# Ultralytics YOLO 🚀, AGPL-3.0 license
"""
Helper file to build Ultralytics Docs reference section. Recursively walks through ultralytics dir and builds an MkDocs
reference section of *.md files composed of classes and functions, and also creates a nav menu for use in mkdocs.yaml.

Note: Must be run from repository root directory. Do not run from docs directory.
"""

import re
from collections import defaultdict
from pathlib import Path

from ultralytics.utils import ROOT

NEW_YAML_DIR = ROOT.parent
CODE_DIR = ROOT
REFERENCE_DIR = ROOT.parent / 'docs/en/reference'


def extract_classes_and_functions(filepath: Path) -> tuple:
    """Extracts class and function names from a given Python file."""
    content = filepath.read_text()
    class_pattern = r'(?:^|\n)class\s(\w+)(?:\(|:)'
    func_pattern = r'(?:^|\n)def\s(\w+)\('

    classes = re.findall(class_pattern, content)
    functions = re.findall(func_pattern, content)

    return classes, functions


def create_markdown(py_filepath: Path, module_path: str, classes: list, functions: list):
    """Creates a Markdown file containing the API reference for the given Python module."""
    md_filepath = py_filepath.with_suffix('.md')

    # Read existing content and keep header content between first two ---
    header_content = ''
    if md_filepath.exists():
        existing_content = md_filepath.read_text()
        header_parts = existing_content.split('---')
        for part in header_parts:
            if 'description:' in part or 'comments:' in part:
                header_content += f'---{part}---\n\n'

    module_name = module_path.replace('.__init__', '')
    module_path = module_path.replace('.', '/')
    url = f'https://github.com/ultralytics/ultralytics/blob/main/{module_path}.py'
    edit = f'https://github.com/ultralytics/ultralytics/edit/main/{module_path}.py'
    title_content = (
        f'# Reference for `{module_path}.py`\n\n'
        f'!!! Note\n\n'
        f'    This file is available at [{url}]({url}). If you spot a problem please help fix it by [contributing](https://docs.ultralytics.com/help/contributing/) a [Pull Request]({edit}) 🛠️. Thank you 🙏!\n\n'
    )
    md_content = ['<br><br>\n'] + [f'## ::: {module_name}.{class_name}\n\n<br><br>\n' for class_name in classes]
    md_content.extend(f'## ::: {module_name}.{func_name}\n\n<br><br>\n' for func_name in functions)
    md_content = header_content + title_content + '\n'.join(md_content)
    if not md_content.endswith('\n'):
        md_content += '\n'

    md_filepath.parent.mkdir(parents=True, exist_ok=True)
    md_filepath.write_text(md_content)

    return md_filepath.relative_to(NEW_YAML_DIR)


def nested_dict() -> defaultdict:
    """Creates and returns a nested defaultdict."""
    return defaultdict(nested_dict)


def sort_nested_dict(d: dict) -> dict:
    """Sorts a nested dictionary recursively."""
    return {key: sort_nested_dict(value) if isinstance(value, dict) else value for key, value in sorted(d.items())}


def create_nav_menu_yaml(nav_items: list):
    """Creates a YAML file for the navigation menu based on the provided list of items."""
    nav_tree = nested_dict()

    for item_str in nav_items:
        item = Path(item_str)
        parts = item.parts
        current_level = nav_tree['reference']
        for part in parts[2:-1]:  # skip the first two parts (docs and reference) and the last part (filename)
            current_level = current_level[part]

        md_file_name = parts[-1].replace('.md', '')
        current_level[md_file_name] = item

    nav_tree_sorted = sort_nested_dict(nav_tree)

    def _dict_to_yaml(d, level=0):
        """Converts a nested dictionary to a YAML-formatted string with indentation."""
        yaml_str = ''
        indent = '  ' * level
        for k, v in d.items():
            if isinstance(v, dict):
                yaml_str += f'{indent}- {k}:\n{_dict_to_yaml(v, level + 1)}'
            else:
                yaml_str += f"{indent}- {k}: {str(v).replace('docs/en/', '')}\n"
        return yaml_str

    # Print updated YAML reference section
    print('Scan complete, new mkdocs.yaml reference section is:\n\n', _dict_to_yaml(nav_tree_sorted))

    # Save new YAML reference section
    # (NEW_YAML_DIR / 'nav_menu_updated.yml').write_text(_dict_to_yaml(nav_tree_sorted))


def main():
    """Main function to extract class and function names, create Markdown files, and generate a YAML navigation menu."""
    nav_items = []

    for py_filepath in CODE_DIR.rglob('*.py'):
        classes, functions = extract_classes_and_functions(py_filepath)

        if classes or functions:
            py_filepath_rel = py_filepath.relative_to(CODE_DIR)
            md_filepath = REFERENCE_DIR / py_filepath_rel
            module_path = f"ultralytics.{py_filepath_rel.with_suffix('').as_posix().replace('/', '.')}"
            md_rel_filepath = create_markdown(md_filepath, module_path, classes, functions)
            nav_items.append(str(md_rel_filepath))

    create_nav_menu_yaml(nav_items)


if __name__ == '__main__':
    main()