"""
Database management functionality for MarkiTect.

This module provides SQLite database initialization and markdown file storage
with front matter support.
"""

import sqlite3
import json
import os
from datetime import datetime
from pathlib import Path
from typing import Optional, Dict, Any

from .frontmatter import FrontMatterParser


class DatabaseManager:
    """Manager for SQLite database operations."""

    def __init__(self, db_path: str):
        """
        Initialize database manager.

        Args:
            db_path: Path to SQLite database file
        """
        self.db_path = db_path
        self.front_matter_parser = FrontMatterParser()

    def initialize_database(self) -> None:
        """
        Initialize SQLite database with required tables.

        Creates the markdown_files table with the following schema:
        - id: INTEGER PRIMARY KEY
        - filename: TEXT NOT NULL
        - front_matter: TEXT (JSON)
        - content: TEXT
        - created_at: TIMESTAMP DEFAULT CURRENT_TIMESTAMP
        """
        # Ensure directory exists
        db_dir = os.path.dirname(self.db_path)
        if db_dir and not os.path.exists(db_dir):
            os.makedirs(db_dir)

        conn = sqlite3.connect(self.db_path)
        cursor = conn.cursor()

        # Create markdown_files table
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS markdown_files (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                filename TEXT NOT NULL,
                front_matter TEXT,
                content TEXT,
                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
            )
        ''')

        conn.commit()
        conn.close()

    def store_markdown_file(self, filename: str, content: str) -> Optional[int]:
        """
        Store a markdown file in the database.

        Args:
            filename: Name of the markdown file
            content: Raw markdown content with optional front matter

        Returns:
            ID of the inserted record, or None if insertion failed
        """
        # Parse front matter and content
        front_matter, markdown_content = self.front_matter_parser.parse(content)

        # Convert front matter to JSON string
        front_matter_json = json.dumps(front_matter) if front_matter else '{}'

        conn = sqlite3.connect(self.db_path)
        cursor = conn.cursor()

        try:
            cursor.execute('''
                INSERT INTO markdown_files (filename, front_matter, content, created_at)
                VALUES (?, ?, ?, ?)
            ''', (filename, front_matter_json, markdown_content, datetime.now()))

            record_id = cursor.lastrowid
            conn.commit()
            return record_id

        except sqlite3.Error:
            conn.rollback()
            return None

        finally:
            conn.close()

    def get_markdown_file(self, filename: str) -> Optional[Dict[str, Any]]:
        """
        Retrieve a markdown file from the database.

        Args:
            filename: Name of the markdown file to retrieve

        Returns:
            Dictionary containing file data, or None if not found
        """
        conn = sqlite3.connect(self.db_path)
        cursor = conn.cursor()

        cursor.execute('''
            SELECT id, filename, front_matter, content, created_at
            FROM markdown_files
            WHERE filename = ?
        ''', (filename,))

        row = cursor.fetchone()
        conn.close()

        if row:
            return {
                'id': row[0],
                'filename': row[1],
                'front_matter': json.loads(row[2]) if row[2] else {},
                'content': row[3],
                'created_at': row[4]
            }

        return None

    def list_markdown_files(self) -> list:
        """
        List all markdown files in the database.

        Returns:
            List of dictionaries containing file metadata
        """
        conn = sqlite3.connect(self.db_path)
        cursor = conn.cursor()

        cursor.execute('''
            SELECT id, filename, front_matter, created_at
            FROM markdown_files
            ORDER BY created_at DESC
        ''')

        rows = cursor.fetchall()
        conn.close()

        files = []
        for row in rows:
            files.append({
                'id': row[0],
                'filename': row[1],
                'front_matter': json.loads(row[2]) if row[2] else {},
                'created_at': row[3]
            })

        return files

    def execute_query(self, sql: str) -> list:
        """
        Execute a read-only SQL query against the database.

        Args:
            sql: SQL query string (SELECT operations only)

        Returns:
            List of dictionaries representing query results

        Raises:
            ValueError: If query contains non-SELECT operations
            sqlite3.Error: If query execution fails
        """
        # Security check: only allow SELECT queries
        sql_upper = sql.strip().upper()
        if not sql_upper.startswith('SELECT'):
            allowed_starts = ['SELECT', 'WITH']  # Allow WITH for CTEs
            if not any(sql_upper.startswith(start) for start in allowed_starts):
                raise ValueError("Only SELECT and WITH queries are allowed for safety")

        # Additional safety checks for dangerous keywords (as whole words)
        dangerous_keywords = [
            'DROP', 'DELETE', 'UPDATE', 'INSERT', 'CREATE', 'ALTER',
            'TRUNCATE', 'REPLACE', 'PRAGMA'
        ]
        import re
        for keyword in dangerous_keywords:
            # Use word boundaries to match only complete words
            pattern = r'\b' + keyword + r'\b'
            if re.search(pattern, sql_upper):
                raise ValueError(f"Query contains dangerous keyword: {keyword}")

        conn = sqlite3.connect(self.db_path)
        conn.row_factory = sqlite3.Row  # Enable column access by name
        cursor = conn.cursor()

        try:
            cursor.execute(sql)
            rows = cursor.fetchall()

            # Convert rows to dictionaries
            results = []
            for row in rows:
                results.append(dict(row))

            conn.close()
            return results

        except sqlite3.Error as e:
            conn.close()
            raise e

    def get_schema(self) -> dict:
        """
        Get database schema information.

        Returns:
            Dictionary containing table schemas with column information
        """
        conn = sqlite3.connect(self.db_path)
        cursor = conn.cursor()

        schema = {}

        try:
            # Get all table names
            cursor.execute("SELECT name FROM sqlite_master WHERE type='table'")
            tables = cursor.fetchall()

            for table_row in tables:
                table_name = table_row[0]

                # Get column information for each table
                cursor.execute(f"PRAGMA table_info({table_name})")
                columns = cursor.fetchall()

                column_info = []
                for col in columns:
                    column_info.append({
                        'name': col[1],
                        'type': col[2],
                        'nullable': not bool(col[3]),  # notnull flag
                        'default_value': col[4],
                        'primary_key': bool(col[5])
                    })

                schema[table_name] = {
                    'columns': column_info
                }

            conn.close()
            return schema

        except sqlite3.Error as e:
            conn.close()
            raise e