/*
 * Copyright (c) Qualcomm Innovation Center, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree.
 */

// A simple llama2/3 runner that includes preprocessing and post processing
// logic. The module takes in a string as input and emits a string as output.

#if defined(QAIHUB_LLAMA3_RUNNER)
#include <executorch/examples/models/llama/tokenizer/llama_tiktoken.h>
#else
#include <executorch/extension/llm/tokenizer/bpe_tokenizer.h>
#endif
#include <executorch/examples/qualcomm/qaihub_scripts/llama/runner/runner.h>
#include <executorch/extension/evalue_util/print_evalue.h>
#include <executorch/extension/llm/runner/util.h>
#include <executorch/runtime/core/exec_aten/exec_aten.h>
#include <executorch/runtime/core/exec_aten/util/scalar_type_util.h>
#include <executorch/runtime/platform/log.h>

#include <ctime>
#include <memory>
#include <sstream>

#if defined(__aarch64__)
#include "arm_neon.h"
#endif

using executorch::aten::Tensor;
using executorch::extension::Module;
using executorch::extension::llm::Sampler;
using executorch::extension::llm::time_in_ms;
using executorch::runtime::Error;
using executorch::runtime::EValue;
using executorch::runtime::MethodMeta;
using executorch::runtime::Result;

namespace example {

namespace {
static constexpr auto kTopp = 0.9f;
void printReport(const Runner::Stats& stats);
std::string statsToJsonString(const Runner::Stats& stats);
} // namespace

Runner::Runner(
    const std::vector<std::string>& models_path,
    const std::vector<std::string>& pos_embs_path,
    const std::vector<int>& shard_layers,
    const std::string& tokenizer_path,
    const int eval_mode,
    const float temperature,
    const float logits_scale,
    const int logits_offset)
    : tokenizer_path_(tokenizer_path),
      temperature_(temperature),
      n_bos_(1),
      n_eos_(1),
      vocab_size_(QAIHUB_LLAMA_LOGITS),
      max_seq_len_(1024),
      eval_mode_(eval_mode),
      stats_({}),
      logits_scale_(logits_scale),
      logits_offset_(logits_offset) {
  for (size_t i = 0; i < models_path.size(); ++i) {
    modules_.push_back(std::make_shared<Module>(
        models_path[i], Module::LoadMode::MmapUseMlockIgnoreErrors));
    ET_LOG(Info, "creating module: model_path=%s", models_path[i].c_str());
  }
  ET_LOG(Info, "creating runner: tokenizer_path=%s", tokenizer_path_.c_str());

// load tokenizer
#if defined(QAIHUB_LLAMA3_RUNNER)
  tokenizer_ = example::get_tiktoken_for_llama();
  tokenizer_->load(tokenizer_path_);
  eos_id_.insert(tokenizer_->encode("<|eot_id|>", 0, 0).get()[0]);
  version_ = LlamaVersion::kLlama3;
#else
  tokenizer_ = std::make_unique<executorch::extension::llm::BPETokenizer>();
  tokenizer_->load(tokenizer_path_);
  version_ = LlamaVersion::kLlama2;
#endif

  bos_id_ = tokenizer_->bos_tok();
  eos_id_.insert(tokenizer_->eos_tok());

  switch (eval_mode_) {
    case EvalMode::kBert:
      io_mem_ =
          std::make_unique<BertMemory>(pos_embs_path, modules_, shard_layers);
      break;
    case EvalMode::kKVCached:
      io_mem_ = std::make_unique<KVCachedMemory>(
          pos_embs_path, modules_, shard_layers);
      break;
    default:
      ET_CHECK_MSG(false, "unsupported evaluation mode");
  }
  ET_LOG(Info, "creating io_memory");
}

bool Runner::is_loaded() const {
  bool loaded = true;
  for (const std::shared_ptr<Module>& module : modules_) {
    loaded &= module->is_loaded();
  }
  return loaded && tokenizer_ && sampler_;
}

Error Runner::load() {
  if (is_loaded()) {
    return Error::Ok;
  }
  for (std::shared_ptr<Module>& module : modules_) {
    method_names_.emplace_back(*module->method_names()->begin());
    ET_CHECK_OK_OR_RETURN_ERROR(module->load_method(method_names_.back()));
  }

  // create sampler
  sampler_ = std::make_unique<Sampler>(
      vocab_size_,
      temperature_,
      kTopp,
      static_cast<unsigned long long>(std::time(nullptr)));

  // prepare io
  auto methods_meta = get_methods_meta();
  io_mem_->prepare_io(methods_meta);
  return Error::Ok;
}

int32_t Runner::logitsToToken(const Tensor& logits_tensor) {
  static std::vector<float> logits_f(vocab_size_);
  const uint16_t* logits = logits_tensor.data_ptr<uint16_t>();

#if defined(__aarch64__)
  static int32x4_t offset = vmovq_n_s32(logits_offset_);
  static float32x4_t scale = vmovq_n_f32(logits_scale_);
  // dequantize
  for (int i = 0; i < vocab_size_; i += 4) {
    const uint16_t* in = logits + i;
    float* out = logits_f.data() + i;
    int32_t data[4] = {in[0], in[1], in[2], in[3]};
    int32x4_t quantized = vld1q_s32(data);
    int32x4_t shifted = vsubq_s32(quantized, offset);
    float32x4_t shifted_f = vcvtq_f32_s32(shifted);
    vst1q_f32(out, vmulq_f32(shifted_f, scale));
  }
#else
  // dequantize
  for (int i = 0; i < vocab_size_; i++) {
    logits_f[i] = (logits[i] - logits_offset_) * logits_scale_;
  }
#endif

  return sampler_->sample(logits_f.data());
}

void Runner::run_model_step(std::vector<std::vector<EValue>>& inputs) {
  for (size_t i = 0, num_modules = modules_.size(); i < num_modules; ++i) {
    Result<std::vector<EValue>> outputs_res =
        modules_[i]->execute(method_names_[i], inputs[i]);
    ET_CHECK_MSG(
        outputs_res.error() == Error::Ok, "shard %zu inference failed", i);
  }
}

// TODO: add overloaded method for on-device tokenize
Error Runner::generate(
    const std::string& prompt,
    const std::string& system_prompt,
    int32_t seq_len,
    std::function<void(const std::string&)> token_callback,
    std::function<void(const Stats&)> stats_callback) {
  ET_CHECK_MSG(!prompt.empty(), "prompt cannot be null");

  std::vector<std::vector<Tensor>> input_tensors, output_tensors;
  std::vector<std::vector<EValue>> inputs;
  if (!is_loaded()) {
    stats_.model_load_start_ms = time_in_ms();
    ET_CHECK_OK_OR_RETURN_ERROR(load());
    for (int i = 0; i < modules_.size(); ++i) {
      input_tensors.emplace_back(io_mem_->get_input_tensors(i));
      output_tensors.emplace_back(io_mem_->get_output_tensors(i));
      for (size_t j = 0; j < output_tensors[i].size(); ++j) {
        ET_CHECK_MSG(
            modules_[i]->set_output(
                method_names_[i], output_tensors[i][j], j) == Error::Ok,
            "failed to set output tensor for module %d's %zu'th output",
            i,
            j);
      }
      inputs.emplace_back(
          std::vector<EValue>(begin(input_tensors[i]), end(input_tensors[i])));
    }
    stats_.model_load_end_ms = time_in_ms();
  }

  stats_.inference_start_ms = time_in_ms();
  seq_len = (seq_len > 0 && seq_len <= max_seq_len_) ? seq_len : max_seq_len_;

  std::string post_process_prompt;
  switch (version_) {
    case LlamaVersion::kLlama2:
      post_process_prompt.append(prompt);
      break;
    case LlamaVersion::kLlama3:
      if (!system_prompt.empty()) {
        post_process_prompt.append(
            "<|start_header_id|>system<|end_header_id|>\n\n");
        post_process_prompt.append(system_prompt);
        post_process_prompt.append("<|eot_id|>\n");
      }
      post_process_prompt.append(
          "<|start_header_id|>user<|end_header_id|>\n\n");
      post_process_prompt.append(prompt);
      post_process_prompt.append(
          "<|eot_id|><|start_header_id|>assistant<|end_header_id|>");
      // tokenizer_->encode will add <|begin_of_text|> token for us.
      // For now, do token call back so the output format looks the same as
      // llama3 model card.
      if (token_callback && eval_mode_ == EvalMode::kKVCached) {
        token_callback("<|begin_of_text|>");
      }
      break;
    default:
      ET_CHECK_MSG(false, "unsupported llama version");
      break;
  }

  Result<std::vector<uint64_t>> encode_res =
      tokenizer_->encode(post_process_prompt, n_bos_, 0);
  ET_CHECK_OK_OR_RETURN_ERROR(
      encode_res.error(),
      "failed to encode prompt %s",
      post_process_prompt.c_str());

  std::vector<uint64_t> prompt_tokens = encode_res.get();
  int num_prompt_tokens = prompt_tokens.size();
  ET_CHECK_MSG(num_prompt_tokens < max_seq_len_, "max seq length exceeded");
  ET_CHECK_MSG(
      num_prompt_tokens < seq_len,
      "sequence length exceeded - please increase the seq_len value");

  int64_t pos = 0, prev_token, cur_token = prompt_tokens[0];
  if (eval_mode_ == EvalMode::kBert) {
    BertMemory::IO* ptr =
        static_cast<BertMemory::IO*>(io_mem_->get_mutable_ptr());

    int start_index = max_seq_len_ - num_prompt_tokens;
    // indices are filled from behind, take 3 tokens as an example:
    // > tokens : [...tok_pad, tok_bos, tok1, tok2]
    // > indices: [0.....1020, 1021,    1022, 1023]
    for (int i = 0; i < num_prompt_tokens; i++) {
      ptr->input_ids[start_index + i] = static_cast<int32_t>(prompt_tokens[i]);
    }
    // causal attention mask is filled as following:
    // 0, 65535 maps to -100.0, 0.0 after dequantizing
    // 0      : [0,...................0,     0,     0,     0]
    // 1-1019 : ...
    // 1020   : [0,...............65535,     0,     0,     0]
    // 1021   : [0,...............65535, 65535,     0,     0]
    // 1022   : [0,...............65535, 65535, 65535,     0]
    // 1023   : [0,...............65535, 65535, 65535, 65535]
    for (int i = max_seq_len_ - 1, len = num_prompt_tokens; len >= 0;
         --i, --len) {
      for (int j = 0; j <= len; ++j) {
        ptr->attention_mask[i * max_seq_len_ + start_index - 1 + j] = 65535;
      }
    }
    pos = num_prompt_tokens - 1;
    cur_token = prompt_tokens[pos];
  } else if (eval_mode_ == EvalMode::kKVCached) {
    KVCachedMemory::IO* ptr =
        static_cast<KVCachedMemory::IO*>(io_mem_->get_mutable_ptr());
    ptr->input_ids = static_cast<int32_t>(cur_token);
    ptr->attention_mask[max_seq_len_ - 1] = 65535;
  }

  while (pos < seq_len - 1) {
    // inference
    run_model_step(inputs);
    Tensor& logits_tensor = output_tensors.back().back();

    if (pos == num_prompt_tokens) {
      stats_.first_token_ms = time_in_ms();
    } else if (pos == num_prompt_tokens - 1) {
      stats_.prompt_eval_end_ms = time_in_ms();
    }

    long sample_start_time_ms = time_in_ms();
    prev_token = cur_token;
    cur_token = logitsToToken(logits_tensor);
    stats_.aggregate_sampling_time_ms += time_in_ms() - sample_start_time_ms;

    if (pos < num_prompt_tokens - 1) {
      cur_token = prompt_tokens[pos + 1];
    }
    io_mem_->update_io(cur_token, ++pos, output_tensors);

    auto piece_res = tokenizer_->decode(prev_token, cur_token);
    ET_CHECK(piece_res.ok());

    if (token_callback) {
      token_callback(piece_res.get().c_str());
    }

    if (pos >= num_prompt_tokens && eos_id_.count(cur_token) > 0) {
      ET_LOG(Info, "\nReached to the end of generation");
      break;
    }
  }
  stats_.inference_end_ms = time_in_ms();

  if (pos == seq_len) {
    ET_LOG(Info, "\nSequence length (%i tokens) reached!", seq_len);
  }

  stats_.num_prompt_tokens = num_prompt_tokens;
  stats_.num_generated_tokens = pos - num_prompt_tokens;
  printReport(stats_);
  if (stats_callback) {
    stats_callback(stats_);
  }

  return Error::Ok;
}

namespace {
void printReport(const Runner::Stats& stats) {
  printf("PyTorchObserver %s\n", statsToJsonString(stats).c_str());

  ET_LOG(
      Info,
      "\tPrompt Tokens: %" PRIu64 "    Generated Tokens: %" PRIu64,
      stats.num_prompt_tokens,
      stats.num_generated_tokens);

  ET_LOG(
      Info,
      "\tModel Load Time:\t\t%f (seconds)",
      ((double)(stats.model_load_end_ms - stats.model_load_start_ms) /
       stats.SCALING_FACTOR_UNITS_PER_SECOND));
  double inference_time_ms =
      (double)(stats.inference_end_ms - stats.inference_start_ms);
  ET_LOG(
      Info,
      "\tTotal inference time:\t\t%f (seconds)\t\t Rate: \t%f (tokens/second)",
      inference_time_ms / stats.SCALING_FACTOR_UNITS_PER_SECOND,

      (stats.num_generated_tokens) /
          (double)(stats.inference_end_ms - stats.inference_start_ms) *
          stats.SCALING_FACTOR_UNITS_PER_SECOND);
  double prompt_eval_time =
      (double)(stats.prompt_eval_end_ms - stats.inference_start_ms);
  ET_LOG(
      Info,
      "\t\tPrompt evaluation:\t%f (seconds)\t\t Rate: \t%f (tokens/second)",
      prompt_eval_time / stats.SCALING_FACTOR_UNITS_PER_SECOND,
      (stats.num_prompt_tokens) / prompt_eval_time *
          stats.SCALING_FACTOR_UNITS_PER_SECOND);

  double eval_time =
      (double)(stats.inference_end_ms - stats.prompt_eval_end_ms);
  ET_LOG(
      Info,
      "\t\tGenerated %" PRIu64
      " tokens:\t%f (seconds)\t\t Rate: \t%f (tokens/second)",
      stats.num_generated_tokens,
      eval_time / stats.SCALING_FACTOR_UNITS_PER_SECOND,
      stats.num_generated_tokens / eval_time *
          stats.SCALING_FACTOR_UNITS_PER_SECOND);

  // Time to first token is measured from the start of inference, excluding
  // model load time.
  ET_LOG(
      Info,
      "\tTime to first generated token:\t%f (seconds)",
      ((double)(stats.first_token_ms - stats.inference_start_ms) /
       stats.SCALING_FACTOR_UNITS_PER_SECOND));

  ET_LOG(
      Info,
      "\tSampling time over %" PRIu64 " tokens:\t%f (seconds)",
      stats.num_prompt_tokens + stats.num_generated_tokens,
      (double)stats.aggregate_sampling_time_ms /
          stats.SCALING_FACTOR_UNITS_PER_SECOND);
}

std::string statsToJsonString(const Runner::Stats& stats) {
  std::stringstream ss;
  ss << "{\"prompt_tokens\":" << stats.num_prompt_tokens << ","
     << "\"generated_tokens\":" << stats.num_generated_tokens << ","
     << "\"model_load_start_ms\":" << stats.model_load_start_ms << ","
     << "\"model_load_end_ms\":" << stats.model_load_end_ms << ","
     << "\"inference_start_ms\":" << stats.inference_start_ms << ","
     << "\"inference_end_ms\":" << stats.inference_end_ms << ","
     << "\"prompt_eval_end_ms\":" << stats.prompt_eval_end_ms << ","
     << "\"first_token_ms\":" << stats.first_token_ms << ","
     << "\"aggregate_sampling_time_ms\":" << stats.aggregate_sampling_time_ms
     << "," << "\"SCALING_FACTOR_UNITS_PER_SECOND\":"
     << stats.SCALING_FACTOR_UNITS_PER_SECOND << "}";
  return ss.str();
}
} // namespace

std::vector<Result<MethodMeta>> Runner::get_methods_meta() {
  std::vector<Result<MethodMeta>> methods_meta;
  methods_meta.reserve(modules_.size());
  for (size_t i = 0; i < modules_.size(); ++i) {
    methods_meta.emplace_back(modules_[i]->method_meta(method_names_[i]));
  }
  return methods_meta;
}
} // namespace example