feat: Auto unit preference based on location country (#487)

src/accessiweather/display/presentation/current_conditions.py

@@ -15,7 +15,9 @@
     TrendInsight,
     WeatherAlerts,
 )
+from ...units import DisplayUnitSystem
 from ...utils import TemperatureUnit
+from ...utils.unit_utils import format_precipitation, format_wind_speed
 from ..priority_engine import PriorityEngine, WeatherCategory
 from ..weather_presenter import CurrentConditionsPresentation, Metric
 from .environmental import AirQualityPresentation
@@ -40,6 +42,8 @@ def _build_basic_metrics(
     show_dewpoint: bool,
     show_visibility: bool,
     show_uv_index: bool,
+    *,
+    unit_system: DisplayUnitSystem | str | None = None,
 ) -> list[Metric]:
     """Build basic weather metrics (temperature, feels like, humidity, wind, dewpoint, etc.)."""
     # Format temperature with inline feels-like when there's a significant difference
@@ -55,19 +59,29 @@ def _build_basic_metrics(
     if current.humidity is not None:
         metrics.append(Metric("Humidity", f"{current.humidity:.0f}%"))
 
-    wind_value = format_wind(current, unit_pref, precision=precision)
+    wind_value = format_wind(current, unit_pref, precision=precision, unit_system=unit_system)
     if wind_value:
         metrics.append(Metric("Wind", wind_value))
 
     dewpoint_value = format_dewpoint(current, unit_pref, precision)
     if show_dewpoint and dewpoint_value:
         metrics.append(Metric("Dewpoint", dewpoint_value))
 
-    pressure_value = format_pressure_value(current, unit_pref, precision=precision)
+    pressure_value = format_pressure_value(
+        current,
+        unit_pref,
+        precision=precision,
+        unit_system=unit_system,
+    )
     if pressure_value:
         metrics.append(Metric("Pressure", pressure_value))
 
-    visibility_value = format_visibility_value(current, unit_pref, precision=precision)
+    visibility_value = format_visibility_value(
+        current,
+        unit_pref,
+        precision=precision,
+        unit_system=unit_system,
+    )
     if show_visibility and visibility_value:
         metrics.append(Metric("Visibility", visibility_value))
 
@@ -79,31 +93,26 @@ def _build_basic_metrics(
         metrics.append(Metric("Cloud cover", f"{current.cloud_cover:.0f}%"))
 
     if current.wind_gust_mph is not None:
-        if unit_pref == TemperatureUnit.CELSIUS:
-            gust_kph = current.wind_gust_kph or current.wind_gust_mph * 1.60934
-            metrics.append(Metric("Wind gusts", f"{gust_kph:.0f} kph"))
-        elif unit_pref == TemperatureUnit.FAHRENHEIT:
-            metrics.append(Metric("Wind gusts", f"{current.wind_gust_mph:.0f} mph"))
-        else:
-            gust_kph = current.wind_gust_kph or current.wind_gust_mph * 1.60934
-            metrics.append(
-                Metric("Wind gusts", f"{current.wind_gust_mph:.0f} mph ({gust_kph:.0f} kph)")
-            )
+        gust_value = format_wind_speed(
+            current.wind_gust_mph,
+            unit=unit_pref,
+            wind_speed_kph=current.wind_gust_kph,
+            precision=0,
+            unit_system=unit_system,
+        )
+        if unit_system is None:
+            gust_value = gust_value.replace("km/h", "kph")
+        metrics.append(Metric("Wind gusts", gust_value))
 
     if current.precipitation_in is not None and current.precipitation_in > 0:
-        if unit_pref == TemperatureUnit.CELSIUS:
-            precip_mm = current.precipitation_mm or current.precipitation_in * 25.4
-            metrics.append(Metric("Precipitation", f"{precip_mm:.{precision}f} mm"))
-        elif unit_pref == TemperatureUnit.FAHRENHEIT:
-            metrics.append(Metric("Precipitation", f"{current.precipitation_in:.{precision}f} in"))
-        else:
-            precip_mm = current.precipitation_mm or current.precipitation_in * 25.4
-            metrics.append(
-                Metric(
-                    "Precipitation",
-                    f"{current.precipitation_in:.{precision}f} in ({precip_mm:.{precision}f} mm)",
-                )
-            )
+        precip_value = format_precipitation(
+            current.precipitation_in,
+            unit=unit_pref,
+            precipitation_mm=current.precipitation_mm,
+            precision=precision,
+            unit_system=unit_system,
+        )
+        metrics.append(Metric("Precipitation", precip_value))
 
     return metrics
 
@@ -430,6 +439,7 @@ def build_current_conditions(
     hourly_forecast: HourlyForecast | None = None,
     air_quality: AirQualityPresentation | None = None,
     alerts: WeatherAlerts | None = None,
+    unit_system: DisplayUnitSystem | str | None = None,
 ) -> CurrentConditionsPresentation:
     """Create a structured presentation for the current weather using helper functions."""
     title = f"Current conditions for {location.name}"
@@ -467,7 +477,13 @@ def build_current_conditions(
     metrics: list[Metric] = []
     metrics.extend(
         _build_basic_metrics(
-            current, unit_pref, precision, show_dewpoint, show_visibility, show_uv_index
+            current,
+            unit_pref,
+            precision,
+            show_dewpoint,
+            show_visibility,
+            show_uv_index,
+            unit_system=unit_system,
         )
     )
 

src/accessiweather/display/presentation/formatters.py

@@ -6,6 +6,7 @@
 from datetime import UTC, datetime, timedelta
 
 from ...models import CurrentConditions, ForecastPeriod, HourlyForecastPeriod
+from ...units import DisplayUnitSystem
 from ...utils import (
     TemperatureUnit,
     calculate_dewpoint,
@@ -30,7 +31,11 @@ def format_temperature_pair(
 
 
 def format_wind(
-    current: CurrentConditions, unit_pref: TemperatureUnit, precision: int = 1
+    current: CurrentConditions,
+    unit_pref: TemperatureUnit,
+    precision: int = 1,
+    *,
+    unit_system: DisplayUnitSystem | str | None = None,
 ) -> str | None:
     """Describe wind direction and speed or return calm when wind is negligible."""
     if (
@@ -59,6 +64,7 @@ def format_wind(
         unit_pref,
         wind_speed_kph=current.wind_speed_kph,
         precision=precision,
+        unit_system=unit_system,
     )
     if direction and speed:
         return f"{direction} at {speed}"
@@ -100,6 +106,8 @@ def format_pressure_value(
     current: CurrentConditions,
     unit_pref: TemperatureUnit,
     precision: int = 1,
+    *,
+    unit_system: DisplayUnitSystem | str | None = None,
 ) -> str | None:
     """Format station pressure in the preferred unit, if available."""
     if current.pressure_in is None and current.pressure_mb is None:
@@ -108,13 +116,21 @@ def format_pressure_value(
     pressure_mb = current.pressure_mb
     if pressure_in is None and pressure_mb is not None:
         pressure_in = pressure_mb / 33.8639
-    return format_pressure(pressure_in, unit_pref, pressure_mb=pressure_mb, precision=precision)
+    return format_pressure(
+        pressure_in,
+        unit_pref,
+        pressure_mb=pressure_mb,
+        precision=precision,
+        unit_system=unit_system,
+    )
 
 
 def format_visibility_value(
     current: CurrentConditions,
     unit_pref: TemperatureUnit,
     precision: int = 1,
+    *,
+    unit_system: DisplayUnitSystem | str | None = None,
 ) -> str | None:
     """Format horizontal visibility taking unit preference into account."""
     if current.visibility_miles is None and current.visibility_km is None:
@@ -124,6 +140,7 @@ def format_visibility_value(
         unit_pref,
         visibility_km=current.visibility_km,
         precision=precision,
+        unit_system=unit_system,
     )
 
 

src/accessiweather/display/weather_presenter.py

@@ -29,6 +29,7 @@
     WeatherAlerts,
     WeatherData,
 )
+from ..units import resolve_display_unit_system, resolve_temperature_unit_preference
 from ..utils import TemperatureUnit, decode_taf_text
 from .presentation.environmental import AirQualityPresentation, build_air_quality_panel
 
@@ -193,7 +194,7 @@ def __init__(self, settings: AppSettings):
 
     def present(self, weather_data: WeatherData) -> WeatherPresentation:
         """Build a structured presentation for the given weather data."""
-        unit_pref = self._get_temperature_unit_preference()
+        unit_pref, unit_system = self._resolve_unit_preferences(weather_data.location)
 
         air_quality_panel = (
             build_air_quality_panel(
@@ -214,6 +215,7 @@ def present(self, weather_data: WeatherData) -> WeatherPresentation:
                 hourly_forecast=weather_data.hourly_forecast,
                 air_quality=air_quality_panel,
                 alerts=weather_data.alerts,
+                unit_system=unit_system,
             )
             if weather_data.current
             else None
@@ -274,7 +276,7 @@ def present_current(
     ) -> CurrentConditionsPresentation | None:
         if not current or not current.has_data():
             return None
-        unit_pref = self._get_temperature_unit_preference()
+        unit_pref, unit_system = self._resolve_unit_preferences(location)
         air_quality_panel = (
             build_air_quality_panel(location, environmental, settings=self.settings)
             if environmental
@@ -290,6 +292,7 @@ def present_current(
             hourly_forecast=hourly_forecast,
             air_quality=air_quality_panel,
             alerts=alerts,
+            unit_system=unit_system,
         )
 
     def present_forecast(
@@ -301,7 +304,7 @@ def present_forecast(
     ) -> ForecastPresentation | None:
         if not forecast or not forecast.has_data():
             return None
-        unit_pref = self._get_temperature_unit_preference()
+        unit_pref, _unit_system = self._resolve_unit_preferences(location)
         return self._build_forecast(
             forecast, hourly_forecast, location, unit_pref, confidence=confidence
         )
@@ -329,6 +332,7 @@ def _build_current_conditions(
         hourly_forecast: HourlyForecast | None = None,
         air_quality: AirQualityPresentation | None = None,
         alerts: WeatherAlerts | None = None,
+        unit_system=None,
     ) -> CurrentConditionsPresentation:
         return build_current_conditions(
             current,
@@ -340,6 +344,7 @@ def _build_current_conditions(
             hourly_forecast=hourly_forecast,
             air_quality=air_quality,
             alerts=alerts,
+            unit_system=unit_system,
         )
 
     def _build_forecast(
@@ -644,13 +649,14 @@ def _build_source_attribution(
             aria_label=aria_label,
         )
 
-    def _get_temperature_unit_preference(self) -> TemperatureUnit:
-        unit_pref = (self.settings.temperature_unit or "both").lower()
-        if unit_pref in {"fahrenheit", "f"}:
-            return TemperatureUnit.FAHRENHEIT
-        if unit_pref in {"celsius", "c"}:
-            return TemperatureUnit.CELSIUS
-        return TemperatureUnit.BOTH
+    def _resolve_unit_preferences(
+        self, location: Location
+    ) -> tuple[TemperatureUnit, object | None]:
+        preference = getattr(self.settings, "temperature_unit", "both")
+        return (
+            resolve_temperature_unit_preference(preference, location),
+            resolve_display_unit_system(preference, location),
+        )
 
     def _format_timestamp(self, value: datetime) -> str:
         mode = getattr(self.settings, "time_display_mode", "local")

src/accessiweather/pirate_weather_client.py

@@ -86,12 +86,12 @@ def __init__(
             api_key: Pirate Weather API key.
             user_agent: HTTP User-Agent header value.
             units: Unit system – "us" (°F, mph, in), "si" (°C, m/s, mm),
-                   "ca" (°C, km/h, mm), or "uk2" (°C, mph, mm).
+                   "ca" (°C, km/h, mm), or "uk"/"uk2" (°C, mph, mm).
 
         """
         self.api_key = api_key
         self.user_agent = user_agent
-        self.units = units
+        self.units = "uk2" if units == "uk" else units
         self.timeout = 15.0
 
     def _build_url(self, lat: float, lon: float) -> str: