use dotenv::dotenv;
use std::error::Error;


mod gptapi {
    use async_openai::{
        types::{
            ChatCompletionRequestMessageArgs, CreateChatCompletionRequest,
            CreateChatCompletionRequestArgs, CreateChatCompletionResponse, Role,
        },
        Client,
    };
    use csv::Reader;
    use std::fs::OpenOptions;

    pub struct ChatSession {
        request: CreateChatCompletionRequest,
        client: Client,
        history_path: String,
    }

    impl ChatSession {
        pub fn new(model: String, max_tokens: u16, history_path: String) -> Self {
            let request = CreateChatCompletionRequestArgs::default()
                .max_tokens(max_tokens)
                .model(model)
                .messages([])
                .build();

            if request.is_err() {
                panic!("Error creating request");
            }

            let request = request.unwrap();
            let client = Client::new();

            let mut instance = Self { request, client, history_path };
            instance.load_history_messages();
            instance
        }

        pub fn add_message(
            &mut self,
            message: String,
            role: Role,
            ) -> Result<(), Box<dyn std::error::Error>> {
            let message = ChatCompletionRequestMessageArgs::default()
                .role(role)
                .content(message)
                .build()?;
            self.request.messages.push(message);
            Ok(())
        }

        pub async fn chat(&mut self, message: &str
            ) -> Result<CreateChatCompletionResponse, Box<dyn std::error::Error>> {
            self.add_message(message.to_string(), Role::User)?;
            self.save_history_message(message, Role::User);
            let response = self.client.chat().create(self.request.clone()).await?;
            Ok(response)
        }

        pub fn load_history_messages(&mut self) {
            let mut rdr = Reader::from_path(self.history_path.clone()).unwrap();
            
            for result in rdr.records() {
                let record = result.unwrap();
                let role = match &record[0] as &str {
                    "user" => Role::User,
                    "system" => Role::System,
                    "assistant" => Role::Assistant,
                    _ => Role::User,
                };
                self.add_message(record[1].to_string(), role).unwrap();

            }
        }
    
        pub fn save_history_message(&mut self, message: &str, role: Role) {
            let file = OpenOptions::new()
                            .write(true)
                            .append(true)
                            .open(self.history_path.clone())
                            .unwrap();
    
            let mut wtr = csv::Writer::from_writer(file);
            let role = match role {
                Role::User => "user",
                Role::System => "system",
                Role::Assistant => "assistant",
            };
            wtr.write_record(&[role, message]).unwrap();
        }

    }
}


#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    use gptapi::ChatSession;

    dotenv().ok();

    let history_path =  "history.csv".to_string();

    let mut session = ChatSession::new(
        "gpt-3.5-turbo".to_string(), 
        512u16, 
        history_path);


    //loop and take input from the user
    loop {
        let mut input = String::new();
        println!("PROMPT: ");
        std::io::stdin().read_line(&mut input)?;
        let response = session.chat(input.as_str()).await?;
        let message = response.choices[0].message.content.clone();

        print!("<{}>: {}\n", "Bot", message);
        
    }

}