#!/usr/bin/env python3
"""
Fixes misplaced 'using StellaOps.TestKit;' statements in test files.

The validate-test-traits.py --fix script has a bug that inserts
'using StellaOps.TestKit;' after 'using var' statements inside methods,
causing CS1001 compilation errors.

This script:
1. Finds all affected .cs files
2. Removes the misplaced 'using StellaOps.TestKit;' lines (inside methods)
3. Ensures 'using StellaOps.TestKit;' exists at the top of the file
"""

import os
import re
import sys
from pathlib import Path


def fix_file(file_path: Path, dry_run: bool = False) -> bool:
    """Fix a single file by removing misplaced using statements."""
    try:
        content = file_path.read_text(encoding='utf-8-sig')  # Handle BOM
    except Exception as e:
        print(f"  Error reading {file_path}: {e}", file=sys.stderr)
        return False

    original = content

    # Pattern to find 'using var' followed by 'using StellaOps.TestKit;' (bug)
    # This matches the broken pattern inside method bodies
    broken_pattern = re.compile(
        r'(using var [^;]+;\s*\n)(using StellaOps\.TestKit;\s*\n)',
        re.MULTILINE
    )

    # Check if file has the broken pattern
    if not broken_pattern.search(content):
        return False

    # Remove all misplaced 'using StellaOps.TestKit;' lines after 'using var'
    fixed = broken_pattern.sub(r'\1', content)

    # Check if 'using StellaOps.TestKit;' exists at top of file (before namespace)
    namespace_match = re.search(r'^namespace\s+\w+', fixed, re.MULTILINE)
    if namespace_match:
        top_section = fixed[:namespace_match.start()]
        has_top_using = 'using StellaOps.TestKit;' in top_section

        if not has_top_using:
            # Find the last 'using' statement before namespace and add after it
            last_using = None
            for match in re.finditer(r'^using [^;]+;\s*$', top_section, re.MULTILINE):
                last_using = match

            if last_using:
                insert_pos = last_using.end()
                fixed = fixed[:insert_pos] + '\nusing StellaOps.TestKit;' + fixed[insert_pos:]

    if fixed != original:
        if not dry_run:
            # Preserve UTF-8 BOM if present
            encoding = 'utf-8-sig' if content.startswith('\ufeff') else 'utf-8'
            file_path.write_text(fixed, encoding=encoding)
        return True

    return False


def main():
    import argparse
    parser = argparse.ArgumentParser(description='Fix misplaced using statements')
    parser.add_argument('--path', default='src', help='Path to scan')
    parser.add_argument('--dry-run', action='store_true', help='Show what would be fixed')
    args = parser.parse_args()

    root = Path(args.path)
    if not root.exists():
        print(f"Path not found: {root}", file=sys.stderr)
        sys.exit(1)

    fixed_count = 0
    checked_count = 0

    # Find all test .cs files
    for file_path in root.rglob('*.cs'):
        # Skip non-test files
        if '/obj/' in str(file_path) or '/bin/' in str(file_path):
            continue
        if 'node_modules' in str(file_path):
            continue
        if 'Test' not in str(file_path):
            continue

        checked_count += 1
        if fix_file(file_path, dry_run=args.dry_run):
            print(f"{'Would fix' if args.dry_run else 'Fixed'}: {file_path}")
            fixed_count += 1

    print(f"\nChecked: {checked_count} files")
    print(f"Fixed: {fixed_count} files")

    if args.dry_run:
        print("\n(Dry run - no files were modified)")


if __name__ == '__main__':
    main()