from django.contrib.auth.decorators import login_required
import logging
from pathlib import Path

from django.http import FileResponse, Http404, JsonResponse
from django.views.decorators.http import require_http_methods

from review_agent.models import Conversation, ExportedSummaryFile, FileAttachment
from review_agent.models import FileSummaryBatch, WorkflowEvent
from .events import serialize_event

from .storage import save_uploaded_attachment, serialize_attachment


logger = logging.getLogger("review_agent.file_summary.views")


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)
        logger.info(
            "Attachment upload request received",
            extra={
                "conversation_id": conversation.pk,
                "user_id": request.user.pk,
                "file_count": len(files),
                "filenames": [uploaded_file.name for uploaded_file in files],
            },
        )
        saved = [
            save_uploaded_attachment(
                conversation=conversation,
                user=request.user,
                uploaded_file=uploaded_file,
            )
            for uploaded_file in files
        ]
        logger.info(
            "Attachment upload request finished",
            extra={
                "conversation_id": conversation.pk,
                "attachment_ids": [attachment.pk for attachment in saved],
            },
        )
        return JsonResponse({"attachments": [serialize_attachment(item) for item in saved]})

    queryset = FileAttachment.objects.filter(conversation=conversation).order_by(
        "original_name",
        "-version_no",
    )
    logger.info(
        "Attachment list requested",
        extra={"conversation_id": conversation.pk, "attachment_count": queryset.count()},
    )
    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"])
    logger.info(
        "Attachment deleted",
        extra={"conversation_id": conversation.pk, "attachment_id": attachment.pk},
    )
    return JsonResponse({"ok": True, "attachment": serialize_attachment(attachment)})


@require_http_methods(["GET"])
@login_required
def batch_status(request, batch_id: int):
    batch = FileSummaryBatch.objects.filter(pk=batch_id, user=request.user).first()
    if not batch:
        raise Http404("批次不存在。")
    return JsonResponse(
        {
            "batch": {
                "id": batch.pk,
                "batch_no": batch.batch_no,
                "status": batch.status,
                "product_name": batch.product_name,
                "total_files": batch.total_files,
                "success_files": batch.success_files,
                "failed_files": batch.failed_files,
                "total_pages": batch.total_pages,
            },
            "nodes": [
                {
                    "node_code": node.node_code,
                    "node_name": node.node_name,
                    "status": node.status,
                    "progress": node.progress,
                    "message": node.message,
                }
                for node in batch.node_runs.order_by("id")
            ],
        }
    )


@require_http_methods(["GET"])
@login_required
def batch_events(request, batch_id: int):
    batch = FileSummaryBatch.objects.filter(pk=batch_id, user=request.user).first()
    if not batch:
        raise Http404("批次不存在。")
    after = request.GET.get("after") or "0"
    try:
        after_id = int(after)
    except ValueError:
        after_id = 0
    events = WorkflowEvent.objects.filter(batch=batch, pk__gt=after_id).order_by("id")
    return JsonResponse({"events": [serialize_event(event) for event in events]})


@require_http_methods(["GET"])
@login_required
def export_download(request, export_id: int):
    exported = ExportedSummaryFile.objects.filter(
        pk=export_id,
        batch__user=request.user,
    ).first()
    if not exported:
        raise Http404("导出文件不存在。")
    path = Path(exported.storage_path)
    if not path.exists():
        logger.warning(
            "Export download missing file",
            extra={"export_id": exported.pk, "storage_path": exported.storage_path},
        )
        return JsonResponse({"error": "文件不存在。"}, status=404)
    content_type = (
        "text/markdown; charset=utf-8"
        if exported.export_type == ExportedSummaryFile.ExportType.MARKDOWN
        else "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
    )
    logger.info(
        "Export download started",
        extra={
            "export_id": exported.pk,
            "batch_id": exported.batch_id,
            "file_name": exported.file_name,
            "content_type": content_type,
        },
    )
    return FileResponse(
        path.open("rb"),
        as_attachment=True,
        filename=exported.file_name,
        content_type=content_type,
    )