import json

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

from review_agent.application_form_fill.workflow import (
    create_application_form_fill_batch,
    find_latest_successful_summary_batch,
    start_application_form_fill_workflow,
)
from review_agent.models import ApplicationFormFillBatch, Conversation, ExportedSummaryFile, FileSummaryBatch, WorkflowNodeRun


@require_http_methods(["GET"])
def health(request):
    return JsonResponse({"workflow_type": "application_form_fill", "status": "available"})


@login_required
@require_http_methods(["POST"])
def start(request):
    try:
        payload = json.loads(request.body.decode("utf-8") or "{}")
    except json.JSONDecodeError:
        return JsonResponse({"error": "JSON 格式错误。"}, status=400)

    conversation = Conversation.objects.filter(pk=payload.get("conversation_id"), user=request.user).first()
    if not conversation:
        raise Http404("对话不存在。")

    summary_batch = None
    if payload.get("file_summary_batch_id"):
        summary_batch = FileSummaryBatch.objects.filter(
            pk=payload.get("file_summary_batch_id"),
            conversation=conversation,
            user=request.user,
            status=FileSummaryBatch.Status.SUCCESS,
        ).first()
    if summary_batch is None:
        summary_batch = find_latest_successful_summary_batch(conversation)
    if summary_batch is None:
        return JsonResponse({"error": "请先上传资料并完成文件汇总。"}, status=400)

    batch = create_application_form_fill_batch(
        conversation=conversation,
        user=request.user,
        source_summary_batch=summary_batch,
        requested_templates=payload.get("template_codes") or [],
        output_types=payload.get("output_types") or None,
    )
    start_application_form_fill_workflow(batch, async_run=getattr(settings, "APPLICATION_FORM_FILL_ASYNC", True))
    return JsonResponse(
        {
            "batch_id": batch.pk,
            "workflow_type": "application_form_fill",
            "status": batch.status,
            "selected_templates": batch.selected_templates,
        }
    )


@login_required
@require_http_methods(["GET"])
def batch_status(request, batch_id: int):
    batch = ApplicationFormFillBatch.objects.filter(
        pk=batch_id,
        conversation__user=request.user,
        is_deleted=False,
    ).first()
    if not batch:
        raise Http404("填表批次不存在。")
    exports = ExportedSummaryFile.objects.filter(
        workflow_type="application_form_fill",
        workflow_batch_id=batch.pk,
    ).order_by("id")
    return JsonResponse(
        {
            "batch": {
                "id": batch.pk,
                "workflow_type": "application_form_fill",
                "batch_no": batch.batch_no,
                "status": batch.status,
                "product_name": batch.product_name,
                "selected_templates": batch.selected_templates,
                "conflict_count": len(batch.conflict_summary or []),
                "risk_summary_text": _risk_summary_text(batch),
                "error_message": batch.error_message,
            },
            "nodes": [
                {
                    "node_code": node.node_code,
                    "node_name": node.node_name,
                    "status": node.status,
                    "progress": node.progress,
                    "message": node.message,
                }
                for node in WorkflowNodeRun.objects.filter(
                    workflow_type="application_form_fill",
                    workflow_batch_id=batch.pk,
                ).order_by("id")
            ],
            "conflicts": batch.conflict_summary or [],
            "exports": [
                {
                    "id": export.pk,
                    "export_type": export.export_type,
                    "export_category": export.export_category,
                    "file_name": export.file_name,
                    "download_url": f"/api/review-agent/file-summary/exports/{export.pk}/download/",
                }
                for export in exports
            ],
        }
    )


def _risk_summary_text(batch: ApplicationFormFillBatch) -> str:
    parts = []
    if batch.selected_templates:
        parts.append("模板 " + "、".join(batch.selected_templates))
    if batch.conflict_summary:
        parts.append(f"冲突字段 {len(batch.conflict_summary)}")
    if batch.risk_notes:
        parts.append(f"提示 {len(batch.risk_notes)}")
    return " · ".join(parts)