//
// Created by Morgan Funtowicz on 6/30/24.
//

#ifndef TGI_TRTLLM_BACKEND_H
#define TGI_TRTLLM_BACKEND_H

#include <filesystem>
#include <span>

#include <fmt/format.h>
#include <nlohmann/json.hpp>

#include <tensorrt_llm/runtime/common.h>
#include <tensorrt_llm/executor/executor.h>
#include <tensorrt_llm/plugins/api/tllmPlugin.h>

using json = nlohmann::json;
namespace tle = tensorrt_llm::executor;

namespace huggingface::tgi::backends {

    using TokenStreamingCallback = void(tle::TokenIdType);

    /**
     * Initialize all the components required by TRTLLM.
     * It is required to call this function before attempting to load any engine
     */
    void InitializeBackend();

    /**
     *
     * @param config TensorRT-LLM configuration object
     * @param workerPath Path to the "executorWorker" provided by TensorRT-LLM when using orchestrator mode
     * @return
     */
    tle::ExecutorConfig GetExecutorConfig(const json &config, const std::string &workerPath);

    /**
     *
     */
    class TensorRtLlmBackend {
    private:
        const json config;
        tle::Executor executor;

    public:
        explicit TensorRtLlmBackend(
                const std::filesystem::path &engineFolder,
                const std::filesystem::path &executorWorker
        );

        /***
         * Indicate if the backend is ready to accept incoming request
         * @return true if ready, false otherwise
         */
        [[nodiscard]] bool IsReady() const {
            return executor.canEnqueueRequests();
        }

        /***
         * Submit a new generation task to the executor
         * @param tokens
         * @param maxNewTokens
         * @param topK
         * @param topP
         * @param temperature
         * @param minLength
         * @param repetitionPenalty
         * @param frequencyPenalty
         * @param seed
         * @param nTopTokens
         * @return Request id related to this generation for reference
         */
        [[nodiscard]] tle::IdType Submit(
                const std::vector<tle::TokenIdType> &tokens,
                int32_t maxNewTokens,
                int32_t topK,
                float_t topP,
                float_t temperature,
                int32_t minLength,
                std::optional<float_t> repetitionPenalty = std::nullopt,
                std::optional<float_t> frequencyPenalty = std::nullopt,
                std::optional<uint32_t> seed = std::nullopt,
                std::optional<uint32_t> nTopTokens = std::nullopt
        );

        /***
         * Unroll the token generation until end of stream is reached.
         * Every generated token is streamed back through the provided callback for further processing
         * @param reqId The request id to unroll
         * @param cb The callback to stream token back
         * @return Global number of generated tokens for this request id
         */
        size_t Stream(tle::IdType reqId, const std::function<TokenStreamingCallback>& cb);
    };
}


#endif //TGI_TRTLLM_BACKEND_H