"""Additional Utility Metrics"""

import logging
from typing import Any, Dict, List, Optional

import numpy as np
import torch
from sklearn.metrics import mean_absolute_error, mean_squared_error, r2_score

logger = logging.getLogger(__name__)


def compute_all_metrics(
    predictions: np.ndarray,
    references: np.ndarray,
    task: str = "classification",
) -> Dict[str, float]:
    """Compute comprehensive metrics based on task type."""
    if task == "classification":
        return compute_classification_metrics(predictions, references)
    elif task == "regression":
        return compute_regression_metrics(predictions, references)
    elif task == "code_generation":
        return compute_code_metrics(predictions, references)
    elif task == "reasoning":
        return compute_reasoning_metrics(predictions, references)
    else:
        raise ValueError(f"Unknown task: {task}")


def compute_classification_metrics(
    predictions: np.ndarray,
    references: np.ndarray,
    average: str = "macro",
) -> Dict[str, float]:
    """Compute classification metrics."""
    from sklearn.metrics import accuracy_score, f1_score, precision_score, recall_score

    accuracy = accuracy_score(references, predictions)
    f1 = f1_score(references, predictions, average=average, zero_division=0)
    precision = precision_score(references, predictions, average=average, zero_division=0)
    recall = recall_score(references, predictions, average=average, zero_division=0)

    return {
        "accuracy": accuracy,
        "f1": f1,
        "precision": precision,
        "recall": recall,
    }


def compute_regression_metrics(
    predictions: np.ndarray,
    references: np.ndarray,
) -> Dict[str, float]:
    """Compute regression metrics."""
    mae = mean_absolute_error(references, predictions)
    mse = mean_squared_error(references, predictions)
    rmse = np.sqrt(mse)
    r2 = r2_score(references, predictions)

    return {
        "mae": mae,
        "mse": mse,
        "rmse": rmse,
        "r2": r2,
    }


def compute_code_metrics(
    predictions: List[str],
    references: List[str],
) -> Dict[str, float]:
    """Compute code generation metrics."""
    # Exact match
    exact_matches = sum(p.strip() == r.strip() for p, r in zip(predictions, references))
    exact_match_rate = exact_matches / len(predictions) if predictions else 0.0

    # BLEU score (simplified)
    try:
        from nltk.translate.bleu_score import corpus_bleu

        # Tokenize
        pred_tokens = [p.split() for p in predictions]
        ref_tokens = [[r.split()] for r in references]

        bleu = corpus_bleu(ref_tokens, pred_tokens)
    except ImportError:
        bleu = 0.0

    return {
        "exact_match": exact_match_rate,
        "bleu": bleu,
    }


def compute_reasoning_metrics(
    predictions: List[str],
    references: List[str],
    steps_predictions: Optional[List[List[str]]] = None,
    steps_references: Optional[List[List[str]]] = None,
) -> Dict[str, float]:
    """Compute reasoning-specific metrics."""
    # Exact match
    exact_matches = sum(p.strip() == r.strip() for p, r in zip(predictions, references))
    exact_match_rate = exact_matches / len(predictions) if predictions else 0.0

    # Step-level accuracy if available
    step_accuracy = 0.0
    if steps_predictions and steps_references:
        step_scores = []
        for pred_steps, ref_steps in zip(steps_predictions, steps_references):
            # Jaccard similarity
            pred_set = set(pred_steps)
            ref_set = set(ref_steps)
            if ref_set:
                intersection = pred_set & ref_set
                union = pred_set | ref_set
                step_scores.append(len(intersection) / len(union))
        if step_scores:
            step_accuracy = np.mean(step_scores)

    return {
        "exact_match": exact_match_rate,
        "step_accuracy": step_accuracy,
    }


def compute_perplexity_from_loss(loss: float) -> float:
    """Convert loss to perplexity."""
    return float(torch.exp(torch.tensor(loss)).item())


def compute_parameter_count(model: torch.nn.Module) -> Dict[str, int]:
    """Count parameters by type."""
    total_params = sum(p.numel() for p in model.parameters())
    trainable_params = sum(p.numel() for p in model.parameters() if p.requires_grad)

    # Count by module type
    module_counts = {}
    for name, module in model.named_modules():
        module_type = type(module).__name__
        if module_type not in module_counts:
            module_counts[module_type] = 0
        module_counts[module_type] += sum(p.numel() for p in module.parameters())

    return {
        "total": total_params,
        "trainable": trainable_params,
        "frozen": total_params - trainable_params,
        "by_module": module_counts,
    }


def compute_flops(
    model: torch.nn.Module,
    input_shape: tuple,
    forward_pass: bool = True,
) -> Dict[str, float]:
    """Estimate FLOPs for a forward pass."""
    # Simplified FLOPs estimation
    # For transformer: 6 * batch_size * seq_len * d_model^2 per layer (approx)
    total_params = sum(p.numel() for p in model.parameters())

    # Rough estimate: 2 * params per token
    batch_size, seq_len = input_shape[0], input_shape[1]
    flops_per_token = 2 * total_params
    total_flops = flops_per_token * seq_len * batch_size

    return {
        "total_flops": total_flops,
        "flops_per_token": flops_per_token,
        "gflops": total_flops / 1e9,
    }


def compute_memory_usage(
    model: torch.nn.Module,
    batch_size: int,
    seq_len: int,
    dtype: str = "bfloat16",
) -> Dict[str, float]:
    """Estimate memory usage."""
    # Parameter memory
    param_bytes = {
        "float32": 4,
        "float16": 2,
        "bfloat16": 2,
        "int8": 1,
        "int4": 0.5,
    }[dtype]

    param_memory = sum(p.numel() for p in model.parameters()) * param_bytes / 1e9  # GB

    # Activation memory (rough estimate: batch_size * seq_len * d_model * 2 * num_layers)
    # Assuming 2x for activations
    d_model = getattr(model.config, "d_model", 2048)
    num_layers = getattr(model.config, "num_hidden_layers", 24)
    activation_memory = batch_size * seq_len * d_model * 2 * num_layers * param_bytes / 1e9

    # Gradient memory (same as parameters if not using gradient checkpointing)
    gradient_memory = param_memory

    total_memory = param_memory + activation_memory + gradient_memory

    return {
        "parameters_gb": param_memory,
        "activations_gb": activation_memory,
        "gradients_gb": gradient_memory,
        "total_gb": total_memory,
    }


def track_gradient_norms(
    model: torch.nn.Module,
    norm_type: float = 2.0,
) -> Dict[str, float]:
    """Compute gradient norms for debugging."""
    total_norm = 0.0
    param_norms = {}

    for name, param in model.named_parameters():
        if param.grad is not None:
            param_norm = param.grad.data.norm(norm_type).item()
            param_norms[name] = param_norm
            total_norm += param_norm ** norm_type

    total_norm = total_norm ** (1.0 / norm_type)

    return {
        "total_grad_norm": total_norm,
        "param_grad_norms": param_norms,
    }


def compute_parameter_distribution(model: torch.nn.Module) -> Dict[str, Any]:
    """Analyze parameter distribution (mean, std, min, max)."""
    stats = {
        "mean": [],
        "std": [],
        "min": [],
        "max": [],
        "num_zeros": [],
    }

    for name, param in model.named_parameters():
        if param.requires_grad:
            data = param.data.cpu().numpy().flatten()
            stats["mean"].append(float(np.mean(data)))
            stats["std"].append(float(np.std(data)))
            stats["min"].append(float(np.min(data)))
            stats["max"].append(float(np.max(data)))
            stats["num_zeros"].append(int(np.sum(data == 0)))

    # Aggregate
    return {
        "overall_mean": float(np.mean(stats["mean"])),
        "overall_std": float(np.mean(stats["std"])),
        "overall_min": float(np.min(stats["min"])),
        "overall_max": float(np.max(stats["max"])),
        "total_zeros": sum(stats["num_zeros"]),
        "zero_percentage": sum(stats["num_zeros"]) / sum(p.numel() for p in model.parameters() if p.requires_grad),
    }