from __future__ import annotations

from dataclasses import dataclass, field
from itertools import product
from math import prod
from typing import Any

import numpy as np

from .functions import pulse_attn
from .distributions import BaseDistribution
from .motions import BaseMotion


__all__ = [
    'SimParameter',
    'MoleculeParameter',
    'StimEchoParameter',
    'SpectrumParameter',
    'DistParameter',
    'MotionParameter',
    'Parameter',
    'make_filename'
]


@dataclass
class SimParameter:
    seed: int | None
    num_walker: int
    t_max: float

    def header(self) -> str:
        return f'num_traj = {self.num_walker}\nseed = {self.seed}'


@dataclass
class MoleculeParameter:
    delta: float
    eta: float


@dataclass
class StimEchoParameter:
    t_evo: 'ArrayLike'
    t_mix: 'ArrayLike'
    t_echo: float
    t_max: float = field(init=False)

    def __post_init__(self):
        self.t_max = np.max(self.t_mix) + 2 * np.max(self.t_evo) + 2*self.t_echo

    def header(self) -> str:
        return (
            f't_evo = {self.t_evo}\n'
            f't_mix = {self.t_mix}\n'
            f't_echo={self.t_echo}\n'
        )


@dataclass
class SpectrumParameter:
    dwell_time: float
    num_points: int
    t_echo: 'ArrayLike'
    lb: float
    t_pulse: float
    t_acq: 'ArrayLike' = field(init=False)
    freq: 'ArrayLike' = field(init=False)
    t_max: float = field(init=False)
    dampening: 'ArrayLike' = field(init=False)
    pulse_attn: 'ArrayLike' = field(init=False)

    def __post_init__(self):
        self.t_acq = np.arange(self.num_points) * self.dwell_time
        self.dampening = np.exp(-self.lb * self.t_acq)
        self.t_max = np.max(self.t_acq) + 2 * np.max(self.t_echo)
        self.freq = np.fft.fftshift(np.fft.fftfreq(self.num_points, self.dwell_time))
        self.pulse_attn = pulse_attn(self.freq, self.t_pulse)

    def header(self) -> str:
        return (
            f'dwell_time = {self.dwell_time}\n'
            f'num_points = {self.num_points}\n'
            f't_echo = {self.t_echo}\n'
            f'lb = {self.lb}\n'
            f't_pulse = {self.t_pulse}'
        )


@dataclass
class DistParameter:
    name: str
    dist_type: BaseDistribution
    variables: field(default_factory=dict)
    num_variables: int = 0
    iter: field(init=False) = None

    def __post_init__(self):
        self.num_variables = prod(map(len, self.variables.values()))

    def __iter__(self):
        return self

    def __next__(self) -> dict[str, Any]:
        if self.iter is None:
            self.iter = product(*self.variables.values())
        try:
            return dict(zip(self.variables.keys(), next(self.iter)))
        except StopIteration:
            self.iter = None
            raise StopIteration


@dataclass
class MotionParameter:
    name: str
    model: BaseMotion
    variables: field(default_factory=dict)
    num_variables: int = 0
    iter: field(init=False) = None

    def __post_init__(self):
        self.num_variables = prod(map(len, self.variables.values()))

    def __iter__(self):
        return self

    def __next__(self) -> dict[str, Any]:
        if self.iter is None:
            self.iter = product(*self.variables.values())
        try:
            return dict(zip(self.variables.keys(), next(self.iter)))
        except StopIteration:
            self.iter = None
            raise StopIteration


@dataclass
class Parameter:
    ste: StimEchoParameter | None
    spec: SpectrumParameter | None
    sim: SimParameter
    dist: DistParameter
    motion: MotionParameter
    molecule: MoleculeParameter

    def header(self, sim: bool = True, spec: bool = False, ste: bool = False) -> str:
        text = []
        if sim:
            text.append(self.sim.header())

        if spec:
            text.append(self.spec.header())

        if ste:
            text.append(self.ste.header())

        return '\n'.join(text)


def make_filename(dist: BaseDistribution, motion: BaseMotion) -> str:
    filename = f'{dist}_{motion}'
    filename = filename.replace(' ', '_')
    filename = filename.replace('.', 'p')

    return filename