use crate::{
    client::Client,
    error::OpenAIError,
    types::{CompletionResponseStream, CreateCompletionRequest, CreateCompletionResponse},
};

/// Given a prompt, the model will return one or more predicted
/// completions, and can also return the probabilities of alternative
/// tokens at each position.
pub struct Completion;

impl Completion {
    /// Creates a completion for the provided prompt and parameters
    pub async fn create(
        client: &Client,
        request: CreateCompletionRequest,
    ) -> Result<CreateCompletionResponse, OpenAIError> {
        if request.stream.is_some() && request.stream.unwrap() {
            return Err(OpenAIError::InvalidArgument(
                "When stream is true, use Completion::create_stream".into(),
            ));
        }
        client.post("/completions", request).await
    }

    /// Creates a completion request for the provided prompt and parameters
    ///
    /// Stream back partial progress. Tokens will be sent as data-only
    /// [server-sent events](https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events#event_stream_format)
    /// as they become available, with the stream terminated by a data: \[DONE\] message.
    ///
    /// [CompletionResponseStream] is a parsed SSE stream until a \[DONE\] is received from server.
    pub async fn create_stream(
        client: &Client,
        mut request: CreateCompletionRequest,
    ) -> Result<CompletionResponseStream, OpenAIError> {
        if request.stream.is_some() && !request.stream.unwrap() {
            return Err(OpenAIError::InvalidArgument(
                "When stream is false, use Completion::create".into(),
            ));
        }

        request.stream = Some(true);

        Ok(client.post_stream("/completions", request).await)
    }
}