"""
量化相关工具函数
"""

import os
import json
from typing import Dict, Any
from pathlib import Path


def get_model_size(model_path: str) -> Dict[str, Any]:
    """
    获取模型大小
    
    Args:
        model_path: 模型路径
    
    Returns:
        模型大小信息
    """
    total_size = 0
    file_count = 0
    file_sizes = {}
    
    for root, dirs, files in os.walk(model_path):
        for file in files:
            if file.endswith((".bin", ".safetensors", ".pt", ".pth")):
                file_path = os.path.join(root, file)
                size = os.path.getsize(file_path)
                total_size += size
                file_count += 1
                file_sizes[file] = size
    
    # 转换为人类可读格式
    def format_size(size_bytes):
        for unit in ['B', 'KB', 'MB', 'GB', 'TB']:
            if size_bytes < 1024.0:
                return f"{size_bytes:.2f} {unit}"
            size_bytes /= 1024.0
        return f"{size_bytes:.2f} PB"
    
    return {
        "total_size": total_size,
        "total_size_formatted": format_size(total_size),
        "file_count": file_count,
        "file_sizes": file_sizes,
    }


def estimate_quantized_size(
    model_path: str,
    quantization_bits: int = 4,
    overhead: float = 0.1
) -> Dict[str, Any]:
    """
    估算量化后的模型大小
    
    Args:
        model_path: 原始模型路径
        quantization_bits: 量化位数 (4, 8 等)
        overhead: 额外开销比例（元数据、tokenizer 等）
    
    Returns:
        估算的大小信息
    """
    original_size = get_model_size(model_path)
    
    # 计算压缩比
    compression_ratio = quantization_bits / 16  # 假设原始是 FP16 (16bit)
    
    # 估算量化后大小
    estimated_size = original_size["total_size"] * compression_ratio * (1 + overhead)
    
    def format_size(size_bytes):
        for unit in ['B', 'KB', 'MB', 'GB', 'TB']:
            if size_bytes < 1024.0:
                return f"{size_bytes:.2f} {unit}"
            size_bytes /= 1024.0
        return f"{size_bytes:.2f} PB"
    
    return {
        "original_size": original_size["total_size_formatted"],
        "quantization_bits": quantization_bits,
        "compression_ratio": f"{1/compression_ratio:.1f}x",
        "estimated_size": format_size(estimated_size),
        "estimated_size_bytes": estimated_size,
        "space_saved": format_size(original_size["total_size"] - estimated_size),
        "space_saved_percent": f"{(1 - compression_ratio * (1 + overhead)) * 100:.1f}%",
    }


def compare_models(
    model_path_1: str,
    model_path_2: str,
    label_1: str = "原始模型",
    label_2: str = "量化模型"
) -> Dict[str, Any]:
    """
    比较两个模型的大小
    
    Args:
        model_path_1: 第一个模型路径
        model_path_2: 第二个模型路径
        label_1: 第一个模型标签
        label_2: 第二个模型标签
    
    Returns:
        比较结果
    """
    size_1 = get_model_size(model_path_1)
    size_2 = get_model_size(model_path_2)
    
    size_diff = size_1["total_size"] - size_2["total_size"]
    size_diff_percent = (size_diff / size_1["total_size"]) * 100 if size_1["total_size"] > 0 else 0
    
    def format_size(size_bytes):
        for unit in ['B', 'KB', 'MB', 'GB', 'TB']:
            if size_bytes < 1024.0:
                return f"{size_bytes:.2f} {unit}"
            size_bytes /= 1024.0
        return f"{size_bytes:.2f} PB"
    
    return {
        label_1: {
            "size": size_1["total_size_formatted"],
            "files": size_1["file_count"],
        },
        label_2: {
            "size": size_2["total_size_formatted"],
            "files": size_2["file_count"],
        },
        "difference": format_size(abs(size_diff)),
        "difference_percent": f"{size_diff_percent:.1f}%",
        "smaller": label_1 if size_diff > 0 else label_2,
    }


def print_model_info(model_path: str, title: str = "模型信息"):
    """
    打印模型信息
    
    Args:
        model_path: 模型路径
        title: 标题
    """
    print(f"\n{'=' * 60}")
    print(f"{title}")
    print(f"{'=' * 60}")
    
    size_info = get_model_size(model_path)
    print(f"模型路径：{model_path}")
    print(f"总大小：{size_info['total_size_formatted']}")
    print(f"文件数：{size_info['file_count']}")
    
    if size_info['file_sizes']:
        print("\n文件列表:")
        for filename, size in size_info['file_sizes'].items():
            size_mb = size / (1024 * 1024)
            print(f"  {filename}: {size_mb:.2f} MB")
    
    print(f"{'=' * 60}\n")


def save_quantization_report(
    output_path: str,
    quantization_info: Dict[str, Any],
    size_info: Dict[str, Any],
    report_path: Optional[str] = None
):
    """
    保存量化报告
    
    Args:
        output_path: 输出目录
        quantization_info: 量化信息
        size_info: 大小信息
        report_path: 报告路径（可选）
    """
    if report_path is None:
        report_path = os.path.join(output_path, "quantization_report.json")
    
    report = {
        "quantization": quantization_info,
        "size_info": size_info,
        "timestamp": __import__('datetime').datetime.now().isoformat(),
    }
    
    with open(report_path, "w", encoding="utf-8") as f:
        json.dump(report, f, indent=2, ensure_ascii=False)
    
    print(f"量化报告已保存到：{report_path}")
    
    return report_path