import os
import sqlite3
import csv
from dotenv import load_dotenv

# Load environment variables from .env file
load_dotenv()

# SQLite DB path from .env for saving results
db_path = os.getenv("db_path", "./query_logs.db")

# Function to initialize the SQLite database
def initialize_local_db():
    conn = sqlite3.connect(db_path)
    cursor = conn.cursor()

    # Check if the reformulated_query column exists
    cursor.execute("PRAGMA table_info(query_logs);")
    columns = [column[1] for column in cursor.fetchall()]

    # If the reformulated_query column doesn't exist, alter the table
    if 'reformulated_query' not in columns:
        print("Altering table to add reformulated_query column...")
        cursor.execute('''
        CREATE TABLE IF NOT EXISTS query_logs_new (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            natural_language_query TEXT,
            reformulated_query TEXT,
            generated_sql TEXT,
            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
        );
        ''')

        # Copy data from old table to new table
        cursor.execute('''
        INSERT INTO query_logs_new (id, natural_language_query, generated_sql, created_at)
        SELECT id, natural_language_query, generated_sql, created_at FROM query_logs;
        ''')

        # Drop the old table
        cursor.execute("DROP TABLE query_logs;")

        # Rename the new table
        cursor.execute("ALTER TABLE query_logs_new RENAME TO query_logs;")

    conn.commit()
    cursor.close()
    conn.close()

# Function to reset (drop all tables) and recreate the schema
def reset_sqlite_db():
    conn = sqlite3.connect(db_path)
    cursor = conn.cursor()

    # Drop the query_logs table
    cursor.execute("DROP TABLE IF EXISTS query_logs;")
    print("Dropped query_logs table")

    # Recreate the query_logs table
    cursor.execute('''CREATE TABLE query_logs (
                        id INTEGER PRIMARY KEY AUTOINCREMENT,
                        natural_language_query TEXT,
                        reformulated_query TEXT,
                        generated_sql TEXT,
                        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
                      );''')
    print("Recreated the query_logs table.")

    conn.commit()
    cursor.close()
    conn.close()

# Function to save the natural language query, reformulated query, and generated SQL to the local SQLite DB
def save_query_to_local_db(nl_query, reformulated_query, sql_query):
    try:
        conn = sqlite3.connect(db_path)
        cursor = conn.cursor()
        insert_query = '''
        INSERT INTO query_logs (natural_language_query, reformulated_query, generated_sql)
        VALUES (?, ?, ?);
        '''
        cursor.execute(insert_query, (nl_query, reformulated_query, sql_query))
        conn.commit()
        cursor.close()
        conn.close()
    except Exception as e:
        print(f"Error saving query: {e}")

# Function to retrieve saved queries from the local SQLite DB with pagination and search
def get_saved_queries(page=1, per_page=10, search_term=None):
    try:
        offset = (page - 1) * per_page
        conn = sqlite3.connect(db_path)
        cursor = conn.cursor()

        query = "SELECT natural_language_query, reformulated_query, generated_sql, created_at FROM query_logs"
        if search_term:
            query += f" WHERE natural_language_query LIKE '%{search_term}%' OR generated_sql LIKE '%{search_term}%'"
        query += f" ORDER BY created_at DESC LIMIT {per_page} OFFSET {offset};"

        cursor.execute(query)
        rows = cursor.fetchall()

        cursor.close()
        conn.close()

        return rows
    except Exception as e:
        return str(e)

# Manually clear all data (for testing purposes)
def clear_data():
    conn = sqlite3.connect(db_path)
    cursor = conn.cursor()
    cursor.execute("DELETE FROM query_logs")
    conn.commit()
    cursor.close()
    conn.close()

# Function to retrieve the last 50 saved queries from the local SQLite DB
def get_last_50_saved_queries():
    try:
        conn = sqlite3.connect(db_path)
        cursor = conn.cursor()

        query = "SELECT natural_language_query, reformulated_query, generated_sql, created_at FROM query_logs ORDER BY created_at DESC LIMIT 50;"
        cursor.execute(query)
        rows = cursor.fetchall()

        cursor.close()
        conn.close()

        return rows
    except Exception as e:
        return str(e)

# Function to export all saved queries to a CSV file
def export_saved_queries_to_csv(file_path="./saved_queries.csv"):
    try:
        conn = sqlite3.connect(db_path)
        cursor = conn.cursor()

        # Fetch all saved queries (remove LIMIT 50)
        cursor.execute("SELECT natural_language_query, reformulated_query, generated_sql, created_at FROM query_logs ORDER BY created_at DESC;")
        rows = cursor.fetchall()

        # Write the results to a CSV file
        with open(file_path, 'w', newline='') as csvfile:
            csv_writer = csv.writer(csvfile)
            csv_writer.writerow(['Natural Language Query', 'Reformulated Query', 'Generated SQL', 'Timestamp'])
            csv_writer.writerows(rows)

        cursor.close()
        conn.close()

        return file_path
    except Exception as e:
        return str(e)

# Uncomment the following line to reset the SQLite database when you run this script
# reset_sqlite_db()