📈 StreamOpenedOrderProfits (GoMT4)

Goal: subscribe to live profit updates for currently opened orders with auto‑reconnect and clean shutdown.

Real code refs you already ship:

• Streaming helper: examples/mt4/MT4Account.go (OnOpenedOrdersProfit)
• Service method: examples/mt4/MT4_service.go (StreamOpenedOrderProfits)
• Docs: docs/Streaming/StreamOpenedOrderProfits.md

---

✅ 1) Preconditions

• MT4 terminal is running & connected.
• There are open positions; otherwise, the stream will be mostly silent.

---

▶️ 2) Service method example

func (s *MT4Service) StreamOpenedOrderProfits(ctx context.Context) {
    ctx, cancel := context.WithCancel(ctx)
    defer cancel()

    // Second argument = buffer size for channel
    profitCh, errCh := s.account.OnOpenedOrdersProfit(ctx, 1000)

    fmt.Println("🔄 Streaming order profits...")

    for {
        select {
        case profit, ok := <-profitCh:
            if !ok {
                fmt.Println("✅ Profit stream ended.")
                return
            }
            // profit.OpenedOrdersWithProfitUpdated is []*OnOpenedOrdersProfitOrderInfo
            for _, info := range profit.OpenedOrdersWithProfitUpdated {
                fmt.Printf("[Profit] Ticket: %d | Symbol: %s | Profit: %.2f\n",
                    info.Ticket, info.Symbol, info.OrderProfit)
            }

        case err := <-errCh:
            log.Printf("❌ Stream error: %v", err)
            return

        case <-time.After(30 * time.Second):
            fmt.Println("⏱️ Timeout reached.")
            return
        }
    }
}

---

🧭 3) Backoff & health checks

• Under the hood, OnOpenedOrdersProfit auto‑reconnects on transient errors (io.EOF, codes.Unavailable).
• Reconnect delays are controlled by constants in MT4Account.go (backoff+jitter).

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🧰 4) Processing tips

• Keep the loop non‑blocking — heavy work (DB, reporting) should go to a worker via buffered channel.
• Aggregate by ticket to compute running P/L per position.
• Combine with StreamQuotes for unrealized P/L analysis.

---

⚠️ Pitfalls

• No positions → stream may emit nothing; normal if no orders open.
• Context canceled → stream ends; always handle <-ctx.Done()>.
• Backpressure → if you stop reading profitCh, the stream can stall.
• Timeout → in this demo, time.After(30s) closes the loop; in production use context deadlines.

---

🔗 See also

• AccountSummary.md — snapshot of balance/equity/margins.
• StreamQuotes.md — combine with quotes to analyze P/L dynamics.
• Reliability (en) — timeouts, reconnects & backoff patterns.