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herodb_old/src/models/biz/exchange_rate.rs

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+use std::collections::HashMap;
+use std::sync::{Arc, Mutex};
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use crate::db::model::{Model, Storable};
+
+/// ExchangeRate represents an exchange rate between two currencies
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ExchangeRate {
+    pub id: u32,
+    pub base_currency: String,
+    pub target_currency: String,
+    pub rate: f64,
+    pub timestamp: DateTime<Utc>,
+}
+
+impl ExchangeRate {
+    /// Create a new exchange rate
+    pub fn new(id: u32, base_currency: String, target_currency: String, rate: f64) -> Self {
+        Self {
+            id,
+            base_currency,
+            target_currency,
+            rate,
+            timestamp: Utc::now(),
+        }
+    }
+}
+
+/// Builder for ExchangeRate
+pub struct ExchangeRateBuilder {
+    id: Option<u32>,
+    base_currency: Option<String>,
+    target_currency: Option<String>,
+    rate: Option<f64>,
+    timestamp: Option<DateTime<Utc>>,
+}
+
+impl ExchangeRateBuilder {
+    /// Create a new ExchangeRateBuilder with all fields set to None
+    pub fn new() -> Self {
+        Self {
+            id: None,
+            base_currency: None,
+            target_currency: None,
+            rate: None,
+            timestamp: None,
+        }
+    }
+
+    /// Set the id
+    pub fn id(mut self, id: u32) -> Self {
+        self.id = Some(id);
+        self
+    }
+
+    /// Set the base currency
+    pub fn base_currency<S: Into<String>>(mut self, base_currency: S) -> Self {
+        self.base_currency = Some(base_currency.into());
+        self
+    }
+
+    /// Set the target currency
+    pub fn target_currency<S: Into<String>>(mut self, target_currency: S) -> Self {
+        self.target_currency = Some(target_currency.into());
+        self
+    }
+
+    /// Set the rate
+    pub fn rate(mut self, rate: f64) -> Self {
+        self.rate = Some(rate);
+        self
+    }
+
+    /// Set the timestamp
+    pub fn timestamp(mut self, timestamp: DateTime<Utc>) -> Self {
+        self.timestamp = Some(timestamp);
+        self
+    }
+
+    /// Build the ExchangeRate object
+    pub fn build(self) -> Result<ExchangeRate, &'static str> {
+        let now = Utc::now();
+        Ok(ExchangeRate {
+            id: self.id.ok_or("id is required")?,
+            base_currency: self.base_currency.ok_or("base_currency is required")?,
+            target_currency: self.target_currency.ok_or("target_currency is required")?,
+            rate: self.rate.ok_or("rate is required")?,
+            timestamp: self.timestamp.unwrap_or(now),
+        })
+    }
+}
+
+
+
+impl Storable for ExchangeRate {}
+// Implement Model trait
+impl Model for ExchangeRate {
+    fn get_id(&self) -> u32 {
+        self.id
+    }
+
+    fn db_prefix() -> &'static str {
+        "exchange_rate"
+    }
+}
+
+/// ExchangeRateService provides methods to get and set exchange rates
+#[derive(Clone)]
+pub struct ExchangeRateService {
+    rates: Arc<Mutex<HashMap<String, ExchangeRate>>>,
+}
+
+impl ExchangeRateService {
+    /// Create a new exchange rate service
+    pub fn new() -> Self {
+        Self {
+            rates: Arc::new(Mutex::new(HashMap::new())),
+        }
+    }
+
+    /// Set an exchange rate
+    pub fn set_rate(&self, exchange_rate: ExchangeRate) {
+        let key = format!("{}_{}", exchange_rate.base_currency, exchange_rate.target_currency);
+        let mut rates = self.rates.lock().unwrap();
+        rates.insert(key, exchange_rate);
+    }
+
+    /// Get an exchange rate
+    pub fn get_rate(&self, base_currency: &str, target_currency: &str) -> Option<ExchangeRate> {
+        let key = format!("{}_{}", base_currency, target_currency);
+        let rates = self.rates.lock().unwrap();
+        rates.get(&key).cloned()
+    }
+
+    /// Convert an amount from one currency to another
+    pub fn convert(&self, amount: f64, from_currency: &str, to_currency: &str) -> Option<f64> {
+        // If the currencies are the same, return the amount
+        if from_currency == to_currency {
+            return Some(amount);
+        }
+
+        // Try to get the direct exchange rate
+        if let Some(rate) = self.get_rate(from_currency, to_currency) {
+            return Some(amount * rate.rate);
+        }
+
+        // Try to get the inverse exchange rate
+        if let Some(rate) = self.get_rate(to_currency, from_currency) {
+            return Some(amount / rate.rate);
+        }
+
+        // Try to convert via USD
+        if from_currency != "USD" && to_currency != "USD" {
+            if let Some(from_to_usd) = self.convert(amount, from_currency, "USD") {
+                return self.convert(from_to_usd, "USD", to_currency);
+            }
+        }
+
+        None
+    }
+}
+
+// Create a global instance of the exchange rate service
+lazy_static::lazy_static! {
+    pub static ref EXCHANGE_RATE_SERVICE: ExchangeRateService = {
+        let service = ExchangeRateService::new();
+        
+        // Set some default exchange rates
+        service.set_rate(ExchangeRate::new(1, "USD".to_string(), "EUR".to_string(), 0.85));
+        service.set_rate(ExchangeRate::new(2, "USD".to_string(), "GBP".to_string(), 0.75));
+        service.set_rate(ExchangeRate::new(3, "USD".to_string(), "JPY".to_string(), 110.0));
+        service.set_rate(ExchangeRate::new(4, "USD".to_string(), "CAD".to_string(), 1.25));
+        service.set_rate(ExchangeRate::new(5, "USD".to_string(), "AUD".to_string(), 1.35));
+        
+        service
+    };
+}