from utils.admin import admin_url_generator
import os
import hashlib

from django.contrib import admin
from django.contrib import messages
from django import forms
from django.utils.translation import gettext_lazy as _
from django.db import models
from django.utils.html import format_html
from django.shortcuts import redirect, render
from django.urls import reverse_lazy, reverse

from unfold.admin import ModelAdmin, TabularInline
from unfold.decorators import action, display
from unfold.sections import TableSection
from unfold.contrib.filters.admin import (
    ChoicesDropdownFilter,
    MultipleRelatedDropdownFilter,
    RangeDateFilter,
    RangeNumericFilter,
    TextFilter,
)
from unfold.widgets import UnfoldAdminSelectWidget

from .professor_base import DirectCourseAdmin, CourseRelatedAdmin, AttachmentGlossaryBaseAdmin
from utils.admin import project_admin_site, dovoodi_admin_site
from utils.json_editor_field import JsonEditorWidget
from apps.course.models import Course, Glossary, Attachment, CourseCategory, Participant, CourseGlossary, CourseAttachment
from apps.course.models.lesson import Lesson, CourseLesson
from apps.account.models import StudentUser, User
from utils.schema import get_weekly_timing_schema, get_course_feature_schema


class CourseTableSection(TableSection):
    verbose_name = _("Course Categories")
    related_name = "courses"
    height = 380
    fields = [
        "title",
        "status",
        "edit_link"
    ]

    def edit_link(self, instance):
        return format_html(
            '<a href="/admin/course/course/{}/change/" class="leading-none">'
            '<span class="material-symbols-outlined leading-none text-base-500">visibility</span>'
            '</a>',
            instance.id
        )
    edit_link.short_description = _("Edit")

            
class CourseCategoryAdmin(ModelAdmin):
    list_display = ('name', 'slug', 'course_count')
    search_fields = ('name',)
    list_sections = [CourseTableSection]
    fieldsets = (
        (None, {
            'fields': ('name', 'slug')
        }),
    )

    @display(description=_("Courses"))
    def course_count(self, obj):
        count = obj.courses.all().count()
        return format_html('<span class="badge badge-primary">{}</span>', count)


class CourseForm(forms.ModelForm):
    class Meta:
        model = Course
        fields = '__all__'
        exclude = ('slug',)
        widgets = {
            'timing': JsonEditorWidget(attrs={
                'schema': get_weekly_timing_schema(),
                'title': _('Course Weekly Schedule'),
            }),
            'features': JsonEditorWidget(attrs={
                'schema': get_course_feature_schema(),
                'title': _('Course Features'),
            }),
        }
        help_texts = {
            'status': _('If set to inactive, the course will not be displayed.'),
        }
    
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['short_description'].required = True
        if 'thumbnail' in self.fields:
            self.fields['thumbnail'].required = True

    def clean(self):
        cleaned_data = super().clean()
        thumbnail = cleaned_data.get('thumbnail')
        has_existing_thumbnail = bool(getattr(self.instance, 'thumbnail', None))

        if thumbnail is False:
            self.add_error('thumbnail', _('This field is required and cannot be cleared.'))
            return cleaned_data

        if (thumbnail is None or thumbnail == '') and not has_existing_thumbnail:
            self.add_error('thumbnail', _('This field is required.'))
        return cleaned_data

# --- WIDTH ENFORCEMENT & PLACEHOLDER TEXT FOR DROPDOWNS ---
class MinWidthInlineForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        target_dropdown_fields = ['lesson', 'attachment', 'glossary', 'student']
        
        for field_name, field in self.fields.items():
            if field_name in target_dropdown_fields:
                if hasattr(field.widget, 'attrs'):
                    existing_class = field.widget.attrs.get('class', '')
                    field.widget.attrs['class'] = f"{existing_class} min-w-[250px] w-full"
                    
                    existing_style = field.widget.attrs.get('style', '')
                    field.widget.attrs['style'] = f"{existing_style} min-width: 250px; width: 250px;"
                
                # 🔔 Add the custom placeholder text
                if hasattr(field, 'empty_label'):
                    field.empty_label = _("Select a value")


class CourseAttachmentInline(TabularInline):
    model = CourseAttachment
    form = MinWidthInlineForm
    extra = 1  # Show 1 empty dropdown by default
    fields = ('attachment',)
    tab = True
    # Removed autocomplete_fields to restore Unfold UI
    verbose_name = _("Course Attachment")
    verbose_name_plural = _("Course Attachments")


class CourseGlossaryInline(TabularInline):
    model = CourseGlossary
    form = MinWidthInlineForm
    fields = ('glossary',)
    extra = 1  # Show 1 empty dropdown by default
    tab = True
    tab_id = "glossaries_tab"
    show_change_link = True
    # Removed autocomplete_fields to restore Unfold UI


class CourseLessonInline(TabularInline):
    model = CourseLesson
    form = MinWidthInlineForm
    fields = ('lesson', 'title', 'is_active', 'priority',)
    extra = 1  # Show 1 empty dropdown by default
    tab = True
    tab_id = "lessons_tab"
    show_change_link = True
    ordering_field = "priority"
    # Removed autocomplete_fields to restore Unfold UI


class ParticipantInline(TabularInline):
    model = Participant
    form = MinWidthInlineForm
    fields = ('student', 'joined_date',)
    readonly_fields = ('joined_date', 'student')
    extra = 0 # Remains 0 because users are added via action buttons
    tab = True
    tab_id = "participants_tab"
    verbose_name = _("Recent Participant")
    verbose_name_plural = _("Recent Participants (Latest 10)")
    show_change_link = True
    
    def get_queryset(self, request):
        qs = super().get_queryset(request)
        object_id = request.resolver_match.kwargs.get('object_id')
        
        if object_id:
            latest_ids = list(qs.filter(course_id=object_id).order_by('-joined_date').values_list('id', flat=True)[:10])
            return qs.filter(id__in=latest_ids).order_by('-joined_date')
            
        return qs.none() 

    def has_add_permission(self, request, obj):
        return False
    def has_change_permission(self, request, obj=None):
        return False
    def has_delete_permission(self, request, obj=None):
        return False


class AddStudentForm(forms.Form):
    student = forms.ModelChoiceField(
        queryset=User.objects.filter(is_active=True , email__isnull=False),
        label=_("Select Student"),
        widget=UnfoldAdminSelectWidget,  
        required=True
    )
        
        
class CourseAdmin(DirectCourseAdmin):
    form = CourseForm
    inlines = [CourseLessonInline, CourseAttachmentInline, CourseGlossaryInline, ParticipantInline]
    
    list_display = ('display_header', 'category', 'display_professor', 'status', 'display_price', 'is_online')
    list_filter = [
        ('status', ChoicesDropdownFilter),
        ('level', ChoicesDropdownFilter),
        'is_online',
        'is_free',
        ('category', MultipleRelatedDropdownFilter),
        ('price', RangeNumericFilter),
    ]
    save_as = True
    warn_unsaved_form = True
    search_fields = ('id','title', 'description')
    exclude = ('slug', )
    readonly_fields = ('final_price',)
    autocomplete_fields = ('category', 'professor',)
    list_filter_submit = True
    change_form_show_cancel_button = True
    
    radio_fields = {
        "video_type": admin.HORIZONTAL,
        "status": admin.HORIZONTAL,
        "level": admin.HORIZONTAL,
    }
    
    conditional_fields = {
        'price': "is_free == false",
        'discount_percentage': "is_free == false",
        'final_price': "is_free == false",
        'online_link': "is_online",
        'video_file': "video_type == 'video_file'",
        'video_link': "video_type == 'youtube_link'",
    }

    fieldsets = (
        (None, {
            'fields': ('title', 'category', 'professor', 'thumbnail', 'description', 'short_description')
        }),
        (_('Settings & Status'), {
            'fields': (
                ('status', 'level'), 
                ('duration', 'lessons_count'),
                ('is_group_chat_locked', 'is_professor_chat_locked'),
                ('is_online', 'online_link')
            ),
            'classes': ['tab'],
        }),
        (_('Media'), {
            'fields': (
                ('video_type', 'video_file', 'video_link'),
            ),
            'classes': ['tab'],
        }),
        (_('Pricing'), {
            'fields': (
                ('is_free', 'price'),
                ('discount_percentage', 'final_price')
            ),
            'classes': ['tab'],
        }),
        (_('Advanced Configuration'), {
            'fields': ('timing', 'features'),
            'classes': ['tab'], 
        }),
    )

        
    @display(description=_("Course"), header=True)
    def display_header(self, instance):
        from django.templatetags.static import static
        thumbnail_path = instance.thumbnail.url if instance.thumbnail else None
        return [
            instance.title,
            None, None,
            {
                "path": thumbnail_path,
                "height": 40,
                "width": 60,
                "squared": True,
                "borderless": True,
            },
        ]
    
    @display(description=_("Professor"))
    def display_professor(self, instance):
        return instance.professor.fullname
    
    @display(description=_("Price"))
    def display_price(self, instance):
        if instance.is_free:
            return format_html('<span class="text-green-600 font-medium">{}</span>', _("Free"))
        
        if instance.discount_percentage > 0:
            return format_html(
                '<span class="line-through text-gray-400 mr-2">${}</span>'
                '<span class="text-green-600 font-medium">${}</span>',
                instance.price,
                instance.final_price
            )
        return format_html('<span>${}</span>', instance.final_price)
    
    
    actions_row = ["add_student_to_course"]
    actions_detail = ['add_student_to_course', 'manage_all_students']

    def has_is_course_professor_permission(self, request, object_id=None):
        try:
            if request.user.is_staff:
                return True
            course = self.get_object(request, object_id)
            return course and request.user.can_manage_course(course)
        except Exception as e:
            return False

    @action(
        description=_("Add Student"),
        icon="person_add",
        permissions=["is_course_professor"],
    )
    def add_student_to_course(self, request, object_id):
        course = self.get_object(request, object_id)
        if not course:
            messages.error(request, _("Course not found"))
            return redirect(admin_url_generator(request, "course_course_changelist"))

        if request.method == 'POST':
            form = AddStudentForm(request.POST)
            if form.is_valid():
                student = form.cleaned_data['student']
                if Participant.objects.filter(student=student, course=course).exists():
                    messages.warning(request, _("Student {} is already enrolled in this course").format(student.fullname))
                else:
                    if not student.has_role('student'):
                        student.add_role('student')
                    Participant.objects.create(student=student, course=course)
                    messages.success(request, _("Student {} has been successfully added to {}").format(student.fullname, course.title))
                return redirect(admin_url_generator(request, "course_course_changelist"))
        else:
            form = AddStudentForm()

        return render(
            request,
            "course/add_student_form.html",
            {
                "form": form,
                "object": object,
                "title": _("Add Student to {}").format(course.title),
                **self.admin_site.each_context(request),
            },
        )

    @action(
        description=_("Manage All Students"),
        icon="groups",
        permissions=["is_course_professor"],
    )
    def manage_all_students(self, request, object_id):
        course = self.get_object(request, object_id)
        if not course:
            messages.error(request, _("Course not found"))
            return redirect(admin_url_generator(request, "course_course_changelist"))

        base_url = admin_url_generator(request, "course_participant_changelist")
        url = f"{base_url}?course__id__exact={object_id}"
        return redirect(url)
    
class GlossaryAdmin(AttachmentGlossaryBaseAdmin):
    list_display = ('title', 'description')
    search_fields = ('title', 'description')
    ordering = ('-id',)

    def is_used_in_professor_courses(self, user, obj):
        return obj.courseglossary_set.filter(course__professor=user).exists()

    def filter_by_professor_usage(self, user, queryset):
        return queryset.filter(courseglossary__course__professor=user).distinct()


class CourseGlossaryAdmin(CourseRelatedAdmin):
    list_display = ('course', 'glossary_title', 'glossary_description')
    list_filter = ('course',)
    search_fields = ('glossary__title', 'glossary__description', 'course__title')
    ordering = ('-id',)
    autocomplete_fields = ('course', 'glossary')
    
    # 🔔 REMOVES FROM "ALL APPLICATIONS" MODAL
    def has_module_permission(self, request):
        return False
    
    @admin.display(description=_("Title"))
    def glossary_title(self, obj):
        return obj.glossary.title
        
    @admin.display(description=_("Description"))
    def glossary_description(self, obj):
        return obj.glossary.description


class AttachmentAdminForm(forms.ModelForm):
    class Meta:
        model = Attachment
        fields = '__all__'
        
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if 'file' in self.data or 'file' in self.files:
            file = self.files.get('file') 
            if file:
                file.name = self._shorten_file_name(file.name)
    
    def _shorten_file_name(self, file_name):
        max_length = 100
        if len(file_name) > max_length:
            base_name, ext = os.path.splitext(file_name) 
            allowed_length = max_length - len(ext) 
            base_length = int(allowed_length * 0.8) 
            hash_length = allowed_length - base_length 
            base_part = base_name[:base_length] 
            hash_part = hashlib.sha256(base_name.encode('utf-8')).hexdigest()[:hash_length] 
            return f"{base_part}{hash_part}{ext}" 
        return file_name


class AttachmentAdmin(AttachmentGlossaryBaseAdmin):
    form = AttachmentAdminForm
    list_display = ('title', 'file', 'file_size')
    search_fields = ('title', 'file')

    def save_model(self, request, obj, form, change):
        if obj.file:
            obj.file_size = obj.file.size
        super().save_model(request, obj, form, change)

    def is_used_in_professor_courses(self, user, obj):
        return obj.courseattachment_set.filter(course__professor=user).exists()

    def filter_by_professor_usage(self, user, queryset):
        return queryset.filter(courseattachment__course__professor=user).distinct()


class CourseAttachmentAdmin(CourseRelatedAdmin):
    list_display = ('course', 'attachment_title', 'attachment_file', 'attachment_file_size')
    list_filter = ('course',)
    search_fields = ('attachment__title', 'course__title')
    autocomplete_fields = ('course', 'attachment')
    
    # 🔔 REMOVES FROM "ALL APPLICATIONS" MODAL
    def has_module_permission(self, request):
        return False
    
    @admin.display(description=_("Title"))
    def attachment_title(self, obj):
        return obj.attachment.title
        
    @admin.display(description=_("File"))
    def attachment_file(self, obj):
        return obj.attachment.file
        
    @admin.display(description=_("File Size"))
    def attachment_file_size(self, obj):
        return obj.attachment.file_size


class ParticipantAdmin(ModelAdmin):
    list_display = ('student_name', 'course_title', 'joined_date',)
    list_filter = (
        ('course', MultipleRelatedDropdownFilter),
    )
    search_fields = ('student__email', 'student__fullname', 'course__title')
    readonly_fields = ('joined_date',)
    autocomplete_fields = ('student', 'course')
    
    fieldsets = (
        (None, {
            'fields': ('student', 'course', 'is_active')
        }),
        (_('Enrollment Details'), {
            'fields': ('joined_date', 'unread_messages_count') 
        }),
    )

    @display(description=_("Student"), header=True)
    def student_name(self, instance):
        from django.templatetags.static import static

        avatar_path = instance.student.avatar.url if getattr(instance.student, 'avatar', None) else static("images/reading(1).png")

        return [
            instance.student.fullname,
            None,
            None,
            {
            "path": avatar_path,
            "height": 30,
            "width": 36,
            "borderless": True,
            },
        ]
            
    @display(description=_("Course"))
    def course_title(self, obj):
        if obj.course:
            return obj.course.title
        return "-"


# =========================================================
# REGISTRATIONS
# =========================================================
from django.contrib import admin as django_admin

try:
    django_admin.site.register(Course, CourseAdmin)
    django_admin.site.register(CourseCategory, CourseCategoryAdmin)
    django_admin.site.register(Glossary, GlossaryAdmin)
    django_admin.site.register(Attachment, AttachmentAdmin)
except django_admin.sites.AlreadyRegistered:
    pass

project_admin_site.register(Course, CourseAdmin)
project_admin_site.register(CourseCategory, CourseCategoryAdmin)
project_admin_site.register(Glossary, GlossaryAdmin)
project_admin_site.register(CourseGlossary, CourseGlossaryAdmin)
project_admin_site.register(Attachment, AttachmentAdmin)
project_admin_site.register(CourseAttachment, CourseAttachmentAdmin)
project_admin_site.register(Participant, ParticipantAdmin)

class HiddenCourseAdmin(ModelAdmin):
    search_fields = ('title', 'id') 
    
    def has_module_permission(self, request):
        return False
    def has_add_permission(self, request):
        return False
    def has_change_permission(self, request, obj=None):
        return False
    def has_delete_permission(self, request, obj=None):
        return False

dovoodi_admin_site.register(Course, HiddenCourseAdmin)