app.py

from flask import Flask, request, render_template, jsonify, session
import mysql.connector
from mysql.connector import Error
import os
from groq import Groq
from dotenv import load_dotenv
import re
import uuid

app = Flask(__name__)
app.secret_key = os.urandom(24)  # Required for session management
load_dotenv()

# Default database configuration from .env (no localhost default)
default_db_config = {
    'host': os.getenv('DB_HOST', ''),
    'user': os.getenv('DB_USER', 'root'),
    'password': os.getenv('DB_PASSWORD', ''),
    'port': int(os.getenv('DB_PORT', 3306))
}

# Groq API configuration with error handling
try:
    groq_client = Groq(api_key=os.getenv('GROQ_API_KEY'))
except Exception as e:
    groq_client = None
    print(f"Failed to initialize Groq client: {str(e)}")

# Temporary storage for current database name and schema
current_db_name = None
current_schema = {}
current_summary = {}

def get_db_connection(db_name=None):
    """Establish a database connection using session or default config."""
    config = session.get('db_config', default_db_config).copy()
    if not config['host'] or not config['user']:
        return None, "Please configure a valid MySQL connection using the 'Configure MySQL Connection' modal."
    if db_name:
        config['database'] = db_name
    try:
        conn = mysql.connector.connect(**config)
        return conn, None
    except Error as e:
        return None, f"Database connection failed: {str(e)}. Ensure the MySQL server is running and accessible, and check your credentials."

def parse_sql_file(file_content):
    """Parse SQL file to extract database name and clean statements."""
    file_content = file_content.decode('utf-8') if isinstance(file_content, bytes) else file_content
    statements = []
    current_statement = ""
    in_comment = False

    # Extract database name
    db_name_match = re.search(r"CREATE\s+DATABASE\s+[`']?(\w+)[`']?", file_content, re.IGNORECASE)
    db_name = db_name_match.group(1) if db_name_match else f"temp_db_{uuid.uuid4().hex[:8]}"

    # Split SQL into statements
    for line in file_content.splitlines():
        line = line.strip()
        if not line or line.startswith('--'):
            continue
        if line.startswith('/*'):
            in_comment = True
            continue
        if line.endswith('*/'):
            in_comment = False
            continue
        if not in_comment:
            current_statement += line + ' '
            if line.endswith(';'):
                statements.append(current_statement.strip())
                current_statement = ""

    return db_name, statements

def generate_schema_summary(schema, db_name):
    """Generate a dynamic summary of any MySQL database schema."""
    summary = {
        'description': '',
        'main_tables': {},
        'relationships': [],
        'suggestions': {
            'evaluation': 'Good',
            'note': '',
            'recommendations': []
        }
    }

    # Infer description based on table names
    table_names = list(schema.keys())
    if any(table in table_names for table in ['patient', 'doctor', 'admission', 'appointment']):
        summary['description'] = f"{db_name} appears to be a Hospital Management Database for tracking entities like patients, staff, and appointments."
    elif any(table in table_names for table in ['customer', 'order', 'product', 'employee']):
        summary['description'] = f"{db_name} appears to be a Retail or E-commerce Database for managing customers, orders, and products."
    elif any(table in table_names for table in ['book', 'author', 'loan', 'member']):
        summary['description'] = f"{db_name} appears to be a Library Management Database for tracking books, authors, and loans."
    else:
        summary['description'] = f"{db_name} is a database with {len(table_names)} tables for managing various entities."

    # Select main tables (up to 5, prioritized by column count or presence of 'id')
    sorted_tables = sorted(schema.items(), key=lambda x: len(x[1]), reverse=True)[:5]
    for table, columns in sorted_tables:
        key_columns = [col for col in columns if 'id' in col.lower() or col in ['name', 'first_name', 'last_name', 'title', 'amount', 'status', 'price']]
        summary['main_tables'][table] = key_columns[:3]  # Limit to 3 key columns

    # Connect to database to detect relationships and suggestions
    conn, error = get_db_connection(db_name)
    if conn:
        cursor = conn.cursor()
        try:
            # Detect foreign keys using INFORMATION_SCHEMA
            cursor.execute("""
                SELECT TABLE_NAME, COLUMN_NAME, REFERENCED_TABLE_NAME, REFERENCED_COLUMN_NAME
                FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
                WHERE TABLE_SCHEMA = %s AND REFERENCED_TABLE_NAME IS NOT NULL
            """, (db_name,))
            relationships = cursor.fetchall()
            for rel in relationships[:5]:  # Limit to 5 relationships
                summary['relationships'].append(f"{rel[0]} links to {rel[2]} via {rel[1]}")

            # Fallback: Infer relationships from common column names
            if not relationships:
                for table1, columns1 in schema.items():
                    for col1 in columns1:
                        if '_id' in col1 and col1 != f"{table1}_id":
                            target_table = col1.replace('_id', '')
                            if target_table in schema:
                                summary['relationships'].append(f"{table1} likely links to {target_table} via {col1}")

            # Check for indexes and constraints
            cursor.execute("""
                SELECT TABLE_NAME, NON_UNIQUE, INDEX_NAME
                FROM INFORMATION_SCHEMA.STATISTICS
                WHERE TABLE_SCHEMA = %s AND INDEX_NAME != 'PRIMARY'
            """, (db_name,))
            indexes = cursor.fetchall()
            indexed_columns = set(row[0] + '.' + row[2] for row in indexes if row[1] == 0)

            # Evaluate schema
            has_foreign_keys = bool(relationships)
            has_indexes = bool(indexes)
            if has_foreign_keys and has_indexes:
                summary['suggestions']['evaluation'] = 'Excellent'
                summary['suggestions']['note'] = 'The schema is well-structured with defined foreign key constraints and indexes, supporting efficient queries.'
            elif has_foreign_keys:
                summary['suggestions']['evaluation'] = 'Good'
                summary['suggestions']['note'] = 'The schema has clear foreign key relationships but may lack sufficient indexes.'
            else:
                summary['suggestions']['evaluation'] = 'Needs Improvement'
                summary['suggestions']['note'] = 'The schema lacks explicit foreign key constraints, which may affect query reliability.'

            # Recommendations
            if not has_foreign_keys:
                summary['suggestions']['recommendations'].append('Add explicit foreign key constraints to ensure data integrity.')
            if not has_indexes:
                summary['suggestions']['recommendations'].append('Add indexes on frequently queried columns (e.g., foreign keys, date fields) to improve performance.')
            summary['suggestions']['recommendations'].append('Verify that date and numeric fields use appropriate data types for efficient querying.')

            cursor.close()
            conn.close()
        except Error as e:
            summary['suggestions']['note'] = f'Analysis limited due to: {str(e)}'
            if not summary['relationships']:
                summary['relationships'] = ['Unable to detect relationships due to limited metadata access.']

    return summary

def load_sql_file(file):
    """Load SQL file into MySQL database and generate schema summary."""
    global current_db_name, current_schema, current_summary
    try:
        file_content = file.read()
        db_name, statements = parse_sql_file(file_content)

        # Connect without specifying a database
        conn, error = get_db_connection()
        if error:
            return False, error, None
        cursor = conn.cursor()

        # Drop existing database if it exists
        cursor.execute(f"DROP DATABASE IF EXISTS `{db_name}`")
        cursor.execute(f"CREATE DATABASE `{db_name}`")
        conn.commit()
        cursor.close()
        conn.close()

        # Connect to the new database
        conn, error = get_db_connection(db_name)
        if error:
            return False, error, None
        cursor = conn.cursor()

        # Execute SQL statements
        for statement in statements:
            cursor.execute(statement)
        conn.commit()

        # Extract schema
        cursor.execute("SHOW TABLES")
        tables = [row[0] for row in cursor.fetchall()]
        schema = {}
        for table in tables:
            cursor.execute(f"SHOW COLUMNS FROM `{table}`")
            columns = [row[0] for row in cursor.fetchall()]
            schema[table] = columns

        # Generate summary
        summary = generate_schema_summary(schema, db_name)

        current_db_name = db_name
        current_schema = schema
        current_summary = summary

        cursor.close()
        conn.close()
        return True, schema, summary
    except Error as e:
        return False, f"Failed to load SQL file: {str(e)}", None

def generate_sql_query(question, schema):
    """Generate SQL query using Groq API with user-friendly aliases."""
    if not groq_client:
        return "ERROR: Groq client not initialized. Check API key and try again."

    schema_text = "\n".join([f"Table: {table}\nColumns: {', '.join(columns)}" for table, columns in schema.items()])
    prompt = f"""
You are a SQL expert. Based on the following database schema, generate a valid MySQL query for the user's question. Only use tables and columns that exist in the schema. Use user-friendly aliases for column names (e.g., 'cust_id' becomes 'Customer ID', 'admission_date' becomes 'Admission Date'). Return ONLY the SQL query, without explanations, markdown, or code block formatting (e.g., no ```). If the question references non-existent tables or columns, return an error message starting with 'ERROR:'. Do not use GROUP BY or aggregation functions (e.g., SUM, COUNT, AVG) unless the question explicitly requests aggregation (e.g., 'sum of all bills', 'average cost', 'count of patients'). Treat 'total bill amount' as the individual bill amount (e.g., bill.amount) unless aggregation is clearly specified. For names, concatenate first_name and last_name if applicable (e.g., CONCAT(first_name, ' ', last_name) AS 'Full Name'). Use direct JOINs with correct foreign key relationships. Avoid subqueries unless absolutely necessary. Place filtering conditions (e.g., department name, status) in the WHERE clause, not JOIN clauses. Handle case sensitivity in string comparisons by using LOWER() for status fields (e.g., LOWER(status) = 'unpaid'). Verify table relationships before joining.

Schema:
{schema_text}

User Question: {question}
"""
    try:
        response = groq_client.chat.completions.create(
            messages=[{"role": "user", "content": prompt}],
            model="llama3-70b-8192"
        )
        query = response.choices[0].message.content.strip()
        query = re.sub(r'```(?:sql)?\n?', '', query)  # Remove any markdown
        query = query.strip()
        return query
    except Exception as e:
        return f"ERROR: Failed to generate SQL query: {str(e)}"

def execute_sql_query(query):
    """Execute SQL query on the current database."""
    if not current_db_name:
        return False, "No database loaded. Please upload an SQL file.", None
    conn, error = get_db_connection(current_db_name)
    if error:
        return False, error, None
    try:
        cursor = conn.cursor(dictionary=True)
        cursor.execute(query)
        results = cursor.fetchall()
        conn.commit()
        cursor.close()
        conn.close()
        return True, results, None
    except Error as e:
        return False, f"SQL execution failed: {str(e)}", None

@app.route('/', methods=['GET', 'POST'])
def index():
    error = None
    schema = current_schema
    summary = current_summary
    results = None
    generated_query = None

    if not groq_client:
        error = "Groq client not initialized. Please check GROQ_API_KEY and restart the app."

    if request.method == 'POST':
        if 'sql_file' in request.files:
            file = request.files['sql_file']
            if file and file.filename.endswith('.sql'):
                success, result, summary = load_sql_file(file)
                if success:
                    schema = result
                else:
                    error = result
            else:
                error = "Please upload a valid .sql file."
        elif 'question' in request.form:
            question = request.form['question']
            if not current_db_name or not current_schema:
                error = "No database loaded. Please upload an SQL file first."
            else:
                generated_query = generate_sql_query(question, current_schema)
                if not generated_query.startswith('ERROR:'):
                    success, result, _ = execute_sql_query(generated_query)
                    if success:
                        results = result
                    else:
                        error = result
                else:
                    error = generated_query

    return render_template('index.html', error=error, schema=schema, summary=summary, results=results, query=generated_query)

@app.route('/configure_db', methods=['POST'])
def configure_db():
    """Handle MySQL connection configuration."""
    host = request.form.get('host', '').strip()
    user = request.form.get('user', '').strip()
    password = request.form.get('password', '')
    port = request.form.get('port', '3306').strip()

    if not host or not user:
        return render_template('index.html', error="Host and user are required.", schema=current_schema, summary=current_summary)

    try:
        port = int(port)
    except ValueError:
        return render_template('index.html', error="Port must be a valid number.", schema=current_schema, summary=current_summary)

    # Test connection
    test_config = {'host': host, 'user': user, 'password': password, 'port': port}
    conn, error = get_db_connection()
    if error:
        return render_template('index.html', error=error, schema=current_schema, summary=current_summary)
    
    # Store in session
    session['db_config'] = test_config
    conn.close()
    return render_template('index.html', error=None, schema=current_schema, summary=current_summary, success="MySQL connection configured successfully.")

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=int(os.getenv('PORT', 7860)), debug=False)