Initial commit

src/planetarytime/body.py

@@ -0,0 +1,94 @@
+from __future__ import annotations
+
+from enum import Enum
+
+from planetarytime.moon import (
+    ARIEL,
+    CALLISTO,
+    DEIMOS,
+    ENCELADUS,
+    EUROPA,
+    GANYMEDE,
+    IO,
+    MIRANDA,
+    Moon,
+    OBERON,
+    PHOBOS,
+    TITAN,
+    TITANIA,
+    TRITON,
+    UMBRIEL,
+)
+
+
+class Body(Enum):
+    """Planetary body in the Solar System."""
+
+    MERCURY = "Mercury"
+    VENUS = "Venus"
+    MARS = "Mars"
+    JUPITER = "Jupiter"
+    SATURN = "Saturn"
+    URANUS = "Uranus"
+    NEPTUNE = "Neptune"
+
+    @property
+    def rotation_hours(self) -> float:
+        """Sidereal rotation period in Earth hours."""
+        return _ROTATION_HOURS[self]
+
+    @property
+    def orbital_hours(self) -> float:
+        """Orbital period around the Sun in Earth hours."""
+        return _ORBITAL_HOURS[self]
+
+    @property
+    def hours_per_sol(self) -> int:
+        """Number of hours in one sol (rotation period rounded to nearest hour)."""
+        return round(self.rotation_hours)
+
+    @property
+    def sols_per_year(self) -> int:
+        """Number of sols in one planetary year (orbital period / rotation period, rounded)."""
+        return round(self.orbital_hours / self.rotation_hours)
+
+    @property
+    def display_name(self) -> str:
+        return self.value
+
+    def __getitem__(self, index: int) -> Moon:
+        """Return the moon at the given index for this body."""
+        return _MOONS[self][index]
+
+
+_ROTATION_HOURS: dict[Body, float] = {
+    Body.MERCURY: 1407.6,
+    Body.VENUS:   5832.5,
+    Body.MARS:    24.6,
+    Body.JUPITER: 9.9,
+    Body.SATURN:  10.7,
+    Body.URANUS:  17.2,
+    Body.NEPTUNE: 16.1,
+}
+
+# Orbital periods in Earth hours
+_ORBITAL_HOURS: dict[Body, float] = {
+    Body.MERCURY: 87.97   * 24,
+    Body.VENUS:   224.70  * 24,
+    Body.MARS:    686.97  * 24,
+    Body.JUPITER: 4332.59 * 24,
+    Body.SATURN:  10759.22 * 24,
+    Body.URANUS:  30688.50 * 24,
+    Body.NEPTUNE: 60182.00 * 24,
+}
+
+# Moons per body, ordered by orbital distance from the planet
+_MOONS: dict[Body, list[Moon]] = {
+    Body.MERCURY: [],
+    Body.VENUS:   [],
+    Body.MARS:    [PHOBOS, DEIMOS],
+    Body.JUPITER: [IO, EUROPA, GANYMEDE, CALLISTO],
+    Body.SATURN:  [TITAN, ENCELADUS],
+    Body.URANUS:  [MIRANDA, ARIEL, UMBRIEL, TITANIA, OBERON],
+    Body.NEPTUNE: [TRITON],
+}