from rest_framework.decorators import api_view, permission_classes
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from django.db.models import Count
from apps.material.models import Material
from apps.factory.models import Factory


def _build_brochure_url(request, brochure_field):
    if brochure_field and request:
        return request.build_absolute_uri(brochure_field.url)
    return None


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def overview_statistics(request):
    """
    数据总览统计
    """
    # 只有管理员可访问
    if request.user.role != 'admin':
        return Response({"detail": "无权访问"}, status=403)

    approved_materials = Material.objects.filter(status='approved')

    # 材料总数
    total_materials = approved_materials.count()

    # 材料种类（材料子类数量）
    total_material_categories = approved_materials.values('material_subcategory').distinct().count()

    # 品牌数（工厂数）
    total_brands = Factory.objects.count()

    # 按专业类别的材料数量分布
    major_category_stats = approved_materials.values('major_category').annotate(
        count=Count('id')
    ).order_by('-count')

    # 按材料子类的材料数量分布
    material_subcategory_stats = approved_materials.values('material_subcategory').annotate(
        count=Count('id')
    ).order_by('-count')[:10]

    # 按所属品牌的材料数量分布
    brand_stats = approved_materials.values('factory__factory_name').annotate(
        count=Count('id')
    ).order_by('-count')

    # 按地区的工厂数量分布
    region_stats = Factory.objects.values('province', 'city').annotate(
        count=Count('id')
    ).order_by('-count')

    # 应用案例列表
    cases_list = []
    for item in approved_materials.filter(cases__isnull=False).exclude(cases='')[:10]:
        cases_list.append({
            'id': item.id,
            'name': item.name,
            'cases': item.cases,
            'factory_name': item.factory.factory_name if item.factory else None,
            'brochure_url': _build_brochure_url(request, item.brochure),
        })

    return Response({
        'total_materials': total_materials,
        'total_material_categories': total_material_categories,
        'total_brands': total_brands,
        'major_category_stats': list(major_category_stats),
        'material_subcategory_stats': list(material_subcategory_stats),
        'brand_stats': list(brand_stats),
        'region_stats': list(region_stats),
        'cases_list': cases_list,
    })


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def material_statistics(request):
    """
    材料库统计
    """
    if request.user.role != 'admin':
        return Response({"detail": "无权访问"}, status=403)

    material_subcategory = request.query_params.get('material_subcategory')
    queryset = Material.objects.filter(status='approved')

    if material_subcategory:
        queryset = queryset.filter(material_subcategory=material_subcategory)

    subcategories = list(Material.objects.filter(status='approved').values_list(
        'material_subcategory', flat=True
    ).distinct())

    def _level_counts(qs, field):
        raw = qs.values(field).annotate(count=Count('id'))
        mapping = {item[field]: item['count'] for item in raw if item[field] is not None}
        return [mapping.get(1, 0), mapping.get(2, 0), mapping.get(3, 0)]

    star_stats = {
        'quality_level': _level_counts(queryset, 'quality_level'),
        'durability_level': _level_counts(queryset, 'durability_level'),
        'eco_level': _level_counts(queryset, 'eco_level'),
        'carbon_level': _level_counts(queryset, 'carbon_level'),
        'score_level': _level_counts(queryset, 'score_level'),
    }

    # 竞争优势与替代材料对比（优势为多选）
    advantage_replace_counter = {}
    for material in queryset:
        advantages = material.advantage or []
        for adv in advantages:
            key = (adv, material.replace_type)
            advantage_replace_counter[key] = advantage_replace_counter.get(key, 0) + 1

    advantage_replace_stats = [
        {'advantage': key[0], 'replace_type': key[1], 'count': count}
        for key, count in advantage_replace_counter.items()
    ]

    # 应用场景对比（多选）
    application_scene_counter = {}
    for material in queryset:
        scenes = material.application_scene or []
        for scene in scenes:
            application_scene_counter[scene] = application_scene_counter.get(scene, 0) + 1

    application_scene_stats = [
        {'application_scene': key, 'count': count}
        for key, count in application_scene_counter.items()
    ]

    # 材料列表
    materials_list = []
    for item in queryset[:20]:
        materials_list.append({
            'id': item.id,
            'name': item.name,
            'material_category': item.material_category,
            'material_subcategory': item.material_subcategory,
            'factory_name': item.factory.factory_name if item.factory else None,
            'brochure_url': _build_brochure_url(request, item.brochure),
        })

    return Response({
        'levels': [1, 2, 3],
        'subcategories': subcategories,
        'star_stats': star_stats,
        'advantage_replace_stats': advantage_replace_stats,
        'application_scene_stats': application_scene_stats,
        'materials_list': materials_list,
        'advantage_choices': Material.ADVANTAGE_CHOICES,
        'replace_type_choices': Material.REPLACE_TYPE_CHOICES,
        'application_scene_choices': Material.APPLICATION_SCENE_CHOICES,
    })


@api_view(['GET'])
@permission_classes([IsAuthenticated])
def factory_statistics(request):
    """
    工厂库统计
    """
    if request.user.role != 'admin':
        return Response({"detail": "无权访问"}, status=403)

    region_stats = list(Factory.objects.values('province', 'city').annotate(
        count=Count('id')
    ).order_by('-count'))

    factory_category_stats = []
    approved_materials = Material.objects.filter(status='approved')
    for factory in Factory.objects.all():
        material_categories = approved_materials.filter(factory=factory).values(
            'material_category'
        ).annotate(
            count=Count('id')
        )

        factory_category_stats.append({
            'factory_id': factory.id,
            'factory_name': factory.factory_name,
            'categories': list(material_categories),
            'total_materials': approved_materials.filter(factory=factory).count()
        })

    factories_list = list(Factory.objects.values(
        'id', 'factory_name', 'factory_short_name', 'province', 'city', 'website'
    ))

    return Response({
        'region_stats': region_stats,
        'factory_category_stats': factory_category_stats,
        'factories_list': factories_list,
    })