import asyncio
from datetime import datetime
from typing import Optional

from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from shared.database.database import get_db_session
from shared.models.identity import User
from moldinsight.models import ProcessingTask
from shared.services.auth_service import get_current_active_user
from moldinsight.services.cam_bundle_service import cam_bundle_service
from moldinsight.services.task_query_service import TaskQueryService
from shared.utils.logger import get_logger

logger = get_logger(__name__)

router = APIRouter()
DEFAULT_CAM_PREFERENCES = {
    "mold_steel": "P20",
    "surface_quality": "standard",
    "controller": "fanuc",
    "include_gcode": True,
}


class CamPlanRequest(BaseModel):
    """未提供的偏好字段回落到任务持久化偏好，再回落到默认值。"""
    task_id: str
    scheme_id: Optional[str] = None
    mold_steel: Optional[str] = None
    surface_quality: Optional[str] = None
    controller: Optional[str] = None
    include_gcode: Optional[bool] = None


@router.post("/cam/plan")
async def generate_cam_plan(
    body: CamPlanRequest,
    db_session: AsyncSession = Depends(get_db_session),
    current_user: User = Depends(get_current_active_user),
):
    """基于任务分模结果生成 CAM 准备包（MVP）。"""
    _ = current_user
    task_id = body.task_id

    task_result = await db_session.execute(
        select(ProcessingTask).where(ProcessingTask.task_id == task_id)
    )
    processing_task = task_result.scalar_one_or_none()

    persisted_preferences = {}
    if processing_task and isinstance(processing_task.parameters, dict):
        persisted_preferences = (
            processing_task.parameters.get("cam_preferences", {}) or {}
        )

    # 注意 include_gcode 显式判 None：False 是有效值，不能走 or 回落
    mold_steel = (
        body.mold_steel
        if body.mold_steel is not None
        else persisted_preferences.get("mold_steel", DEFAULT_CAM_PREFERENCES["mold_steel"])
    )
    surface_quality = (
        body.surface_quality
        if body.surface_quality is not None
        else persisted_preferences.get("surface_quality", DEFAULT_CAM_PREFERENCES["surface_quality"])
    )
    controller = (
        body.controller
        if body.controller is not None
        else persisted_preferences.get("controller", DEFAULT_CAM_PREFERENCES["controller"])
    )
    include_gcode = (
        body.include_gcode
        if body.include_gcode is not None
        else persisted_preferences.get("include_gcode", DEFAULT_CAM_PREFERENCES["include_gcode"])
    )

    task_view = await TaskQueryService.get_task_view(db_session, task_id)
    if not task_view:
        raise HTTPException(status_code=404, detail="任务不存在")
    if task_view.get("status") != "completed":
        raise HTTPException(status_code=400, detail="任务尚未完成，无法生成CAM计划")

    try:
        # CAM 刀路计算为纯 Python 重计算，投放线程池避免阻塞事件循环
        data = await asyncio.to_thread(
            cam_bundle_service.build_bundle,
            task_view=task_view,
            scheme_id=body.scheme_id,
            mold_steel=mold_steel,
            surface_quality=surface_quality,
            controller=controller,
            include_gcode=include_gcode,
        )
        cam_preferences = {
            "mold_steel": mold_steel,
            "surface_quality": surface_quality,
            "controller": controller,
            "include_gcode": include_gcode,
        }
        if processing_task:
            parameters = processing_task.parameters if isinstance(processing_task.parameters, dict) else {}
            parameters["cam_preferences"] = cam_preferences
            parameters["cam_last_plan"] = {
                "scheme_id": data.get("scheme_id"),
                "generated_at": datetime.now().isoformat(),
            }
            processing_task.parameters = parameters
            await db_session.commit()
            # parameters 已变更，任务视图缓存失效
            TaskQueryService.invalidate_task_view(task_id)

        return {"status": "success", "data": data, "cam_preferences": cam_preferences}
    except Exception as exc:
        logger.error(f"生成CAM准备包失败 task_id={task_id}: {exc}")
        raise HTTPException(status_code=500, detail=f"生成CAM准备包失败: {exc}")