from collections import Counter
from typing import Callable, Any, Optional
import dsp
from dsp.utils import zipstar, normalize_text
from dsp.primitives.inspect import FuncInspector
from dsp.utils.utils import dotdict
from dsp.templates.template_v3 import Template
from dsp.primitives.demonstrate import Example


# NOTE: Truncation code start
import tiktoken

# NOTE: Truncation code end


class Completions:
    """A state object that holds the valid LM completions for a given Template."""

    def __init__(self, completions: list[Example], template: Template):
        self.data = completions
        self.template = template

    def __iter__(self):
        return self.data.__iter__()

    def __getitem__(self, item):
        return self.data[item]

    def __len__(self):
        return len(self.data)

    def unpack(self, key=None):
        if key:
            return [getattr(c, key) for c in self.data]

        return zipstar(self.data)

    def __getattr__(self, name):
        assert len(self.data) == 1

        completion = self.data[0]

        if name in completion.keys():
            return getattr(completion, name)

        if name.endswith("s") and name[:-1] in completion.keys():
            pass

        assert False, name


def generate(
    template: Template, model_name, max_prompt_length, max_gen_length, **kwargs
) -> Callable:
    """Returns a callable function that generates completions for a given example using the provided template."""
    if hasattr(dsp.settings, "inspect"):
        inspector = dsp.settings.inspect
        _generate = inspector.inspect_func(dsp.predict._generate)
        return _generate(template, **kwargs)
    else:
        return dsp.predict._generate(
            template, model_name, max_prompt_length, max_gen_length, **kwargs
        )


def _generate(
    template: Template, model_name, max_prompt_length, max_gen_length, **kwargs
) -> Callable:
    """Returns a callable function that generates completions for a given example using the provided template."""
    if not dsp.settings.lm:
        raise AssertionError("No LM is loaded.")

    generator = dsp.settings.lm

    # NOTE: Truncation code start
    enc = tiktoken.encoding_for_model(model_name)
    # NOTE: Truncation code end

    def do_generate(
        example: Example, stage: str, max_depth: int = 2, original_example=None
    ):
        if not dsp.settings.lm:
            raise AssertionError("No LM is loaded.")
        original_example = original_example or example
        assert stage is not None

        # Look up the appropriate fields in each demonstration.
        example = example.demos_at(lambda d: d[stage])

        # Generate and extract the fields.
        prompt = template(example)

        # NOTE: Truncation code start
        prompt_without_answer = prompt.strip("\nAnswer:")
        prompt_tokenized = enc.encode(prompt_without_answer)
        chat_penalty = 8 if dsp.settings.lm.model_type == "chat" else 0
        prompt_truncated = prompt_tokenized[
            : max_prompt_length
            - len(enc.encode("\nAnswer:"))
            - max_gen_length
            - chat_penalty
        ]
        prompt_truncated_with_answer = enc.decode(prompt_truncated) + "\nAnswer:"
        prompt = prompt_truncated_with_answer
        # NOTE: Truncation code end

        completions: list[dict[str, Any]] = generator(prompt, **kwargs)
        completions: list[Example] = [template.extract(example, p) for p in completions]

        # Find the completions that are most complete.
        field_names: list[str] = [field.input_variable for field in template.fields]

        last_field_idx = 0
        for field_idx, key in enumerate(field_names):
            completions_ = [
                c for c in completions if key in c.keys() and c[key] is not None
            ]

            # Filter out completions that are missing fields that are present in at least one completion.
            if len(completions_):
                completions = completions_
                last_field_idx = field_idx + 1

        # If none of the completions is completed (i.e., none has the final field set).
        if last_field_idx < len(field_names):
            # Pick the first completion that has gone farthest.
            completion = completions[0]
            completion[field_names[last_field_idx]] = ""

            # Recurse with greedy decoding and a shorter length.
            max_tokens = kwargs.get("max_tokens", dsp.settings.lm.kwargs["max_tokens"])
            max_tokens = min(max(75, max_tokens // 2), max_tokens)
            new_kwargs = {
                **kwargs,
                "max_tokens": max_tokens,
                "n": 1,
                "temperature": 0.0,
            }

            assert max_depth > 0
            return generate(template, **new_kwargs)(
                completion,
                stage=stage,
                max_depth=max_depth - 1,
                original_example=original_example,
            )

        completions = Completions(completions, template=template)
        example = example.copy(completions=completions)

        if len(completions) == 1:
            completion = completions[0]
            example[stage] = example.copy(**completion)

            if dsp.settings.compiling:
                inputs_ = set(original_example.keys())
                inputs = [
                    f.input_variable
                    for f in template.fields
                    if f.input_variable in inputs_
                ]
                outputs = [
                    f.output_variable
                    for f in template.fields
                    if f.input_variable not in inputs_
                ]

                example.compiling_stages = example.get("compiling_stages", [])
                example.compiling_stages.append(
                    {
                        "name": stage,
                        "template": template,
                        "inputs": inputs,
                        "outputs": outputs,
                    }
                )
        else:
            # assert not dsp.settings.compiling, "TODO: At this point, cannot compile n>1 generations"
            example[stage] = dotdict(completions=completions)

        return example, completions

    return do_generate


def generate_sc(
    example, prompt, normalize=True, extract=None, prediction_field=None, **kwargs
):
    if not dsp.settings.lm:
        raise AssertionError("No LM is loaded.")
    kwargs = {"temperature": 0.7, "n": 20, "max_tokens": 150, **kwargs}

    completions = dsp.settings.lm(prompt, **kwargs)
    completions = extract_final_answer(example, completions, extract=extract)
    return majority_vote_(
        completions, normalize=normalize, prediction_field=prediction_field
    )


def extract_final_answer(example, completions, extract=None):
    if not dsp.settings.lm:
        raise AssertionError("No LM is loaded.")
    if extract:
        completions = [extract(example, p) for p in completions]
    else:
        completions = [
            p.strip().split("\n")[-1].split(":", 1)[-1].strip() for p in completions
        ]

    dsp.settings.lm.history.append(
        {**dsp.settings.lm.history[-1], "completions": completions}
    )

    return completions


def majority(
    completions: Completions, normalize: bool = True, field: Optional[str] = None
):
    """Returns the most common completion for the target field or the last field in the template."""
    field = completions.template.fields[-1].output_variable if field is None else field

    return Completions(
        majority_vote_(completions, normalize=normalize, prediction_field=field),
        template=completions.template,
    )


def majority_vote_(completions: Completions, normalize: bool, prediction_field: str):
    """Core logic for majority vote."""

    if not dsp.settings.lm:
        raise AssertionError("No LM is loaded.")

    normalized_to_original = {}
    if normalize:
        original_completions = completions
        completions_ = []
        for pred in completions:
            if prediction_field in pred:
                completions_.append(normalize_text(pred[prediction_field]))
            else:
                completions_.append("")
        completions = completions_

        for completion, normalized_completion in zip(original_completions, completions):
            if normalized_completion not in normalized_to_original:
                normalized_to_original[normalized_completion] = completion

    completions_ = [x for x in completions if x]

    if completions_:
        completions = completions_

    topk = Counter(completions).most_common()
    pred, _ = topk[0]

    if normalize:
        pred = normalized_to_original[pred]

    dsp.settings.lm.history.append(
        {**dsp.settings.lm.history[-1], "topk": topk, "completions": [pred]}
    )

    return [pred]
