from django.contrib import admin
from django.http import JsonResponse
from django.shortcuts import get_object_or_404, render
from django.urls import path, reverse
from django.utils.html import format_html
from imagekit import ImageSpec
from imagekit.admin import AdminThumbnail
from imagekit.cachefiles import ImageCacheFile
from imagekit.processors import ResizeToFit

from gallery.models import Album, City, Location, Photo, Redir


# Thumbnail-luokka admin-näkymää varten
class AdminThumbnailSpec(ImageSpec):
    processors = [ResizeToFit(100, 100)]
    format = 'JPEG'
    options = {'quality': 60}


def cached_admin_thumb(instance):
    """Palauttaa cachetetun thumbnailin, jos kuva on olemassa."""
    if instance.photo:
        cached = ImageCacheFile(AdminThumbnailSpec(instance.photo))
        cached.generate()
        return cached
    return None


# 🔹 RedirAdmin – uudelleenohjausten hallinta
class RedirAdmin(admin.ModelAdmin):
    list_display = ('path', 'album', 'test_url')
    search_fields = ('path',)
    ordering = ('path',)
    list_per_page = 30
    list_editable = ('album',)

    def formfield_for_foreignkey(self, db_field, request, **kwargs):
        """Järjestää albumivalikon aakkosjärjestykseen."""
        if db_field.name == "album":
            kwargs["queryset"] = Album.objects.all().order_by('name')
        return super().formfield_for_foreignkey(db_field, request, **kwargs)

    def test_url(self, obj):
        """Luo linkin, jolla voi testata uudelleenohjauksen."""
        return format_html(
            '<a href="/{}" target="_blank">http://nyymix.net/{}</a>',
            obj.path, obj.path
        )
    test_url.short_description = "Test Redirection"


# 🔹 CityAdmin – kaupunkien hallinta
class CityAdmin(admin.ModelAdmin):
    list_display = ('name',)
    search_fields = ('name',)
    ordering = ('name',)
    list_per_page = 30


# 🔹 LocationAdmin – sijaintien hallinta
class LocationAdmin(admin.ModelAdmin):
    list_display = ('city', 'place')
    list_filter = ('city',)
    ordering = ('city__name',)
    search_fields = ('place', 'city__name',)
    list_per_page = 30


# 🔹 AlbumAdmin – albumien hallinta
class AlbumAdmin(admin.ModelAdmin):
    prepopulated_fields = {'slug': ('name',)}
    list_display = ('name', 'location', 'album_date', 'is_public', 'upload_link', 'thumbnail')
    search_fields = ('name',)
    ordering = ('-album_date',)
    list_per_page = 20
    list_editable = ('is_public',)
    readonly_fields = ['cover_preview']
    change_form_template = "admin/gallery/album/change_form.html"

    def get_urls(self):
        """Lisää mukautetun URL-reitin valokuvien lataamiselle."""
        urls = super().get_urls()
        custom_urls = [
            path('<int:album_id>/upload/', self.admin_site.admin_view(self.upload_photos), name="gallery_album_upload"),
        ]
        return custom_urls + urls

    def upload_photos(self, request, album_id, *args, **kwargs):
        """Käsittelee valokuvien lataamisen albumiin."""
        album = get_object_or_404(Album, id=album_id)

        if request.method == 'POST' and request.FILES:
            uploaded_files = request.FILES.getlist('photo')
            if not uploaded_files:
                return JsonResponse({"error": "No files uploaded."}, status=400)

            Photo.objects.bulk_create([Photo(album=album, photo=file) for file in uploaded_files])
            return JsonResponse({"message": "Photos uploaded successfully!"})

        return render(request, 'admin/upload_photos.html', {'album': album})

    def upload_link(self, obj):
        """Lisää 'Upload Photos' -painikkeen albumin muokkaussivulle."""
        if obj.id:
            url = reverse("admin:gallery_album_upload", kwargs={"album_id": obj.id})
            return format_html('<a href="{}" class="button">Upload Photos</a>', url)
        return "-"
    upload_link.short_description = "Upload Photos"

    def thumbnail(self, obj):
        """Näyttää albumin kansikuvan pikkukuvan."""
        if obj.cover and obj.cover.photo:
            return format_html(
                '<img src="{}" style="width: 50px; height: auto;"/>',
                obj.cover.photo_sm.url,
            )
        return "-"
    thumbnail.short_description = "Thumbnail"

    def cover_preview(self, obj):
        """Näyttää albumin kansikuvan suurempana esikatseluna."""
        if obj.cover and obj.cover.photo:
            return format_html(
                '<img src="{}" style="max-width: 300px; height: auto;"/>',
                obj.cover.photo_sm.url,
            )
        return "No cover image available"
    cover_preview.short_description = "Cover Preview"

    def formfield_for_foreignkey(self, db_field, request, **kwargs):
        """
        Suodattaa 'cover'-valinnan niin, että se näyttää vain albumiin kuuluvat kuvat.
        Uuden albumin luonnissa vaihtoehto pidetään tyhjänä.
        """
        if db_field.name == "cover":
            # Jos albumia ollaan luomassa (ei pk:ta), ei anneta mitään vaihtoehtoja
            if request.resolver_match.kwargs.get("object_id") is None:
                kwargs["queryset"] = Photo.objects.none()
            else:
                # Haetaan vain nykyiseen albumiin kuuluvat kuvat
                album_id = request.resolver_match.kwargs.get("object_id")
                kwargs["queryset"] = Photo.objects.filter(album_id=album_id)
        return super().formfield_for_foreignkey(db_field, request, **kwargs)


# 🔹 PhotoAdmin – kuvien hallinta
class PhotoAdmin(admin.ModelAdmin):
    list_display = ('slug', 'album', 'is_favorite', 'admin_thumbnail')
    list_display_links = ('slug',)
    search_fields = ('slug', 'photo')
    readonly_fields = ['slug', 'taken_at', 'height', 'width', 'exif']
    admin_thumbnail = AdminThumbnail(image_field=cached_admin_thumb)
    list_filter = ('album',)
    list_per_page = 30
    list_editable = ('is_favorite',)


# 🔹 Rekisteröidään admin-paneeliin
admin.site.register(City, CityAdmin)
admin.site.register(Location, LocationAdmin)
admin.site.register(Album, AlbumAdmin)
admin.site.register(Photo, PhotoAdmin)
admin.site.register(Redir, RedirAdmin)