// Copyright (c) 2026 Charles KWON OhJun (charleskwonohjun@gmail.com)
// All rights reserved.

// RTL goroutine functions for PRG code:
// GO(bBlock|cFunc, ...) — launch goroutine
// CHANNEL([nSize]) — create channel
// CHSEND(ch, xValue) — send to channel
// CHRECEIVE(ch) ��� receive from channel
// CHCLOSE(ch) — close channel
// WAITGROUP(nCount) — create WaitGroup
// WGDONE(wg) — WaitGroup.Done()
// WGWAIT(wg) — WaitGroup.Wait()
// WGADD(wg, n) — WaitGroup.Add(n)
// MUTEX() — create Mutex
// LOCK(mtx) — Mutex.Lock()
// UNLOCK(mtx) — Mutex.Unlock()
// SLEEP(nSeconds) — time.Sleep

package hbrtl

import (
	"five/hbrt"
	"time"
)

// GO(bBlock [, args...]) — launch goroutine with code block or function
// Returns NIL immediately (goroutine runs in background).
func GoFunc(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()

	first := t.Local(1)

	// Collect args
	args := make([]hbrt.Value, 0, nParams-1)
	for i := 2; i <= nParams; i++ {
		args = append(args, t.Local(i))
	}

	vm := t.VM()

	if first.IsBlock() {
		blk := first.AsBlock()
		vm.GoLaunchBlock(blk, args)
	} else if first.IsString() {
		// Function name as string — find symbol and launch
		sym := vm.FindSymbol(first.AsString())
		if sym != nil && sym.Func != nil {
			vm.GoLaunch(sym.Func, args)
		}
	}

	t.RetNil()
}

// CHANNEL([nBufferSize]) → pChannel
func ChannelFunc(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()

	size := 0
	if nParams >= 1 && !t.Local(1).IsNil() {
		size = t.Local(1).AsInt()
	}
	t.RetVal(hbrt.MakeChannel(size))
}

// CHSEND(pChannel, xValue) → NIL
func ChSend(t *hbrt.Thread) {
	t.Frame(2, 0)
	defer t.EndProc()

	ch := t.Local(1).AsChannel()
	if ch == nil {
		t.RetNil()
		return
	}
	ch.Send(t.Local(2))
	t.RetNil()
}

// CHRECEIVE(pChannel) → xValue
func ChReceive(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()

	ch := t.Local(1).AsChannel()
	if ch == nil {
		t.RetNil()
		return
	}
	t.RetVal(ch.Receive())
}

// CHCLOSE(pChannel) → NIL
func ChClose(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()

	ch := t.Local(1).AsChannel()
	if ch != nil {
		ch.Close()
	}
	t.RetNil()
}

// WAITGROUP([nCount]) → pWaitGroup
func WaitGroupFunc(t *hbrt.Thread) {
	nParams := t.ParamCount()
	t.Frame(nParams, 0)
	defer t.EndProc()

	n := 0
	if nParams >= 1 && !t.Local(1).IsNil() {
		n = t.Local(1).AsInt()
	}
	t.RetVal(hbrt.MakeWaitGroup(n))
}

// WGDONE(pWaitGroup) �� NIL
func WgDone(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()

	wg := t.Local(1).AsWaitGroup()
	if wg != nil {
		wg.WG.Done()
	}
	t.RetNil()
}

// WGWAIT(pWaitGroup) → NIL
func WgWait(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()

	wg := t.Local(1).AsWaitGroup()
	if wg != nil {
		wg.WG.Wait()
	}
	t.RetNil()
}

// WGADD(pWaitGroup, nDelta) → NIL
func WgAdd(t *hbrt.Thread) {
	t.Frame(2, 0)
	defer t.EndProc()

	wg := t.Local(1).AsWaitGroup()
	if wg != nil {
		wg.WG.Add(t.Local(2).AsInt())
	}
	t.RetNil()
}

// MUTEX() → pMutex
func MutexFunc(t *hbrt.Thread) {
	t.Frame(0, 0)
	defer t.EndProc()
	t.RetVal(hbrt.MakeMutex())
}

// LOCK(pMutex) → NIL
func LockFunc(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()

	mu := t.Local(1).AsMutex()
	if mu != nil {
		mu.Mu.Lock()
	}
	t.RetNil()
}

// UNLOCK(pMutex) → NIL
func UnlockFunc(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()

	mu := t.Local(1).AsMutex()
	if mu != nil {
		mu.Mu.Unlock()
	}
	t.RetNil()
}

// SLEEP(nSeconds) → NIL
// Supports fractional seconds: Sleep(0.1) = 100ms
func SleepFunc(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()

	val := t.Local(1)
	var dur time.Duration
	if val.IsNumInt() {
		dur = time.Duration(val.AsLong()) * time.Second
	} else {
		dur = time.Duration(val.AsNumDouble() * float64(time.Second))
	}
	time.Sleep(dur)
	t.RetNil()
}