using Microsoft.Data.Sqlite;

namespace DataBase {
    
    public class DbDriver {
        
        static bool Initilized = false;

        public DbDriver() {
            // Load in the datastore if not already loaded
            if (!Initilized) {
                // Open a connection with auto dispose when done
                using (SqliteConnection sqlite = new SqliteConnection("Data Source=test.db")) {
                    // Open the connection
                    sqlite.Open();
                    // Create the key value store if not exist
                    using var command = sqlite.CreateCommand();
                    command.CommandText = """
                        CREATE TABLE IF NOT EXISTS KeyValuePair (
                            key TEXT NOT NULL,
                            value TEXT,
                            PRIMARY KEY(key)
                        );
                    """;
                    // Run the command
                    command.ExecuteReader();
                }
            }
        }

        // Return Values from keys
        public string Get(string Key) {
            // Open a connection with auto dispose when done
            using (SqliteConnection sqlite = new SqliteConnection("Data Source=test.db")) {
                // Open the connection
                sqlite.Open();
                // Create the key value store if not exist
                using var command = sqlite.CreateCommand();
                command.CommandText = """
                    SELECT value
                    FROM KeyValuePair
                    Where key = $key;
                """;
                // Add the parameter to prevent sql injection
                command.Parameters.AddWithValue("$key", Key);
                // Run the command
                using var reader = command.ExecuteReader();
                // Read off the result if exists
                if (reader.Read()) {
                    // Return the results
                    return reader.GetString(0);
                }
                // Return something if nothing existed
                return "";
            }
        }

        // Set a key value pair in the store
        public void Set(string Key, string Value) {
            // Open a connection with auto dispose when done
            using (SqliteConnection sqlite = new SqliteConnection("Data Source=test.db")) {
                // Open the connection
                sqlite.Open();
                // Create the key value store if not exist
                using var command = sqlite.CreateCommand();
                command.CommandText = """
                    INSERT INTO KeyValuePair
                    (key,value)
                    VALUES
                    ($key, $value)
                    ON CONFLICT(key)
                    DO UPDATE
                    SET value = excluded.value;
                """;
                // Add the parameters to prevent sql injection
                command.Parameters.AddWithValue("$key", Key);
                command.Parameters.AddWithValue("$value", Value);
                // Process the command
                command.ExecuteReader();
            }
        }

    }

}