import copy
import functools
from pathlib import Path

ROOT = Path(__file__).resolve().parents[1]

BASE_CFG = {
    "planet": {"radius_km": 12742.0, "gravity_g": 1.05, "day_hours": 31.149, "year_days": 216,
               "tilt_deg": 20.0, "sea_level_pressure_bar": 1.0, "scale_height_km": 8.0, "o2_fraction": 0.21},
    "build": {"seed": 7, "res_dev": 2, "res_final": 2, "raster_width": 256, "preview_width": 128,
              "land_fraction": 0.22},
}


@functools.lru_cache(maxsize=4)
def small_grid(res: int = 2):
    from mapgen.grid import build_grid
    return build_grid(res, 12742.0)


def make_ctx(res=2, data=None, cfg=None, tect=None, root=None):
    from mapgen.pipeline import Ctx
    c = copy.deepcopy(BASE_CFG)
    for sec, vals in (cfg or {}).items():
        c.setdefault(sec, {}).update(vals)
    ctx = Ctx(root or ROOT, c, tect or {"plate": []}, res)
    ctx.grid = small_grid(res)
    ctx.data = dict(data or {})
    return ctx


def big_river(a) -> int:
    """The cell of the biggest river that flows on over land (not into a lake at its own level, which cuts no
    valley, nor off a coast, like a basin lake's spillway): the fixtures' river."""
    import numpy as np
    river, lake = np.asarray(a["river"]).astype(bool), np.asarray(a["lake"]).astype(bool)
    recv = np.asarray(a["recv"])
    wet = lake | np.asarray(a["ocean"]).astype(bool)
    return int(np.argmax(np.asarray(a["discharge_km3_yr"]) * (river & ~wet & ~wet[recv])))