// Five Goroutine Demo — Go's concurrency power in Harbour syntax
// This is impossible in original Harbour!
// Copyright (c) 2026 Charles KWON OhJun (charleskwonohjun@gmail.com)

FUNCTION Main()
   LOCAL ch, wg, i, result, nTotal

   ? "=== Five Goroutine Demo ==="
   ? ""

   // --- 1. Basic goroutine with channel ---
   ? "--- 1. Goroutine + Channel ---"
   ch := Channel()
   Go({|c| ChSend(c, "Hello from goroutine!")}, ch)
   result := ChReceive(ch)
   ? "  Received:", result
   ? ""

   // --- 2. Fan-out: 5 goroutines computing in parallel ---
   ? "--- 2. Fan-out: 5 parallel workers ---"
   ch := Channel(5)
   wg := WaitGroup(5)

   FOR i := 1 TO 5
      Go("WORKER", i, ch, wg)
   NEXT

   WgWait(wg)

   FOR i := 1 TO 5
      ? " ", ChReceive(ch)
   NEXT
   ? ""

   // --- 3. Producer-Consumer pattern ---
   ? "--- 3. Producer-Consumer ---"
   ch := Channel(10)
   wg := WaitGroup(1)

   Go("PRODUCER", ch)
   Go("CONSUMER", ch, wg)

   WgWait(wg)
   ? ""

   // --- 4. Ping-Pong between two goroutines ---
   ? "--- 4. Ping-Pong ---"
   ch := Channel()
   wg := WaitGroup(1)

   Go("PINGER", ch, 5)
   Go("PONGER", ch, wg, 5)

   WgWait(wg)
   ? ""

   ? "=== Done! Harbour syntax, Go power. ==="
   RETURN NIL

// Worker: compute id^2, send result to channel
FUNCTION Worker(nId, ch, wg)
   Sleep(0.05)
   ChSend(ch, Str(nId) + "^2 = " + Str(nId * nId))
   WgDone(wg)
   RETURN NIL

// Producer: send 1..10 then sentinel -1
FUNCTION Producer(ch)
   LOCAL j
   FOR j := 1 TO 10
      ChSend(ch, j)
   NEXT
   ChSend(ch, -1)
   RETURN NIL

// Consumer: receive until sentinel, print sum
FUNCTION Consumer(ch, wg)
   LOCAL val, nSum
   nSum := 0
   DO WHILE .T.
      val := ChReceive(ch)
      IF val = -1
         EXIT
      ENDIF
      nSum += val
   ENDDO
   ? "  Sum of 1..10 =", nSum
   WgDone(wg)
   RETURN NIL

// Pinger: send "ping" n times
FUNCTION Pinger(ch, nCount)
   LOCAL i
   FOR i := 1 TO nCount
      ChSend(ch, "ping " + Str(i))
   NEXT
   RETURN NIL

// Ponger: receive and reply n times
FUNCTION Ponger(ch, wg, nCount)
   LOCAL i, msg
   FOR i := 1 TO nCount
      msg := ChReceive(ch)
      ?? "  " + msg + " -> pong!"
      ? ""
   NEXT
   WgDone(wg)
   RETURN NIL