import json
import logging

from django.db import transaction
from rest_framework import status
from rest_framework.decorators import api_view, permission_classes
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response

from .llm import analyze_requirements
from .models import Requirement, Submission

logger = logging.getLogger(__name__)


def _parse_llm_override(request) -> dict:
    raw = request.data.get("llm")
    if not raw:
        return {}
    if isinstance(raw, str):
        try:
            raw = json.loads(raw)
        except json.JSONDecodeError:
            return {}
    return raw if isinstance(raw, dict) else {}


def _validate_llm_override(override: dict) -> str | None:
    if override.get("mode") != "custom":
        return None
    if not (override.get("base_url") or "").strip() or not (override.get("model") or "").strip():
        return "custom 模式必须提供 llm.base_url 和 llm.model"
    return None


@api_view(["POST"])
@permission_classes([IsAuthenticated])
@transaction.atomic
def create_requirement(request):
    title = (request.data.get("title") or "").strip()
    content = (request.data.get("content") or "").strip()
    if not title or not content:
        return Response({"detail": "title 和 content 不能为空"}, status=status.HTTP_400_BAD_REQUEST)
    override = _parse_llm_override(request)
    err = _validate_llm_override(override)
    if err:
        return Response({"detail": err}, status=status.HTTP_400_BAD_REQUEST)
    try:
        spec = analyze_requirements(content, override)
    except Exception:
        logger.exception("AI 分析作业要求失败, 使用默认检测计划")
        from .llm import _default_spec
        spec = _default_spec()
    requirement = Requirement.objects.create(
        title=title, content=content, spec=spec, llm_config=override,
    )
    from .serializers import RequirementSerializer
    return Response(RequirementSerializer(requirement).data, status=status.HTTP_201_CREATED)


@api_view(["GET"])
@permission_classes([IsAuthenticated])
def list_requirements(request):
    qs = Requirement.objects.all()
    q = request.query_params.get("q")
    if q:
        qs = qs.filter(title__icontains=q) | qs.filter(content__icontains=q)
    from .serializers import RequirementSerializer
    page = int(request.query_params.get("page", 1))
    size = int(request.query_params.get("size", 20))
    items = qs[(page - 1) * size: page * size]
    return Response({
        "count": qs.count(),
        "page": page,
        "items": RequirementSerializer(items, many=True).data,
    })


@api_view(["GET"])
@permission_classes([IsAuthenticated])
def get_requirement(request, pk):
    try:
        requirement = Requirement.objects.get(pk=pk)
    except Requirement.DoesNotExist:
        return Response({"detail": "不存在"}, status=status.HTTP_404_NOT_FOUND)
    from .serializers import RequirementSerializer
    return Response(RequirementSerializer(requirement).data)


@api_view(["POST"])
@permission_classes([IsAuthenticated])
@transaction.atomic
def create_submission(request, pk):
    try:
        requirement = Requirement.objects.get(pk=pk)
    except Requirement.DoesNotExist:
        return Response({"detail": "作业要求不存在"}, status=status.HTTP_404_NOT_FOUND)
    name = (request.data.get("name") or "").strip()
    file = request.FILES.get("file")
    if not file:
        return Response({"detail": "缺少上传文件 file"}, status=status.HTTP_400_BAD_REQUEST)
    submission = Submission.objects.create(
        requirement=requirement,
        name=name or file.name,
        file=file,
        submitted_by=request.user,
    )
    from .tasks import run_submission
    try:
        run_submission(submission.id)
    except Exception:
        logger.exception("检测任务启动失败")
        submission.status = "failed"
        submission.save(update_fields=["status"])
    from .serializers import SubmissionSerializer
    return Response(SubmissionSerializer(submission).data, status=status.HTTP_201_CREATED)


@api_view(["GET"])
@permission_classes([IsAuthenticated])
def list_submissions(request):
    qs = Submission.objects.all()
    req_id = request.query_params.get("requirement")
    if req_id:
        qs = qs.filter(requirement_id=req_id)
    from .serializers import SubmissionSerializer
    return Response({"items": SubmissionSerializer(qs, many=True).data})


@api_view(["GET"])
@permission_classes([IsAuthenticated])
def get_submission(request, pk):
    try:
        submission = Submission.objects.get(pk=pk)
    except Submission.DoesNotExist:
        return Response({"detail": "不存在"}, status=status.HTTP_404_NOT_FOUND)
    from .serializers import SubmissionSerializer
    return Response(SubmissionSerializer(submission).data)


@api_view(["GET"])
@permission_classes([IsAuthenticated])
def get_report(request, pk):
    try:
        submission = Submission.objects.get(pk=pk)
    except Submission.DoesNotExist:
        return Response({"detail": "不存在"}, status=status.HTTP_404_NOT_FOUND)
    if not submission.report:
        return Response({"detail": "报告尚未生成", "status": submission.status},
                        status=status.HTTP_202_ACCEPTED)
    return Response(submission.report)