# markdown_sqlite.py
"""
This script processes a markdown file by reading its content and
updates an SQLite database with document content and metadata.
The user can then select specific topics based on command-line arguments.
The script tracks changes using MD5 hashes and ensures the database 
reflects the current state of the markdown file.
"""

import os
import sqlite3
import uuid
import hashlib
import argparse
import logging
from datetime import datetime
from typing import List, Tuple, Dict, Set, Optional
from markdown_it import MarkdownIt
from thefuzz import fuzz, process

class DatabaseManager:
    """Manages database connections and table creation."""

    def __init__(self, db_file: str):
        """Initialize the DatabaseManager."""
        self.conn: sqlite3.Connection = sqlite3.connect(db_file, timeout=10)
        self.cursor: sqlite3.Cursor = self.conn.cursor()
        self.create_tables()

    def create_tables(self) -> None:
        """Create necessary tables in the database if they don't exist."""
        self.cursor.executescript('''
            CREATE TABLE IF NOT EXISTS documents (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                name TEXT NOT NULL UNIQUE,
                file_path TEXT NOT NULL,
                md5sum TEXT,
                added_timestamp DATETIME DEFAULT CURRENT_TIMESTAMP,
                updated_timestamp DATETIME,
                deleted_timestamp DATETIME,
                isDeleted BOOLEAN DEFAULT 0
            );

            CREATE TABLE IF NOT EXISTS headings (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                uuid TEXT NOT NULL UNIQUE,
                level INTEGER NOT NULL,
                title TEXT NOT NULL,
                parent_uuid TEXT,
                document_id INTEGER NOT NULL,
                path TEXT NOT NULL,
                headings_order INTEGER,
                added_timestamp DATETIME DEFAULT CURRENT_TIMESTAMP,
                updated_timestamp DATETIME,
                deleted_timestamp DATETIME,
                isDeleted BOOLEAN DEFAULT 0,
                FOREIGN KEY (parent_uuid) REFERENCES headings(uuid),
                FOREIGN KEY (document_id) REFERENCES documents(id)
            );

            CREATE TABLE IF NOT EXISTS body (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                uuid TEXT NOT NULL UNIQUE,
                content TEXT,
                heading_uuid TEXT NOT NULL,
                document_id INTEGER NOT NULL,
                md5sum TEXT,
                added_timestamp DATETIME DEFAULT CURRENT_TIMESTAMP,
                updated_timestamp DATETIME,
                deleted_timestamp DATETIME,
                isDeleted BOOLEAN DEFAULT 0,
                FOREIGN KEY (heading_uuid) REFERENCES headings(uuid),
                FOREIGN KEY (document_id) REFERENCES documents(id)
            );
        ''')

    def close(self) -> None:
        """Close the database connection."""
        self.conn.close()

class DocumentManager:
    """Manages document-related operations in the database."""

    def __init__(self, db_manager: 'DatabaseManager'):
        self.db_manager: DatabaseManager = db_manager

    def document_exists(self, document_name: str) -> Optional[Tuple[int]]:
        """
        Check if a document exists in the database.
        """
        self.db_manager.cursor.execute('SELECT id FROM documents WHERE name = ?', (document_name,))
        return self.db_manager.cursor.fetchone()

    def create_document(self, name: str, file_path: str) -> Optional[int]:
        """Create a new document entry in the database."""
        logging.debug(f"** Creating new document entry to database")
        now: str = datetime.now().isoformat()
        self.db_manager.cursor.execute('''
            INSERT INTO documents (name, file_path, added_timestamp) VALUES (?, ?, ?)
        ''', (name, file_path, now))
        self.db_manager.conn.commit()
        return self.db_manager.cursor.lastrowid

    def update_document(self, document_id: int, name: Optional[str] = None, file_path: Optional[str] = None) -> None:
        """Update an existing document in the database."""
        logging.debug(f"** Updating document, document_id: {document_id}")
        now: str = datetime.now().isoformat()
        if name:
            self.db_manager.cursor.execute('''
                UPDATE documents SET name = ?, updated_timestamp = ? WHERE id = ?
            ''', (name, now, document_id))
        if file_path:
            self.db_manager.cursor.execute('''
                UPDATE documents SET file_path = ?, updated_timestamp = ? WHERE id = ?
            ''', (file_path, now, document_id))
        self.db_manager.conn.commit()

    def soft_delete_document(self, document_id: int) -> None:
        """Soft delete a document by marking it as deleted in the database."""
        logging.debug(f"** This document is now soft deleted, document_id: {document_id}")
        now: str = datetime.now().isoformat()
        self.db_manager.cursor.execute('''
            UPDATE documents SET isDeleted = 1, deleted_timestamp = ? WHERE id = ?
        ''', (now, document_id))
        self.db_manager.conn.commit()

    def read_documents(self) -> List[Tuple]:
        """Retrieve all non-deleted documents from the database."""
        self.db_manager.cursor.execute('SELECT * FROM documents WHERE isDeleted = 0')
        return self.db_manager.cursor.fetchall()

    def update_document_hash(self, document_id: int, md5sum: str) -> None:
        """Update the MD5 hash of a document in the database."""
        self.db_manager.cursor.execute('UPDATE documents SET md5sum = ? WHERE id = ?', (md5sum, document_id))
        self.db_manager.conn.commit()

class MarkdownProcessor:
    """Processes markdown files and stores content in the database."""
    def __init__(self, db_manager: 'DatabaseManager') -> None:
        self.db_manager = db_manager

    def process_markdown(self, markdown_file: str, document_id: int) -> None:
        markdown_text = self.read_markdown_file(markdown_file)
        md = MarkdownIt()
        tokens = md.parse(markdown_text)
        
        print('### Calling update_document_content')
        self.update_document_content(tokens, document_id)

    def read_markdown_file(self, file_path: str) -> str:
        with open(file_path, 'r', encoding='utf-8') as file:
            return file.read()

    def update_document_content(self, tokens: List, document_id: int) -> None:
        existing_structure = self.get_existing_document_structure(document_id)
        new_structure = self.parse_new_structure(tokens, document_id)
        
        print('### Calling merg_structures...')
        self.merge_structures(existing_structure, new_structure, document_id)

    def get_existing_document_structure(self, document_id: int) -> Dict:
        structure = {}
        self.db_manager.cursor.execute('''
            SELECT h.uuid, h.level, h.title, h.parent_uuid, h.path, b.content, b.uuid
            FROM headings h
            LEFT JOIN body b ON h.uuid = b.heading_uuid
            WHERE h.document_id = ? AND h.isDeleted = 0
            ORDER BY h.level, h.id
        ''', (document_id,))
        for heading_uuid, level, title, parent_uuid, path, content, body_uuid in self.db_manager.cursor.fetchall():
            structure[heading_uuid] = {
                'uuid': heading_uuid,
                'level': level,
                'title': title,
                'parent_uuid': parent_uuid,
                'path': path,
                'content': content,
                'body_uuid': body_uuid,
                'children': []
            }
        # Build the tree structure
        for uuid, node in structure.items():
            if node['parent_uuid'] in structure:
                structure[node['parent_uuid']]['children'].append(uuid)
        return structure 

    def parse_new_structure(self, tokens: List, document_id: int) -> Dict:
        structure = {}
        current_heading = None
        current_content = []
        parent_stack = [{"uuid": None, "level": 0, "path": ""}]

        for token in tokens:
            if token.type == 'heading_open':
                if current_heading:
                    structure[current_heading]['content'] = ''.join(current_content).strip()
                level = int(token.tag.strip('h'))
                while parent_stack[-1]['level'] >= level:
                    parent_stack.pop()
                current_heading = str(uuid.uuid4())
                parent_path = parent_stack[-1]['path']
                structure[current_heading] = {
                    'uuid': current_heading,
                    'level': level,
                    'title': '',
                    'parent_uuid': parent_stack[-1]['uuid'],
                    'path': f"{parent_path}/{current_heading}" if parent_path else current_heading,
                    'content': '',
                    'children': []
                }
                parent_stack.append({"uuid": current_heading, "level": level, "path": structure[current_heading]['path']})
                current_content = []
            elif token.type == 'heading_close':
                structure[current_heading]['content'] = ''.join(current_content).strip()
            elif token.type == 'inline' and current_heading:
                if structure[current_heading]['title'] == '':
                    structure[current_heading]['title'] = token.content
                else:
                    current_content.append(token.content)
            elif current_heading:
                current_content.append(token.content)

        if current_heading:
            structure[current_heading]['content'] = ''.join(current_content).strip()

        return structure

    def merge_structures(self, existing: Dict, new: Dict, document_id: int) -> None:
        def merge_recursive(existing_node, new_node, parent_uuid):
            if not existing_node:
                # This is a new node, insert it
                heading_uuid = self.insert_heading(new_node['level'], new_node['title'], parent_uuid, document_id, new_node['path'])
                body_uuid = self.insert_body(new_node['content'], heading_uuid, document_id)
                for child in new_node['children']:
                    merge_recursive(None, new[child], heading_uuid)
            else:
                # Update existing node
                self.update_heading(existing_node['uuid'], new_node['title'], new_node['level'], parent_uuid, new_node['path'])
                self.update_body(existing_node['body_uuid'], new_node['content'], document_id)
                
                # Process children
                existing_children = {child['title']: child for child in existing_node['children']}
                new_children = {child['title']: child for child in new_node['children']}
                
                for title, child in new_children.items():
                    if title in existing_children:
                        merge_recursive(existing_children[title], child, existing_node['uuid'])
                    else:
                        merge_recursive(None, child, existing_node['uuid'])
                
                for title, child in existing_children.items():
                    if title not in new_children:
                        self.soft_delete_heading(child['uuid'])

        for new_root in new.values():
            existing_root = next((node for node in existing.values() if node['path'] == new_root['path']), None)
            merge_recursive(existing_root, new_root, None)

    def insert_heading(self, level: int, title: str, parent_uuid: Optional[str], document_id: int, path: str) -> str:
        heading_uuid = str(uuid.uuid4())
        self.db_manager.cursor.execute('''
            INSERT INTO headings (uuid, level, title, parent_uuid, document_id, path)
            VALUES (?, ?, ?, ?, ?, ?)
        ''', (heading_uuid, level, title, parent_uuid, document_id, path))
        return heading_uuid

    def update_heading(self, heading_uuid: str, title: str, level: int, parent_uuid: Optional[str], path: str) -> None:
        self.db_manager.cursor.execute('''
            UPDATE headings
            SET title = ?, level = ?, parent_uuid = ?, path = ?, updated_timestamp = CURRENT_TIMESTAMP
            WHERE uuid = ?
        ''', (title, level, parent_uuid, path, heading_uuid))

    def insert_body(self, content: str, heading_uuid: str, document_id: int) -> str:
        body_uuid = str(uuid.uuid4())
        md5sum = hashlib.md5(content.encode()).hexdigest()
        self.db_manager.cursor.execute('''
            INSERT INTO body (uuid, content, heading_uuid, document_id, md5sum)
            VALUES (?, ?, ?, ?, ?)
        ''', (body_uuid, content, heading_uuid, document_id, md5sum))
        return body_uuid

    def update_body(self, body_uuid: str, content: str, document_id: int) -> None:
        md5sum = hashlib.md5(content.encode()).hexdigest()
        self.db_manager.cursor.execute('''
            UPDATE body
            SET content = ?, md5sum = ?, updated_timestamp = CURRENT_TIMESTAMP
            WHERE uuid = ? AND document_id = ?
        ''', (content, md5sum, body_uuid, document_id))

    def soft_delete_heading(self, heading_uuid: str) -> None:
        now = datetime.now().isoformat()
        self.db_manager.cursor.execute('''
            UPDATE headings
            SET isDeleted = 1, deleted_timestamp = ?
            WHERE uuid = ?
        ''', (now, heading_uuid))
        # Also soft delete associated body content
        self.db_manager.cursor.execute('''
            UPDATE body
            SET isDeleted = 1, deleted_timestamp = ?
            WHERE heading_uuid = ?
        ''', (now, heading_uuid))

class TopicReader:
    """Reads and retrieves topics from the database."""
    def __init__(self, db_manager: 'DatabaseManager'):
        self.db_manager = db_manager

    def fetch_headings(self) -> List[Tuple[str, str, int, Optional[str]]]:
        self.db_manager.cursor.execute('''
            SELECT uuid, title, level, parent_uuid 
            FROM headings 
            WHERE isDeleted = 0 
            ORDER BY level, headings_order
        ''')
        return self.db_manager.cursor.fetchall()

    def fetch_topic_chain(self, heading_uuid: str) -> List[Tuple[str, str, int]]:
        chain = []
        current_uuid = heading_uuid

        while current_uuid is not None:
            self.db_manager.cursor.execute('''
                SELECT uuid, title, level, parent_uuid 
                FROM headings 
                WHERE uuid = ?
            ''', (current_uuid,))
            result = self.db_manager.cursor.fetchone()
            if result:
                chain.append((result[0], result[1], result[2]))
                current_uuid = result[3]
            else:
                break

        return list(reversed(chain))

    def list_headings(self) -> str:
        headings = self.fetch_headings()
        result = "Available headings:\n"
        
        def build_tree(parent_uuid, level):
            tree = ""
            for uuid, title, hlevel, parent in headings:
                if parent == parent_uuid:
                    indent = "  " * (hlevel - 1)
                    tree += f"{indent}- {title}\n"
                    tree += build_tree(uuid, hlevel + 1)
            return tree
        
        result += build_tree(None, 1)
        return result.strip()

    def get_topic_content(self, input_title: str) -> Optional[str]:
        heading_uuid = self.find_closest_heading(input_title)
        if heading_uuid:
            topic_chain = self.fetch_topic_chain(heading_uuid)
            result = self.build_full_content(topic_chain[-1][0])
            return result
        return None

    def build_full_content(self, heading_uuid: str, level_offset: int = 0) -> str:
        self.db_manager.cursor.execute('''
            SELECT h.level, h.title, b.content
            FROM headings h
            LEFT JOIN body b ON h.uuid = b.heading_uuid
            WHERE h.uuid = ? AND h.isDeleted = 0
        ''', (heading_uuid,))
        heading = self.db_manager.cursor.fetchone()
        if not heading:
            return ""

        level, title, content = heading
        adjusted_level = max(1, level - level_offset)
        result = f"{'#' * adjusted_level} {title}\n\n"
        if content:
            result += f"{content.strip()}\n\n"

        # Fetch and process all child headings
        self.db_manager.cursor.execute('''
            SELECT uuid FROM headings
            WHERE parent_uuid = ? AND isDeleted = 0
            ORDER BY level, headings_order
        ''', (heading_uuid,))
        children = self.db_manager.cursor.fetchall()
        for child in children:
            result += self.build_full_content(child[0], level_offset)

        return result

    def find_closest_heading(self, input_title: str) -> Optional[str]:
        headings = self.fetch_headings()
        if not headings:
            print("No topics found in the database.")
            return None

        heading_titles = [title for _, title, _, _ in headings]
        closest_match, confidence = process.extractOne(input_title, heading_titles, scorer=fuzz.token_sort_ratio)

        if confidence < 50:
            print(f"No close matches found for '{input_title}' (Confidence: {confidence})")
            return None

        for heading_uuid, title, _, _ in headings:
            if title == closest_match:
                return heading_uuid

        return None

def compute_file_hash(file_path: str) -> str:
    """
    Compute the MD5 hash of a file.
    """
    hash_md5 = hashlib.md5()
    with open(file_path, "rb") as f:
        for chunk in iter(lambda: f.read(4096), b""):
            hash_md5.update(chunk)
    return hash_md5.hexdigest()
    
def generate_calendar(year: int, db_manager: 'DatabaseManager', document_id: int) -> str:
    """
    Generate a markdown calendar for the specified year.
    """
    calendar_markdown = f"# {year}\n\n"
    current_date = datetime.now().date()

    # Loop through the months
    for month in range(1, 13):
        month_name = datetime(year, month, 1).strftime('%B')
        calendar_markdown += f"## {month:02d} / {month_name}\n\n"

        # Determine the number of days in the month
        if month == 12:
            num_days = (datetime(year + 1, 1, 1) - datetime(year, month, 1)).days
        else:
            num_days = (datetime(year, month + 1, 1) - datetime(year, month, 1)).days

        # Create calendar entries for each day in order
        for day in range(1, num_days + 1):
            day_date = datetime(year, month, day).date()
            day_name = day_date.strftime('%a')

            # Add bold styling for the current date
            if str(day_date) == str(current_date):
                calendar_markdown += f"**{day:02d} / {day_name}**\n"
            else:
                calendar_markdown += f"{day:02d} / {day_name}\n"

        calendar_markdown += '\n'

    # Now parse the markdown and insert into the database
    #parse_and_insert_markdown(calendar_markdown, db_manager, document_id, year)
    
    return calendar_markdown
    
def convert_to_html(markdown_content: str, heading_uuid: Optional[str] = None) -> str:
    """
    Convert Markdown content (or specific section) to HTML.
    """
    md = MarkdownIt()
    
    if heading_uuid:
        # Fetch content for a specific heading and its sub-headings from the database
        # Example SQL to get heading content based on UUID:
        # SELECT title, content FROM headings WHERE uuid = ?
        pass

    html_content = md.render(markdown_content)

    # Wrap the content in a basic HTML structure
    html_document = f"""
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Document</title>
        <style>
            body {{ font-family: Arial, sans-serif; line-height: 1.6; padding: 20px; }}
            h1, h2, h3, h4, h5, h6 {{ margin-top: 24px; margin-bottom: 16px; }}
            h1 {{ font-size: 2em; }}
            h2 {{ font-size: 1.5em; }}
            h3 {{ font-size: 1.25em; }}
        </style>
    </head>
    <body>
    {html_content}
    </body>
    </html>
    """

    return html_document

def bootstrap_calendar(year: int, db_manager: DatabaseManager, markdown_file: str):
    """Generate and store a full year's markdown calendar in the database using UUIDs."""
    document_manager = DocumentManager(db_manager)
    markdown_processor = MarkdownProcessor(db_manager)

    # Generate calendar markdown and insert into the database
    print('## Generating calendar')
    calendar_content = generate_calendar(year, db_manager, document_id=document_manager.create_document(f"{year} Calendar", markdown_file))

    # Write the calendar to the markdown file
    print('## Reading the newly created calendar')
    with open(markdown_file, 'w', encoding='utf-8') as f:
        f.write(calendar_content)

    # Process the markdown to update or store in the database
    markdown_processor.process_markdown(markdown_file, document_manager.document_exists(f"{year} Calendar")[0])
    print(f"Calendar for year {year} has been generated and stored in the database.")

def main():
    """
    This script processes a markdown file, updates an SQLite database,
    and optionally selects a topic based on user input.
    """
    parser = argparse.ArgumentParser(description='Process markdown file and optionally select a topic.')
    parser.add_argument('-m', '--markdown', type=str, default='calendar.md', help='Input/output markdown file (default: calendar.md)')
    parser.add_argument('-d', '--database', type=str, default='markdown.db', help='SQLite database file (default: markdown.db)')
    parser.add_argument('topic_title', nargs='?', type=str, help='Topic title to select (fuzzy matching enabled)')
    parser.add_argument('--bootstrap', action='store_true', help='Generate markdown calendar for the current year and load it to the database.')
    parser.add_argument('--ls', action='store_true', help='List all available headings.')
    parser.add_argument('--html', action='store_true', help='Generate an HTML version of the output.')
    parser.add_argument('--uuid', type=str, help='Specify a UUID to retrieve content.')
    parser.add_argument('--debug', action='store_true', help='Enable debug printing')
    args = parser.parse_args()

    # Setup basic logging
    logging.basicConfig(level=logging.DEBUG if args.debug else logging.INFO)

    # Check for markdown file presence
    if not os.path.exists(args.markdown) and not args.bootstrap:
        print(f"Error: Markdown file '{args.markdown}' not found. Use --bootstrap to create a new calendar.")
        db_manager.close()
        return
    # Check for databse file presence
    if not os.path.exists(args.database) and not args.bootstrap:
        print(f"Error: Database file '{args.database}' not found. Use --bootstrap to create a new calendar.")
        db_manager.close()
        return

    # Initialize manager objects
    db_manager = DatabaseManager(args.database)

    if args.bootstrap:
        print('## Running calendar bootstrap')
        bootstrap_calendar(datetime.now().year, db_manager, args.markdown)
        db_manager.close()
        return
        

    document_manager = DocumentManager(db_manager)
    
    if args.ls:
        topic_reader = TopicReader(db_manager)
        print(topic_reader.list_headings())
        db_manager.close()
        return

    # Topic or UUID-based content retrieval
    if args.topic_title or args.uuid:
        topic_reader = TopicReader(db_manager)

        if args.uuid:
            content = topic_reader.build_full_content(args.uuid)
        else:
            content = topic_reader.get_topic_content(args.topic_title)

        if content:
            # Write the selected content to the markdown file
            with open(args.markdown, 'w', encoding='utf-8') as file:
                file.write(content)
                file.write('\n')
            print(f"Selected content written to {args.markdown}")

        # Optionally convert to HTML
        if args.html:
            html_file = f"{args.markdown}.html"
            with open(html_file, 'w', encoding='utf-8') as file:
                file.write(convert_to_html(content))
            print(f"HTML version written to {html_file}")
    
    db_manager.close()

if __name__ == '__main__':
    main()