"""B05 설계 지형 바꿈(PLAN 626-1 · 요구 530 · 결정 A④ · D2) — 평면 도구줄 지형 칩.

`POST /api/projects/{id}/route/design-terrain` 본문 `{terrain: "las" | "sheet"}` →
설계 지형만 바꾸고(`switch_design_terrain`) 노선 저장 체인을 다시 탐
(종단 · 횡단 · 배수 · 관 · 구조물 따라감 ·
계획고 옮김 없음 = 옛 · 새 계획 폴리라인 같음). 노선 · 노드 · 곡선표 = 지금 저장본 그대로(안 씀).
초기값(`initial_snapshot/`) · 추천 저장본 · 예정노선 안 씀(옛 추천 [적용] 길 `as_initial` 대신).
[저장]과 같은 프로젝트 잠금 · 떠 두고 실패면 되돌림(`common_util_save_guard`) · 같은 지형 = 바꿀 것 없음.
"""

import asyncio
import logging
from typing import Literal
from uuid import UUID

from fastapi.responses import JSONResponse
from pydantic import BaseModel

from B05_Profile.B05_Profile_Router_Terrain import router
from common_util.common_util_surface_confirmation import (
    design_terrain,
    get_surface_confirmation_params,
)
from config.config_db import get_db_pool

logger = logging.getLogger(__name__)


class DesignTerrainRequest(BaseModel):
    terrain: Literal["las", "sheet"]


@router.post("/{project_id}/route/design-terrain", response_model=None)
async def switch_route_design_terrain(
    project_id: UUID, body: DesignTerrainRequest
) -> dict | JSONResponse:
    """설계 지형을 바꾸고 뒤 단계를 모두 다시 셈 — 노선 값 · 초기값은 그대로."""
    from B05_Profile.B05_Profile_Router_Replan import (
        _PROJECT_PATH_MISSING,
        _planned_line,
        _project_paths,
        _recompute,
    )
    from B06_Section.B06_Section_Router_DesignSave import _restore
    from common_util import common_util_save_guard as guard

    lock = guard.project_lock(str(project_id))
    async with lock:
        paths = await _project_paths(project_id)
        if paths is None:
            return JSONResponse(status_code=404, content=_PROJECT_PATH_MISSING)
        project_root, stored_path = paths
        pool = get_db_pool()
        async with pool.acquire() as connection:
            now = design_terrain(await get_surface_confirmation_params(connection, str(project_id)))
            if now == body.terrain:
                return {"status": "success", "design": now, "changed": False}
            rows = await guard.snapshot_rows(connection, str(project_id), surface=True)
        files = await asyncio.to_thread(
            guard.snapshot_storage, project_root, guard.STORAGE_SCOPE + guard.PIPE_SCOPE
        )
        try:
            line = await asyncio.to_thread(_planned_line, project_root)
            result = await _recompute(
                project_id, project_root, stored_path, None, body.terrain, (line, line), False
            )
            if "error" in result:
                await _restore(project_id, rows, files)
                return JSONResponse(
                    status_code=409, content={"status": "error", "message": result["error"]}
                )
        except Exception:
            await _restore(project_id, rows, files)
            raise
        finally:
            files.discard()
    logger.info("설계 지형 바꿈: project_id=%s %s → %s", project_id, now, body.terrain)
    return {"status": "success", "design": body.terrain, "changed": True, **result}