import pathlib
import re

from fluidfoam import readof
import numpy as np


class OFModel:
    def __init__(self, root):
        self._root = root
        self._fields = {}
        self._post_fields = {}

    def read_mesh(self):
        self._x, self._y, self._z = readof.readmesh(str(self._root))
        self._n = self._x.size

    def read_time(self):
        _dirs = np.fromiter(
            map(
                lambda f: f.name,
                filter(
                    lambda f: re.match(r"^[0-9]+(\.[0-9]+)?$", f.name),
                    self._root.glob("*"),
                ),
            ),
            dtype="U10",
        )
        _t = _dirs.astype(np.half)
        _sort = np.argsort(_t)

        self._t_dirs = _dirs[_sort]
        self._t = _t[_sort]
        return self.t

    def read_field(self, field, t):
        if not self._root.joinpath(t, field).exists():
            return np.empty((self._n))
        return readof.readfield(self._root, time_name=t, name=field)

    def read_field_all(self, field):
        _shape = (
            (self.t.size, self._n)
            if readof.typefield(self._root, time_name=self._t_dirs[-1], name=field)
            == "scalar"
            else (self.t.size, 3, self._n)
        )

        _field = np.empty(_shape, dtype=np.single)
        for _f, _dir in zip(_field, self._t_dirs):
            _f[:] = self.read_field(field, _dir)
        self.fields[field] = _field
        return _field

    def read_post(self, func, field):
        _ft = lambda _d: self._root.joinpath("postProcessing", func, _d, f"line_{field}.xy")
        _res_0 = np.loadtxt(_ft(self._t_dirs[0]))
        _x = _res_0[:, 0]
        _res = np.empty((self._t.size, _x.size))
        _res[0] = _res_0[:, 1]
        for _r, _dir in zip(_res[1:], self._t_dirs[1:]):
            _r[:] = np.loadtxt(_ft(_dir))[:, 1]
        _dict = {
            f"x_{field}": _x,
            field: _res,
        }
        if func not in self._post_fields.keys(): self._post_fields[func] = {}
        self._post_fields[func] |= _dict
        return _dict 

    def write_field(self, field, values):
        with open(self._root.joinpath("0", field), "r") as aw_file:
            aw_raw = aw_file.read()

        with open(self._root.joinpath("0", field), "w") as aw_file:
            aw_file.write(
                re.sub(
                    r"(?<=\(\n).*?(?=\n\))",
                    "\n".join(values.astype(str)),
                    aw_raw,
                    count=1,
                    flags=re.S,
                )
            )

    def write_vector_field(self, field, values):
        with open(self._root.joinpath("0", field), "r") as aw_file:
            aw_raw = aw_file.read()

        with open(self._root.joinpath("0", field), "w") as aw_file:
            aw_file.write(
                re.sub(
                    r"(?<=\(\n).*?(?=\n\))",
                    "\n".join(map(lambda x: f"({' '.join(x.astype('str'))})", values)),
                    aw_raw,
                    count=1,
                    flags=re.S,
                )
            )

    @property
    def x(self):
        return self._x

    @property
    def y(self):
        return self._y

    @property
    def z(self):
        return self._z

    @property
    def coords(self):
        return np.stack((self._x, self._y, self._z), axis=1)

    @property
    def t(self):
        return self._t

    @property
    def fields(self):
        return self._fields

    @property
    def post_fields(self):
        return self._post_fields