import os
import markdown
import json
from typing import List, Dict


class MetadataProcessor:
    """
    A class to scan Markdown files, extract front matter metadata,
    and generate a structured JSON file.
    """

    def __init__(self, input_dir: str, output_file: str):
        """
        Initialize the MetadataProcessor.

        Args:
            input_dir (str): Directory containing Markdown files.
            output_file (str): Path to save the generated JSON file.
        """
        self.input_dir = input_dir
        self.output_file = output_file
        self.data = {"categories": [], "favorites": []}

    def _extract_metadata(self, file_path: str) -> Dict:
        """
        Extract front matter metadata using the 'markdown' package.

        Args:
            file_path (str): Path to the Markdown file.

        Returns:
            dict: A dictionary containing the extracted metadata.
        """
        with open(file_path, "r", encoding="utf-8") as file:
            markdown_content = file.read()

            # Initialize Markdown with meta extension
            md = markdown.Markdown(extensions=["extra", "nl2br", "meta"])
            md.convert(markdown_content)

            # Metadata is stored in md.Meta as a dictionary of lists
            meta = {key: " ".join(value) for key, value in md.Meta.items()} if md.Meta else {}
            return meta

    def _process_directory(self):
        """
        Recursively scan the input directory for Markdown files
        and extract metadata to build the JSON structure.
        """
        for root, _, files in os.walk(self.input_dir):
            for file in files:
                if file.endswith(".md"):
                    file_path = os.path.join(root, file)
                    metadata = self._extract_metadata(file_path)

                    if metadata:
                        # Add to 'categories'
                        self.data["categories"].append({
                            "name": metadata.get("name", "Unknown"),
                            "path": os.path.relpath(root, self.input_dir).replace(os.sep, "/"),
                            "author": metadata.get("author", "Unknown")
                        })

                        # Add to 'favorites' if 'favorite' is true
                        if metadata.get("favorite") and metadata["favorite"].lower() == "true":
                            self.data["favorites"].append({
                                "name": metadata.get("name", "Unknown"),
                                "image": metadata.get("image", "images/default.jpg"),
                                "description": metadata.get("summary", "No description provided"),
                                "path": os.path.relpath(root, self.input_dir).replace(os.sep, "/"),
                            })

    def generate_json(self):
        """
        Generate the JSON structure, deduplicate and sort categories by 'path',
        then save it to the output file.
        """
        self._process_directory()  # Extract all markdown data into self.data

        # Ensure 'categories' exists and is a list
        if "categories" not in self.data:
            self.data["categories"] = []

        # Deduplicate 'categories' using 'path' as the unique key
        unique_categories = { }
        for category in self.data["categories"]:
            if isinstance( category, dict ):  # Ensure valid category structure
                path = category.get( "path", "unknown" )  # Use 'path' as the unique key
                if path not in unique_categories:
                    unique_categories[path] = category

        # Replace the 'categories' list with a sorted version by 'path'
        self.data["categories"] = sorted(
            unique_categories.values(),
            key = lambda x: x.get( "path", "unknown" )
        )

        # Save the updated JSON to file
        with open( self.output_file, "w", encoding = "utf-8" ) as json_file:
            json.dump( self.data, json_file, indent = 4, ensure_ascii = False )

        print( f"Generated JSON saved to {self.output_file}" )