"""따라가기 곡선 최적의 지형 · 제약 읽기(758-1) — 체인 처음 · `/route/plan` · `/route/replan` ·
`/route/follow` 가 `followed_table` 에 넘김.

값 = 추천 엔진 기본 풀이와 같은 자리(`..._Router_RouteInitial.compute_initial`): 종단기울기 상한 =
법정(임도 종류 · 설계속도 · 지형 · 비포장) · 지형 = 설계 지형 비용면 · 계류 · 표준 횡단면 = 프로젝트
저장값 · 나머지는 엔진 기본값. 못 읽으면 None(옛 길 — 순수 기하 따라가기).
"""

from __future__ import annotations

import asyncio
import logging
from pathlib import Path
from uuid import UUID

from B05_Profile.B05_Profile_Engine_RouteInitial_Follow import FollowLand
from common_util.common_util_route_geometry import (
    expected_route_csv_path,
    planned_route_initial_path,
)
from config.config_db import get_db_pool

logger = logging.getLogger(__name__)


async def follow_land(project_id: UUID, project_root: Path) -> FollowLand | None:
    """이 프로젝트의 따라가기 곡선 최적 입력 · 못 읽으면 None."""
    from B05_Profile.B05_Profile_Engine_Grade import legal_grade_limit_pct
    from B05_Profile.B05_Profile_Engine_RouteInitial import (
        load_terrain_and_streams,
        resolve_inputs,
    )
    from B05_Profile.B05_Profile_Router_Replan import _road_settings
    from B05_Profile.B05_Profile_Router_RouteInitial import project_standard
    from common_util.common_util_surface_confirmation import (
        analysis_terrain_params,
        get_surface_confirmation_params,
    )

    try:
        grade_class, design_speed, terrain_type = await _road_settings(project_id)
        max_grade = legal_grade_limit_pct(grade_class, terrain_type, False, design_speed) / 100.0
        async with get_db_pool().acquire() as connection:
            selection = await get_surface_confirmation_params(connection, str(project_id))
        terrain, streams = await asyncio.to_thread(
            load_terrain_and_streams, project_root, analysis_terrain_params(selection, None)
        )
        stream_offset, grade_smooth, goal_grade = resolve_inputs(max_grade, None, None, None)
        return FollowLand(
            terrain,
            streams,
            max_grade,
            stream_offset,
            grade_smooth,
            goal_grade,
            await project_standard(project_id),
        )
    except Exception:  # noqa: BLE001 — 지형이 없어도 따라가기는 이어 감(순수 기하)
        logger.warning("따라가기 곡선 최적 지형을 못 읽어 순수 기하로 따라갑니다: %s", project_id)
        return None


async def initial_land(project_id: UUID, project_root: Path) -> FollowLand | None:
    """초기 폴리라인을 새로 세울 때만 지형을 읽음(`_ensure_planned_initial` 과 같은 낡음 판정)."""
    target = planned_route_initial_path(project_root)
    source = expected_route_csv_path(project_root)
    if target.is_file():
        if not source.is_file() or source.stat().st_mtime <= target.stat().st_mtime:
            return None
    return await follow_land(project_id, project_root)