from dataclasses import dataclass
import time

from .filters import ExponentialFilter


def shear_magnitude(sample):
    return (float(sample["fshearx"]) ** 2 + float(sample["fsheary"]) ** 2) ** 0.5


@dataclass
class ForceBaseline:
    left_normal: float = 0.0
    right_normal: float = 0.0
    left_shear: float = 0.0
    right_shear: float = 0.0


@dataclass
class ForceFeedback:
    left_normal: float
    right_normal: float
    min_normal: float
    max_normal: float
    normal_diff: float
    left_shear: float
    right_shear: float
    max_shear: float
    shear_diff: float


class TactileFeedbackProcessor:
    def __init__(self, config, normal_converter, shear_converter):
        self.config = config
        self.normal_converter = normal_converter
        self.shear_converter = shear_converter
        self.baseline = ForceBaseline()
        self.reset_filters()

    def reset_filters(self):
        self.left_normal_filter = ExponentialFilter(self.config.filter_alpha)
        self.right_normal_filter = ExponentialFilter(self.config.filter_alpha)
        self.left_shear_filter = ExponentialFilter(self.config.shear_filter_alpha)
        self.right_shear_filter = ExponentialFilter(self.config.shear_filter_alpha)

    def calibrate_baseline(self, reader):
        seconds = self.config.baseline_seconds
        if seconds <= 0:
            self.baseline = ForceBaseline()
            return self.baseline

        left_values = []
        right_values = []
        left_shear_values = []
        right_shear_values = []
        deadline = time.perf_counter() + seconds
        while time.perf_counter() < deadline:
            left, right = reader.get_samples(timeout=0.2)
            if left is not None:
                left_values.append(self.normal_converter.convert(left["fnormal"]))
                left_shear_values.append(self.shear_converter.convert(shear_magnitude(left)))
            if right is not None:
                right_values.append(self.normal_converter.convert(right["fnormal"]))
                right_shear_values.append(self.shear_converter.convert(shear_magnitude(right)))
            time.sleep(0.01)

        self.baseline = ForceBaseline(
            left_normal=sum(left_values) / len(left_values) if left_values else 0.0,
            right_normal=sum(right_values) / len(right_values) if right_values else 0.0,
            left_shear=sum(left_shear_values) / len(left_shear_values) if left_shear_values else 0.0,
            right_shear=sum(right_shear_values) / len(right_shear_values) if right_shear_values else 0.0,
        )
        return self.baseline

    def read(self, reader, timeout=0.3):
        left, right = reader.get_samples(timeout=timeout)
        if left is None or right is None:
            return None

        left_force = max(
            0.0,
            self.normal_converter.convert(left["fnormal"]) - self.baseline.left_normal,
        )
        right_force = max(
            0.0,
            self.normal_converter.convert(right["fnormal"]) - self.baseline.right_normal,
        )
        left_shear = max(
            0.0,
            self.shear_converter.convert(shear_magnitude(left)) - self.baseline.left_shear,
        )
        right_shear = max(
            0.0,
            self.shear_converter.convert(shear_magnitude(right)) - self.baseline.right_shear,
        )

        left_normal = self.left_normal_filter.update(left_force)
        right_normal = self.right_normal_filter.update(right_force)
        left_shear_filtered = self.left_shear_filter.update(left_shear)
        right_shear_filtered = self.right_shear_filter.update(right_shear)

        return ForceFeedback(
            left_normal=left_normal,
            right_normal=right_normal,
            min_normal=min(left_normal, right_normal),
            max_normal=max(left_normal, right_normal),
            normal_diff=left_normal - right_normal,
            left_shear=left_shear_filtered,
            right_shear=right_shear_filtered,
            max_shear=max(left_shear_filtered, right_shear_filtered),
            shear_diff=left_shear_filtered - right_shear_filtered,
        )