from rest_framework.decorators import api_view
from rest_framework.response import Response
from rest_framework import status
from django.conf import settings
from .models import LibraryAsset, Project, Asset
from .serializers import LibraryAssetSerializer
import os


@api_view(['GET'])
def library_list(request):
    """列出所有预设素材（按主题分组）"""
    assets = LibraryAsset.objects.all()
    serializer = LibraryAssetSerializer(assets, many=True, context={'request': request})

    # 按 theme_id 分组
    grouped = {}
    for a in serializer.data:
        a['file_url'] = f'{settings.MEDIA_URL}{a["file_path"]}'
        grouped.setdefault(a['theme_id'], {
            'theme_id': a['theme_id'],
            'theme_name': a['theme_name'],
            'description': a['description'],
            'items': [],
        })['items'].append(a)

    return Response(list(grouped.values()))


@api_view(['GET'])
def library_themes(request):
    """返回所有主题的元信息（不含具体素材项，用于渲染主题筛选器）"""
    themes = LibraryAsset.objects.values('theme_id', 'theme_name', 'description').distinct()
    return Response(list(themes))


@api_view(['GET'])
def library_detail(request, pk):
    """单个预设素材的详情"""
    try:
        a = LibraryAsset.objects.get(pk=pk)
    except LibraryAsset.DoesNotExist:
        return Response({'error': 'Not found'}, status=status.HTTP_404_NOT_FOUND)
    data = LibraryAssetSerializer(a, context={'request': request}).data
    data['file_url'] = f'{settings.MEDIA_URL}{data["file_path"]}'
    return Response(data)


@api_view(['POST'])
def library_apply(request, project_pk, pk):
    """把预设素材应用到项目某张牌（默认：spade-J / joker-big 等）
    请求体: { card_key?: 'spade-J' }  可选；不传则用预设素材的 role + 默认 spade
    """
    try:
        project = Project.objects.get(pk=project_pk)
        lib = LibraryAsset.objects.get(pk=pk)
    except (Project.DoesNotExist, LibraryAsset.DoesNotExist):
        return Response({'error': 'not found'}, status=status.HTTP_404_NOT_FOUND)

    card_key = request.data.get('card_key')
    if not card_key:
        # 默认: spade-{role} 或 joker-{which}
        if lib.role == 'joker':
            card_key = 'joker-big'  # 默认应用到 big；用户可换
        else:
            card_key = f'spade-{lib.role}'

    # 决定 asset_type: J/Q/K -> face_card；joker -> joker
    asset_type = 'face_card' if lib.role in ('J', 'Q', 'K') else 'joker'
    asset_key = card_key

    # 删除该项目同 (asset_type, asset_key) 的旧记录（避免重复）
    Asset.objects.filter(project=project, asset_type=asset_type, asset_key=asset_key).delete()

    # 复制 library 文件到 projects/<pid>/ 下，避免污染原文件
    import shutil
    from time import time
    project_media_dir = os.path.join('projects', str(project.id), asset_type)
    full_dir = os.path.join(settings.MEDIA_ROOT, project_media_dir)
    os.makedirs(full_dir, exist_ok=True)

    src_path = os.path.join(settings.MEDIA_ROOT, lib.file_path)
    ts = int(time() * 1000)
    new_file_name = f'{asset_key}_{ts}_{lib.file_name}'
    dst_rel = os.path.join(project_media_dir, new_file_name)
    dst_abs = os.path.join(settings.MEDIA_ROOT, dst_rel)
    shutil.copy2(src_path, dst_abs)

    # 读 svg 尺寸
    width = height = None
    try:
        from PIL import Image
        with Image.open(dst_abs) as im:
            width, height = im.size
    except Exception:
        pass

    asset = Asset.objects.create(
        project=project,
        asset_type=asset_type,
        asset_key=asset_key,
        file_path=dst_rel,
        file_name=new_file_name,
        width=width,
        height=height,
    )

    return Response({
        'ok': True,
        'asset_id': asset.id,
        'card_key': card_key,
        'asset_type': asset_type,
        'file_url': f'{settings.MEDIA_URL}{dst_rel}',
    }, status=status.HTTP_201_CREATED)