from geolysis.foundation import Foundation
from geolysis.utils import round_

from ._core import AllowableBearingCapacity


class TerzaghiABC4PadFoundation(AllowableBearingCapacity):
    r"""Allowable bearing capacity for pad foundation on cohesionless
    soils according to `Terzaghi & Peck (1948)`.

    $$
     q_a(kPa) = 12N \dfrac{1}{c_w f_d}\left(\dfrac{S}{25.4}\right),
                 \ B \ \le 1.2m
    $$

    $$
     q_a(kPa) = 8N\left(\dfrac{3.28B + 1}{3.28B} \right)^2\dfrac{1}
                 {c_w f_d}\left(\dfrac{S}{25.4}\right), \ B \ \gt 1.2m
    $$

    $$
     f_d = 1 + 0.25 \cdot \frac{D_f}{B} \le 1.25
    $$

    $$
     c_w = 2 - \frac{D_w}{2B} \le 2, D_w \gt D_f
    $$

    $$
     c_w = 2 - \frac{D_f}{2B} \le 2, D_w \le D_f
    $$

    - $q_a$ (kPa): Allowable bearing capacity
    - $N$: Corrected SPT N-value
    - $f_d$: Depth factor
    - $c_w$: Water correction factor
    - $S$ (mm): Tolerable settlement
    - $B$ (m): Width of foundation footing
    - $D_f$ (m): Depth of foundation footing
    - $D_w$ (m): Depth of water below ground level

    """

    def __init__(
            self,
            corrected_spt_n_value: float,
            tol_settlement: float,
            foundation_size: Foundation,
    ) -> None:
        """
        :param corrected_spt_n_value: Lowest (or average) uncorrected
                                      SPT N-value (60% energy) within
                                      the foundation influence zone i.e.
                                      $D_f$ to $D_f + 2B$
        :param tol_settlement: Tolerable settlement of foundation (mm).
        :param foundation_size: Size of the foundation.
        """
        super().__init__(
            corrected_spt_n_value=corrected_spt_n_value,
            tol_settlement=tol_settlement,
            foundation_size=foundation_size,
        )

    def _fd(self) -> float:
        """Calculate the depth factor."""
        depth = self.foundation_size.depth
        width = self.foundation_size.width

        return min(1.0 + 0.25 * depth / width, 1.25)

    def _cw(self):
        """Calculate the water correction factor."""
        depth = self.foundation_size.depth
        width = self.foundation_size.width
        water_level = self.foundation_size.ground_water_level

        if water_level is None:
            return 2.0

        if water_level <= depth:
            cw = 2.0 - depth / (2.0 * width)
        else:
            cw = 2.0 - water_level / (2.0 * width)

        return min(cw, 2.0)

    @round_(ndigits=2)
    def bearing_capacity(self):
        """
        Calculates the allowable bearing capacity of the pad foundation.
        """
        n_corr = self.corrected_spt_n_value
        width = self.foundation_size.width

        if width <= 1.2:
            return 12 * n_corr * (1 / (self._cw() * self._fd())) * self._sr()

        return (
                8
                * n_corr
                * ((3.28 * width + 1) / (3.28 * width)) ** 2
                * (1 / (self._cw() * self._fd()))
                * self._sr()
        )

    def bearing_capacity_results(self) -> dict:
        res = super().bearing_capacity_results()
        res["water_correction_factor"] = self._cw()
        return res


class TerzaghiABC4MatFoundation(TerzaghiABC4PadFoundation):
    r"""Allowable bearing capacity for mat foundation on cohesionless
    soils according to `Terzaghi & Peck (1948)`.

    $$
     q_a(kPa) = 8N\dfrac{1}{c_w f_d}\left(\dfrac{S}{25.4}\right)
    $$

    $$
     f_d = 1 + 0.25 \cdot \frac{D_f}{B} \le 1.25
    $$

    $$
     c_w = 2 - \frac{D_w}{2B} \le 2, D_w \gt D_f
    $$

    $$
     c_w = 2 - \frac{D_f}{2B} \le 2, D_w \le D_f
    $$

    - $q_a$ (kPa): Allowable bearing capacity
    - $N$: Corrected SPT N-value
    - $f_d$: Depth factor
    - $c_w$: Water correction factor
    - $S$ (mm): Tolerable settlement
    - $B$ (m): Width of foundation footing
    - $D_f$ (m): Depth of foundation footing
    - $D_w$ (m): Depth of water below ground level
    """

    @round_(ndigits=2)
    def bearing_capacity(self):
        """
        Calculates the allowable bearing capacity of the mat foundation.
        """
        n_corr = self.corrected_spt_n_value
        return 8 * n_corr * (1 / (self._cw() * self._fd())) * self._sr()
