#!/usr/bin/env python3
"""YAML linter using pure Python - no external dependencies."""

import sys
import re
from pathlib import Path


def check_yaml_basic(filepath):
    """Basic YAML syntax check without external libs."""
    errors = []
    
    with open(filepath, "r") as f:
        lines = f.readlines()
    
    # Check for tabs (YAML spec violation)
    for i, line in enumerate(lines, 1):
        if "\t" in line:
            errors.append(f"Line {i}: Tab found (YAML uses spaces)")
    
    # Check for consistent indentation
    for i, line in enumerate(lines, 1):
        if line.strip() and not line.startswith("#"):  # non-empty, non-comment
            indent = len(line) - len(line.lstrip())
            if indent % 2 != 0:
                errors.append(f"Line {i}: Odd indentation ({indent} spaces)")
    
    # Check for valid key: value pattern
    for i, line in enumerate(lines, 1):
        stripped = line.strip()
        if stripped and not stripped.startswith("#"):
            if ":" not in stripped and not stripped.startswith("-"):
                # Could be a continuation line, skip
                pass
    
    return errors


def main():
    target_dir = sys.argv[1] if len(sys.argv) > 1 else "."
    base = Path(target_dir)
    
    yaml_files = []
    for ext in ("*.yaml", "*.yml", "*.YML", "*.YAML"):
        yaml_files.extend(base.rglob(ext))
    
    if not yaml_files:
        print(f"No YAML files found in {target_dir}")
        sys.exit(0)
    
    valid = []
    invalid = []
    
    for yf in sorted(yaml_files):
        errors = check_yaml_basic(yf)
        if errors:
            invalid.append((str(yf), errors))
        else:
            valid.append(str(yf))
    
    print(f"Checked {len(yaml_files)} YAML file(s)")
    print(f"Valid: {len(valid)}")
    
    if valid:
        for f in valid[:5]:
            print(f"  ✓ {f}")
        if len(valid) > 5:
            print(f"  ... and {len(valid) - 5} more")
    
    print(f"\nInvalid: {len(invalid)}")
    for filepath, errs in invalid[:5]:
        print(f"  ✗ {filepath}")
        for e in errs[:3]:
            print(f"      {e}")
    
    if invalid:
        print(f"\nVERDICT: {len(invalid)} YAML file(s) have syntax issues.")
        sys.exit(1)
    
    print("\nVERDICT: All YAML files pass basic syntax validation.")


if __name__ == "__main__":
    main()