'use strict';

// Documentation for writing LLM Transformation handlers: https://github.com/oracle/bots-node-sdk/blob/master/LLM_TRANSFORMATION_HANDLER.md

// You can use your favorite http client package to make REST calls, however, the node fetch API is pre-installed with the bots-node-sdk.
// Documentation can be found at https://www.npmjs.com/package/node-fetch
// Un-comment the next line if you want to make REST calls using node-fetch.
// const fetch = require("node-fetch");

module.exports = {
  metadata: {
    name: 'Azure_Transformer',
    eventHandlerType: 'LlmTransformation'
  },
  handlers: {

    /**
    * Handler to transform the request payload
    * @param {TransformPayloadEvent} event - event object contains the following properties:
    * - payload: the request payload object
    * @param {LlmTransformationContext} context - see https://oracle.github.io/bots-node-sdk/LlmTransformationContext.html
    * @returns {object} the transformed request payload
    */
transformRequestPayload: async (event, context) => {
  let payload = { "model": "gpt-4-0314",
                    "messages": event.payload.messages.map(m => { return {"role": m.role, "content": m.content}; }),                     "max_tokens": event.payload.maxTokens,
                    "temperature": event.payload.temperature,
                    "stream": event.payload.streamResponse
                  };
  return payload;
},

    /**
    * Handler to transform the response payload
    * @param {TransformPayloadEvent} event - event object contains the following properties:
    * - payload: the response payload object
    * @param {LlmTransformationContext} context - see https://oracle.github.io/bots-node-sdk/LlmTransformationContext.html
    * @returns {object} the transformed response payload
    */
transformResponsePayload: async (event, context) => {
     let llmPayload = {};      
     if (event.payload.responseItems) {
       // streaming case
       llmPayload.responseItems = [];
       event.payload.responseItems
           .filter(item => item.choices.length > 0)
           .forEach(item => {
         llmPayload.responseItems.push({"candidates": item.choices.map( c => {return {"content": c.delta.content || "" };})});
       });
     } else {
        // non-streaming case
        llmPayload.candidates = event.payload.choices.map( c => {return {"content": c.message.content || "" };});
     } 
     return llmPayload;
   },

    /**
    * Handler to transform the error response payload, invoked when HTTP status code is 400 or higher and the error
    * response body received is a JSON object
    * @param {TransformPayloadEvent} event - event object contains the following properties:
    * - payload: the error response payload object
    * @param {LlmTransformationContext} context - see https://oracle.github.io/bots-node-sdk/LlmTransformationContext.html
    * @returns {object} the transformed error response payload
    */
transformErrorResponsePayload: async (event, context) => {
  let errorCode = 'unknown';
  if (event.payload.error) {
    if ( 'context_length_exceeded' === event.payload.error.code) {
      errorCode = 'modelLengthExceeded';
    }  else if ('content_filter' === event.payload.error.code) {
      errorCode = 'flagged'; 
    } 
    return {"errorCode" : errorCode, "errorMessage": event.payload.error.message};
  } else {
    return {"errorCode" : errorCode, "errorMessage": JSON.stringify(event.payload)};
  }   
}

  }
};