import torch
import tqdm
import json
import time
import asyncio
import os
from importlib import import_module
from transformers import StoppingCriteria
from minimal_multitask.eval.dispatch_openai_requests import (
    dispatch_openai_chat_requesets,
    dispatch_openai_prompt_requesets,
)


class KeyWordsCriteria(StoppingCriteria):
    def __init__(self, stop_id_sequences):
        assert isinstance(stop_id_sequences[0], list), "stop_id_sequences should be a list of list of ids"
        self.stop_sequences = stop_id_sequences

    def __call__(self, input_ids: torch.LongTensor, scores: torch.FloatTensor, **kwargs) -> bool:
        sequences_should_be_stopped = []
        for i in range(input_ids.shape[0]):
            sequence_should_be_stopped = False
            for stop_sequence in self.stop_sequences:
                if input_ids[i][-len(stop_sequence):].tolist() == stop_sequence:
                    sequence_should_be_stopped = True
                    break
            sequences_should_be_stopped.append(sequence_should_be_stopped)
        return all(sequences_should_be_stopped)


@torch.no_grad()
def generate_completions(
    model,
    tokenizer,
    prompts,
    batch_size=1,
    stop_id_sequences=None,
    add_special_tokens=True,
    disable_tqdm=False,
    **generation_kwargs,
):
    generations = []
    if not disable_tqdm:
        progress = tqdm.tqdm(total=len(prompts), desc="Generating Completions")

    num_return_sequences = generation_kwargs.get("num_return_sequences", 1)
    for i in range(0, len(prompts), batch_size):
        batch_prompts = prompts[i: i + batch_size]
        tokenized_prompts = tokenizer(
            batch_prompts, padding="longest", return_tensors="pt", add_special_tokens=add_special_tokens
        )
        batch_input_ids = tokenized_prompts.input_ids
        attention_mask = tokenized_prompts.attention_mask
        if model.device.type == "cuda":
            batch_input_ids = batch_input_ids.cuda()
            attention_mask = attention_mask.cuda()

        try:
            batch_outputs = model.generate(
                input_ids=batch_input_ids,
                attention_mask=attention_mask,
                eos_token_id=tokenizer.eos_token_id,
                stopping_criteria=[KeyWordsCriteria(stop_id_sequences)] if stop_id_sequences else None,
                **generation_kwargs,
            )

            # the stopping criteria is applied at batch level, so if other examples are not stopped, the entire batch will continue to generate.
            # so some outputs still have the stop sequence, which we need to remove.
            if stop_id_sequences:
                for output_idx in range(batch_outputs.shape[0]):
                    for token_idx in range(batch_input_ids.shape[1], batch_outputs.shape[1]):
                        if any(
                            batch_outputs[output_idx, token_idx: token_idx + len(stop_sequence)].tolist()
                            == stop_sequence
                            for stop_sequence in stop_id_sequences
                        ):
                            batch_outputs[output_idx, token_idx:] = tokenizer.pad_token_id
                            break

            # remove the prompt from the output
            # we need to re-encode the prompt because we need to make sure the special tokens are treated the same way as in the outputs.
            # we changed our previous way of truncating the output token ids dicrectly because some tokenizer (e.g., llama) won't add space token before the first token.
            # space is important for some tasks (e.g., code completion).
            batch_outputs = tokenizer.batch_decode(batch_outputs, skip_special_tokens=True)
            batch_prompts = tokenizer.batch_decode(batch_input_ids, skip_special_tokens=True)
            # duplicate the prompts to match the number of return sequences
            batch_prompts = [prompt for prompt in batch_prompts for _ in range(num_return_sequences)]
            batch_generations = [output[len(prompt):] for prompt, output in zip(batch_prompts, batch_outputs)]
        except Exception as e:
            print("Error when generating completions for batch:")
            print(batch_prompts)
            print("Error message:")
            print(e)
            print("Use empty string as the completion.")
            batch_generations = [""] * len(batch_prompts) * num_return_sequences

        generations += batch_generations

        # for prompt, generation in zip(batch_prompts, batch_generations):
        #     print("========")
        #     print(prompt)
        #     print("--------")
        #     print(generation)

        if not disable_tqdm:
            progress.update(len(batch_prompts) // num_return_sequences)

    assert (
        len(generations) == len(prompts) * num_return_sequences
    ), "number of generations should be equal to number of prompts * num_return_sequences"
    return generations


@torch.no_grad()
def get_next_word_predictions(
    model,
    tokenizer,
    prompts,
    candidate_token_ids=None,
    batch_size=1,
    return_token_predictions=False,
    add_special_tokens=True,
    disable_tqdm=False,
):
    predictions, probs = [], []
    if not disable_tqdm:
        progress = tqdm.tqdm(total=len(prompts), desc="Getting Predictions")

    for i in range(0, len(prompts), batch_size):
        batch_prompts = prompts[i: i + batch_size]
        tokenized_prompts = tokenizer(
            batch_prompts, padding="longest", return_tensors="pt", add_special_tokens=add_special_tokens
        )
        batch_input_ids = tokenized_prompts.input_ids
        attention_mask = tokenized_prompts.attention_mask

        if model.device.type == "cuda":
            batch_input_ids = batch_input_ids.cuda()
            attention_mask = attention_mask.cuda()

        batch_logits = model(input_ids=batch_input_ids, attention_mask=attention_mask).logits[:, -1, :]
        batch_probs = torch.softmax(batch_logits, dim=-1)
        if candidate_token_ids is not None:
            batch_probs = batch_probs[:, candidate_token_ids]
        batch_prediction_indices = torch.argmax(batch_probs, dim=-1)
        if return_token_predictions:
            if candidate_token_ids is not None:
                candidate_tokens = tokenizer.convert_ids_to_tokens(candidate_token_ids)
                batch_predictions = [candidate_tokens[idx] for idx in batch_prediction_indices]
            else:
                batch_predictions = tokenizer.convert_ids_to_tokens(batch_prediction_indices)
            predictions += batch_predictions
        else:
            predictions += batch_prediction_indices.tolist()
        probs += batch_probs.tolist()

        if not disable_tqdm:
            progress.update(len(batch_prompts))

    assert len(predictions) == len(prompts), "number of predictions should be equal to number of prompts"
    return predictions, probs


@torch.no_grad()
def score_completions(model, tokenizer, scoring_examples, batch_size=1, aggregation="sum", disable_tqdm=False):
    """
    Each scoring example is a dict, which contains the following keys:
    - prompt: the prompt to score
    - completions: a list of completions to score
    """

    # unroll the scoring examples
    unrolled_examples = []
    for scoring_example in scoring_examples:
        prompt = scoring_example["prompt"]
        for completion in scoring_example["completions"]:
            unrolled_examples.append({"prompt": prompt, "completion": completion})

    if not disable_tqdm:
        progress = tqdm.tqdm(total=len(unrolled_examples), desc="Scoring Completions")

    scores = []
    for i in range(0, len(unrolled_examples), batch_size):
        batch_prompts = [example["prompt"] for example in unrolled_examples[i: i + batch_size]]
        batch_examples = [
            (example["prompt"] if example["prompt"][-1] in ["\n", " "] else example["prompt"] + " ")
            + example["completion"]
            for example in unrolled_examples[i: i + batch_size]
        ]
        tokenized_batch = tokenizer(batch_examples, padding="longest", return_tensors="pt")
        if model.device.type == "cuda":
            tokenized_batch = {key: value.cuda() for key, value in tokenized_batch.items()}
        tokenized_batch.pop("token_type_ids", None)
        outputs = model(**tokenized_batch)

        for example_idx, (prompt, example) in enumerate(zip(batch_prompts, batch_examples)):
            tokenized_prompt = tokenizer(prompt, padding=False, return_tensors="pt").input_ids.squeeze(0)
            tokenized_example = tokenizer(example, padding=False, return_tensors="pt").input_ids.squeeze(0)
            completion_ids = tokenized_example[len(tokenized_prompt):]

            # get the logits for the entire example, removing the padding logits
            if tokenizer.padding_side == "right":
                example_logits = outputs.logits[example_idx, : len(tokenized_example), :]
            else:
                example_logits = outputs.logits[example_idx, -len(tokenized_example):, :]

            # get the logits for the completion portion - note we need to shift the index left by 1 because logits are computed for the next token
            completion_logits = example_logits[len(tokenized_prompt) - 1: len(tokenized_example) - 1, :]
            completion_log_probs = torch.log_softmax(completion_logits, dim=-1)[
                range(len(completion_ids)), completion_ids
            ]

            if aggregation == "sum":
                score = completion_log_probs.sum().item()
            elif aggregation == "mean":
                score = completion_log_probs.mean().item()
            elif aggregation == "max":
                score = completion_log_probs.max().item()
            else:
                raise ValueError("Invalid aggregation method: {}".format(aggregation))
            scores.append(score)

        if not disable_tqdm:
            progress.update(len(batch_examples))

    # roll up the scores
    rolled_up_scores = {}
    for unrolled_example, score in zip(unrolled_examples, scores):
        prompt = unrolled_example["prompt"]
        completion = unrolled_example["completion"]
        if prompt not in rolled_up_scores:
            rolled_up_scores[prompt] = {}
        rolled_up_scores[prompt][completion] = score

    return rolled_up_scores


def load_hf_lm(
    model_name_or_path,
    device_map="auto",
    torch_dtype="auto",
    load_in_8bit=False,
    convert_to_half=False,
    gptq_model=False,
    token=os.getenv("HF_TOKEN", None),
):
    # Loading OLMo models from HF requires `trust_remote_code=True`.
    # TODO: Implement this via command-line flag rather than hardcoded list.
    trusted_models = ["allenai/OLMo-7B", "allenai/OLMo-7B-Twin-2T", "allenai/OLMo-1B"]
    if model_name_or_path in trusted_models:
        trust_remote_code = True
    else:
        trust_remote_code = False

    from transformers import AutoModelForCausalLM

    if gptq_model:
        from auto_gptq import AutoGPTQForCausalLM

        model_wrapper = AutoGPTQForCausalLM.from_quantized(
            model_name_or_path, device="cuda:0", use_triton=True, trust_remote_code=trust_remote_code
        )
        model = model_wrapper.model
    elif load_in_8bit:
        model = AutoModelForCausalLM.from_pretrained(
            model_name_or_path,
            device_map=device_map,
            load_in_8bit=True,
            token=token,
            trust_remote_code=trust_remote_code,
        )
    else:
        if device_map:
            model = AutoModelForCausalLM.from_pretrained(
                model_name_or_path,
                device_map=device_map,
                torch_dtype=torch_dtype,
                token=token,
                trust_remote_code=trust_remote_code,
            )
        else:
            model = AutoModelForCausalLM.from_pretrained(
                model_name_or_path,
                torch_dtype=torch_dtype,
                token=token,
                trust_remote_code=trust_remote_code,
            )
            if torch.cuda.is_available():
                model = model.cuda()
        if convert_to_half:
            model = model.half()
    model.eval()
    return model


def load_hf_tokenizer(
    model_name_or_path,
    tokenizer_name_or_path=None,
    use_fast_tokenizer=True,
    padding_side="left",
    token=os.getenv("HF_TOKEN", None),
):
    from transformers import AutoTokenizer

    if not tokenizer_name_or_path:
        tokenizer_name_or_path = model_name_or_path
    try:
        tokenizer = AutoTokenizer.from_pretrained(tokenizer_name_or_path, use_fast=use_fast_tokenizer, token=token)
    except:  # noqa: E722
        # some tokenizers (e.g., GPTNeoXTokenizer) don't have the slow or fast version, so we just roll back to the default one
        tokenizer = AutoTokenizer.from_pretrained(tokenizer_name_or_path, token=token)
    # set padding side to left for batch generation
    tokenizer.padding_side = padding_side
    # set pad token to eos token if pad token is not set (as is the case for llama models)
    if tokenizer.pad_token is None:
        tokenizer.pad_token = tokenizer.eos_token
        tokenizer.pad_token_id = tokenizer.eos_token_id
    return tokenizer


def load_hf_lm_and_tokenizer(
    model_name_or_path,
    tokenizer_name_or_path=None,
    device_map="auto",
    torch_dtype="auto",
    load_in_8bit=False,
    convert_to_half=False,
    gptq_model=False,
    padding_side="left",
    use_fast_tokenizer=True,
    token=os.getenv("HF_TOKEN", None),
):
    tokenizer = load_hf_tokenizer(
        model_name_or_path=model_name_or_path,
        tokenizer_name_or_path=tokenizer_name_or_path,
        use_fast_tokenizer=use_fast_tokenizer,
        padding_side=padding_side,
        token=token,
    )
    model = load_hf_lm(
        model_name_or_path=model_name_or_path,
        device_map=device_map,
        torch_dtype=torch_dtype,
        load_in_8bit=load_in_8bit,
        convert_to_half=convert_to_half,
        gptq_model=gptq_model,
        token=token,
    )
    from transformers import GPTNeoXForCausalLM, OPTForCausalLM

    if isinstance(model, GPTNeoXForCausalLM) or isinstance(model, OPTForCausalLM):
        tokenizer.model_max_length = model.config.max_position_embeddings
        print(
            "Set tokenizer.model_max_length to model.config.max_position_embeddings: {}".format(
                model.config.max_position_embeddings
            )
        )
    return model, tokenizer


def query_openai_chat_model(
    engine, instances, output_path=None, batch_size=10, retry_limit=5, reuse_existing_outputs=True, **completion_kwargs
):
    """
    Query OpenAI chat model and save the results to output_path.
    `instances` is a list of dictionaries, each dictionary contains a key "prompt" and a key "id".
    """
    existing_data = {}
    if reuse_existing_outputs and output_path is not None and os.path.exists(output_path):
        with open(output_path, "r") as f:
            for line in f:
                instance = json.loads(line)
                existing_data[instance["id"]] = instance

    # by default, we use temperature 0.0 to get the most likely completion.
    if "temperature" not in completion_kwargs:
        completion_kwargs["temperature"] = 0.0

    results = []
    if output_path is not None:
        fout = open(output_path, "w")

    retry_count = 0
    progress_bar = tqdm.tqdm(total=len(instances))
    for i in range(0, len(instances), batch_size):
        batch = instances[i: i + batch_size]
        if all([x["id"] in existing_data for x in batch]):
            results.extend([existing_data[x["id"]] for x in batch])
            if output_path is not None:
                for instance in batch:
                    fout.write(json.dumps(existing_data[instance["id"]]) + "\n")
                    fout.flush()
            progress_bar.update(batch_size)
            continue
        messages_list = []
        for instance in batch:
            messages = [{"role": "user", "content": instance["prompt"]}]
            messages_list.append(messages)
        while retry_count < retry_limit:
            try:
                outputs = asyncio.run(
                    dispatch_openai_chat_requesets(
                        messages_list=messages_list,
                        model=engine,
                        **completion_kwargs,
                    )
                )
                retry_count = 0
                break
            except Exception as e:
                retry_count += 1
                print("Error while requesting OpenAI API.")
                print(e)
                print(f"Sleep for {30*retry_count} seconds.")
                time.sleep(30 * retry_count)
                print(f"Retry for the {retry_count} time.")
        if retry_count == retry_limit:
            raise RuntimeError(f"Failed to get response from OpenAI API after {retry_limit} retries.")
        assert len(outputs) == len(batch)
        for instance, output in zip(batch, outputs):
            instance["output"] = output["choices"][0]["message"]["content"]
            instance["response_metadata"] = output
            results.append(instance)
            if output_path is not None:
                fout.write(json.dumps(instance) + "\n")
                fout.flush()
        progress_bar.update(batch_size)
    return results


def query_openai_model(
    engine, instances, output_path=None, batch_size=10, retry_limit=5, reuse_existing_outputs=True, **completion_kwargs
):
    """
    Query OpenAI chat model and save the results to output_path.
    `instances` is a list of dictionaries, each dictionary contains a key "prompt" and a key "id".
    """
    existing_data = {}
    if reuse_existing_outputs and output_path is not None and os.path.exists(output_path):
        with open(output_path, "r") as f:
            for line in f:
                instance = json.loads(line)
                existing_data[instance["id"]] = instance

    # by default, we use temperature 0.0 to get the most likely completion.
    if "temperature" not in completion_kwargs:
        completion_kwargs["temperature"] = 0.0

    results = []
    if output_path is not None:
        fout = open(output_path, "w")

    retry_count = 0
    progress_bar = tqdm.tqdm(total=len(instances))
    for i in range(0, len(instances), batch_size):
        batch = instances[i: i + batch_size]
        if all([x["id"] in existing_data for x in batch]):
            results.extend([existing_data[x["id"]] for x in batch])
            if output_path is not None:
                for instance in batch:
                    fout.write(json.dumps(existing_data[instance["id"]]) + "\n")
                    fout.flush()
            progress_bar.update(batch_size)
            continue
        messages_list = []
        for instance in batch:
            messages = instance["prompt"]
            messages_list.append(messages)
        while retry_count < retry_limit:
            try:
                outputs = asyncio.run(
                    dispatch_openai_prompt_requesets(
                        prompt_list=messages_list,
                        model=engine,
                        **completion_kwargs,
                    )
                )
                retry_count = 0
                break
            except Exception as e:
                retry_count += 1
                print("Error while requesting OpenAI API.")
                print(e)
                print(f"Sleep for {30*retry_count} seconds.")
                time.sleep(30 * retry_count)
                print(f"Retry for the {retry_count} time.")
        if retry_count == retry_limit:
            raise RuntimeError(f"Failed to get response from OpenAI API after {retry_limit} retries.")
        assert len(outputs) == len(batch)
        for instance, output in zip(batch, outputs):
            instance["output"] = output["choices"][0]["text"]
            instance["response_metadata"] = output
            results.append(instance)
            if output_path is not None:
                fout.write(json.dumps(instance) + "\n")
                fout.flush()
        progress_bar.update(batch_size)
    return results


def dynamic_import_function(function_path):
    """
    Dynamically import a function from a path string (e.g., "module.submodule.my_function")
    """
    module_path, function_name = function_path.rsplit(".", 1)
    module = import_module(module_path)
    function = getattr(module, function_name)
    return function
