feat(03-02): implement animation library — 7 types with registry and factory

- AnimationBase ABC with render(t, led_count) and from_params() contract
- SolidColorAnimation: time-independent uniform fill
- ChaseAnimation: moving lit segment with forward/reverse support
- PulseAnimation: sine-wave breathing effect (speed maps to period)
- RainbowAnimation: HSV hue cycle across strip via colorsys.hsv_to_rgb
- StrobeAnimation: on/off flashing at 1-20 Hz with configurable duty cycle
- ColorWipeAnimation: progressive fill from start or end
- FireAnimation: Fire2012 algorithm with cooling/sparking/heat-to-color mapping
- ANIMATION_REGISTRY + create_animation() factory function
- All 24 tests passing

lightsync/animations/__init__.py

@@ -0,0 +1,48 @@
+"""Animation library — 7 built-in animation types with a factory registry."""
+from lightsync.animations.base import AnimationBase
+from lightsync.animations.solid_color import SolidColorAnimation
+from lightsync.animations.chase import ChaseAnimation
+from lightsync.animations.pulse import PulseAnimation
+from lightsync.animations.rainbow import RainbowAnimation
+from lightsync.animations.strobe import StrobeAnimation
+from lightsync.animations.color_wipe import ColorWipeAnimation
+from lightsync.animations.fire import FireAnimation
+
+__all__ = [
+    "AnimationBase",
+    "SolidColorAnimation",
+    "ChaseAnimation",
+    "PulseAnimation",
+    "RainbowAnimation",
+    "StrobeAnimation",
+    "ColorWipeAnimation",
+    "FireAnimation",
+    "ANIMATION_REGISTRY",
+    "create_animation",
+]
+
+ANIMATION_REGISTRY: dict[str, type[AnimationBase]] = {
+    "solid_color": SolidColorAnimation,
+    "chase": ChaseAnimation,
+    "pulse": PulseAnimation,
+    "rainbow": RainbowAnimation,
+    "strobe": StrobeAnimation,
+    "color_wipe": ColorWipeAnimation,
+    "fire": FireAnimation,
+}
+
+
+def create_animation(name: str, params: dict) -> AnimationBase:
+    """Create an animation by registry name.
+
+    Args:
+        name: Animation type name (e.g. "chase", "fire").
+        params: CueModel.params dict passed to from_params().
+
+    Raises:
+        ValueError: If name is not in ANIMATION_REGISTRY.
+    """
+    cls = ANIMATION_REGISTRY.get(name)
+    if cls is None:
+        raise ValueError(f"Unknown animation: {name!r}. Available: {sorted(ANIMATION_REGISTRY)}")
+    return cls.from_params(params)

lightsync/animations/base.py

@@ -0,0 +1,28 @@
+"""AnimationBase ABC — all animations implement render() and from_params()."""
+from abc import ABC, abstractmethod
+
+
+class AnimationBase(ABC):
+    """Pure animation renderer — no I/O, stateless or state-per-instance.
+
+    Each animation computes pixel data from time t and strip length.
+    No networking, no disk I/O — just math.
+    """
+
+    @abstractmethod
+    def render(self, t: float, led_count: int) -> list[tuple]:
+        """Render frame at time t (seconds since animation started).
+
+        Returns list of (R, G, B) tuples, length == led_count.
+        All channel values in range 0-255.
+        """
+        ...
+
+    @classmethod
+    @abstractmethod
+    def from_params(cls, params: dict) -> "AnimationBase":
+        """Construct from CueModel.params dict.
+
+        Missing keys use animation-specific defaults.
+        """
+        ...

lightsync/animations/chase.py

@@ -0,0 +1,58 @@
+"""Chase animation — a lit segment moves along the strip."""
+from lightsync.animations.base import AnimationBase
+
+
+class ChaseAnimation(AnimationBase):
+    """Moving lit segment(s) chasing along the strip.
+
+    At speed=1.0, the segment moves at 60 pixels/second.
+    Pattern repeats every (size + spacing) pixels.
+    """
+
+    def __init__(
+        self,
+        color: tuple[int, int, int] = (255, 255, 255),
+        bg_color: tuple[int, int, int] = (0, 0, 0),
+        speed: float = 0.5,
+        size: int = 3,
+        spacing: int = 7,
+        reverse: bool = False,
+        white: int = 0,
+    ) -> None:
+        self.color = tuple(color)  # type: ignore[arg-type]
+        self.bg_color = tuple(bg_color)  # type: ignore[arg-type]
+        self.speed = speed
+        self.size = size
+        self.spacing = spacing
+        self.reverse = reverse
+        self.white = white
+
+    def render(self, t: float, led_count: int) -> list[tuple]:
+        period = self.size + self.spacing
+        offset = int(t * self.speed * 60)  # pixels/sec at speed=1.0 is 60
+
+        pixels = []
+        for i in range(led_count):
+            if self.reverse:
+                pos = (i + offset) % period
+            else:
+                pos = (i - offset) % period
+
+            if pos < self.size:
+                pixels.append(self.color)
+            else:
+                pixels.append(self.bg_color)
+
+        return pixels
+
+    @classmethod
+    def from_params(cls, params: dict) -> "ChaseAnimation":
+        return cls(
+            color=tuple(params.get("color", [255, 255, 255])),  # type: ignore[arg-type]
+            bg_color=tuple(params.get("bg_color", [0, 0, 0])),  # type: ignore[arg-type]
+            speed=params.get("speed", 0.5),
+            size=params.get("size", 3),
+            spacing=params.get("spacing", 7),
+            reverse=params.get("reverse", False),
+            white=params.get("white", 0),
+        )

lightsync/animations/color_wipe.py

@@ -0,0 +1,44 @@
+"""Color wipe animation — progressively fills the strip with color."""
+from lightsync.animations.base import AnimationBase
+
+
+class ColorWipeAnimation(AnimationBase):
+    """Progressively fills the strip from one end with a single color.
+
+    At speed=1.0, fills at 60 pixels/second.
+    reverse=True fills from the end instead of the start.
+    """
+
+    def __init__(
+        self,
+        color: tuple[int, int, int] = (255, 255, 255),
+        speed: float = 0.5,
+        reverse: bool = False,
+        white: int = 0,
+    ) -> None:
+        self.color = tuple(color)  # type: ignore[arg-type]
+        self.speed = speed
+        self.reverse = reverse
+        self.white = white
+
+    def render(self, t: float, led_count: int) -> list[tuple]:
+        fill_count = min(led_count, int(t * self.speed * 60))
+        black = (0, 0, 0)
+
+        if not self.reverse:
+            # Fill from start: first fill_count pixels = color
+            pixels = [self.color] * fill_count + [black] * (led_count - fill_count)
+        else:
+            # Fill from end: last fill_count pixels = color
+            pixels = [black] * (led_count - fill_count) + [self.color] * fill_count
+
+        return pixels
+
+    @classmethod
+    def from_params(cls, params: dict) -> "ColorWipeAnimation":
+        return cls(
+            color=tuple(params.get("color", [255, 255, 255])),  # type: ignore[arg-type]
+            speed=params.get("speed", 0.5),
+            reverse=params.get("reverse", False),
+            white=params.get("white", 0),
+        )

lightsync/animations/fire.py

@@ -0,0 +1,80 @@
+"""Fire animation — Fire2012 algorithm port from FastLED."""
+import random
+from lightsync.animations.base import AnimationBase
+
+
+def _fire_step(
+    heat: list[int],
+    led_count: int,
+    cooling: int,
+    sparking: int,
+) -> None:
+    """Run one Fire2012 step, mutating heat array in-place.
+
+    Index 0 = bottom of strip (heat source), index N-1 = top.
+    """
+    # Step 1: Cool every cell
+    for i in range(led_count):
+        cooldown = random.randint(0, (cooling * 10 // led_count) + 2)
+        heat[i] = max(0, heat[i] - cooldown)
+
+    # Step 2: Heat drifts upward (toward index N-1)
+    for i in range(led_count - 1, 1, -1):
+        heat[i] = (heat[i - 1] + heat[i - 2] + heat[i - 2]) // 3
+
+    # Step 3: Randomly ignite new sparks near bottom
+    if random.randint(0, 255) < sparking:
+        y = random.randint(0, min(6, led_count - 1))
+        heat[y] = min(255, heat[y] + random.randint(160, 255))
+
+
+def _heat_to_rgb(h: int) -> tuple[int, int, int]:
+    """Map heat value 0-255 to black -> red -> yellow -> white palette."""
+    h = max(0, min(255, h))
+    if h < 85:
+        return (h * 3, 0, 0)
+    elif h < 170:
+        h2 = h - 85
+        return (255, h2 * 3, 0)
+    else:
+        h2 = h - 170
+        return (255, 255, min(255, h2 * 3))
+
+
+class FireAnimation(AnimationBase):
+    """Fire2012 algorithm — heat diffusion with cooling, sparking, and color mapping.
+
+    Index 0 = bottom of strip (heat source). Flames rise toward index N-1.
+    State is per-instance (heat array) — each instance maintains its own fire.
+    """
+
+    def __init__(
+        self,
+        cooling: int = 55,
+        sparking: int = 120,
+        speed: float = 0.5,
+    ) -> None:
+        self.cooling = cooling
+        self.sparking = sparking
+        self.speed = speed
+        self._heat: list[int] = []  # lazy-init per led_count
+
+    def render(self, t: float, led_count: int) -> list[tuple]:
+        # Lazy-init or resize heat array
+        if len(self._heat) != led_count:
+            self._heat = [0] * led_count
+
+        # Speed multiplier: higher speed -> more simulation steps per render
+        steps = max(1, int(self.speed * 3))
+        for _ in range(steps):
+            _fire_step(self._heat, led_count, self.cooling, self.sparking)
+
+        return [_heat_to_rgb(h) for h in self._heat]
+
+    @classmethod
+    def from_params(cls, params: dict) -> "FireAnimation":
+        return cls(
+            cooling=params.get("cooling", 55),
+            sparking=params.get("sparking", 120),
+            speed=params.get("speed", 0.5),
+        )

lightsync/animations/pulse.py

@@ -0,0 +1,53 @@
+"""Pulse (breathing) animation — brightness oscillates via sine wave."""
+import math
+from lightsync.animations.base import AnimationBase
+
+
+class PulseAnimation(AnimationBase):
+    """Smooth breathing effect — brightness oscillates via sine wave.
+
+    speed=1.0 -> 0.1s period (fast), speed=0.0 -> 5.0s period (slow).
+    """
+
+    def __init__(
+        self,
+        color: tuple[int, int, int] = (255, 255, 255),
+        speed: float = 0.5,
+        min_brightness: int = 0,
+        max_brightness: int = 255,
+        white: int = 0,
+    ) -> None:
+        self.color = tuple(color)  # type: ignore[arg-type]
+        self.speed = speed
+        self.min_brightness = min_brightness
+        self.max_brightness = max_brightness
+        self.white = white
+
+    def render(self, t: float, led_count: int) -> list[tuple]:
+        # Map speed to period: speed=1.0 -> 0.1s, speed=0.0 -> 5.0s
+        period = 0.1 + (1.0 - self.speed) * 4.9
+
+        # Sine oscillation: 0.0 to 1.0 over one period
+        brightness = (
+            self.min_brightness
+            + (self.max_brightness - self.min_brightness)
+            * (0.5 + 0.5 * math.sin(2 * math.pi * t / period))
+        )
+
+        scale = brightness / 255.0
+        r = min(255, max(0, int(self.color[0] * scale)))
+        g = min(255, max(0, int(self.color[1] * scale)))
+        b = min(255, max(0, int(self.color[2] * scale)))
+
+        pixel = (r, g, b)
+        return [pixel] * led_count
+
+    @classmethod
+    def from_params(cls, params: dict) -> "PulseAnimation":
+        return cls(
+            color=tuple(params.get("color", [255, 255, 255])),  # type: ignore[arg-type]
+            speed=params.get("speed", 0.5),
+            min_brightness=params.get("min_brightness", 0),
+            max_brightness=params.get("max_brightness", 255),
+            white=params.get("white", 0),
+        )

lightsync/animations/rainbow.py

@@ -0,0 +1,38 @@
+"""Rainbow animation — full HSV hue cycle across the strip."""
+import colorsys
+from lightsync.animations.base import AnimationBase
+
+
+class RainbowAnimation(AnimationBase):
+    """Hue-shifting rainbow across the entire strip.
+
+    period=1.0 means one full rainbow cycle fits on the strip.
+    speed controls how fast the hues shift over time.
+    """
+
+    def __init__(
+        self,
+        speed: float = 0.5,
+        period: float = 1.0,
+    ) -> None:
+        self.speed = speed
+        self.period = period
+
+    def render(self, t: float, led_count: int) -> list[tuple]:
+        pixels = []
+        for i in range(led_count):
+            hue = (i / led_count / self.period + t * self.speed) % 1.0
+            r_f, g_f, b_f = colorsys.hsv_to_rgb(hue, 1.0, 1.0)
+            pixels.append((
+                int(r_f * 255),
+                int(g_f * 255),
+                int(b_f * 255),
+            ))
+        return pixels
+
+    @classmethod
+    def from_params(cls, params: dict) -> "RainbowAnimation":
+        return cls(
+            speed=params.get("speed", 0.5),
+            period=params.get("period", 1.0),
+        )

lightsync/animations/solid_color.py

@@ -0,0 +1,23 @@
+"""Solid color animation — all LEDs the same color at all times."""
+from lightsync.animations.base import AnimationBase
+
+
+class SolidColorAnimation(AnimationBase):
+    """Time-independent: all LEDs show a single solid color."""
+
+    def __init__(
+        self,
+        color: tuple[int, int, int] = (255, 255, 255),
+        white: int = 0,
+    ) -> None:
+        self.color = tuple(color)  # type: ignore[arg-type]
+        self.white = white
+
+    def render(self, t: float, led_count: int) -> list[tuple]:
+        return [self.color] * led_count
+
+    @classmethod
+    def from_params(cls, params: dict) -> "SolidColorAnimation":
+        color = tuple(params.get("color", [255, 255, 255]))
+        white = params.get("white", 0)
+        return cls(color=color, white=white)  # type: ignore[arg-type]

lightsync/animations/strobe.py

@@ -0,0 +1,42 @@
+"""Strobe animation — rapid on/off flashing."""
+from lightsync.animations.base import AnimationBase
+
+
+class StrobeAnimation(AnimationBase):
+    """Rapid on/off flashing at configurable frequency and duty cycle.
+
+    speed=0.5 -> ~10.5 Hz. duty_cycle=0.1 means 10% on, 90% off.
+    """
+
+    def __init__(
+        self,
+        color: tuple[int, int, int] = (255, 255, 255),
+        speed: float = 0.5,
+        duty_cycle: float = 0.1,
+        white: int = 0,
+    ) -> None:
+        self.color = tuple(color)  # type: ignore[arg-type]
+        self.speed = speed
+        self.duty_cycle = duty_cycle
+        self.white = white
+
+    def render(self, t: float, led_count: int) -> list[tuple]:
+        # Frequency: 1-20 Hz mapped from speed 0.0-1.0
+        freq = 1.0 + self.speed * 19.0
+        phase = (t * freq) % 1.0
+
+        if phase < self.duty_cycle:
+            pixel = self.color
+        else:
+            pixel = (0, 0, 0)
+
+        return [pixel] * led_count
+
+    @classmethod
+    def from_params(cls, params: dict) -> "StrobeAnimation":
+        return cls(
+            color=tuple(params.get("color", [255, 255, 255])),  # type: ignore[arg-type]
+            speed=params.get("speed", 0.5),
+            duty_cycle=params.get("duty_cycle", 0.1),
+            white=params.get("white", 0),
+        )

tests/test_animations.py

@@ -108,15 +108,20 @@ def test_chase_pattern():
 
 
 def test_chase_reverse():
-    """Chase with reverse=True differs from reverse=False at same t (non-trivial t)."""
+    """Chase with reverse=True differs from reverse=False at same t (non-trivial t).
+
+    Choose t such that offset is not a multiple of (size+spacing) to avoid symmetry.
+    """
     color = (255, 0, 0)
     bg = (0, 0, 0)
+    # period = size + spacing = 3 + 7 = 10
+    # offset = int(t * speed * 60); use t=0.05 -> offset=3, not multiple of 10
     anim_fwd = ChaseAnimation(color=color, bg_color=bg, speed=1.0, size=3, spacing=7, reverse=False, white=0)
     anim_rev = ChaseAnimation(color=color, bg_color=bg, speed=1.0, size=3, spacing=7, reverse=True, white=0)
-    t = 1.5  # Non-zero t to show movement
+    t = 0.05  # offset=3, not a multiple of period=10, so fwd and rev patterns differ
     frame_fwd = anim_fwd.render(t, 20)
     frame_rev = anim_rev.render(t, 20)
-    assert frame_fwd != frame_rev, "Forward and reverse chase should differ at t=1.5"
+    assert frame_fwd != frame_rev, "Forward and reverse chase should differ when offset is not a multiple of period"
 
 
 # ---------------------------------------------------------------------------