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

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

from crispy_forms.helper import FormHelper
from crispy_forms.layout import Div, Field, 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.utils.translation import gettext_lazy as _
import pandas
from pypdf import PdfReader
from registration.models import VolunteerRegistration

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."))
        else:
            team = Team.objects.get(access_code=access_code)
            if team.participation.valid is not None:
                raise ValidationError(_("The team is already validated or the validation is pending."))
        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
        exclude = ('notes_sheet_id', )
        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', 'jury_president', 'juries',)
        widgets = {
            "jury_president": forms.Select(attrs={
                'class': 'selectpicker',
                'data-live-search': 'true',
                'data-live-search-normalize': 'true',
            }),
            "juries": forms.SelectMultiple(attrs={
                'class': 'selectpicker',
                'data-live-search': 'true',
                'data-live-search-normalize': 'true',
            }),
        }


class AddJuryForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['first_name'].required = True
        self.fields['last_name'].required = True
        self.fields['email'].required = True
        self.helper = FormHelper()
        self.helper.form_class = 'form-inline'
        self.helper.layout = Div(
            Div(
                Div(
                    Field('email', autofocus="autofocus", list="juries-email"),
                    css_class='col-md-5 px-1',
                ),
                Div(
                    Field('first_name', list="juries-first-name"),
                    css_class='col-md-3 px-1',
                ),
                Div(
                    Field('last_name', list="juries-last-name"),
                    css_class='col-md-3 px-1',
                ),
                Div(
                    Submit('submit', _("Add")),
                    css_class='col-md-1 py-md-4 px-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.instance = User.objects.get(email=email)
            if self.instance.registration.participates:
                self.add_error(None, _("This user already exists, but is a participant."))
                return
        return email

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


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

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

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

        if 'file' in cleaned_data:
            file = cleaned_data['file']
            if file.name.endswith('.csv'):
                with file:
                    try:
                        data: bytes = file.read()
                        try:
                            content = data.decode()
                        except UnicodeDecodeError:
                            # This is not UTF-8, grrrr
                            content = data.decode('latin1')

                        table = pandas.read_csv(StringIO(content), sep=None, header=None)
                        self.process(table, 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."))
            elif file.name.endswith('.ods'):
                table = pandas.read_excel(file, header=None, engine='odf')
                self.process(table, cleaned_data)

        return cleaned_data

    def process(self, df: pandas.DataFrame, cleaned_data: dict):
        parsed_notes = {}
        valid_lengths = [2 + 6 * 3, 2 + 7 * 4, 2 + 6 * 5]  # Per pool sizes
        pool_size = 0
        line_length = 0
        for line in df.values.tolist():
            # Remove NaN
            line = [s for s in line if s == s]
            # Strip cases
            line = [str(s).strip() for s in line if str(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⋅e", "juré?e", "moyenne", "coefficient", "sous-total", "équipe", "equipe"]:
                continue
            notes = line[2:line_length]
            if not all(s.isnumeric() or s[0] == '-' and s[1:].isnumeric() for s in notes):
                continue
            notes = list(map(lambda x: int(float(x)), notes))

            max_notes = pool_size * ([20, 20, 10, 10, 10, 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 volunteer id
            jury = VolunteerRegistration.objects.filter(pk=int(float(line[1])))
            if jury.count() != 1:
                raise ValidationError({'file': _("The following user was not found:") + " " + name})
            jury = jury.get()
            parsed_notes[jury] = 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', )