_data['parsed_notes'] = parsed_notes

        return cleaned_data


class PassageForm(forms.ModelForm):
    def clean(self):
        cleaned_data = super().clean()
        if "defender" in cleaned_data and "opponent" in cleaned_data and "reporter" in cleaned_data \
                and len({cleaned_data["defender"], cleaned_data["opponent"], cleaned_data["reporter"]}) < 3:
            self.add_error(None, _("The defender, the opponent and the reporter must be different."))
        if "defender" in self.cleaned_data and "solution_number" in self.cleaned_data \
                and not Solution.objects.filter(participation=cleaned_data["defender"],
                                                problem=cleaned_data["solution_number"]).exists():
            self.add_error("solution_number", _("This defender did not work on this problem."))
        return cleaned_data

    class Meta:
        model = Passage
        fields = ('position', 'solution_number', 'defender', 'opponent', 'reporter', 'observer', 'defender_penalties',)


class SynthesisForm(forms.ModelForm):
    def clean_file(self):
        if "file" in self.files:
            file = self.files["file"]
            if file.size > 2e6:
                raise ValidationError(_("The uploaded file size must be under 2 Mo."))
            if file.content_type != "application/pdf":
                raise ValidationError(_("The uploaded file must be a PDF file."))
            pdf_reader = PdfReader(file)
            pages = len(pdf_reader.pages)
            if pages > 2:
                raise ValidationError(_("The PDF file must not have more than 2 pages."))
            return self.cleaned_data["file"]

    def save(self, commit=True):
        """
        Don't save a synthesis with this way. Use a view instead
        """

    class Meta:
        model = Synthesis
        fields = ('file',)


class NoteForm(forms.ModelForm):
    class Meta:
        model = Note
        fields = ('defender_writing', 'defender_oral', 'opponent_writing',
                  'opponent_oral', 'reporter_writing', 'reporter_oral', 'observer_oral', )