from django.contrib.auth.decorators import login_required
from django.http import Http404, JsonResponse
from django.views.decorators.http import require_http_methods

from review_agent.models import Conversation, FileAttachment

from .storage import save_uploaded_attachment, serialize_attachment


def _conversation_for_user(user, conversation_id: int) -> Conversation:
    conversation = Conversation.objects.filter(pk=conversation_id, user=user).first()
    if not conversation:
        raise Http404("对话不存在。")
    return conversation


@require_http_methods(["POST", "GET"])
@login_required
def attachments(request, conversation_id: int):
    conversation = _conversation_for_user(request.user, conversation_id)

    if request.method == "POST":
        files = request.FILES.getlist("files")
        if not files:
            return JsonResponse({"error": "请选择至少一个文件。"}, status=400)
        saved = [
            save_uploaded_attachment(
                conversation=conversation,
                user=request.user,
                uploaded_file=uploaded_file,
            )
            for uploaded_file in files
        ]
        return JsonResponse({"attachments": [serialize_attachment(item) for item in saved]})

    queryset = FileAttachment.objects.filter(conversation=conversation).order_by(
        "original_name",
        "-version_no",
    )
    return JsonResponse({"attachments": [serialize_attachment(item) for item in queryset]})


@require_http_methods(["DELETE"])
@login_required
def attachment_detail(request, conversation_id: int, attachment_id: int):
    conversation = _conversation_for_user(request.user, conversation_id)
    attachment = FileAttachment.objects.filter(
        pk=attachment_id,
        conversation=conversation,
        user=request.user,
    ).first()
    if not attachment:
        raise Http404("附件不存在。")

    attachment.upload_status = FileAttachment.UploadStatus.DELETED
    attachment.is_active = False
    attachment.save(update_fields=["upload_status", "is_active"])
    return JsonResponse({"ok": True, "attachment": serialize_attachment(attachment)})