# 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 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.views import generic
from django.views.decorators.http import require_GET

from accounting.models import Record
from mia_core.period import PeriodParser
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_parser (PeriodParser): The period parser
    """
    page_no = None
    page_size = None
    pagination = None
    period_parser = 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_parser"] = self.period_parser
        data["pagination_links"] = self.pagination.links
        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
        """
        self.period_parser = PeriodParser(self.kwargs["period_spec"])
        if self.kwargs["subject_code"] == "0":
            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_parser.start, self.period_parser.end])
        else:
            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_parser.start,
                 self.period_parser.end,
                 self.kwargs["subject_code"] + "%",
                 self.kwargs["subject_code"] + "%"])
        self.pagination = Pagination(
            self.request.get_full_path(), records,
            self.page_no, self.page_size, True)
        return self.pagination.records