"""예정노선 다시 추적(626-2 · 요구 530) — 고친 예정노선 → 평면선(노드 · 곡선 · 편집표) · 저장 0.

계산 자리 ③ 서버 단독 — 체인 초기 폴리라인(`_ensure_planned_initial`)과 같은 함수
`followed_table`(곡선 최적 · 지형 · 계류 격자 잼 · 758-1 · 못 읽으면 순수 기하) · 추적 전 체인
예정노선과 같은 간격 조밀화(635-2 —
성긴 원본 꼭짓점 = 체인 초기선과 같은 선 · 촘촘한 입력은 그대로).
화면은 받은 노드를 편집기 한 걸음으로 싣고 페이지 [저장] 길로 보냄(고친 예정노선 = 초안 `expected`
→ `expected_route_edit.csv`). `/route/replan` · `as_initial` · `expected_route.csv` · 초기값 ·
추천 저장본은 안 건드림.

  POST /api/projects/{id}/route/follow
    본문 {points: [[x, y], …], crs: "tm" | "lonlat", keep_curves?: int}   ("lonlat" = [경도, 위도])
    → {status, planned, nodes, curves, node_edits, station_snap, min_radius_m,
       curve_count, violation_count, keep_curves, curve_note}
    (GET /route/plan 칸 이름 · 사업지 TM)
    `keep_curves`(775-2) = 수정 전 평면계획선 곡선 수 — 안 주면 저장 노선(수정본 → 초기본)
    곡선표에서 읽음 · 곡선 수가 그와 다르면 `curve_note` 안내 글
    (굽이가 모자람 · 맞춤 못 해 지금 측점 맞춤).
    400 점 2 미만 · 404 프로젝트 없음 · 409 좌표계 모름(lonlat)
"""

from __future__ import annotations

import asyncio
from pathlib import Path
from typing import Any, Literal
from uuid import UUID

from fastapi.responses import JSONResponse
from pydantic import BaseModel

from B05_Profile.B05_Profile_Repository import get_surface_crs_epsg
from B05_Profile.B05_Profile_Route_Polyline_Write import _read_curves, followed_table
from B05_Profile.B05_Profile_Router_FollowLand import follow_land
from B05_Profile.B05_Profile_Router_Replan import (
    _PROJECT_PATH_MISSING,
    _plan_criteria,
    _project_paths,
    router,
)
from common_util.common_util_crs import lonlat_to_tm
from common_util.common_util_route_geometry import (
    densify_route,
    planned_route_initial_path,
    planned_route_working_path,
)
from config.config_db import get_db_pool
from config.config_system import (
    ROUTE_DIRECT_LINK_CELL_FACTOR,
    ROUTE_GRID_RES_M,
    ROUTE_PLANNED_DENSIFY_SAFETY,
)


class RouteFollowRequest(BaseModel):
    points: list[tuple[float, float]]
    crs: Literal["tm", "lonlat"] = "tm"
    keep_curves: int | None = None


def saved_curve_count(project_root: Path) -> int | None:
    """저장 노선 곡선 수(수정본 → 초기본 · 775-2) · 곡선표 없으면 None."""
    for path in (
        planned_route_working_path(project_root),
        planned_route_initial_path(project_root),
    ):
        if path.is_file():
            return len(_read_curves(path)) or None
    return None


def follow_route_line(
    points: list[tuple[float, float]],
    radius_m: float,
    land: Any = None,
    keep_curves: int | None = None,
) -> dict[str, Any]:
    """점 묶음(TM) → 예정노선 추적 평면선 — 파일 꼴(csv 4자리)과 같은 값 · `land` = 곡선 최적 ·
    `keep_curves` = 지킬 곡선 수(지형 있을 때만)."""
    spacing = ROUTE_DIRECT_LINK_CELL_FACTOR * ROUTE_GRID_RES_M * ROUTE_PLANNED_DENSIFY_SAFETY
    result, table = followed_table(densify_route(points, spacing), radius_m, land, keep_curves)
    note = None
    if land is not None and keep_curves and result.curve_count != keep_curves:
        note = (
            f"수정 전 곡선 {keep_curves}개를 지키지 못해 {result.curve_count}개로 그었습니다"
            " — 굽이가 모자라거나 측점 맞춤으로 물러남."
        )
    return {
        "planned": [[round(x, 4), round(y, 4)] for x, y in result.vertices],
        "nodes": [node.as_dict() for node in result.nodes],
        "curves": table["curves"],
        "node_edits": table.get("edits"),
        "station_snap": table["station_snap"],
        "min_radius_m": round(radius_m, 2),
        "curve_count": result.curve_count,
        "violation_count": result.violation_count,
        "keep_curves": keep_curves if land is not None else None,
        "curve_note": note,
    }


@router.post("/{project_id}/route/follow", response_model=None)
async def follow_route(project_id: UUID, body: RouteFollowRequest) -> dict[str, Any] | JSONResponse:
    """고친 예정노선을 다시 추적한 평면선 — 아무것도 안 씀(626-2)."""
    if len(body.points) < 2:
        return JSONResponse(
            status_code=400,
            content={"status": "error", "message": "예정노선은 점이 2개 이상이어야 합니다."},
        )
    paths = await _project_paths(project_id)
    if paths is None:
        return JSONResponse(status_code=404, content=_PROJECT_PATH_MISSING)
    points = [(float(x), float(y)) for x, y in body.points]
    if body.crs == "lonlat":
        async with get_db_pool().acquire() as connection:
            epsg = await get_surface_crs_epsg(connection, project_id, 0)
        if epsg is None:
            return JSONResponse(
                status_code=409,
                content={
                    "status": "error",
                    "message": "사업지 좌표계를 몰라 경위도를 바꿀 수 없습니다.",
                },
            )
        points = [lonlat_to_tm(lon, lat, epsg) for lon, lat in points]
    radius_m = (await _plan_criteria(project_id))[0]
    land = await follow_land(project_id, paths[0])
    keep = body.keep_curves or await asyncio.to_thread(saved_curve_count, paths[0])
    line = await asyncio.to_thread(follow_route_line, points, radius_m, land, keep)
    return {"status": "success", "project_id": str(project_id), **line}