"""Thin host adapter for the shared C99 reconstruction/DAC algorithms."""
from __future__ import annotations
import ctypes as C
from dataclasses import dataclass
from functools import lru_cache
from protocan.native import NativeProtocol

METHODS = {"polynomial": "Аппроксимация: полином МНК", "linear": "Интерполяция: линейная",
           "pchip": "Интерполяция: PCHIP", "spline": "Восстановление: кубический сплайн"}

@dataclass
class Reconstruction:
    points: list
    input_count: int
    unique_count: int
    rmse: float
    pieces: tuple = ()

@lru_cache(maxsize=1)
def library():
    try:
        lib = NativeProtocol().lib
        pointer = C.POINTER(C.c_double)
        lib.set_signal_reconstruct.argtypes = [pointer, pointer, C.c_size_t, C.c_int, C.c_uint,
            C.c_size_t, C.c_int, pointer, pointer, pointer, pointer, C.c_size_t]
        lib.set_signal_reconstruct.restype = C.c_int
        lib.set_signal_dac12.argtypes = [pointer, C.c_size_t, C.c_double, C.POINTER(C.c_uint16)]
        lib.set_signal_dac12.restype = C.c_int
        return lib
    except (AttributeError, OSError, RuntimeError) as error:
        raise ValueError("Пересоберите SETProtocol с set_signal.c и set_wavegen.c") from error

def reconstruct(points, method="pchip", output_count=1000, degree=2, *, endpoint=True, with_model=False):
    if method not in METHODS or type(output_count) is not int or not 2 <= output_count <= 10000:
        raise ValueError("Неизвестный метод или число выходных точек вне 2…10000")
    count = len(points)
    if not 2 <= count <= 100000 or type(degree) is not int or not 1 <= degree <= 5:
        raise ValueError("Нужно 2…100000 исходных точек, степень 1…5")
    x, y = (C.c_double * count)(*(p[0] for p in points)), (C.c_double * count)(*(p[1] for p in points))
    ox, oy, meta = (C.c_double * output_count)(), (C.c_double * output_count)(), (C.c_double * 3)()
    work = (C.c_double * (14 * count + 128))()
    code = library().set_signal_reconstruct(x, y, count, list(METHODS).index(method), degree,
        output_count, int(endpoint), ox, oy, meta, work, len(work))
    if code:
        raise ValueError({1: "Недостаточно точек для выбранной степени или неверные параметры",
                          2: "Нужны конечные значения и минимум две различные временные точки",
                          3: "Неустойчивая аппроксимация: уменьшите степень"}.get(code, "Ошибка расчёта"))
    pieces = ()
    if with_model:
        from .plot_formula import reconstruction_pieces
        if method == 'polynomial' and output_count <= degree:
            pieces = reconstruct(points, method, degree + 1, degree, with_model=True).pieces
        else:
            pieces = reconstruction_pieces(work, count, int(meta[1]), method, degree, oy, endpoint)
    return Reconstruction(list(zip(ox, oy)), int(meta[0]), int(meta[1]), meta[2], pieces)

def dac12(volts, vref=3.3):
    data = (C.c_double * len(volts))(*volts)
    codes = (C.c_uint16 * len(volts))()
    if library().set_signal_dac12(data, len(data), vref, codes):
        raise ValueError("Расчётная кривая выходит за диапазон ЦАП 0…Vref; измените точки или метод")
    return tuple(codes)