weathr 1.2.2

A terminal-based ASCII weather application with animated scenes driven by real-time weather data
Documentation 
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use crate::geolocation::GeoLocation;
use crate::weather::WeatherData;
use serde::{Deserialize, Serialize};
use std::fs;
use std::path::PathBuf;

const LOCATION_CACHE_DURATION_SECS: u64 = 86400;
const WEATHER_CACHE_DURATION_SECS: u64 = 300;

#[derive(Serialize, Deserialize)]
struct LocationCache {
    location: GeoLocation,
    cached_at: u64,
}

#[derive(Serialize, Deserialize)]
struct WeatherCache {
    data: WeatherData,
    cached_at: u64,
    location_key: String,
}

fn get_cache_dir() -> Option<PathBuf> {
    let cache_dir = if let Ok(xdg_cache) = std::env::var("XDG_CACHE_HOME") {
        PathBuf::from(xdg_cache)
    } else {
        dirs::home_dir()?.join(".cache")
    };
    Some(cache_dir.join("weathr"))
}

fn current_timestamp() -> u64 {
    std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .map(|d| d.as_secs())
        .unwrap_or(0)
}

fn make_location_key(latitude: f64, longitude: f64) -> String {
    format!("{:.2},{:.2}", latitude, longitude)
}

pub fn load_cached_location() -> Option<GeoLocation> {
    let cache_path = get_cache_dir()?.join("location.json");
    let contents = fs::read_to_string(&cache_path).ok()?;
    let cache: LocationCache = serde_json::from_str(&contents).ok()?;

    let now = current_timestamp();
    if now - cache.cached_at < LOCATION_CACHE_DURATION_SECS {
        Some(cache.location)
    } else {
        None
    }
}

pub fn save_location_cache(location: &GeoLocation) {
    if let Some(cache_dir) = get_cache_dir() {
        let _ = fs::create_dir_all(&cache_dir);

        let cache = LocationCache {
            location: location.clone(),
            cached_at: current_timestamp(),
        };

        if let Ok(json) = serde_json::to_string(&cache) {
            let _ = fs::write(cache_dir.join("location.json"), json);
        }
    }
}

pub fn load_cached_weather(latitude: f64, longitude: f64) -> Option<WeatherData> {
    let cache_path = get_cache_dir()?.join("weather.json");
    let contents = fs::read_to_string(&cache_path).ok()?;
    let cache: WeatherCache = serde_json::from_str(&contents).ok()?;

    let location_key = make_location_key(latitude, longitude);
    if cache.location_key != location_key {
        return None;
    }

    let now = current_timestamp();
    if now - cache.cached_at < WEATHER_CACHE_DURATION_SECS {
        Some(cache.data)
    } else {
        None
    }
}

pub fn save_weather_cache(weather: &WeatherData, latitude: f64, longitude: f64) {
    if let Some(cache_dir) = get_cache_dir() {
        let _ = fs::create_dir_all(&cache_dir);

        let cache = WeatherCache {
            data: weather.clone(),
            cached_at: current_timestamp(),
            location_key: make_location_key(latitude, longitude),
        };

        if let Ok(json) = serde_json::to_string(&cache) {
            let _ = fs::write(cache_dir.join("weather.json"), json);
        }
    }
}