"""추가 측점 정본(`B05_Profile/route/plus_stations.json`) — 구조물 정본 곁(368-2 · 요구 240-21).

사용자가 종단 원지반선에서 넣은 일반 측점(정수 m) · 이름 없음. 자리 정본 = 좌표(x · y) — 노선이
바뀌면 관 · 구조물처럼 새 노선에 투영해 누가거리를 다시 매김(`follow_structures` 재사용).
측점 계획에는 `resolve_extra_stations` → `plan_stations(plus=)` 로 들어감(TS `planStations` 짝).
"""

from __future__ import annotations

import json
import os
from pathlib import Path
from types import SimpleNamespace
from typing import Any, Sequence

from common_util.common_util_json import atomic_write_json
from common_util.common_util_route_follow import follow_structures

PLUS_STATIONS_FILE_NAME = "plus_stations.json"


def plus_stations_path(project_root: str | Path) -> Path:
    return Path(project_root) / "B05_Profile" / "route" / PLUS_STATIONS_FILE_NAME


def load_plus_stations(project_root: str | Path) -> list[dict[str, Any]]:
    """[{chainage_m, x, y}] — 없거나 깨졌으면 빈 목록."""
    path = plus_stations_path(project_root)
    if not path.is_file():
        return []
    try:
        rows = json.loads(path.read_text(encoding="utf-8")).get("stations") or []
    except (OSError, ValueError, AttributeError):
        return []
    return [
        row
        for row in rows
        if isinstance(row, dict) and isinstance(row.get("chainage_m"), (int, float))
    ]


def plus_chainages(project_root: str | Path) -> list[float]:
    return sorted({float(row["chainage_m"]) for row in load_plus_stations(project_root)})


def save_plus_stations(
    project_root: str | Path, chainages: Sequence[float], xy: Sequence[Sequence[float]] | None
) -> list[float]:
    """정수 m 로 맞춰(0 ~ 노선 끝 · 같은 m 하나) 좌표와 함께 씀 → 쓴 누가거리."""
    from shapely.geometry import LineString

    line = LineString([(float(p[0]), float(p[1])) for p in xy]) if xy and len(xy) > 1 else None
    end = float(line.length) if line is not None else float("inf")
    values = sorted({float(round(c)) for c in chainages if 0 <= round(c) <= end})
    rows = []
    for value in values:
        point = line.interpolate(value) if line is not None else None
        rows.append(
            {
                "chainage_m": value,
                "x": round(float(point.x), 4) if point is not None else None,
                "y": round(float(point.y), 4) if point is not None else None,
            }
        )
    path = plus_stations_path(project_root)
    if not rows and not path.exists():
        return []
    os.makedirs(path.parent, exist_ok=True)
    atomic_write_json(str(path), {"stations": rows})
    return values


def follow_plus_stations(project_root: str | Path, new_xy: Sequence[Sequence[float]]) -> int:
    """노선이 바뀔 때 좌표를 새 노선에 투영해 누가거리를 다시 매김 → 옮긴 수(같은 m 는 하나)."""
    rows = load_plus_stations(project_root)
    items = [
        SimpleNamespace(chainage_m=float(r["chainage_m"]), x=r.get("x"), y=r.get("y")) for r in rows
    ]
    if not items:
        return 0
    before = [item.chainage_m for item in items]
    follow_structures(items, new_xy)
    moved = sum(a != item.chainage_m for a, item in zip(before, items))
    if moved:
        seen: set[float] = set()
        kept = []
        for item in sorted(items, key=lambda i: i.chainage_m):
            if item.chainage_m in seen:
                continue
            seen.add(item.chainage_m)
            kept.append({"chainage_m": item.chainage_m, "x": item.x, "y": item.y})
        atomic_write_json(str(plus_stations_path(project_root)), {"stations": kept})
    return moved