"""
Oscillator sensor - Modular synth-style oscillator as a pipeline sensor.

Provides various waveforms that can be:
1. Self-driving (phase accumulates over time)
2. Sensor-driven (phase modulated by external sensor)

Built-in waveforms:
- sine: Pure sine wave
- square: Square wave (0 to 1)
- sawtooth: Rising sawtooth (0 to 1, wraps)
- triangle: Triangle wave (0 to 1 to 0)
- noise: Random values (0 to 1)

Example usage:
    osc = OscillatorSensor(waveform="sine", frequency=0.5)
    # Or driven by mic sensor:
    osc = OscillatorSensor(waveform="sine", frequency=1.0, input_sensor="mic")
"""

import math
import random
import time
from enum import Enum

from engine.sensors import Sensor, SensorRegistry, SensorValue


class Waveform(Enum):
    """Built-in oscillator waveforms."""

    SINE = "sine"
    SQUARE = "square"
    SAWTOOTH = "sawtooth"
    TRIANGLE = "triangle"
    NOISE = "noise"


class OscillatorSensor(Sensor):
    """Oscillator sensor that generates periodic or random values.

    Can run in two modes:
    - Self-driving: phase accumulates based on frequency
    - Sensor-driven: phase modulated by external sensor value
    """

    WAVEFORMS = {
        "sine": lambda p: (math.sin(2 * math.pi * p) + 1) / 2,
        "square": lambda p: 1.0 if (p % 1.0) < 0.5 else 0.0,
        "sawtooth": lambda p: p % 1.0,
        "triangle": lambda p: 2 * abs(2 * (p % 1.0) - 1) - 1,
        "noise": lambda _: random.random(),
    }

    def __init__(
        self,
        name: str = "osc",
        waveform: str = "sine",
        frequency: float = 1.0,
        input_sensor: str | None = None,
        input_scale: float = 1.0,
    ):
        """Initialize oscillator sensor.

        Args:
            name: Sensor name
            waveform: Waveform type (sine, square, sawtooth, triangle, noise)
            frequency: Frequency in Hz (self-driving mode)
            input_sensor: Optional sensor name to drive phase
            input_scale: Scale factor for input sensor
        """
        self.name = name
        self.unit = ""
        self._waveform = waveform
        self._frequency = frequency
        self._input_sensor = input_sensor
        self._input_scale = input_scale
        self._phase = 0.0
        self._start_time = time.time()

    @property
    def available(self) -> bool:
        return True

    @property
    def waveform(self) -> str:
        return self._waveform

    @waveform.setter
    def waveform(self, value: str) -> None:
        if value not in self.WAVEFORMS:
            raise ValueError(f"Unknown waveform: {value}")
        self._waveform = value

    @property
    def frequency(self) -> float:
        return self._frequency

    @frequency.setter
    def frequency(self, value: float) -> None:
        self._frequency = max(0.0, value)

    def start(self) -> bool:
        self._phase = 0.0
        self._start_time = time.time()
        return True

    def stop(self) -> None:
        pass

    def _get_input_value(self) -> float:
        """Get value from input sensor if configured."""
        if self._input_sensor:
            from engine.sensors import SensorRegistry

            sensor = SensorRegistry.get(self._input_sensor)
            if sensor:
                reading = sensor.read()
                if reading:
                    return reading.value * self._input_scale
        return 0.0

    def read(self) -> SensorValue | None:
        current_time = time.time()
        elapsed = current_time - self._start_time

        if self._input_sensor:
            input_val = self._get_input_value()
            phase_increment = (self._frequency * elapsed) + input_val
        else:
            phase_increment = self._frequency * elapsed

        self._phase += phase_increment

        waveform_fn = self.WAVEFORMS.get(self._waveform)
        if waveform_fn is None:
            return None

        value = waveform_fn(self._phase)
        value = max(0.0, min(1.0, value))

        return SensorValue(
            sensor_name=self.name,
            value=value,
            timestamp=current_time,
            unit=self.unit,
        )

    def set_waveform(self, waveform: str) -> None:
        """Change waveform at runtime."""
        self.waveform = waveform

    def set_frequency(self, frequency: float) -> None:
        """Change frequency at runtime."""
        self.frequency = frequency


def register_oscillator_sensor(name: str = "osc", **kwargs) -> None:
    """Register an oscillator sensor with the global registry."""
    sensor = OscillatorSensor(name=name, **kwargs)
    SensorRegistry.register(sensor)