import { Observable } from "rxjs";
import { EngineSettings, OpenAIModel } from "../@types/global";

/**
 * Sends a request to the inference server to generate a response based on the recent messages.
 * @param recentMessages - An array of recent messages to use as context for the inference.
 * @param engine - The engine settings to use for the inference.
 * @param model - The model to use for the inference.
 * @returns An Observable that emits the generated response as a string.
 */
export function requestInference(
  recentMessages: any[],
  engine: EngineSettings,
  model: OpenAIModel,
  controller?: AbortController
): Observable<string> {
  return new Observable((subscriber) => {
    let model_id: string = model.id
    if (engine.full_url.includes("openai.azure.com")){
      model_id = engine.full_url.split("/")[5]
    }
    const requestBody = JSON.stringify({
      messages: recentMessages,
      stream: true,
      model: model_id,
      ...model.parameters,
    });
    fetch(`${engine.full_url}`, {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        Accept: "text/event-stream",
        "Access-Control-Allow-Origin": "*",
        Authorization: `Bearer ${engine.api_key}`,
        "api-key": `${engine.api_key}`,
      },
      body: requestBody,
      signal: controller?.signal,
    })
      .then(async (response) => {
        const stream = response.body;
        const decoder = new TextDecoder("utf-8");
        const reader = stream?.getReader();
        let content = "";

        while (true && reader) {
          const { done, value } = await reader.read();
          if (done) {
            break;
          }
          const text = decoder.decode(value);
          const lines = text.trim().split("\n");
          for (const line of lines) {
            if (line.startsWith("data: ") && !line.includes("data: [DONE]")) {
              const data = JSON.parse(line.replace("data: ", ""));
              content += data.choices[0]?.delta?.content ?? "";
              if (content.startsWith("assistant: ")) {
                content = content.replace("assistant: ", "");
              }
              subscriber.next(content);
            }
          }
        }
        subscriber.complete();
      })
      .catch((err) => subscriber.error(err));
  });
}