from __future__ import annotations

import asyncio
import logging
from pathlib import Path

from django.conf import settings
from django.utils import timezone

from apps.express_query.models import ExpressQueryTask, ExpressQueryTaskStatus
from apps.express_query.services import ExpressBrowserQueryService, TrackingExtractionService

logger = logging.getLogger("apps.express_query")


def execute_express_query_task(task_id: int) -> None:
    """执行快递查询任务（从文件识别运单号）"""
    logger.info("开始执行快递查询任务", extra={"task_id": task_id})

    try:
        task = ExpressQueryTask.objects.get(id=task_id)
    except ExpressQueryTask.DoesNotExist:
        logger.error("快递查询任务不存在", extra={"task_id": task_id})
        return

    task.status = ExpressQueryTaskStatus.OCR_PARSING
    task.started_at = timezone.now()
    task.error_message = ""
    task.save(update_fields=["status", "started_at", "error_message", "updated_at"])

    try:
        extraction_service = TrackingExtractionService()
        extraction = extraction_service.extract(Path(task.waybill_image.path))

        task.ocr_text = extraction.ocr_text
        task.carrier_type = extraction.carrier_type
        task.tracking_number = extraction.tracking_number

        # PDF 只用第一页做 OCR，截断多页 PDF 节省空间
        if task.waybill_image and (task.waybill_image.name or "").endswith(".pdf"):
            TrackingExtractionService.truncate_pdf_to_first_page(Path(task.waybill_image.path))

        if not extraction.tracking_number:
            raise ValueError("OCR 未识别到有效运单号")

        if extraction.carrier_type not in {"sf", "ems"}:
            raise ValueError("OCR 已识别运单号，但未能识别承运商（仅支持 EMS/顺丰）")

        task.status = ExpressQueryTaskStatus.WAITING_LOGIN
        task.save(
            update_fields=[
                "ocr_text",
                "carrier_type",
                "tracking_number",
                "status",
                "updated_at",
            ]
        )

        # 继续执行浏览器查询（复用代码）
        _execute_browser_query(task)

    except Exception as exc:
        logger.error("快递查询任务执行失败", extra={"task_id": task_id, "error": str(exc)}, exc_info=True)
        task.status = ExpressQueryTaskStatus.FAILED
        task.error_message = str(exc)
        task.finished_at = timezone.now()
        task.save(update_fields=["status", "error_message", "finished_at", "updated_at"])


def execute_manual_express_query_task(task_id: int) -> None:
    """执行手动输入的快递查询任务（跳过OCR）"""
    logger.info("开始执行手动输入快递查询任务", extra={"task_id": task_id})

    try:
        task = ExpressQueryTask.objects.get(id=task_id)
    except ExpressQueryTask.DoesNotExist:
        logger.error("快递查询任务不存在", extra={"task_id": task_id})
        return

    task.started_at = timezone.now()
    task.error_message = ""
    task.save(update_fields=["started_at", "error_message", "updated_at"])

    try:
        # 验证承运商和运单号已设置
        if not task.tracking_number or not task.carrier_type:
            raise ValueError("缺少运单号或承运商信息")

        if task.carrier_type not in {"sf", "ems"}:
            raise ValueError(f"不支持的承运商: {task.carrier_type}（仅支持 SF/EMS）")

        # 直接执行浏览器查询
        _execute_browser_query(task)

    except Exception as exc:
        logger.error("手动输入快递查询任务执行失败", extra={"task_id": task_id, "error": str(exc)}, exc_info=True)
        task.status = ExpressQueryTaskStatus.FAILED
        task.error_message = str(exc)
        task.finished_at = timezone.now()
        task.save(update_fields=["status", "error_message", "finished_at", "updated_at"])


def _execute_browser_query(task: ExpressQueryTask) -> None:
    """执行浏览器查询（公共逻辑）"""
    task.status = ExpressQueryTaskStatus.QUERYING
    task.save(update_fields=["status", "updated_at"])

    output_rel_path = Path("express_query/results") / f"{task.id}_{task.carrier_type}_{task.tracking_number}.pdf"
    output_abs_path = Path(settings.MEDIA_ROOT) / output_rel_path

    browser_service = ExpressBrowserQueryService()
    coro = browser_service.query_and_save_pdf(
        carrier_type=task.carrier_type,
        tracking_number=task.tracking_number,
        output_pdf=output_abs_path,
    )

    # Django-Q2 worker 已有事件循环，不能直接用 asyncio.run()
    try:
        asyncio.get_running_loop()
        # 已有运行中的循环 → 用线程隔离执行
        import concurrent.futures

        with concurrent.futures.ThreadPoolExecutor(max_workers=1) as pool:
            future = pool.submit(asyncio.run, coro)
            final_url = future.result(timeout=600)
    except RuntimeError:
        # 没有运行中的循环 → 直接用 asyncio.run()
        final_url = asyncio.run(coro)

    task.status = ExpressQueryTaskStatus.SUCCESS
    task.query_url = final_url
    task.result_pdf.name = output_rel_path.as_posix()
    task.result_payload = {
        "carrier_type": task.carrier_type,
        "tracking_number": task.tracking_number,
        "query_url": final_url,
        "pdf_path": output_rel_path.as_posix(),
    }
    task.finished_at = timezone.now()
    task.save(
        update_fields=[
            "status",
            "query_url",
            "result_pdf",
            "result_payload",
            "finished_at",
            "updated_at",
        ]
    )
    logger.info("快递查询任务执行成功", extra={"task_id": task.id})