feat: support external model and pricing configuration from TOML (#140)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jimyag

src/config.rs

@@ -1,6 +1,8 @@
+use crate::models::ModelInfo;
 use anyhow::{Context, Result};
 use serde::{Deserialize, Serialize};
 use std::cell::RefCell;
+use std::collections::HashMap;
 use std::fs;
 use std::path::PathBuf;
 
@@ -9,6 +11,10 @@ pub struct Config {
     pub server: ServerConfig,
     pub upload: UploadConfig,
     pub formatting: FormattingConfig,
+    #[serde(default)]
+    pub models: HashMap<String, ModelInfo>,
+    #[serde(default)]
+    pub aliases: HashMap<String, String>,
 }
 
 #[derive(Debug, Serialize, Deserialize, Clone)]
@@ -52,6 +58,8 @@ impl Default for Config {
                 locale: "en".to_string(),
                 decimal_places: 2,
             },
+            models: HashMap::new(),
+            aliases: HashMap::new(),
         }
     }
 }
@@ -171,6 +179,12 @@ pub fn show_config() -> Result<()> {
             println!("   Number Human: {}", config.formatting.number_human);
             println!("   Locale: {}", config.formatting.locale);
             println!("   Decimal Places: {}", config.formatting.decimal_places);
+            if !config.models.is_empty() {
+                println!("   Custom Models: {}", config.models.len());
+            }
+            if !config.aliases.is_empty() {
+                println!("   Custom Aliases: {}", config.aliases.len());
+            }
         }
         None => {
             println!("❌ No configuration file found.");
@@ -226,6 +240,7 @@ pub fn set_config_value(key: &str, value: &str) -> Result<()> {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::models::PricingStructure;
     use tempfile::TempDir;
 
     fn setup_test_config() -> (TempDir, PathBuf) {
@@ -235,6 +250,54 @@ mod tests {
         (dir, config_path)
     }
 
+    #[test]
+    fn test_config_with_custom_models() {
+        let toml_str = r#"
+[server]
+url = "https://custom.example.com"
+api_token = "test-token"
+
+[upload]
+auto_upload = true
+upload_today_only = false
+retry_attempts = 5
+last_date_uploaded = 0
+
+[formatting]
+number_comma = true
+number_human = false
+locale = "zh"
+decimal_places = 4
+
+[models."custom-model"]
+pricing = { Flat = { input_per_1m = 10.0, output_per_1m = 20.0 } }
+caching = "None"
+is_estimated = true
+
+[aliases]
+"my-alias" = "custom-model"
+"#;
+
+        let config: Config = toml::from_str(toml_str).unwrap();
+
+        assert_eq!(config.server.url, "https://custom.example.com");
+        assert!(config.models.contains_key("custom-model"));
+
+        let custom_model = config.models.get("custom-model").unwrap();
+        match &custom_model.pricing {
+            PricingStructure::Flat {
+                input_per_1m,
+                output_per_1m,
+            } => {
+                assert_eq!(*input_per_1m, 10.0);
+                assert_eq!(*output_per_1m, 20.0);
+            }
+            _ => panic!("Expected flat pricing"),
+        }
+
+        assert_eq!(config.aliases.get("my-alias").unwrap(), "custom-model");
+    }
+
     #[test]
     fn default_config_round_trip() {
         let (_dir, _path) = setup_test_config();

src/main.rs

@@ -131,6 +131,9 @@ async fn main() {
     // Load config file to get defaults
     let config = config::Config::load().unwrap_or(None).unwrap_or_default();
 
+    // Initialize external models from config
+    models::init_external_models(config.models.clone(), config.aliases.clone());
+
     // Create format options merging config defaults with CLI overrides
     let format_options = utils::NumberFormatOptions {
         use_comma: cli.number_comma || config.formatting.number_comma,