#
# Marcus and Asymptotic Marcus-Hush-Chidsey classes
#

import pybamm
import numpy as np
from .base_kinetics import BaseKinetics


class Marcus(BaseKinetics):
    """
    Submodel which implements Marcus kinetics.

    Parameters
    ----------
    param : parameter class
        model parameters
    domain : str
        The domain to implement the model, either: 'Negative' or 'Positive'.
    reaction : str
        The name of the reaction being implemented
    options: dict
        A dictionary of options to be passed to the model.
        See :class:`pybamm.BaseBatteryModel`

    **Extends:** :class:`pybamm.interface.kinetics.BaseKinetics`
    """

    def __init__(self, param, domain, reaction, options):
        super().__init__(param, domain, reaction, options)
        pybamm.citations.register("Sripad2020")

    def _get_kinetics(self, j0, ne, eta_r, T, u):
        if self.domain == "Negative":
            mhc_lambda = self.param.mhc_lambda_n
        else:
            mhc_lambda = self.param.mhc_lambda_p
        kT = 1 + self.param.Theta * T  # dimensionless

        exp_arg_ox = -((mhc_lambda + eta_r) ** 2) / (4 * mhc_lambda * kT)
        exp_arg_red = -((mhc_lambda - eta_r) ** 2) / (4 * mhc_lambda * kT)
        return u * j0 * (pybamm.exp(exp_arg_ox) - pybamm.exp(exp_arg_red))


class MarcusHushChidsey(BaseKinetics):
    """
    Submodel which implements asymptotic Marcus-Hush-Chidsey kinetics, as derived in
    [1]_.

    References
    ----------
    .. [1] <NAME>., <NAME>., <NAME>., & <NAME>. (2020). "Kinetics
           of lithium electrodeposition and stripping".
           [The Journal of Chemical Physics](https://doi.org/10.1063/5.0023771),
           153(19), 194701.

    Parameters
    ----------
    param : parameter class
        model parameters
    domain : str
        The domain to implement the model, either: 'Negative' or 'Positive'.
    reaction : str
        The name of the reaction being implemented
    options: dict
        A dictionary of options to be passed to the model.
        See :class:`pybamm.BaseBatteryModel`

    **Extends:** :class:`pybamm.interface.kinetics.BaseKinetics`
    """

    def __init__(self, param, domain, reaction, options):
        super().__init__(param, domain, reaction, options)
        pybamm.citations.register("Sripad2020")

    def _get_kinetics(self, j0, ne, eta_r, T, u):
        if self.domain == "Negative":
            mhc_lambda = self.param.mhc_lambda_n
        else:
            mhc_lambda = self.param.mhc_lambda_p
        kT = 1 + self.param.Theta * T  # dimensionless

        lambda_T = mhc_lambda / kT
        eta = eta_r / kT
        a = 1 + pybamm.sqrt(lambda_T)
        arg = (lambda_T - pybamm.sqrt(a + eta ** 2)) / (2 * pybamm.sqrt(lambda_T))
        pref = pybamm.sqrt(np.pi * lambda_T) * pybamm.tanh(eta / 2)
        return u * j0 * pref * pybamm.erfc(arg)
