from django.contrib import admin
from django.utils.translation import gettext_lazy as _
from django.urls import reverse
from django.utils.html import format_html
from ajaxdatatable.admin import AjaxDatatable

from apps.library.models import *


@admin.register(Book)
class BookAdmin(AjaxDatatable):
    list_display = ('title', 'slug', 'status', 'pin', 'file_type', 'view_count', 'created_at')
    list_filter = ('status', 'pin', 'file_type', 'created_at', 'updated_at')
    search_fields = ('title', 'slug', 'summary', 'description')
    # autocomplete_fields = ('categories', 'collections', )
    fieldsets = (
        (None, {
            'fields': ('title', 'slug', 'summary', 'description', 'thumbnail', 'pages_count')
        }),
        (_('Status'), {
            'fields': ('status', 'pin')
        }),
        (_('File Information'), {
            'fields': ('file_type', 'book_file')
        }),
        (_('Relations'), {
            'fields': ('categories', 'collections')
        }),
        (_('Statistics'), {
            'fields': ('view_count',)
        }),
    )



class BookCollectionAdminBase(AjaxDatatable):
    """Base admin class for all book collection types"""
    list_display = ('get_title', 'status', 'order', 'count_books')
    list_filter = ('status',)
    search_fields = ('title',)
    autocomplete_fields = ('books',)
    ordering = ('order',)

    fieldsets = (
        (None, {
            'fields': ('title', 'summary', 'status', 'order')
        }),
        (_('Books'), {
            'fields': ('books',)
        }),
    )

    exclude = ('display_position',)

    def get_title(self, obj):
        return str(obj.title)
    get_title.short_description = _('Title')
    

    @admin.display(description=_('Number of Books'))
    def count_books(self, obj):
        count = obj.books.count()
        if count > 0:
            url = reverse('admin:library_book_changelist') + f'?collections__id__exact={obj.id}'
            return format_html('<a href="{}">{}</a>', url, count)
        return count






@admin.register(PinnedBookCollection)
class PinnedBookCollectionAdmin(BookCollectionAdminBase):
    """Admin for pinned book collections only"""

    def get_queryset(self, request):
        # Only show pinned collections
        return super().get_queryset(request).filter(display_position=BookCollection.DisplayPosition.PINNED)

    def save_model(self, request, obj, form, change):
        # Ensure the display_position is always set to PINNED
        obj.display_position = BookCollection.DisplayPosition.PINNED
        super().save_model(request, obj, form, change)


@admin.register(MiddleBookCollection)
class MiddleBookCollectionAdmin(BookCollectionAdminBase):
    """Admin for middle section book collections only"""

    def get_queryset(self, request):
        # Only show middle section collections
        return super().get_queryset(request).filter(display_position=BookCollection.DisplayPosition.MIDDLE)

    def has_add_permission(self, request):
        # Check if a middle collection already exists
        exists = BookCollection.objects.filter(display_position=BookCollection.DisplayPosition.MIDDLE).exists()
        # Only allow adding if no middle collection exists
        return not exists

    def has_delete_permission(self, request, obj=None):
        # Prevent deletion of the middle collection
        return False

    def save_model(self, request, obj, form, change):
        # Ensure the display_position is always set to MIDDLE
        obj.display_position = BookCollection.DisplayPosition.MIDDLE
        super().save_model(request, obj, form, change)

    def changelist_view(self, request, extra_context=None):
        # Check if a middle collection exists
        try:
            # Try to get the first (and should be only) middle collection
            obj = self.get_queryset(request).first()
            if obj:
                # If it exists, redirect to the change view for this object
                from django.http import HttpResponseRedirect
                from django.urls import reverse
                url = reverse(
                    'admin:%s_%s_change' % (obj._meta.app_label, obj._meta.model_name),
                    args=[obj.pk]
                )
                return HttpResponseRedirect(url)
        except Exception:
            # If any error occurs, just show the changelist view as usual
            pass

        # If no object exists or there was an error, show the default changelist view
        return super().changelist_view(request, extra_context)


@admin.register(BottomBookCollection)
class BottomBookCollectionAdmin(BookCollectionAdminBase):
    """Admin for bottom section book collections only"""

    def get_queryset(self, request):
        # Only show bottom section collections
        return super().get_queryset(request).filter(display_position=BookCollection.DisplayPosition.BOTTOM)

    def has_add_permission(self, request):
        # Check if a bottom collection already exists
        exists = BookCollection.objects.filter(display_position=BookCollection.DisplayPosition.BOTTOM).exists()
        # Only allow adding if no bottom collection exists
        return not exists

    def has_delete_permission(self, request, obj=None):
        # Prevent deletion of the bottom collection
        return False

    def save_model(self, request, obj, form, change):
        # Ensure the display_position is always set to BOTTOM
        obj.display_position = BookCollection.DisplayPosition.BOTTOM
        super().save_model(request, obj, form, change)

    def changelist_view(self, request, extra_context=None):
        # Check if a bottom collection exists
        try:
            # Try to get the first (and should be only) bottom collection
            obj = self.get_queryset(request).first()
            if obj:
                # If it exists, redirect to the change view for this object
                from django.http import HttpResponseRedirect
                from django.urls import reverse
                url = reverse(
                    'admin:%s_%s_change' % (obj._meta.app_label, obj._meta.model_name),
                    args=[obj.pk]
                )
                return HttpResponseRedirect(url)
        except Exception:
            # If any error occurs, just show the changelist view as usual
            pass

        # If no object exists or there was an error, show the default changelist view
        return super().changelist_view(request, extra_context)



@admin.register(Category)
class CategoryAdmin(AjaxDatatable):
    list_display = ('title', 'slug', 'status', 'count_books', 'created_at')
    list_filter = ('status', 'created_at', 'updated_at')
    search_fields = ('title', 'slug')
    # autocomplete_fields = ('books',)

    @admin.display(description=_('Number of Books'))
    def count_books(self, obj):
        count = obj.books_count
        if count > 0:
            url = reverse('admin:library_book_changelist') + f'?categories__id__exact={obj.id}'
            return format_html('<a href="{}">{}</a>', url, count)
        return count