#!/usr/bin/env python3
"""Directory analyzer: counts files, sizes, and types."""
import os
import json
import sys
from pathlib import Path
from collections import Counter

def analyze_dir(path: str) -> dict:
    """Analyze a directory and return statistics."""
    p = Path(path)
    if not p.exists():
        return {"error": f"Path does not exist: {path}"}
    
    stats = {
        "path": str(p.resolve()),
        "total_files": 0,
        "total_dirs": 0,
        "total_size_bytes": 0,
        "file_extensions": Counter(),
        "largest_file": {"path": None, "size": 0},
        "smallest_file": {"path": None, "size": float('inf')},
    }
    
    for item in p.rglob('*'):
        if item.is_file():
            stats["total_files"] += 1
            size = item.stat().st_size
            stats["total_size_bytes"] += size
            
            ext = item.suffix.lower() if item.suffix else "(no extension)"
            stats["file_extensions"][ext] += 1
            
            if size > stats["largest_file"]["size"]:
                stats["largest_file"] = {"path": str(item), "size": size}
            if size < stats["smallest_file"]["size"]:
                stats["smallest_file"] = {"path": str(item), "size": size}
        elif item.is_dir():
            stats["total_dirs"] += 1
    
    if stats["smallest_file"]["path"] is None:
        stats["smallest_file"] = {"path": None, "size": 0}
    
    stats["file_extensions"] = dict(stats["file_extensions"])
    stats["total_size_human"] = f"{stats['total_size_bytes'] / 1024:.2f} KB"
    
    return stats

def summary_report(path: str) -> str:
    """Generate a human-readable summary."""
    result = analyze_dir(path)
    if "error" in result:
        return f"Error: {result['error']}"
    
    lines = [
        f"Directory: {result['path']}",
        f"Total files: {result['total_files']}",
        f"Total directories: {result['total_dirs']}",
        f"Total size: {result['total_size_human']} ({result['total_size_bytes']:,} bytes)",
        "",
        "Top 5 extensions by count:",
    ]
    
    sorted_exts = sorted(result['file_extensions'].items(), key=lambda x: -x[1])[:5]
    for ext, count in sorted_exts:
        lines.append(f"  {ext or '(none)'}: {count}")
    
    lines.append("")
    lines.append(f"Largest file: {result['largest_file']['path']}")
    lines.append(f"  Size: {result['largest_file']['size']:,} bytes")
    lines.append("")
    lines.append(f"Smallest file: {result['smallest_file']['path']}")
    lines.append(f"  Size: {result['smallest_file']['size']} bytes")
    
    return "\n".join(lines)

if __name__ == "__main__":
    target = sys.argv[1] if len(sys.argv) > 1 else "/etc"
    if "--json" in sys.argv:
        result = analyze_dir(target)
        print(json.dumps(result, indent=2))
    else:
        print(summary_report(target))