from django.contrib.auth.decorators import login_required
from django.db.models import Count, Q
from django.http import HttpRequest, HttpResponse, JsonResponse, StreamingHttpResponse
from django.shortcuts import redirect, render
from django.views.decorators.http import require_http_methods

from .services import (
    create_conversation,
    get_conversation_for_user,
    list_conversations,
    send_message,
    stream_message,
)
from .models import Conversation, FileAttachment, FileSummaryBatch


@login_required
@require_http_methods(["GET", "POST"])
def workspace(request: HttpRequest) -> HttpResponse:
    """Renders the review-agent workspace and handles conversation actions."""

    if request.method == "POST":
        action = request.POST.get("action")
        conversation = get_conversation_for_user(request.user, request.POST.get("conversation_id"))

        if action == "new_conversation":
            conversation = create_conversation(request.user)
            return redirect(f"/?conversation={conversation.pk}")

        if action == "send_message":
            content = (request.POST.get("prompt") or "").strip()
            if not conversation:
                conversation = create_conversation(request.user)
            if content:
                send_message(conversation, content)
            return redirect(f"/?conversation={conversation.pk}")

    search = (request.GET.get("q") or "").strip()
    conversations = list_conversations(request.user, search)
    current = get_conversation_for_user(request.user, request.GET.get("conversation"))

    if current is None and conversations.exists():
        current = conversations.first()

    return render(
        request,
        "home.html",
        {
            "page_title": "审核智能体",
            "search_query": search,
            "conversations": conversations,
            "current_conversation": current,
            "messages": current.messages.all() if current else [],
            "attachments": FileAttachment.objects.filter(conversation=current).order_by("original_name", "-version_no") if current else [],
            "summary_batches": FileSummaryBatch.objects.filter(conversation=current).prefetch_related("node_runs").order_by("-created_at")[:5] if current else [],
        },
    )


@login_required
@require_http_methods(["GET"])
def attachment_manager(request: HttpRequest) -> HttpResponse:
    conversations = (
        Conversation.objects.filter(user=request.user)
        .annotate(
            attachment_count=Count(
                "file_attachments",
                filter=~Q(file_attachments__upload_status=FileAttachment.UploadStatus.DELETED),
            )
        )
        .order_by("-updated_at", "-id")
    )
    selected = get_conversation_for_user(request.user, request.GET.get("conversation"))
    attachments = (
        FileAttachment.objects.filter(conversation=selected)
        .order_by("original_name", "-version_no")
        if selected
        else []
    )
    return render(
        request,
        "attachment_manager.html",
        {
            "page_title": "附件管理",
            "conversations": conversations,
            "selected_conversation": selected,
            "attachments": attachments,
        },
    )


@login_required
@require_http_methods(["POST"])
def stream_chat(request: HttpRequest) -> HttpResponse:
    """Streams one assistant reply so the UI can render incremental output."""

    content = (request.POST.get("prompt") or "").strip()
    if not content:
        return JsonResponse({"error": "消息内容不能为空。"}, status=400)

    conversation = get_conversation_for_user(request.user, request.POST.get("conversation_id"))
    if not conversation:
        conversation = create_conversation(request.user)

    response = StreamingHttpResponse(
        streaming_content=stream_message(conversation, content),
        content_type="text/event-stream",
    )
    response["Cache-Control"] = "no-cache"
    response["X-Accel-Buffering"] = "no"
    return response