import csv

from django.apps import apps
from django.http import HttpResponse, HttpResponseForbidden
from django.template.defaultfilters import slugify


def export(qs, fields=None):
    model = qs.model
    response = HttpResponse(content_type="text/csv")
    response["Content-Disposition"] = "attachment; filename=%s.csv" % slugify(
        model.__name__
    )
    writer = csv.writer(response)
    # Write headers to CSV file
    if fields:
        headers = fields
    else:
        headers = []
        for field in model._meta.fields:
            headers.append(field.name)
    writer.writerow(headers)
    # Write data to CSV file
    for obj in qs:
        row = []
        for field in headers:
            if field in headers:
                val = getattr(obj, field)
                if callable(val):
                    val = val()
                row.append(val)
        writer.writerow(row)
    # Return CSV file to browser as download
    return response


def admin_list_export(
    request, model_name, app_label, queryset=None, fields=None, list_display=True
):
    """
    Put the following line in your urls.py BEFORE your admin include:

    path(
        "admin/<slug:app_label>/<slug:model_name>/csv/",
        csv_views.admin_list_export,
        {"fields": ["username"]},
    ),
    """
    if not request.user.is_staff:
        return HttpResponseForbidden()
    if not queryset:
        model = apps.get_model(app_label, model_name)
        queryset = model.objects.all()
        queryset = queryset.filter(profile__is_cof=True)
    if not fields:
        if list_display and len(queryset.model._meta.admin.list_display) > 1:
            fields = queryset.model._meta.admin.list_display
        else:
            fields = None
    return export(queryset, fields)
    """
    Create your own change_list.html for your admin view and put something
    like this in it:
    {% block object-tools %}
    <ul class="object-tools">
        <li><a href="csv/{%if request.GET%}?{{request.GET.urlencode}}
        {%endif%}" class="addlink">Export to CSV</a></li>
    {% if has_add_permission %}
        <li><a href="add/{% if is_popup %}?_popup=1{% endif %}"
                class="addlink">
            {% blocktrans with cl.opts.verbose_name|escape as name %}
            Add {{ name }}{% endblocktrans %}</a></li>
    {% endif %}
    </ul>
    {% endblock %}
    """