openmeteo-rs 1.0.0

//! Ensemble forecast endpoint builder.

use reqwest::Url;
use time::{Date, PrimitiveDateTime};

use super::url::{
    QueryParam, build_endpoint_url, push_api_param, push_api_values, push_display_param,
    push_float_param,
};
use super::validation::{
    format_hour, is_non_zero_u8, is_non_zero_u16, validate_at_most, validate_coordinates,
    validate_fixed_range_windows,
};
use crate::response::decode_forecast_json;
use crate::units::{
    CellSelection, PrecipitationUnit, TemperatureUnit, TimeFormat, Timezone, WindSpeedUnit,
};
use crate::variables::{DailyVar, EnsembleModel, HourlyVar};
use crate::{Client, EnsembleResponse, Error, Result};

const MAX_FORECAST_DAYS: u8 = 35;
const MAX_PAST_DAYS: u8 = 92;
const MAX_FORECAST_HOURS: u16 = 35 * 24;

/// Builder for the `/v1/ensemble` endpoint.
#[derive(Debug)]
#[must_use = "ensemble builders do nothing until `.send().await` is called"]
pub struct EnsembleBuilder<'a> {
    client: &'a Client,
    latitude: f64,
    longitude: f64,
    hourly: Vec<HourlyVar>,
    daily: Vec<DailyVar>,
    models: Vec<EnsembleModel>,
    temperature_unit: Option<TemperatureUnit>,
    wind_speed_unit: Option<WindSpeedUnit>,
    precipitation_unit: Option<PrecipitationUnit>,
    timeformat: Option<TimeFormat>,
    timezone: Option<Timezone>,
    past_days: Option<u8>,
    forecast_days: Option<u8>,
    past_hours: Option<u16>,
    forecast_hours: Option<u16>,
    date_range: Option<(Date, Date)>,
    hour_range: Option<(PrimitiveDateTime, PrimitiveDateTime)>,
    cell_selection: Option<CellSelection>,
    elevation: Option<f64>,
}

impl<'a> EnsembleBuilder<'a> {
    pub(crate) fn new(client: &'a Client, latitude: f64, longitude: f64) -> Self {
        Self {
            client,
            latitude,
            longitude,
            hourly: Vec::new(),
            daily: Vec::new(),
            models: Vec::new(),
            temperature_unit: None,
            wind_speed_unit: None,
            precipitation_unit: None,
            timeformat: None,
            timezone: None,
            past_days: None,
            forecast_days: None,
            past_hours: None,
            forecast_hours: None,
            date_range: None,
            hour_range: None,
            cell_selection: None,
            elevation: None,
        }
    }

    /// Adds hourly variables to the request.
    pub fn hourly<I>(mut self, variables: I) -> Self
    where
        I: IntoIterator<Item = HourlyVar>,
    {
        self.hourly.extend(variables);
        self
    }

    /// Adds daily variables to the request.
    pub fn daily<I>(mut self, variables: I) -> Self
    where
        I: IntoIterator<Item = DailyVar>,
    {
        self.daily.extend(variables);
        self
    }

    /// Pins one or more ensemble models.
    pub fn models<I>(mut self, models: I) -> Self
    where
        I: IntoIterator<Item = EnsembleModel>,
    {
        self.models.extend(models);
        self
    }

    /// Sets the response temperature unit.
    pub fn temperature_unit(mut self, unit: TemperatureUnit) -> Self {
        self.temperature_unit = Some(unit);
        self
    }

    /// Sets the response wind-speed unit.
    pub fn wind_speed_unit(mut self, unit: WindSpeedUnit) -> Self {
        self.wind_speed_unit = Some(unit);
        self
    }

    /// Sets the response precipitation unit.
    pub fn precipitation_unit(mut self, unit: PrecipitationUnit) -> Self {
        self.precipitation_unit = Some(unit);
        self
    }

    /// Sets the response timestamp format.
    pub fn timeformat(mut self, format: TimeFormat) -> Self {
        self.timeformat = Some(format);
        self
    }

    /// Sets the response timezone.
    pub fn timezone(mut self, timezone: Timezone) -> Self {
        self.timezone = Some(timezone);
        self
    }

    /// Requests a number of past days.
    pub fn past_days(mut self, days: u8) -> Self {
        self.past_days = Some(days);
        self
    }

    /// Requests a number of forecast days.
    pub fn forecast_days(mut self, days: u8) -> Self {
        self.forecast_days = Some(days);
        self
    }

    /// Requests a number of past hourly timesteps.
    pub fn past_hours(mut self, hours: u16) -> Self {
        self.past_hours = Some(hours);
        self
    }

    /// Requests a number of forecast hourly timesteps.
    pub fn forecast_hours(mut self, hours: u16) -> Self {
        self.forecast_hours = Some(hours);
        self
    }

    /// Sets an inclusive date range using Open-Meteo's `start_date` and `end_date`.
    ///
    /// This is mutually exclusive with relative day/hour windows and with
    /// [`Self::hour_range`].
    pub fn date_range(mut self, start: Date, end: Date) -> Self {
        self.date_range = Some((start, end));
        self
    }

    /// Sets an hour-grained range using Open-Meteo's `start_hour` and `end_hour`.
    ///
    /// This is mutually exclusive with relative day/hour windows and with
    /// [`Self::date_range`].
    pub fn hour_range(mut self, start: PrimitiveDateTime, end: PrimitiveDateTime) -> Self {
        self.hour_range = Some((start, end));
        self
    }

    /// Sets grid-cell selection near coastlines.
    pub fn cell_selection(mut self, selection: CellSelection) -> Self {
        self.cell_selection = Some(selection);
        self
    }

    /// Overrides the elevation used for downscaling.
    pub fn elevation(mut self, meters: f64) -> Self {
        self.elevation = Some(meters);
        self
    }

    /// Sends the request and decodes the JSON ensemble response.
    pub async fn send(self) -> Result<EnsembleResponse> {
        let url = self.build_url()?;
        let body = self.client.execute(self.client.http.get(url)).await?;
        decode_forecast_json(&body)
    }

    pub(crate) fn build_url(&self) -> Result<Url> {
        self.validate()?;

        let mut params: Vec<QueryParam> = vec![
            ("latitude", self.latitude.to_string()),
            ("longitude", self.longitude.to_string()),
        ];
        push_api_values(&mut params, "hourly", &self.hourly);
        push_api_values(&mut params, "daily", &self.daily);
        push_api_values(&mut params, "models", &self.models);
        push_api_param(
            &mut params,
            "temperature_unit",
            self.temperature_unit.as_ref(),
        );
        push_api_param(
            &mut params,
            "wind_speed_unit",
            self.wind_speed_unit.as_ref(),
        );
        push_api_param(
            &mut params,
            "precipitation_unit",
            self.precipitation_unit.as_ref(),
        );
        push_api_param(&mut params, "timeformat", self.timeformat.as_ref());
        push_api_param(&mut params, "timezone", self.timezone.as_ref());
        push_display_param(
            &mut params,
            "past_days",
            self.past_days.filter(|days| *days > 0),
        );
        push_display_param(&mut params, "forecast_days", self.forecast_days);
        push_display_param(
            &mut params,
            "past_hours",
            self.past_hours.filter(|hours| *hours > 0),
        );
        push_display_param(
            &mut params,
            "forecast_hours",
            self.forecast_hours.filter(|hours| *hours > 0),
        );
        if let Some((start, end)) = self.date_range {
            params.push(("start_date", start.to_string()));
            params.push(("end_date", end.to_string()));
        }
        if let Some((start, end)) = self.hour_range {
            params.push(("start_hour", format_hour(start)?));
            params.push(("end_hour", format_hour(end)?));
        }
        push_api_param(&mut params, "cell_selection", self.cell_selection.as_ref());
        push_float_param(&mut params, "elevation", self.elevation);

        build_endpoint_url(
            &self.client.ensemble_base,
            "ensemble_base_url",
            "v1/ensemble",
            self.client.api_key.as_deref(),
            params,
        )
    }

    fn validate(&self) -> Result<()> {
        validate_coordinates(self.latitude, self.longitude)?;
        if self.hourly.is_empty() && self.daily.is_empty() {
            return Err(Error::InvalidParam {
                field: "variables",
                reason: "set at least one hourly or daily variable".into(),
            });
        }
        if self.models.is_empty() {
            return Err(Error::InvalidParam {
                field: "models",
                reason: "set at least one ensemble model".into(),
            });
        }
        validate_at_most("past_days", self.past_days, MAX_PAST_DAYS)?;
        validate_at_most("forecast_days", self.forecast_days, MAX_FORECAST_DAYS)?;
        validate_at_most("forecast_hours", self.forecast_hours, MAX_FORECAST_HOURS)?;
        self.validate_hourly_variables()?;
        validate_fixed_range_windows(
            self.date_range,
            self.hour_range,
            &[
                ("past_days", is_non_zero_u8(self.past_days)),
                ("forecast_days", self.forecast_days.is_some()),
                ("past_hours", is_non_zero_u16(self.past_hours)),
                ("forecast_hours", is_non_zero_u16(self.forecast_hours)),
            ],
        )
    }

    fn validate_hourly_variables(&self) -> Result<()> {
        for var in &self.hourly {
            var.validate_weather_request()?;
        }

        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::{EnsembleModel, HourlyVar, TemperatureUnit, Timezone};
    use time::macros::{date, datetime};

    #[test]
    fn build_ensemble_url_with_hourly_variables() {
        let client = Client::builder()
            .ensemble_base_url("https://example.com/ensemble?token=abc")
            .unwrap()
            .build()
            .unwrap();

        let url = client
            .ensemble(47.3769, 8.5417)
            .hourly([HourlyVar::Temperature2m])
            .models([EnsembleModel::IconSeamlessEps])
            .timezone(Timezone::Iana("Europe/Zurich".to_owned()))
            .temperature_unit(TemperatureUnit::Fahrenheit)
            .forecast_hours(1)
            .build_url()
            .unwrap();

        assert_eq!(
            url.as_str(),
            "https://example.com/ensemble/v1/ensemble?token=abc&latitude=47.3769&longitude=8.5417&hourly=temperature_2m&models=icon_seamless_eps&temperature_unit=fahrenheit&timezone=Europe%2FZurich&forecast_hours=1"
        );
    }

    #[test]
    fn build_ensemble_url_with_date_and_hour_ranges() {
        let client = Client::builder()
            .ensemble_base_url("https://example.com")
            .unwrap()
            .build()
            .unwrap();

        let date_url = client
            .ensemble(47.3769, 8.5417)
            .hourly([HourlyVar::Temperature2m])
            .models([EnsembleModel::IconSeamlessEps])
            .date_range(date!(2026 - 05 - 01), date!(2026 - 05 - 02))
            .build_url()
            .unwrap();
        assert!(date_url.as_str().contains("start_date=2026-05-01"));
        assert!(date_url.as_str().contains("end_date=2026-05-02"));

        let hour_url = client
            .ensemble(47.3769, 8.5417)
            .hourly([HourlyVar::Temperature2m])
            .models([EnsembleModel::IconSeamlessEps])
            .hour_range(datetime!(2026-05-01 00:00), datetime!(2026-05-01 01:00))
            .build_url()
            .unwrap();
        assert!(hour_url.as_str().contains("start_hour=2026-05-01T00%3A00"));
        assert!(hour_url.as_str().contains("end_hour=2026-05-01T01%3A00"));
    }

    #[test]
    fn rejects_empty_ensemble_variable_set() {
        let client = Client::new();
        let err = client
            .ensemble(47.3769, 8.5417)
            .models([EnsembleModel::IconSeamlessEps])
            .build_url()
            .unwrap_err();

        assert!(matches!(
            err,
            Error::InvalidParam {
                field: "variables",
                ..
            }
        ));
    }

    #[test]
    fn rejects_missing_ensemble_models() {
        let client = Client::new();
        let err = client
            .ensemble(47.3769, 8.5417)
            .hourly([HourlyVar::Temperature2m])
            .build_url()
            .unwrap_err();

        assert!(matches!(
            err,
            Error::InvalidParam {
                field: "models",
                ..
            }
        ));
    }

    #[test]
    fn rejects_ensemble_date_range_with_relative_window() {
        let client = Client::new();
        let err = client
            .ensemble(47.3769, 8.5417)
            .hourly([HourlyVar::Temperature2m])
            .models([EnsembleModel::IconSeamlessEps])
            .forecast_hours(1)
            .date_range(date!(2026 - 05 - 01), date!(2026 - 05 - 02))
            .build_url()
            .unwrap_err();

        assert!(matches!(
            err,
            Error::MutuallyExclusive {
                first: "date_range",
                second: "forecast_hours",
            }
        ));
    }
}