source: server/account.go@ a531b45

package main

import (
        "fmt"
        "strconv"
        "strings"

        "bp_project/server/db"
)

// ShowBalance prints the logged-in user's balances.
func ShowBalance(s *Session) {
        var avail, invested float64
        err := db.DB.QueryRow(
                `SELECT available_balance, invested_balance FROM users WHERE id = $1`,
                s.UserID,
        ).Scan(&avail, &invested)
        if err != nil {
                fmt.Println("Error:", err)
                return
        }
        fmt.Printf("\n  Available: %.4f USD\n", avail)
        fmt.Printf("  Invested : %.4f USD\n", invested)
        fmt.Printf("  Total    : %.4f USD\n", avail+invested)
}

// Deposit - UC0003
// Transactional: updates users.available_balance and inserts a ledger row.
func Deposit(s *Session) {
        fmt.Println("\n-- Deposit virtual funds --")
        amtStr := prompt("Amount (USD): ")
        amt, err := strconv.ParseFloat(amtStr, 64)
        if err != nil || amt <= 0 {
                fmt.Println("Invalid amount.")
                return
        }

        tx, err := db.DB.Begin()
        if err != nil {
                fmt.Println("Error:", err)
                return
        }
        defer tx.Rollback()

        if _, err := tx.Exec(
                `UPDATE users
                    SET available_balance = available_balance + $1,
                        updated_at        = now()
                  WHERE id = $2`,
                amt, s.UserID,
        ); err != nil {
                fmt.Println("Error:", err)
                return
        }
        if _, err := tx.Exec(
                `INSERT INTO transactions (user_id, type, amount, currency, description)
                 VALUES ($1, 'deposit', $2, 'USD', 'Virtual deposit')`,
                s.UserID, amt,
        ); err != nil {
                fmt.Println("Error:", err)
                return
        }
        if err := tx.Commit(); err != nil {
                fmt.Println("Error:", err)
                return
        }
        fmt.Printf("Deposited %.4f USD.\n", amt)
}

// ShowTransactions lists the last 20 ledger entries for the user.
func ShowTransactions(s *Session) {
        rows, err := db.DB.Query(
                `SELECT created_at, type, amount, currency, COALESCE(description, '')
                   FROM transactions
                  WHERE user_id = $1
                  ORDER BY created_at DESC
                  LIMIT 20`,
                s.UserID,
        )
        if err != nil {
                fmt.Println("Error:", err)
                return
        }
        defer rows.Close()

        fmt.Println()
        fmt.Printf("  %-20s  %-8s  %12s  %-3s  %s\n", "When", "Type", "Amount", "Cur", "Description")
        fmt.Println("  " + strings.Repeat("-", 70))
        for rows.Next() {
                var when, typ, cur, desc string
                var amt float64
                if err := rows.Scan(&when, &typ, &amt, &cur, &desc); err != nil {
                        fmt.Println("scan error:", err)
                        return
                }
                fmt.Printf("  %-20s  %-8s  %12.4f  %-3s  %s\n", when[:19], typ, amt, cur, desc)
        }
}