import importlib
import inspect
import json
import logging
import os
import re
from pathlib import Path
import argparse

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
# Base URL for all class documentation
_BASE_URL = "https://api.python.langchain.com/en/latest/"

# Regular expression to match Python code blocks
code_block_re = re.compile(r"^(```python\n)(.*?)(```\n)", re.DOTALL | re.MULTILINE)
# Regular expression to match langchain import lines
_IMPORT_RE = re.compile(
    r"from\s+(langchain\.\w+(\.\w+)*?)\s+import\s+"
    r"((?:\w+(?:,\s*)?)*"  # Match zero or more words separated by a comma+optional ws
    r"(?:\s*\(.*?\))?)",  # Match optional parentheses block
    re.DOTALL,  # Match newlines as well
)

_CURRENT_PATH = Path(__file__).parent.absolute()
# Directory where generated markdown files are stored
_DOCS_DIR = _CURRENT_PATH / "docs"
_JSON_PATH = _CURRENT_PATH / "api_reference" / "guide_imports.json"


def find_files(path):
    """Find all MDX files in the given path"""
    # Check if is file first
    if os.path.isfile(path):
        yield path
        return
    for root, _, files in os.walk(path):
        for file in files:
            if file.endswith(".mdx") or file.endswith(".md"):
                yield os.path.join(root, file)


def get_full_module_name(module_path, class_name):
    """Get full module name using inspect"""
    module = importlib.import_module(module_path)
    class_ = getattr(module, class_name)
    return inspect.getmodule(class_).__name__


def get_args():
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--docs_dir",
        type=str,
        default=_DOCS_DIR,
        help="Directory where generated markdown files are stored",
    )
    return parser.parse_args()


def main():
    """Main function"""
    args = get_args()
    global_imports = {}

    for file in find_files(args.docs_dir):
        print(f"Adding links for imports in {file}")
        file_imports = replace_imports(file)

        if file_imports:
            # Use relative file path as key
            relative_path = (
                os.path.relpath(file, _DOCS_DIR).replace(".mdx", "").replace(".md", "")
            )

            doc_url = f"https://python.langchain.com/docs/{relative_path}"
            for import_info in file_imports:
                doc_title = import_info["title"]
                class_name = import_info["imported"]
                if class_name not in global_imports:
                    global_imports[class_name] = {}
                global_imports[class_name][doc_title] = doc_url

    # Write the global imports information to a JSON file
    _JSON_PATH.parent.mkdir(parents=True, exist_ok=True)
    with _JSON_PATH.open("w") as f:
        json.dump(global_imports, f)


def _get_doc_title(data: str, file_name: str) -> str:
    try:
        return re.findall(r"^#\s+(.*)", data, re.MULTILINE)[0]
    except IndexError:
        pass
    # Parse the rst-style titles
    try:
        return re.findall(r"^(.*)\n=+\n", data, re.MULTILINE)[0]
    except IndexError:
        return file_name


def replace_imports(file):
    """Replace imports in each Python code block with links to their
    documentation and append the import info in a comment"""
    all_imports = []
    with open(file, "r") as f:
        data = f.read()

    file_name = os.path.basename(file)
    _DOC_TITLE = _get_doc_title(data, file_name)

    def replacer(match):
        # Extract the code block content
        code = match.group(2)
        # Replace if any import comment exists
        # TODO: Use our own custom <code> component rather than this
        # injection method
        existing_comment_re = re.compile(r"^<!--IMPORTS:.*?-->\n", re.MULTILINE)
        code = existing_comment_re.sub("", code)

        # Process imports in the code block
        imports = []
        for import_match in _IMPORT_RE.finditer(code):
            module = import_match.group(1)
            imports_str = (
                import_match.group(3).replace("(\n", "").replace("\n)", "")
            )  # Handle newlines within parentheses
            # remove any newline and spaces, then split by comma
            imported_classes = [
                imp.strip()
                for imp in re.split(r",\s*", imports_str.replace("\n", ""))
                if imp.strip()
            ]
            for class_name in imported_classes:
                try:
                    module_path = get_full_module_name(module, class_name)
                except AttributeError as e:
                    logger.warning(f"Could not find module for {class_name}, {e}")
                    continue
                except ImportError as e:
                    logger.warning(f"Failed to load for class {class_name}, {e}")
                    continue

                url = (
                    _BASE_URL
                    + module_path.split(".")[1]
                    + "/"
                    + module_path
                    + "."
                    + class_name
                    + ".html"
                )

                # Add the import information to our list
                imports.append(
                    {
                        "imported": class_name,
                        "source": module,
                        "docs": url,
                        "title": _DOC_TITLE,
                    }
                )

        if imports:
            all_imports.extend(imports)
            # Create a unique comment containing the import information
            import_comment = f"<!--IMPORTS:{json.dumps(imports)}-->"
            # Inject the import comment at the start of the code block
            return match.group(1) + import_comment + "\n" + code + match.group(3)
        else:
            # If there are no imports, return the original match
            return match.group(0)

    # Use re.sub to replace each Python code block
    data = code_block_re.sub(replacer, data)

    with open(file, "w") as f:
        f.write(data)
    return all_imports


if __name__ == "__main__":
    main()