import os
import markdown
import secrets
from flask import current_app
from werkzeug.utils import secure_filename
import json

def get_uri_map_path():
    """Get the path to the URI mapping file"""
    return os.path.join(current_app.config['UPLOAD_FOLDER'], 'uri_map.json')

def load_uri_map():
    """Load the URI mapping from file"""
    map_path = get_uri_map_path()
    if os.path.exists(map_path):
        with open(map_path, 'r') as f:
            return json.load(f)
    return {}

def save_uri_map(uri_map):
    """Save the URI mapping to file"""
    with open(get_uri_map_path(), 'w') as f:
        json.dump(uri_map, f, indent=2)

def generate_unique_uri():
    """Generate a unique URI for a file"""
    uri_map = load_uri_map()
    while True:
        uri = secrets.token_urlsafe(6)  # Generate a short random string
        if uri not in uri_map:
            return uri

def save_file(file, custom_uri=None):
    """Save the uploaded file to the upload folder and assign a URI"""
    # Secure the filename first
    filename = secure_filename(file.filename)
    
    # Generate or use custom URI
    uri = custom_uri if custom_uri else generate_unique_uri()
    
    # Save the file with its original name
    filepath = os.path.join(current_app.config['UPLOAD_FOLDER'], filename)
    file.save(filepath)
    
    # Update the URI map
    uri_map = load_uri_map()
    uri_map[uri] = {
        'filename': filename,
        'path': filepath
    }
    save_uri_map(uri_map)
    
    return uri, filename

def get_file_by_uri(uri):
    """Get file info by URI"""
    uri_map = load_uri_map()
    if uri in uri_map:
        return uri_map[uri]
    return None

def read_markdown_file(filepath):
    """Read and convert markdown file to HTML"""
    with open(filepath, 'r', encoding='utf-8') as f:
        md_content = f.read()
        html_content = markdown.markdown(md_content, extensions=['tables', 'fenced_code'])
    return html_content