# coding=utf-8
# Copyright (c) 2024, MeetKai Inc. All rights reserved.
"""PyTorch LLaMA model."""

import json
from typing import TYPE_CHECKING, Callable, List, Optional, Tuple, Union

import torch
import torch.utils.checkpoint

from transformers.generation.configuration_utils import GenerationConfig
from transformers.generation.logits_process import LogitsProcessorList
from transformers.generation.stopping_criteria import StoppingCriteriaList
from transformers.generation.utils import (
    GenerateBeamDecoderOnlyOutput,
    GenerateBeamEncoderDecoderOutput,
    GenerateDecoderOnlyOutput,
    GenerateEncoderDecoderOutput
)
from transformers.models.llama.modeling_llama import LlamaForCausalLM
from transformers.utils import logging


if TYPE_CHECKING:
    from transformers.modeling_utils import PreTrainedModel
    from transformers.generation.streamers import BaseStreamer

logger = logging.get_logger(__name__)

GenerateNonBeamOutput = Union[GenerateDecoderOnlyOutput, GenerateEncoderDecoderOutput]
GenerateBeamOutput = Union[GenerateBeamDecoderOnlyOutput, GenerateBeamEncoderDecoderOutput]
GenerateOutput = Union[GenerateNonBeamOutput, GenerateBeamOutput]


class FunctionaryForCausalLM(LlamaForCausalLM):

    def generate_tool_use(
        self,
        inputs: Optional[torch.Tensor] = None,
        generation_config: Optional[GenerationConfig] = None,
        logits_processor: Optional[LogitsProcessorList] = None,
        stopping_criteria: Optional[StoppingCriteriaList] = None,
        prefix_allowed_tokens_fn: Optional[Callable[[int, torch.Tensor], List[int]]] = None,
        synced_gpus: Optional[bool] = None,
        assistant_model: Optional["PreTrainedModel"] = None,
        streamer: Optional["BaseStreamer"] = None,
        negative_prompt_ids: Optional[torch.Tensor] = None,
        negative_prompt_attention_mask: Optional[torch.Tensor] = None,
        **kwargs,
    ) -> Union[GenerateOutput, torch.LongTensor]:

        tokenizer = kwargs.pop("tokenizer", None)  # Pull this out first, we use it to parse raw output

        results = self.generate(
            inputs=inputs,
            generation_config=generation_config,
            logits_processor=logits_processor,
            stopping_criteria=stopping_criteria,
            prefix_allowed_tokens_fn=prefix_allowed_tokens_fn,
            synced_gpus=synced_gpus,
            assistant_model=assistant_model,
            streamer=streamer,
            negative_prompt_ids=negative_prompt_ids,
            negative_prompt_attention_mask=negative_prompt_attention_mask,
            **kwargs,
        )

        input_ids = kwargs.pop("input_ids")
        function_call_token = "<function="
        
        correct_results = []
        for input_id, result in zip(input_ids, results):
            final_output_json = {"role": "assistant", "content": None, "tool_calls": None}
            tool_calls = []
            raw_output_str = tokenizer.decode(result[len(input_id):].cpu())
            has_text = False if raw_output_str.startswith(function_call_token) else True
            chunks = raw_output_str.split(function_call_token)
            for i, chunk in enumerate(chunks):
                if len(chunk) == 0:
                    continue

                chunk = chunk.replace(tokenizer.pad_token, "")

                if i == 0 and has_text is not False:
                    final_output_json["content"] = chunk.removesuffix("<|eom_id|>").removesuffix("<|eot_id|>")
                else:
                    tool_calls.append(
                        {
                            "name": chunk[: chunk.index(">{")],
                            "arguments": chunk[chunk.index(">{") + 1: ].removesuffix("<|eom_id|>").removesuffix("</function>")
                        }
                    )
            if len(tool_calls) > 0:
                final_output_json["tool_calls"] = tool_calls
            final_output_str = json.dumps(final_output_json, indent=4)
            final_output_ids = tokenizer(final_output_str, add_special_tokens=False)["input_ids"]
            correct_results.append(
                torch.cat(
                    (result[:len(input_id)].cpu(), torch.tensor(final_output_ids))
                )
            )
        max_len = max([tensor.shape[0] for tensor in correct_results])
        correct_results = [
            torch.nn.functional.pad(
                correct_result, (0, max_len - correct_result.shape[0]), value=tokenizer.eos_token_id
            ) for correct_result in correct_results
        ]
        correct_results = torch.stack(correct_results)
        
        return correct_results