gemini-client-api 7.4.5

use gemini_client_api::gemini::ask::Gemini;
use gemini_client_api::gemini::types::request::Tool;
use gemini_client_api::gemini::types::sessions::Session;
use gemini_client_api::gemini::utils::{GeminiSchema, execute_function_calls, gemini_function};
use std::env;
use std::error::Error;

/// This function will be made available to Gemini.
/// The doc comments are used as descriptions for the tool.
#[gemini_function]
/// Returns the result of adding two numbers.
fn add_numbers(
    /// The first number.
    a: f64,
    /// The second number.
    b: f64,
) -> f64 {
    println!("[Executing Tool] adding {} + {}", a, b);
    a + b
}

#[gemini_function]
/// Function to get the current temperature.
fn get_temperature(location: String) -> Result<String, &'static str> {
    println!("[Executing Tool] getting temperature for {}", location);
    Err("API is out of service")
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let mut session = Session::new(10);
    let api_key = env::var("GEMINI_API_KEY").expect("GEMINI_API_KEY must be set");

    // 1. Initialize Gemini and register tools
    let ai =
        Gemini::new(api_key, "gemini-2.5-flash", None).set_tools(vec![Tool::FunctionDeclarations(
            vec![
                add_numbers::gemini_schema(),
                get_temperature::gemini_schema(),
            ],
        )]);

    let prompt = "What is 123.45 plus 678.9, and what's the weather like in London?";
    println!("User: {}\n", prompt);

    // 2. Ask Gemini. It might reply with one or more function calls.
    let mut response = ai.ask(session.ask(prompt)).await?;

    // 3. Loop to handle potential multiple rounds of function calls
    loop {
        if response.get_chat().has_function_call() {
            println!("Gemini requested function calls...");

            // 4. Use the macro to execute all requested calls and update the session
            let results = execute_function_calls!(session, add_numbers, get_temperature);

            for (idx, res) in results.iter().enumerate() {
                if let Some(r) = res {
                    println!("  Call #{} result: {:?}", idx, r);
                }
            }

            // 5. Send the results back to Gemini to get the final natural language response
            response = ai.ask(&mut session).await?;
        } else {
            // No more function calls, show the final response
            println!("\nGemini: {}", response.get_chat().get_text_no_think(""));
            break;
        }
    }

    Ok(())
}

#[tokio::test]
async fn handle_manually() {
    let mut session = Session::new(10);
    let api_key = env::var("GEMINI_API_KEY").expect("GEMINI_API_KEY must be set");

    // 1. Initialize Gemini and register tools
    let ai =
        Gemini::new(api_key, "gemini-2.5-flash", None).set_tools(vec![Tool::FunctionDeclarations(
            vec![
                add_numbers::gemini_schema(),
                get_temperature::gemini_schema(),
            ],
        )]);

    let prompt = "What is 123.45 plus 678.9, and what's the weather like in London?";
    println!("User: {}\n", prompt);

    // 2. Ask Gemini. It might reply with one or more function calls.
    let mut response = ai.ask(session.ask(prompt)).await?;

    // 3. Loop to handle potential multiple rounds of function calls
    loop {
        if response.get_chat().has_function_call() {
            println!("Gemini requested function calls...");

            // 4. Use the macro to execute one requested calls and update the session
            let _ = execute_function_calls!(session, add_numbers);

            for call in response.get_chat().get_function_calls() {
                if call.name() == "get_temperature" {
                    let (location,) =
                        get_temperature::parse_arguments(call.args().as_ref().unwrap())
                            .expect("Gemini responded with wrong argument format");

                    println!("[Executing call] getting temperature for {}", location);
                    session // Note: You must update session manually
                        .add_function_response(
                            call.name(),
                            format!("temperature of {location} is 38 degree Celsius"),
                        )
                        .unwrap();
                }
            }

            // 5. Send the results back to Gemini to get the final natural language response
            response = ai.ask(&mut session).await?;
        } else {
            // No more function calls, show the final response
            println!("\nGemini: {}", response.get_chat().get_text_no_think(""));
            break;
        }
    }
}