jp_network.py

"""
日本铁路线路网络 — 从 piuccio/open-data-jp-railway-stations 拉全量,
按 line_code 分组, 用 ekidata_id 末 2 位(站序)排序, 构建每条线的有序站序列(几何)。

缓存:
- lines_cache_jp/stations.json (源, ~6MB, 首次联网下载)
- lines_cache_jp/lines.json   (解析后, ~100KB, 145 条 line)

对外接口:
- load_lines():  返回 [{code, name, points:[(lat,lon),...], n}, ...]
- load_colors(): 返回 {line_code: '#RRGGBB'}  公司/线路代表色
- nearby_lines(bounds, source): 给定视野矩形 + 当前底图(amap/osm),
  返 {wsen, neen, lines: [{name, points, color, code}, ...]}
"""
from __future__ import annotations
import json
import math
import os
import urllib.request
from collections import defaultdict

_THIS = os.path.dirname(os.path.abspath(__file__))
# 缓存放可写的 app 数据目录(打包后模块目录是只读 bundle, 写不进去)
try:
    import paths
    _CACHE_DIR = os.path.join(paths.app_data_dir(), "lines_cache_jp")
except Exception:
    _CACHE_DIR = os.path.join(_THIS, "lines_cache_jp")
_SRC_URL = "https://raw.githubusercontent.com/piuccio/open-data-jp-railway-stations/master/stations.json"
_SRC = os.path.join(_CACHE_DIR, "stations.json")
_LINES = os.path.join(_CACHE_DIR, "lines_v3.json")   # v3: 真实 ekidata 顺序 + 每点站名(供高亮沿网格切段)

_lines_cache = None

# 公司 / 线路代表色(主要 JR/私铁, 资料来源: 维基百科 + 官方网站)
# 凡是代码中查不到的, fallback 用 ROUTE_GREEN
COLORS = {
    # JR 北海道
    "JR-Hokkaido.Hakodate":        "#EB1C24", "JR-Hokkaido.Sassho":        "#EB1C24",
    "JR-Hokkaido.Chitose":         "#F38B14", "JR-Hokkaido.Sekisho":       "#F38B14",
    # JR 东
    "JR-East.Yamanote":            "#9ACD43", "JR-East.ChuoRapid":         "#F15A22",
    "JR-East.ChuoSobuLocal":       "#FFD400", "JR-East.Chuo":              "#F15A22",
    "JR-East.Sobu":                "#FFD400", "JR-East.KeihinTohoku":      "#00B2DD",
    "JR-East.KeihinTohokuNegishi": "#00B2DD", "JR-East.Tokaido":           "#F18E40",
    "JR-East.Yokosuka":            "#E3522F", "JR-East.Saikyo":            "#2DC4A4",
    "JR-East.SaikyoKawagoe":       "#2DC4A4", "JR-East.Utsunomiya":        "#F18E40",
    "JR-East.Takasaki":            "#F18E40", "JR-East.Joban":             "#808080",
    "JR-East.JobanLocal":          "#808080", "JR-East.JobanRapid":        "#808080",
    "JR-East.Keiyo":               "#D80073", "JR-East.Musashino":         "#D80073",
    "JR-East.Narita":              "#D80073", "JR-East.NaritaAbikoBranch": "#D80073",
    "JR-East.NaritaAirportBranch": "#D80073", "JR-East.Yokohama":          "#B6B6B6",
    "JR-East.Nambu":               "#FFD400", "JR-East.NambuBranch":       "#FFD400",
    "JR-East.Ome":                 "#F18E40", "JR-East.Itsukaichi":        "#F18E40",
    "JR-East.Hachiko":             "#D7B268", "JR-East.Kawagoe":           "#D7B268",
    "JR-East.Sotobo":              "#E95464", "JR-East.Uchibo":            "#E95464",
    "JR-East.ShinganMon":          "#E2585E", "JR-East.Tohoku":            "#E2585E",
    "JR-East.Ou":                  "#E2585E", "JR-East.Senseki":           "#3CB371",
    "JR-East.Senzan":              "#F18E40", "JR-East.Tsurumi":           "#F18E40",
    "JR-East.Tokaido":             "#F18E40", "JR-East.ShonanShinjuku":    "#E2585E",
    "JR-East.UenoTokyo":           "#F18E40", "JR-East.Tazawako":          "#E2585E",
    "JR-East.Kesennuma":           "#3CB371", "JR-East.Ofunato":           "#3CB371",
    "JR-East.Yamada":              "#3CB371", "JR-East.Ishinomaki":        "#3CB371",
    "JR-East.Kitakami":            "#3CB371", "JR-East.Hanawa":            "#3CB371",
    "JR-East.Ominato":             "#3CB371", "JR-East.Gono":              "#E2585E",
    "JR-East.Tsugaru":             "#E2585E", "JR-East.Hachinohe":         "#3CB371",
    "JR-East.Aterazawa":           "#E2585E", "JR-East.Yonesaka":          "#E2585E",
    "JR-East.RikuuEast":           "#E2585E", "JR-East.RikuuWest":         "#E2585E",
    "JR-East.BanetsuEast":         "#E2585E", "JR-East.BanetsuWest":       "#E2585E",
    "JR-East.Tadami":              "#E2585E", "JR-East.Suigun":            "#E2585E",
    "JR-East.Mito":                "#E2585E", "JR-East.Nikko":             "#E2585E",
    "JR-East.Ryomo":               "#E2585E", "JR-East.Joetsu":            "#E2585E",
    "JR-East.Agatsuma":            "#E2585E", "JR-East.Karasuyama":        "#E2585E",
    "JR-East.Kashima":             "#E2585E", "JR-East.Kururi":            "#E2585E",
    "JR-East.Togane":              "#E2585E",
    # JR 中央
    "JR-Central.Tokaido":          "#F18E40", "JR-Central.Mikawa":         "#F18E40",
    "JR-Central.Iida":             "#AB3A2F", "JR-Central.Minobu":         "#F18E40",
    "JR-Central.Kansai":           "#F18E40", "JR-Central.Kisei":          "#F18E40",
    "JR-Central.Taketoyo":         "#F18E40", "JR-Central.Sangu":          "#F18E40",
    "JR-Central.Meisho":           "#F18E40", "JR-Central.Ito":            "#F18E40",
    "JR-Central.Gotemba":          "#F18E40", "JR-Central.Taita":          "#F18E40",
    "JR-Central.Takayama":         "#76BC21", "JR-Central.Himi":           "#76BC21",
    "JR-Central.Johana":           "#76BC21", "JR-Central.Tsuruga":        "#76BC21",
    "JR-Central.Hokuriku":         "#76BC21", "JR-Central.Oito":           "#76BC21",
    # JR 西
    "JR-West.Sanin":               "#9078AF", "JR-West.Sanyo":             "#F8A11A",
    "JR-West.OsakaLoop":           "#E80033", "JR-West.Hanwa":             "#4D8C49",
    "JR-West.Kansai":              "#F8A11A", "JR-West.Yamatoji":          "#E80033",
    "JR-West.Takarazuka":          "#E80033", "JR-West.Fukuchiyama":       "#E80033",
    "JR-West.Sagano":              "#9078AF", "JR-West.Biwako":            "#E60012",
    "JR-West.Kyoto":               "#E60012", "JR-West.Kobe":              "#E60012",
    "JR-West.Nara":                "#E60012", "JR-West.Sakurai":           "#E60012",
    "JR-West.KansaiAirport":       "#E60012", "JR-West.Wakayama":          "#4D8C49",
    "JR-West.Maizuru":             "#9078AF", "JR-West.Hagoromo":          "#4D8C49",
    "JR-West.Tokaido":             "#F18E40", "JR-West.SanyoShinkansen":   "#0F64B0",
    "JR-West.HokurikuShinkansen":  "#0F64B0", "JR-West.Yosan":             "#A8C100",
    "JR-West.Dosan":               "#A8C100", "JR-West.Tokushima":         "#0099CC",
    "JR-West.Kotoku":              "#0099CC", "JR-West.Mugi":              "#0099CC",
    "JR-West.Naruto":              "#0099CC", "JR-West.Kibi":              "#FF7E00",
    "JR-West.Ako":                 "#F8A11A", "JR-West.Bantan":            "#F8A11A",
    "JR-West.Kishin":              "#F8A11A", "JR-West.Hakubi":            "#9078AF",
    "JR-West.Inbi":                "#9078AF", "JR-West.Sakai":             "#9078AF",
    "JR-West.Kisuki":              "#9078AF", "JR-West.Yamaguchi":         "#E2585E",
    "JR-West.Uno":                 "#FF7E00", "JR-West.Kure":              "#E2585E",
    "JR-West.Kabe":                "#E2585E", "JR-West.Fukuen":            "#E2585E",
    "JR-West.Iwami":               "#9078AF", "JR-West.SaninShinkansen":   "#0F64B0",
    "JR-West.YamaguchiShinkansen": "#0F64B0", "JR-West.NishiKyushuShinkansen": "#0F64B0",
    # JR 九州
    "JR-Kyushu.Kagoshima":         "#EE3D38", "JR-Kyushu.Nippo":           "#3CB371",
    "JR-Kyushu.Nagasaki":          "#F8A11A", "JR-Kyushu.Sasebo":          "#F8A11A",
    "JR-Kyushu.Kyudai":            "#FF7E00", "JR-Kyushu.Hitahikosan":     "#3CB371",
    "JR-Kyushu.Gotoji":            "#F8A11A", "JR-Kyushu.Kashii":          "#FF7E00",
    "JR-Kyushu.Chikuhi":           "#F8A11A", "JR-Kyushu.Hohi":            "#76BC21",
    "JR-Kyushu.Misumi":            "#3CB371", "JR-Kyushu.IbusukiMakurazaki":"EE3D38",
    "JR-Kyushu.KyushuShinkansen":  "#EE3D38", "JR-Kyushu.NishiKyushuShinkansen": "#EE3D38",
    "JR-Kyushu.Chikuho":           "#3CB371", "JR-Kyushu.FukuhokuYutaka":  "#3CB371",
    "JR-Kyushu.Karatsu":           "#F8A11A", "JR-Kyushu.Omura":           "#F8A11A",
    "JR-Kyushu.Sasaguri":          "#3CB371", "JR-Kyushu.Tagawa":          "#3CB371",
    "JR-Kyushu.Itoda":             "#3CB371", "JR-Kyushu.Gotanji":         "#3CB371",
    "JR-Kyushu.Mojiko":            "#3CB371", "JR-Kyushu.TenjinOmuta":     "#3CB371",
    "JR-Kyushu.kyudaiMain":        "#FF7E00",
    # 新干线
    "JR-East.TohokuShinkansen":    "#0F64B0", "JR-East.JoetsuShinkansen":  "#0F64B0",
    "JR-East.HokurikuShinkansen":  "#0F64B0", "JR-East.YamagataShinkansen":"0F64B0",
    "JR-East.AkitaShinkansen":     "#0F64B0", "JR-Central.TokaidoShinkansen": "#F18040",
    "JR-Central.TokaidoShinkansens": "#F18040", "JR-Central.TokaidoShinkansensBranch": "#F18040",
    "JR-Hokkaido.HokkaidoShinkansen": "#0F64B0",
    # 东京地铁
    "TokyoMetro.Ginza":            "#FF9500", "TokyoMetro.Marunouchi":     "#F62E36",
    "TokyoMetro.Hibiya":           "#B5B5AC", "TokyoMetro.Tozai":          "#009BBF",
    "TokyoMetro.Chiyoda":          "#00BB85", "TokyoMetro.Yurakucho":      "#C1A470",
    "TokyoMetro.Hanzomon":         "#8F76D6", "TokyoMetro.Namboku":        "#00AC9B",
    "TokyoMetro.Fukutoshin":       "#9C5E31",
    # 都营
    "Toei.Asakusa":                "#EC619F", "Toei.Mita":                 "#0079C2",
    "Toei.Shinjuku":               "#6CBB5A", "Toei.Oedo":                 "#B6007A",
    # 其他主要私铁
    "Tokyu.Toyoko":                "#DA0042", "Tokyu.Denentoshi":          "#20A286",
    "Tokyu.Oimachi":               "#EE8E33", "Tokyu.Meguro":              "#0072BA",
    "Tokyu.TokyuTamagawa":         "#AE0072", "Tokyu.Ikegami":             "#E5171F",
    "Tokyu.Poolyakken":            "#E5171F", "Tokyu.Setagaya":            "#FF6E00",
    "Keio.Keio":                   "#C00",    "Keio.KeioNew":              "#C00",
    "Keio.Sagamihara":             "#C00",    "Keio.KeioDobutsuen":        "#C00",
    "Keio.Takao":                  "#C00",
    "Keisei.KeiseiMain":           "#005AAA", "Keisei.KeiseiNaritaAirport": "#FF8000",
    "Keisei.KeiseiOta":            "#FF8000", "Keisei.KeiseiHigashiNarawa": "#FF8000",
    "Keisei.KeiseiKanamachi":      "#005AAA", "Keisei.Skyliner":           "#FF8000",
    "Odakyu.Odakyu":               "#008833", "Odakyu.OdakyuEnoshima":     "#008833",
    "Seibu.Ikebukuro":             "#E03C31", "Seibu.Shinjuku":            "#A14012",
    "Seibu.SeibuIkebukuro":        "#E03C31", "Seibu.SeibuShinjuku":       "#A14012",
    "Tobu.TobuSkytree":            "#1F60A1", "Tobu.TobuIsesaki":         "#1F60A1",
    "Tobu.TobuTojo":              "#E5171F", "Tobu.TobuNikko":           "#1F60A1",
    "Tobu.TobuKameido":           "#1F60A1", "Tobu.TobuDaishi":          "#1F60A1",
    "Tobu.TobuUtsunomiya":        "#1F60A1", "Tobu.TobuKawagoe":         "#1F60A1",
 "Keihin.Keihin":               "#1F60A1",
 # 京急
 "Keikyu.Main":                 "#E5171F", "Keikyu.Airport":             "#E5171F",
 "Keikyu.Daishi":               "#E5171F", "Keikyu.Zushi":               "#E5171F",
 "Keikyu.Kurihama":             "#E5171F",
 # 小田急
 "Odakyu.Odawara":              "#008833", "Odakyu.Enoshima":            "#1F60A1",
 "Odakyu.Tama":                 "#008833",
 # 京王新线
 "Keio.Inokashira":             "#DD0077", "Keio.Keibajo":               "#C00",
 "Keio.KeioDobutsuen":          "#C00",    "Keio.Takao":                 "#C00",
 # 西武
 "Seibu.Haijima":               "#E03C31", "Seibu.Kokubunji":            "#E03C31",
 "Seibu.SeibuYurakucho":        "#E03C31", "Seibu.Tamagawa":             "#E03C31",
 "Seibu.Tamako":                "#E03C31", "Seibu.Toshima":              "#E03C31",
 "Seibu.SeibuIkebukuro":        "#E03C31", "Seibu.SeibuShinjuku":        "#A14012",
 # 京成
 "Keisei.Kanamachi":            "#005AAA", "Keisei.Oshiage":             "#005AAA",
 "Keisei.NaritaSkyAccess":      "#FF8000", "Keisei.Main":                "#005AAA",
 # 临海 / 百合海鸥
 "TWR.Rinkai":                  "#00418E", "Yurikamome.Yurikamome":      "#0073C2",
 # 东武分支
 "Tobu.Daishi":                 "#1F60A1", "Tobu.Kameido":               "#1F60A1",
 "Tobu.TobuSkytreeBranch":      "#1F60A1", "Tobu.TobuIsesaki":           "#1F60A1",
 "Tobu.TobuNikko":              "#1F60A1", "Tobu.TobuTojo":              "#E5171F",
 "Tobu.TobuUtsunomiya":         "#1F60A1", "Tobu.TobuKawagoe":           "#1F60A1",
 "SaitamaRailway.SaitamaRailway": "#00B5B8",
    # 都电 / 新交通
    "Toei.Arakawa":                "#70C419", "Toei.NipporiToneri":         "#E68C3A",
    # 北总 / 各类
    "Hokuso.Hokuso":               "#00418E", "JR-East.SobuRapid":          "#FFD400",
    "Tobu.Tojo":                   "#E5171F", "TokyoMetro.MarunouchiBranch":"F62E36",
    # 各种新干线
    "JR-East.TohokuShinkansen":    "#0F64B0", "JR-East.JoetsuShinkansen":   "#0F64B0",
    "JR-East.HokurikuShinkansen":  "#0F64B0", "JR-East.YamagataShinkansen":"#0F64B0",
    "JR-East.AkitaShinkansen":     "#0F64B0",
    "JR-Central.TokaidoShinkansen":"#F18040", "JR-Hokkaido.HokkaidoShinkansen": "#0F64B0",
    # 其他 JR 区域
    "JR-Hokkaido.Hakodate":        "#EB1C24", "JR-Hokkaido.Sassho":        "#EB1C24",
    "JR-Hokkaido.Chitose":         "#F38B14", "JR-Hokkaido.Sekisho":       "#F38B14",
    "JR-Hokkaido.Nemuro":          "#F38B14", "JR-Hokkaido.Muroran":        "#F38B14",
    "JR-East.Joban":               "#808080",
    "JR-Central.Tokaido":          "#F18E40", "JR-Central.Mikawa":         "#F18E40",
}

# 兜底色(JP unknown)
_FALLBACK_COLOR = "#3CFF6A"   # ROUTE_GREEN


def _ensure_cache():
    """首次启动下载 stations.json(若缺失)。"""
    os.makedirs(_CACHE_DIR, exist_ok=True)
    if not os.path.exists(_SRC):
        req = urllib.request.Request(_SRC_URL, headers={"User-Agent": "NekoCardReader/1.0"})
        with urllib.request.urlopen(req, timeout=60) as r:
            data = r.read()
        with open(_SRC, "wb") as f:
            f.write(data)


def _build_lines_index():
    """从 stations.json 解析成 [{code,name,points,n}] 列表, 写缓存。
    用 ekidata 自带的真实线内顺序排站:
      - 按 ekidata_line_id 分组(同一条物理线)
      - 组内按 int(ekidata_id) 升序 —— ekidata_id = 线号 + 站序, 整数排序即真实走向
        (已用山手线验证: 大崎→…→品川, 0 处异常跳跃)
    color/name 用 line_code(如 JR-East.Yamanote), 没有就退回 ekidata_line_id。"""
    d = json.load(open(_SRC, encoding="utf-8"))
    byline = defaultdict(list)
    for grp in d:
        for s in grp.get("stations", []):
            lid = s.get("ekidata_line_id") or ""
            lat, lon = s.get("lat"), s.get("lon")
            if not lid or lat is None or lon is None:
                continue
            try:
                seq = int(s.get("ekidata_id") or "0")
            except (TypeError, ValueError):
                seq = 0
            byline[lid].append((seq, lat, lon, s.get("line_code") or "", s.get("name_kanji") or ""))
    out = []
    for lid, rows in byline.items():
        rows.sort(key=lambda r: r[0])          # 真实线内顺序
        seen = set(); pts = []; names = []; lc = ""
        for _seq, lat, lon, code, nm in rows:
            if code and not lc:
                lc = code
            k = (round(lat, 5), round(lon, 5))
            if k in seen:                       # 去重但保持顺序
                continue
            seen.add(k); pts.append((lat, lon)); names.append(nm)
        if len(pts) < 2:
            continue
        code = lc or lid
        out.append({
            "code": code,
            "name": code.split(".", 1)[-1] if "." in code else code,
            "points": pts,
            "names": names,           # 每点对应站名, 供 route_between 沿网格切段
            "n": len(pts),
        })
    out.sort(key=lambda x: x["code"])
    with open(_LINES, "w", encoding="utf-8") as f:
        json.dump(out, f, ensure_ascii=False, separators=(",", ":"))
    return out


def load_lines(force=False):
    """返回全部线路 [{code,name,points,n}], 内存缓存, 二次启动零延迟。"""
    global _lines_cache
    if _lines_cache is not None and not force:
        return _lines_cache
    if not os.path.exists(_LINES) or force:
        _ensure_cache()
        _lines_cache = _build_lines_index()
    else:
        try:
            _lines_cache = json.load(open(_LINES, encoding="utf-8"))
        except (OSError, json.JSONDecodeError):
            _ensure_cache()
            _lines_cache = _build_lines_index()
    return _lines_cache


def color_for(line_code: str) -> str:
    return COLORS.get(line_code, _FALLBACK_COLOR)


def _norm_name(s: str) -> str:
    return (s or "").strip().replace("ヶ", "ケ").replace("ヵ", "カ").replace("　", "").replace(" ", "").replace("駅", "").replace("站", "")


_st_index = None


def _station_index():
    """站名(规整) -> 所属线路 code 列表。一次性构建并缓存。"""
    global _st_index
    if _st_index is not None:
        return _st_index
    idx = {}
    for L in load_lines():
        code = L.get("code")
        for nm in (L.get("names") or []):
            k = _norm_name(nm)
            if not k:
                continue
            lst = idx.setdefault(k, [])
            if code not in lst:
                lst.append(code)
    _st_index = idx
    return idx


# 线路代码 → 日文线名(关东为主, 覆盖常用线; 没收录的退回罗马字)
LINE_KANJI = {
    # JR 东日本
    "JR-East.Yamanote": "山手線", "JR-East.ChuoRapid": "中央線快速", "JR-East.Chuo": "中央線",
    "JR-East.ChuoSobuLocal": "中央・総武線", "JR-East.Sobu": "総武線",
    "JR-East.KeihinTohoku": "京浜東北線", "JR-East.KeihinTohokuNegishi": "京浜東北・根岸線",
    "JR-East.Tokaido": "東海道線", "JR-East.Yokosuka": "横須賀線", "JR-East.Saikyo": "埼京線",
    "JR-East.SaikyoKawagoe": "埼京・川越線", "JR-East.Utsunomiya": "宇都宮線", "JR-East.Takasaki": "高崎線",
    "JR-East.Joban": "常磐線", "JR-East.JobanLocal": "常磐線各駅停車", "JR-East.JobanRapid": "常磐線快速",
    "JR-East.Keiyo": "京葉線", "JR-East.Musashino": "武蔵野線", "JR-East.Narita": "成田線",
    "JR-East.Yokohama": "横浜線", "JR-East.Nambu": "南武線", "JR-East.NambuBranch": "南武支線",
    "JR-East.Ome": "青梅線", "JR-East.Itsukaichi": "五日市線", "JR-East.Hachiko": "八高線",
    "JR-East.Kawagoe": "川越線", "JR-East.Sotobo": "外房線", "JR-East.Uchibo": "内房線",
    "JR-East.ShonanShinjuku": "湘南新宿ライン", "JR-East.UenoTokyo": "上野東京ライン",
    "JR-East.Tsurumi": "鶴見線",
    # 东京地下铁(Tokyo Metro)
    "TokyoMetro.Ginza": "銀座線", "TokyoMetro.Marunouchi": "丸ノ内線", "TokyoMetro.Hibiya": "日比谷線",
    "TokyoMetro.Tozai": "東西線", "TokyoMetro.Chiyoda": "千代田線", "TokyoMetro.Yurakucho": "有楽町線",
    "TokyoMetro.Hanzomon": "半蔵門線", "TokyoMetro.Namboku": "南北線", "TokyoMetro.Fukutoshin": "副都心線",
    # 都营(Toei)
    "Toei.Asakusa": "都営浅草線", "Toei.Mita": "都営三田線", "Toei.Shinjuku": "都営新宿線",
    "Toei.Oedo": "都営大江戸線",
    # 私铁
    "Keio.Keio": "京王線", "Keio.Inokashira": "井の頭線", "Keio.Sagamihara": "京王相模原線",
    "Keio.Takao": "京王高尾線", "Keio.Keibajo": "京王競馬場線", "Keio.Dobutsuen": "京王動物園線",
    "Odakyu.Odawara": "小田急小田原線", "Odakyu.Enoshima": "小田急江ノ島線", "Odakyu.Tama": "小田急多摩線",
    "Tokyu.Toyoko": "東急東横線", "Tokyu.Denentoshi": "東急田園都市線", "Tokyu.Oimachi": "東急大井町線",
    "Tokyu.Meguro": "東急目黒線", "Tokyu.Ikegami": "東急池上線", "Tokyu.Tamagawa": "東急多摩川線",
    "Tokyu.Setagaya": "東急世田谷線", "Tokyu.Kodomonokuni": "こどもの国線",
    "Keikyu.Main": "京急本線", "Keikyu.Airport": "京急空港線", "Keikyu.Daishi": "京急大師線",
    "Keikyu.Zushi": "京急逗子線", "Keikyu.Kurihama": "京急久里浜線",
    "Seibu.Ikebukuro": "西武池袋線", "Seibu.Shinjuku": "西武新宿線", "Seibu.Toshima": "西武豊島線",
    "Seibu.Tamako": "西武多摩湖線", "Seibu.Kokubunji": "西武国分寺線",
    "Tobu.Tojo": "東武東上線", "Tobu.Isesaki": "東武伊勢崎線", "Tobu.Skytree": "東武スカイツリーライン",
    "Tobu.Nikko": "東武日光線", "Tobu.Noda": "東武野田線",
    "Keisei.Main": "京成本線", "Keisei.Oshiage": "京成押上線", "Keisei.Chiba": "京成千葉線",
    "TsukubaExpress.TX": "つくばエクスプレス", "Yurikamome.Yurikamome": "ゆりかもめ",
    "TWR.Rinkai": "りんかい線", "TokyoMonorail.Haneda": "東京モノレール",
    "Sotetsu.Main": "相鉄本線", "Sotetsu.Izumino": "相鉄いずみ野線",
    # 数字 ekidata_line_id(这些线在数据里 line_code 为空, 只能按 ID 映射) —— 关东
    "11311": "中央線快速", "11328": "東海道線", "11343": "上野東京ライン", "11505": "御殿場線",
    "22002": "西武秩父線", "23002": "京成金町線", "23006": "京成本線", "24001": "京王線",
    "26001": "東急東横線", "26002": "東急目黒線", "26003": "東急田園都市線", "26004": "東急大井町線",
    "26005": "東急池上線", "26006": "東急多摩川線", "26007": "東急世田谷線", "26008": "こどもの国線",
    "29001": "相鉄本線", "29002": "相鉄いずみ野線", "99306": "秩父鉄道", "99307": "埼玉高速鉄道",
    "99308": "いすみ鉄道", "99309": "つくばエクスプレス", "99310": "みなとみらい線", "99313": "ユーカリが丘線",
    "99314": "伊豆箱根大雄山線", "99316": "横浜市営地下鉄ブルーライン", "99317": "金沢シーサイドライン",
    "99320": "江ノ島電鉄", "99321": "ニューシャトル", "99324": "京成東成田線", "99325": "小湊鉄道",
    "99326": "湘南モノレール", "99329": "新京成線", "99331": "千葉モノレール", "99332": "千葉モノレール",
    "99333": "流鉄流山線", "99334": "多摩都市モノレール", "99335": "銚子電鉄", "99336": "東京モノレール",
    "99338": "東葉高速線", "99339": "箱根登山鉄道", "99340": "北総線",
    "99343": "横浜市営地下鉄グリーンライン", "99344": "箱根登山ケーブルカー",
}


def line_display(code: str) -> str:
    """线路代码 → 日文线名(查 LINE_KANJI); 罗马字代码退回其后缀;
    纯数字 ekidata_id 且未收录 → 返回 ""(别让 "26004" 这种丑数字漏出去, 上层退回公司名)。"""
    if code in LINE_KANJI:
        return LINE_KANJI[code]
    if "." in code:
        return code.split(".", 1)[-1]
    return "" if str(code).isdigit() else code


def lines_for_trip(name_a, name_b):
    """从站名反推线路代码。同一条线 → [一个]; 跨线/换乘(两端不同线)→ [两端各自线]; 找不到 → []。"""
    try:
        idx = _station_index()
    except Exception:
        return []
    la = idx.get(_norm_name(name_a), [])
    lb = idx.get(_norm_name(name_b), [])
    common = [c for c in la if c in lb]
    if common:
        return [common[0]]
    out = []
    if la:
        out.append(la[0])
    if lb and (not out or lb[0] != out[0]):
        out.append(lb[0])
    return out


def colors_for_trip(name_a, name_b):
    """线路代表色, 和 lines_for_trip 一一对应。同线 → [单色]; 跨线 → [两色]; 找不到 → []。"""
    return [color_for(c) for c in lines_for_trip(name_a, name_b)]


def route_between(name_a, name_b):
    """在网格线里找同时经过 a、b 两站的线, 截取它们之间那一段(沿真实网格走向),
    返回 [{name,lat,lon}, ...](含端点)。多条命中取最短一段。找不到返回 None。
    高亮行程线用它 → 必然贴着网格底图。"""
    na, nb = _norm_name(name_a), _norm_name(name_b)
    if not na or not nb or na == nb:
        return None
    best = None
    for L in load_lines():
        names = L.get("names")
        if not names:
            continue
        ia = ib = -1
        for i, nm in enumerate(names):
            n = _norm_name(nm)
            if n == na and ia < 0:
                ia = i
            if n == nb:
                ib = i
        if ia < 0 or ib < 0:
            continue
        pts = L["points"]
        idxs = range(ia, ib + 1) if ia <= ib else range(ia, ib - 1, -1)
        seg = [{"name": names[i], "lat": pts[i][0], "lon": pts[i][1]} for i in idxs]
        if len(seg) >= 2 and (best is None or len(seg) < len(best)):
            best = seg
    return best


def nearby_lines(trips, padding_deg=0.5):
    """按行程经纬度矩形(自动扩 padding)取该区域内涉及的线路。

    返回 [{name, points:[[lat,lon],...], color, code}], 给 web_map 当 network 用。
    trips: [{ci/co/path...}] — 任一端点 / 路径点 都参与计算边界
    padding_deg: 边界向外扩多少度(默认 0.15° ≈ 16km, 城市内刚好覆盖)
    """
    all_lats, all_lons = [], []
    for t in trips:
        path = t.get("path") or []
        if path:
            for p in path:
                if p.get("lat") is not None: all_lats.append(p["lat"])
                if p.get("lon") is not None: all_lons.append(p["lon"])
        else:
            for k in ("ci", "co"):
                ll = t.get(k)
                if ll and ll[0] is not None: all_lats.append(ll[0])
                if ll and ll[1] is not None: all_lons.append(ll[1])
    if not all_lats or not all_lons:
        return []
    min_lat = min(all_lats) - padding_deg
    max_lat = max(all_lats) + padding_deg
    min_lon = min(all_lons) - padding_deg
    max_lon = max(all_lons) + padding_deg

    out = []
    for L in load_lines():
        pts = L["points"]
        # 任一站落在范围内即纳入
        hit = False
        for lat, lon in pts:
            if min_lat <= lat <= max_lat and min_lon <= lon <= max_lon:
                hit = True; break
        if not hit:
            continue
        out.append({
            "name": L["name"],
            "code": L["code"],
            "color": color_for(L["code"]),
            "points": [[p[0], p[1]] for p in pts],
        })
    return out


def _clip_line_segment(a, b, bounds):
    """Clip one (lat, lon) segment to bounds with Liang-Barsky."""
    min_lat, min_lon, max_lat, max_lon = bounds
    y0, x0 = a; y1, x1 = b
    dx, dy = x1 - x0, y1 - y0
    low, high = 0.0, 1.0
    for p, q in ((-dx, x0 - min_lon), (dx, max_lon - x0),
                 (-dy, y0 - min_lat), (dy, max_lat - y0)):
        if abs(p) < 1e-12:
            if q < 0:
                return None
            continue
        ratio = q / p
        if p < 0:
            low = max(low, ratio)
        else:
            high = min(high, ratio)
        if low > high:
            return None
    return ((y0 + low * dy, x0 + low * dx),
            (y0 + high * dy, x0 + high * dx))


def clipped_network(trips, padding_deg=None, view_aspect=2.35):
    """Return known-color local rail lines clipped to the current trip view.

    This is a bounded supplement for gaps around the OSM query/cache extent.
    """
    lats, lons = [], []
    for trip in trips:
        for key in ("ci", "co"):
            point = trip.get(key)
            if point and point[0] is not None and point[1] is not None:
                lats.append(float(point[0])); lons.append(float(point[1]))
        for point in (trip.get("path") or []):
            if point.get("lat") is not None and point.get("lon") is not None:
                lats.append(float(point["lat"])); lons.append(float(point["lon"]))
    if not lats or not lons:
        return []
    raw_lat_span = max(lats) - min(lats)
    raw_lon_span = max(lons) - min(lons)
    lat_span = max(raw_lat_span, 0.02)
    lon_span = max(raw_lon_span, 0.03)
    if padding_deg is None:
        # fitBounds expands the short axis to the map viewport. Mirror that
        # expansion here so a wide window does not expose an empty outer strip.
        cos_lat = max(0.2, math.cos(math.radians(sum(lats) / len(lats))))
        aspect = max(view_aspect, 0.5)
        target_lat = max(lat_span, lon_span * cos_lat / aspect)
        target_lon = max(lon_span, lat_span * aspect / cos_lat)
        bounds_lat_span = max(raw_lat_span + 0.08, target_lat * 1.16)
        bounds_lon_span = max(raw_lon_span + 0.14, target_lon * 1.16)
        projected_ratio = aspect / cos_lat
        bounds_lon_span = max(bounds_lon_span, bounds_lat_span * projected_ratio)
        bounds_lat_span = max(bounds_lat_span, bounds_lon_span / projected_ratio)
        pad_lat = (bounds_lat_span - raw_lat_span) * 0.5
        pad_lon = (bounds_lon_span - raw_lon_span) * 0.5
    else:
        pad_lat = pad_lon = float(padding_deg)
    bounds = (min(lats) - pad_lat, min(lons) - pad_lon,
              max(lats) + pad_lat, max(lons) + pad_lon)

    out = []
    for line in load_lines():
        code = str(line.get("code", ""))
        # Unknown codes have no verified representative color; never paint them green.
        if code not in COLORS:
            continue
        points = line.get("points") or []
        segments, current = [], []
        for index in range(1, len(points)):
            clipped = _clip_line_segment(points[index - 1], points[index], bounds)
            if not clipped:
                if len(current) >= 2:
                    segments.append(current)
                current = []
                continue
            start, end = clipped
            if current and abs(current[-1][0] - start[0]) < 1e-9 \
                    and abs(current[-1][1] - start[1]) < 1e-9:
                current.append([end[0], end[1]])
            else:
                if len(current) >= 2:
                    segments.append(current)
                current = [[start[0], start[1]], [end[0], end[1]]]
        if len(current) >= 2:
            segments.append(current)
        if segments:
            out.append({"name": line.get("name", ""), "code": code,
                        "color": COLORS[code], "segments": segments,
                        "bounds": bounds})
    return out


if __name__ == "__main__":
    ls = load_lines()
    print(f"已加载 {len(ls)} 条日本线路")
    print("前 5 条:", [L["code"] for L in ls[:5]])
    # 测附近搜索: 东京站附近
    sample = [{"ci": (35.681, 139.767), "co": (35.466, 139.622)}]
    near = nearby_lines(sample, padding_deg=0.3)
    print(f"东京附近线路(0.3° 范围): {len(near)} 条")
    for L in near[:5]:
        print(f"  {L['code']:30} color={L['color']}")