Add clamp/wrap/remap to template math functions (home-assistant#154537)

Author: akx

homeassistant/helpers/template/extensions/math.py

@@ -6,7 +6,7 @@
 from functools import wraps
 import math
 import statistics
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, Literal
 
 import jinja2
 from jinja2 import pass_environment
@@ -77,6 +77,10 @@ def __init__(self, environment: TemplateEnvironment) -> None:
                 TemplateFunction(
                     "bitwise_xor", self.bitwise_xor, as_global=True, as_filter=True
                 ),
+                # Value constraint functions (as globals and filters)
+                TemplateFunction("clamp", self.clamp, as_global=True, as_filter=True),
+                TemplateFunction("wrap", self.wrap, as_global=True, as_filter=True),
+                TemplateFunction("remap", self.remap, as_global=True, as_filter=True),
             ],
         )
 
@@ -327,3 +331,114 @@ def bitwise_or(first_value: Any, second_value: Any) -> Any:
     def bitwise_xor(first_value: Any, second_value: Any) -> Any:
         """Perform a bitwise xor operation."""
         return first_value ^ second_value
+
+    @staticmethod
+    def clamp(value: Any, min_value: Any, max_value: Any) -> Any:
+        """Filter and function to clamp a value between min and max bounds.
+
+        Constrains value to the range [min_value, max_value] (inclusive).
+        """
+        try:
+            value_num = float(value)
+            min_value_num = float(min_value)
+            max_value_num = float(max_value)
+        except (ValueError, TypeError) as err:
+            raise ValueError(
+                f"function requires numeric arguments, "
+                f"got {value=}, {min_value=}, {max_value=}"
+            ) from err
+        return max(min_value_num, min(max_value_num, value_num))
+
+    @staticmethod
+    def wrap(value: Any, min_value: Any, max_value: Any) -> Any:
+        """Filter and function to wrap a value within a range.
+
+        Wraps value cyclically within [min_value, max_value) (inclusive min, exclusive max).
+        """
+        try:
+            value_num = float(value)
+            min_value_num = float(min_value)
+            max_value_num = float(max_value)
+        except (ValueError, TypeError) as err:
+            raise ValueError(
+                f"function requires numeric arguments, "
+                f"got {value=}, {min_value=}, {max_value=}"
+            ) from err
+        try:
+            range_size = max_value_num - min_value_num
+            return ((value_num - min_value_num) % range_size) + min_value_num
+        except ZeroDivisionError:  # be lenient: if the range is empty, just clamp
+            return min_value_num
+
+    @staticmethod
+    def remap(
+        value: Any,
+        in_min: Any,
+        in_max: Any,
+        out_min: Any,
+        out_max: Any,
+        *,
+        steps: int = 0,
+        edges: Literal["none", "clamp", "wrap", "mirror"] = "none",
+    ) -> Any:
+        """Filter and function to remap a value from one range to another.
+
+        Maps value from input range [in_min, in_max] to output range [out_min, out_max].
+
+        The steps parameter, if greater than 0, quantizes the output into
+        the specified number of discrete steps.
+
+        The edges parameter controls how out-of-bounds input values are handled:
+        - "none": No special handling; values outside the input range are extrapolated into the output range.
+        - "clamp": Values outside the input range are clamped to the nearest boundary.
+        - "wrap": Values outside the input range are wrapped around cyclically.
+        - "mirror": Values outside the input range are mirrored back into the range.
+        """
+        try:
+            value_num = float(value)
+            in_min_num = float(in_min)
+            in_max_num = float(in_max)
+            out_min_num = float(out_min)
+            out_max_num = float(out_max)
+        except (ValueError, TypeError) as err:
+            raise ValueError(
+                f"function requires numeric arguments, "
+                f"got {value=}, {in_min=}, {in_max=}, {out_min=}, {out_max=}"
+            ) from err
+
+        # Apply edge behavior in original space for accuracy.
+        if edges == "clamp":
+            value_num = max(in_min_num, min(in_max_num, value_num))
+        elif edges == "wrap":
+            if in_min_num == in_max_num:
+                raise ValueError(f"{in_min=} must not equal {in_max=}")
+
+            range_size = in_max_num - in_min_num  # Validated against div0 above.
+            value_num = ((value_num - in_min_num) % range_size) + in_min_num
+        elif edges == "mirror":
+            if in_min_num == in_max_num:
+                raise ValueError(f"{in_min=} must not equal {in_max=}")
+
+            range_size = in_max_num - in_min_num  # Validated against div0 above.
+            # Determine which period we're in and whether it should be mirrored
+            offset = value_num - in_min_num
+            period = math.floor(offset / range_size)
+            position_in_period = offset - (period * range_size)
+
+            if (period < 0) or (period % 2 != 0):
+                position_in_period = range_size - position_in_period
+
+            value_num = in_min_num + position_in_period
+        # Unknown "edges" values are left as-is; no use throwing an error.
+
+        steps = max(steps, 0)
+
+        if not steps and (in_min_num == out_min_num and in_max_num == out_max_num):
+            return value_num  # No remapping needed. Save some cycles and floating-point precision.
+
+        normalized = (value_num - in_min_num) / (in_max_num - in_min_num)
+
+        if steps:
+            normalized = round(normalized * steps) / steps
+
+        return out_min_num + (normalized * (out_max_num - out_min_num))

tests/helpers/template/extensions/test_math.py

@@ -8,6 +8,7 @@
 
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import TemplateError
+from homeassistant.helpers.template.extensions import MathExtension
 
 from tests.helpers.template.helpers import render
 
@@ -340,3 +341,206 @@ def test_min_max_attribute(hass: HomeAssistant, attribute) -> None:
         )
         == 3
     )
+
+
+def test_clamp(hass: HomeAssistant) -> None:
+    """Test clamp function."""
+    # Test function and filter usage in templates.
+    assert render(hass, "{{ clamp(15, 0, 10) }}") == 10.0
+    assert render(hass, "{{ -5 | clamp(0, 10) }}") == 0.0
+
+    # Test basic clamping behavior
+    assert MathExtension.clamp(5, 0, 10) == 5.0
+    assert MathExtension.clamp(-5, 0, 10) == 0.0
+    assert MathExtension.clamp(15, 0, 10) == 10.0
+    assert MathExtension.clamp(0, 0, 10) == 0.0
+    assert MathExtension.clamp(10, 0, 10) == 10.0
+
+    # Test with float values
+    assert MathExtension.clamp(5.5, 0, 10) == 5.5
+    assert MathExtension.clamp(5.5, 0.5, 10.5) == 5.5
+    assert MathExtension.clamp(0.25, 0.5, 10.5) == 0.5
+    assert MathExtension.clamp(11.0, 0.5, 10.5) == 10.5
+
+    # Test with negative ranges
+    assert MathExtension.clamp(-5, -10, -1) == -5.0
+    assert MathExtension.clamp(-15, -10, -1) == -10.0
+    assert MathExtension.clamp(0, -10, -1) == -1.0
+
+    # Test with non-range
+    assert MathExtension.clamp(5, 10, 10) == 10.0
+
+    # Test error handling - invalid input types
+    for case in (
+        "{{ clamp('invalid', 0, 10) }}",
+        "{{ clamp(5, 'invalid', 10) }}",
+        "{{ clamp(5, 0, 'invalid') }}",
+    ):
+        with pytest.raises(TemplateError):
+            render(hass, case)
+
+
+def test_wrap(hass: HomeAssistant) -> None:
+    """Test wrap function."""
+    # Test function and filter usage in templates.
+    assert render(hass, "{{ wrap(15, 0, 10) }}") == 5.0
+    assert render(hass, "{{ -5 | wrap(0, 10) }}") == 5.0
+
+    # Test basic wrapping behavior
+    assert MathExtension.wrap(5, 0, 10) == 5.0
+    assert MathExtension.wrap(10, 0, 10) == 0.0  # max wraps to min
+    assert MathExtension.wrap(15, 0, 10) == 5.0
+    assert MathExtension.wrap(25, 0, 10) == 5.0
+    assert MathExtension.wrap(-5, 0, 10) == 5.0
+    assert MathExtension.wrap(-10, 0, 10) == 0.0
+
+    # Test angle wrapping (common use case)
+    assert MathExtension.wrap(370, 0, 360) == 10.0
+    assert MathExtension.wrap(-10, 0, 360) == 350.0
+    assert MathExtension.wrap(720, 0, 360) == 0.0
+    assert MathExtension.wrap(361, 0, 360) == 1.0
+
+    # Test with float values
+    assert MathExtension.wrap(10.5, 0, 10) == 0.5
+    assert MathExtension.wrap(370.5, 0, 360) == 10.5
+
+    # Test with negative ranges
+    assert MathExtension.wrap(-15, -10, 0) == -5.0
+    assert MathExtension.wrap(5, -10, 0) == -5.0
+
+    # Test with arbitrary ranges
+    assert MathExtension.wrap(25, 10, 20) == 15.0
+    assert MathExtension.wrap(5, 10, 20) == 15.0
+
+    # Test with non-range
+    assert MathExtension.wrap(5, 10, 10) == 10.0
+
+    # Test error handling - invalid input types
+    for case in (
+        "{{ wrap('invalid', 0, 10) }}",
+        "{{ wrap(5, 'invalid', 10) }}",
+        "{{ wrap(5, 0, 'invalid') }}",
+    ):
+        with pytest.raises(TemplateError):
+            render(hass, case)
+
+
+def test_remap(hass: HomeAssistant) -> None:
+    """Test remap function."""
+    # Test function and filter usage in templates, with kitchen sink parameters.
+    # We don't check the return value; that's covered by the unit tests below.
+    assert render(hass, "{{ remap(5, 0, 6, 0, 740, steps=10) }}")
+    assert render(hass, "{{ 50 | remap(0, 100, 0, 10, steps=8) }}")
+
+    # Test basic remapping - scale from 0-10 to 0-100
+    assert MathExtension.remap(0, 0, 10, 0, 100) == 0.0
+    assert MathExtension.remap(5, 0, 10, 0, 100) == 50.0
+    assert MathExtension.remap(10, 0, 10, 0, 100) == 100.0
+
+    # Test with different input and output ranges
+    assert MathExtension.remap(50, 0, 100, 0, 10) == 5.0
+    assert MathExtension.remap(25, 0, 100, 0, 10) == 2.5
+
+    # Test with negative ranges
+    assert MathExtension.remap(0, -10, 10, 0, 100) == 50.0
+    assert MathExtension.remap(-10, -10, 10, 0, 100) == 0.0
+    assert MathExtension.remap(10, -10, 10, 0, 100) == 100.0
+
+    # Test inverted output range
+    assert MathExtension.remap(0, 0, 10, 100, 0) == 100.0
+    assert MathExtension.remap(5, 0, 10, 100, 0) == 50.0
+    assert MathExtension.remap(10, 0, 10, 100, 0) == 0.0
+
+    # Test values outside input range, and edge modes
+    assert MathExtension.remap(15, 0, 10, 0, 100, edges="none") == 150.0
+    assert MathExtension.remap(-4, 0, 10, 0, 100, edges="none") == -40.0
+    assert MathExtension.remap(15, 0, 10, 0, 80, edges="clamp") == 80.0
+    assert MathExtension.remap(-5, 0, 10, -1, 1, edges="clamp") == -1
+    assert MathExtension.remap(15, 0, 10, 0, 100, edges="wrap") == 50.0
+    assert MathExtension.remap(-5, 0, 10, 0, 100, edges="wrap") == 50.0
+
+    # Test sensor conversion use case: Celsius to Fahrenheit: 0-100°C to 32-212°F
+    assert MathExtension.remap(0, 0, 100, 32, 212) == 32.0
+    assert MathExtension.remap(100, 0, 100, 32, 212) == 212.0
+    assert MathExtension.remap(50, 0, 100, 32, 212) == 122.0
+
+    # Test time conversion use case: 0-60 minutes to 0-360 degrees, with wrap
+    assert MathExtension.remap(80, 0, 60, 0, 360, edges="wrap") == 120.0
+
+    # Test percentage to byte conversion (0-100% to 0-255)
+    assert MathExtension.remap(0, 0, 100, 0, 255) == 0.0
+    assert MathExtension.remap(50, 0, 100, 0, 255) == 127.5
+    assert MathExtension.remap(100, 0, 100, 0, 255) == 255.0
+
+    # Test with float precision
+    assert MathExtension.remap(2.5, 0, 10, 0, 100) == 25.0
+    assert MathExtension.remap(7.5, 0, 10, 0, 100) == 75.0
+
+    # Test error handling
+    for case in (
+        "{{ remap(5, 10, 10, 0, 100) }}",
+        "{{ remap('invalid', 0, 10, 0, 100) }}",
+        "{{ remap(5, 'invalid', 10, 0, 100) }}",
+        "{{ remap(5, 0, 'invalid', 0, 100) }}",
+        "{{ remap(5, 0, 10, 'invalid', 100) }}",
+        "{{ remap(5, 0, 10, 0, 'invalid') }}",
+    ):
+        with pytest.raises(TemplateError):
+            render(hass, case)
+
+
+def test_remap_with_steps(hass: HomeAssistant) -> None:
+    """Test remap function with steps parameter."""
+    # Test basic stepping - quantize to 10 steps
+    assert MathExtension.remap(0.2, 0, 10, 0, 100, steps=10) == 0.0
+    assert MathExtension.remap(5.3, 0, 10, 0, 100, steps=10) == 50.0
+    assert MathExtension.remap(10, 0, 10, 0, 100, steps=10) == 100.0
+
+    # Test stepping with intermediate values - should snap to nearest step
+    # With 10 steps, normalized values are rounded: 0.0, 0.1, 0.2, ..., 1.0
+    assert MathExtension.remap(2.4, 0, 10, 0, 100, steps=10) == 20.0
+    assert MathExtension.remap(2.5, 0, 10, 0, 100, steps=10) == 20.0
+    assert MathExtension.remap(2.6, 0, 10, 0, 100, steps=10) == 30.0
+
+    # Test with 4 steps (0%, 25%, 50%, 75%, 100%)
+    assert MathExtension.remap(0, 0, 10, 0, 100, steps=4) == 0.0
+    assert MathExtension.remap(2.5, 0, 10, 0, 100, steps=4) == 25.0
+    assert MathExtension.remap(5, 0, 10, 0, 100, steps=4) == 50.0
+    assert MathExtension.remap(7.5, 0, 10, 0, 100, steps=4) == 75.0
+    assert MathExtension.remap(10, 0, 10, 0, 100, steps=4) == 100.0
+
+    # Test with 2 steps (0%, 50%, 100%)
+    assert MathExtension.remap(2, 0, 10, 0, 100, steps=2) == 0.0
+    assert MathExtension.remap(6, 0, 10, 0, 100, steps=2) == 50.0
+    assert MathExtension.remap(8, 0, 10, 0, 100, steps=2) == 100.0
+
+    # Test with 1 step (0%, 100%)
+    assert MathExtension.remap(0, 0, 10, 0, 100, steps=1) == 0.0
+    assert MathExtension.remap(5, 0, 10, 0, 100, steps=1) == 0.0
+    assert MathExtension.remap(6, 0, 10, 0, 100, steps=1) == 100.0
+    assert MathExtension.remap(10, 0, 10, 0, 100, steps=1) == 100.0
+
+    # Test with inverted output range and steps
+    assert MathExtension.remap(4.8, 0, 10, 100, 0, steps=4) == 50.0
+
+    # Test with 0 or negative steps (should be ignored/no quantization)
+    assert MathExtension.remap(5, 0, 10, 0, 100, steps=0) == 50.0
+    assert MathExtension.remap(2.7, 0, 10, 0, 100, steps=0) == 27.0
+    assert MathExtension.remap(5, 0, 10, 0, 100, steps=-1) == 50.0
+
+
+def test_remap_with_mirror(hass: HomeAssistant) -> None:
+    """Test the mirror edge mode of the remap function."""
+
+    assert [
+        MathExtension.remap(i, 0, 4, 0, 1, edges="mirror") for i in range(-4, 9)
+    ] == [1.0, 0.75, 0.5, 0.25, 0.0, 0.25, 0.5, 0.75, 1.0, 0.75, 0.5, 0.25, 0.0]
+
+    # Test with different output range
+    assert MathExtension.remap(15, 0, 10, 50, 150, edges="mirror") == 100.0
+    assert MathExtension.remap(25, 0, 10, 50, 150, edges="mirror") == 100.0
+    # Test with inverted output range
+    assert MathExtension.remap(15, 0, 10, 100, 0, edges="mirror") == 50.0
+    assert MathExtension.remap(12, 0, 10, 100, 0, edges="mirror") == 20.0
+    # Test without remapping
+    assert MathExtension.remap(-0.1, 0, 1, 0, 1, edges="mirror") == pytest.approx(0.1)