# The accounting application of the Mia project.
#   by imacat <imacat@mail.imacat.idv.tw>, 2020/6/30

#  Copyright (c) 2020 imacat.
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

"""The view controllers of the accounting application.

"""
from datetime import date

from django.http import HttpResponseRedirect, HttpResponse

from django.urls import reverse
from django.utils import dateformat
from django.utils.decorators import method_decorator
from django.utils.timezone import localdate
from django.utils.translation import get_language, pgettext
from django.views import generic
from django.views.decorators.http import require_GET

from accounting.models import Record, Transaction, Subject
from mia_core.period import Period
from mia import settings
from mia_core.digest_auth import digest_login_required
from mia_core.utils import UrlBuilder, Pagination, \
    PageNoOutOfRangeException


@require_GET
@digest_login_required
def home(request):
    """The accounting home page.

    Returns:
        HttpResponseRedirect: The redirection to the default
            accounting report.
    """
    return HttpResponseRedirect(reverse("accounting:cash.home"))


@require_GET
@digest_login_required
def cash_home(request):
    """The accounting cash report home page.

    Returns:
        HttpResponseRedirect: The redirection to the default subject
            and month.
    """
    subject_code = settings.ACCOUNTING["DEFAULT_CASH_SUBJECT"]
    period_spec = dateformat.format(localdate(), "Y-m")
    return HttpResponseRedirect(
        reverse("accounting:cash", args=(subject_code, period_spec)))


@method_decorator(digest_login_required, name='dispatch')
class BaseReportView(generic.ListView):
    """A base account report.

    Attributes:
        page_no (int): The specified page number
        page_size (int): The specified page size
        period (Period): The template period helper
        subject (Subject): The currently-specified subject
    """
    page_no = None
    page_size = None
    pagination = None
    period = None
    subject = None

    def get(self, request, *args, **kwargs):
        """Adds object_list to the context.

        Args:
            request (HttpRequest): The request.
            args (list): The remaining arguments.
            kwargs (dict): The keyword arguments.

        Returns:
            The response
        """
        if request.user.is_anonymous:
            return HttpResponse(status=401)
        try:
            self.page_size = int(request.GET["page-size"])
            if self.page_size < 1:
                return HttpResponseRedirect(
                    str(UrlBuilder(request.get_full_path())
                        .del_param("page-size")))
        except KeyError:
            self.page_size = None
        except ValueError:
            return HttpResponseRedirect(
                    str(UrlBuilder(request.get_full_path())
                        .del_param("page-size")))
        try:
            self.page_no = int(request.GET["page"])
            if self.page_no < 1:
                return HttpResponseRedirect(
                    str(UrlBuilder(request.get_full_path())
                        .del_param("page")))
        except KeyError:
            self.page_no = None
        except ValueError:
            return HttpResponseRedirect(
                str(UrlBuilder(request.get_full_path())
                    .del_param("page")))
        try:
            r = super(BaseReportView, self) \
                .get(request, *args, **kwargs)
        except PageNoOutOfRangeException:
            return HttpResponseRedirect(
                str(UrlBuilder(request.get_full_path())
                    .del_param("page")))
        return r

    def get_context_data(self, **kwargs):
        data = super(BaseReportView, self).get_context_data(**kwargs)
        data["period"] = self.period
        data["subject"] = self.subject
        data["pagination"] = self.pagination
        return data


class CashReportView(BaseReportView):
    """The accounting cash report."""
    http_method_names = ["get"]
    template_name = "accounting/cash.html"
    context_object_name = "records"

    def get_queryset(self):
        """Return the accounting records for the cash report.

        Returns:
            List[Record]: The accounting records for the cash report
        """
        first_txn = Transaction.objects.order_by("date").first()
        data_start = first_txn.date if first_txn is not None else None
        last_txn = Transaction.objects.order_by("-date").first()
        data_end = last_txn.date if last_txn is not None else None
        self.period = Period(
            get_language(), data_start, data_end,
            self.kwargs["period_spec"])
        if self.kwargs["subject_code"] == "0":
            self.subject = Subject(code="0")
            self.subject.title_zhtw = pgettext(
                "Accounting|", "Current assets and liabilities")
            records = Record.objects.raw(
                """SELECT r.*
FROM accounting_records AS r
  INNER JOIN (SELECT
         t1.sn AS sn,
         t1.date AS date,
         t1.ord AS ord
      FROM accounting_records AS r1
        LEFT JOIN accounting_transactions AS t1
          ON r1.transaction_sn=t1.sn
        LEFT JOIN accounting_subjects AS s1
          ON r1.subject_sn = s1.sn
      WHERE (s1.code LIKE '11%%'
        OR s1.code LIKE '12%%'
        OR s1.code LIKE '21%%'
        OR s1.code LIKE '22%%')
        AND t1.date >= %s
        AND t1.date <= %s
      GROUP BY t1.sn) AS t
    ON r.transaction_sn=t.sn
  LEFT JOIN accounting_subjects AS s ON r.subject_sn = s.sn
WHERE s.code NOT LIKE '11%%'
  AND s.code NOT LIKE '12%%'
  AND s.code NOT LIKE '21%%'
  AND s.code NOT LIKE '22%%'
ORDER BY
  t.date,
  t.ord,
  CASE WHEN is_credit THEN 1 ELSE 2 END,
  r.ord""",
                [self.period.start, self.period.end])
        else:
            self.subject = Subject.objects.filter(
                code=self.kwargs["subject_code"]).first()
            records = Record.objects.raw(
                """SELECT r.*
FROM accounting_records AS r
  INNER JOIN (SELECT
         t1.sn AS sn,
         t1.date AS date,
         t1.ord AS ord
      FROM accounting_records AS r1
       LEFT JOIN accounting_transactions AS t1
         ON r1.transaction_sn=t1.sn
       LEFT JOIN accounting_subjects AS s1
         ON r1.subject_sn = s1.sn
      WHERE t1.date >= %s
        AND t1.date <= %s
        AND s1.code LIKE %s
      GROUP BY t1.sn) AS t
    ON r.transaction_sn=t.sn
  LEFT JOIN accounting_subjects AS s ON r.subject_sn = s.sn
WHERE s.code NOT LIKE %s
ORDER BY
  t.date,
  t.ord,
  CASE WHEN is_credit THEN 1 ELSE 2 END,
  r.ord""",
                [self.period.start,
                 self.period.end,
                 self.subject.code + "%",
                 self.subject.code + "%"])
        self.pagination = Pagination(
            self.request.get_full_path(), records,
            self.page_no, self.page_size, True)
        return self.pagination.records