Updated database content, new "add" command for earnings.

src/database.rb

@@ -19,27 +19,44 @@ require 'pg'
 class Database
     def initialize
         # Connect once when the bot starts
-        @conn = PG.connect(dbname: 'frugality_database')
+        @conn = PG.connect(dbname: 'fgbot_db')
 
         init_tables
     end
 
     def init_tables
-        sql = <<~SQL
-        CREATE TABLE IF NOT EXISTS total_money (
+        sql_wallet = <<~SQL
+        CREATE TABLE IF NOT EXISTS wallets (
             user_id BIGINT PRIMARY KEY,
             amount BIGINT DEFAULT 0
         );
         SQL
 
-        @conn.exec(sql)
+        sql_ledger = <<~SQL
+        CREATE TABLE IF NOT EXISTS transactions (
+            id SERIAL PRIMARY KEY,
+            user_id BIGINT NOT NULL,
+            amount BIGINT NOT NULL,
+            reason VARCHAR(50),
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+        );
+        SQL
+
+        sql_index = <<~SQL
+        CREATE INDEX IF NOT EXISTS idx_user_history 
+        ON transactions(user_id, created_at);
+        SQL
+
+        @conn.exec(sql_wallet)
+        @conn.exec(sql_ledger)
+        @conn.exec(sql_index)
         puts "Database tables have been initialized."
     end
 
     # We pass the user_id
     def get_currency(user_id)
         # 1. Run the query using parameters ($1) to prevent SQL injection
-        result = @conn.exec_params("SELECT amount FROM total_money WHERE user_id = $1", [user_id])
+        result = @conn.exec_params("SELECT amount FROM wallets WHERE user_id = $1", [user_id])
 
         # 2. Check if the user exists
         if result.num_tuples.zero?
@@ -49,4 +66,23 @@ class Database
             return result[0]['amount'].to_i
         end
     end
+
+    def update_balance(user_id, amount, reason = "transaction")
+        @conn.transaction do
+            @conn.exec_params(
+                "INSERT INTO transactions (user_id, amount, reason) VALUES ($1, $2, $3)",
+                [user_id, amount, reason]
+            )
+            
+            # We update the user's wallet
+            sql_update = <<~SQL
+            INSERT INTO wallets (user_id, amount)
+            VALUES ($1, $2)
+            ON CONFLICT (user_id)
+            DO UPDATE SET amount = wallets.amount + $2
+            SQL
+
+            @conn.exec_params(sql_update, [user_id, amount])
+        end
+    end
 end