package display

import (
	"context"
	"fmt"
	"os"
	"sort"
	"strconv"
	"strings"
	"time"

	"codeberg.org/snonux/loadbars/internal/collector"
	"codeberg.org/snonux/loadbars/internal/config"
	"codeberg.org/snonux/loadbars/internal/constants"
	"codeberg.org/snonux/loadbars/internal/stats"
	"codeberg.org/snonux/loadbars/internal/version"
	"github.com/veandco/go-sdl2/sdl"
)

const smoothFactor = 0.12 // blend toward target each frame; lower = smoother

// runState holds mutable state across the display loop (hotkeys, window size, smoothed data).
type runState struct {
	showCores       bool
	showMem         bool
	showNet         bool
	extended        bool
	winW            int32
	winH            int32
	lastNumBars     int
	lastWinW        int32
	lastWinH        int32
	prevCPU         map[string]collector.CPULine
	smoothedCPU     map[string]*[9]float64
	smoothedMem     map[string]*struct{ ramUsed, swapUsed float64 }
	smoothedNet     map[string]*struct{ rxPct, txPct float64 }
	prevNet         map[string]stats.NetStamp
	netIntIndex     map[string]int
	cycleNetNext    bool
	printNetInfoOnce bool
	peakHistory     map[string][]float64
}

// newRunState builds initial run state from config.
func newRunState(cfg *config.Config, winW, winH int32) *runState {
	return &runState{
		showCores:        cfg.ShowCores,
		showMem:          cfg.ShowMem,
		showNet:          cfg.ShowNet,
		extended:         cfg.Extended,
		winW:             winW,
		winH:             winH,
		lastNumBars:      -1,
		prevCPU:          make(map[string]collector.CPULine),
		smoothedCPU:      make(map[string]*[9]float64),
		smoothedMem:      make(map[string]*struct{ ramUsed, swapUsed float64 }),
		smoothedNet:      make(map[string]*struct{ rxPct, txPct float64 }),
		prevNet:          make(map[string]stats.NetStamp),
		netIntIndex:      make(map[string]int),
		printNetInfoOnce: cfg.ShowNet,
		peakHistory:      make(map[string][]float64),
	}
}

// Run runs the SDL display loop until ctx is cancelled or user presses 'q'.
func Run(ctx context.Context, cfg *config.Config, src stats.Source) error {
	if err := sdl.Init(sdl.INIT_VIDEO); err != nil {
		return fmt.Errorf("sdl init: %w", err)
	}
	defer sdl.Quit()

	const minWindowWidth = 800
	width := clampInt(cfg.BarWidth, minWindowWidth, cfg.MaxWidth)
	height := cfg.Height
	if height < 1 {
		height = 1
	}
	title := cfg.Title
	if title == "" {
		title = "Loadbars " + version.Version + " (press h for help on stdout)"
	}
	window, renderer, err := sdl.CreateWindowAndRenderer(int32(width), int32(height), sdl.WINDOW_RESIZABLE)
	if err != nil {
		return fmt.Errorf("create window: %w", err)
	}
	defer window.Destroy()
	defer renderer.Destroy()
	window.SetTitle(title)

	// On macOS, bring the window to the foreground
	activateWindow()

	state := newRunState(cfg, int32(width), int32(height))
	ticker := time.NewTicker(time.Duration(constants.IntervalSDL * float64(time.Second)))
	defer ticker.Stop()

	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		default:
		}
		if handleEvents(window, cfg, state) {
			return nil
		}
		drawFrame(renderer, src, cfg, state)
		renderer.Present()
		sdl.Delay(10)
		<-ticker.C
	}
}

func clampInt(v, min, max int) int {
	if v < min {
		return min
	}
	if v > max {
		return max
	}
	return v
}

// handleEvents processes all pending SDL events and updates state. Returns true if the user quit.
func handleEvents(window *sdl.Window, cfg *config.Config, state *runState) bool {
	for e := sdl.PollEvent(); e != nil; e = sdl.PollEvent() {
		switch ev := e.(type) {
		case *sdl.QuitEvent:
			return true
		case *sdl.KeyboardEvent:
			if ev.Type != sdl.KEYDOWN || ev.Repeat != 0 {
				continue
			}
			if handleKey(ev.Keysym.Sym, window, cfg, state) {
				return true
			}
		case *sdl.WindowEvent:
			if ev.Event == sdl.WINDOWEVENT_RESIZED {
				state.winW, state.winH = ev.Data1, ev.Data2
			}
		}
	}
	return false
}

// handleKey handles one key press; returns true to quit.
func handleKey(sym sdl.Keycode, window *sdl.Window, cfg *config.Config, state *runState) bool {
	switch sym {
	case sdl.K_q:
		return true
	case sdl.K_1:
		state.showCores = !state.showCores
		fmt.Println("==> Toggled show cores:", state.showCores)
	case sdl.K_2:
		state.showMem = !state.showMem
		fmt.Println("==> Toggled show mem:", state.showMem)
	case sdl.K_3:
		state.showNet = !state.showNet
		fmt.Println("==> Toggled show net:", state.showNet)
		if state.showNet {
			state.printNetInfoOnce = true
		}
	case sdl.K_e:
		state.extended = !state.extended
		fmt.Println("==> Toggled extended (peak line):", state.extended)
	case sdl.K_a:
		cfg.CPUAverage++
		fmt.Println("==> CPU average samples:", cfg.CPUAverage)
	case sdl.K_y:
		if cfg.CPUAverage > 1 {
			cfg.CPUAverage--
		}
		fmt.Println("==> CPU average samples:", cfg.CPUAverage)
	case sdl.K_d:
		cfg.NetAverage++
		fmt.Println("==> Net average samples:", cfg.NetAverage)
	case sdl.K_c:
		if cfg.NetAverage > 1 {
			cfg.NetAverage--
		}
		fmt.Println("==> Net average samples:", cfg.NetAverage)
	case sdl.K_h:
		printHotkeys()
	case sdl.K_n:
		state.cycleNetNext = true
		if state.showNet {
			fmt.Println("==> Cycling to next network interface (per host)")
		}
	case sdl.K_w:
		cfg.ShowCores = state.showCores
		cfg.ShowMem = state.showMem
		cfg.ShowNet = state.showNet
		cfg.Extended = state.extended
		if err := cfg.Write(); err != nil {
			fmt.Fprintf(os.Stderr, "!!! Write config: %v\n", err)
		} else {
			fmt.Println("==> Config written to ~/.loadbarsrc")
		}
	case sdl.K_LEFT:
		state.winW -= 100
		if state.winW < 1 {
			state.winW = 1
		}
		window.SetSize(state.winW, state.winH)
	case sdl.K_RIGHT:
		state.winW += 100
		if state.winW > int32(cfg.MaxWidth) {
			state.winW = int32(cfg.MaxWidth)
		}
		window.SetSize(state.winW, state.winH)
	case sdl.K_UP:
		state.winH -= 100
		if state.winH < 1 {
			state.winH = 1
		}
		window.SetSize(state.winW, state.winH)
	case sdl.K_DOWN:
		state.winH += 100
		window.SetSize(state.winW, state.winH)
	}
	return false
}

// drawFrame updates state from snapshot, clears if layout changed, and draws all bars.
func drawFrame(renderer *sdl.Renderer, src stats.Source, cfg *config.Config, state *runState) {
	snap := src.Snapshot()
	if state.cycleNetNext {
		for _, host := range sortedHosts(snap) {
			state.netIntIndex[host]++
		}
		state.cycleNetNext = false
	}
	if state.printNetInfoOnce && state.showNet {
		state.printNetInfoOnce = false
		printNetInterfaceHelp(snap, cfg, state.netIntIndex)
	}
	numBars := countBars(snap, state.showCores, state.showMem, state.showNet)
	barWidth := state.winW / int32(numBars)
	if barWidth < 1 {
		barWidth = 1
	}
	if numBars != state.lastNumBars || state.winW != state.lastWinW || state.winH != state.lastWinH {
		renderer.SetDrawColor(0, 0, 0, 255)
		renderer.Clear()
		state.lastNumBars = numBars
		state.lastWinW, state.lastWinH = state.winW, state.winH
	}
	drawBars(renderer, snap, cfg, state, barWidth)
}

func countBars(snap map[string]*stats.HostStats, showCores, showMem, showNet bool) int {
	n := 0
	for _, host := range sortedHosts(snap) {
		if h := snap[host]; h != nil {
			n += len(sortedCPUNames(h.CPU, showCores))
			if showMem {
				n++
			}
			if showNet {
				n++
			}
		}
	}
	if n == 0 {
		n = 1
	}
	return n
}

// drawBars draws CPU, memory, and network bars for all hosts in snap.
func drawBars(renderer *sdl.Renderer, snap map[string]*stats.HostStats, cfg *config.Config, state *runState, barWidth int32) {
	x := int32(0)
	for _, host := range sortedHosts(snap) {
		h := snap[host]
		if h == nil {
			continue
		}
		drawHostBars(renderer, h, host, cfg, state, barWidth, &x)
	}
}

// drawHostBars draws CPU, mem, and net bars for one host and advances x.
func drawHostBars(renderer *sdl.Renderer, h *stats.HostStats, host string, cfg *config.Config, state *runState, barWidth int32, x *int32) {
	winH := state.winH
	cpuNames := sortedCPUNames(h.CPU, state.showCores)
	for _, name := range cpuNames {
		key := host + ";" + name
		cur := h.CPU[name]
		prev := state.prevCPU[key]
		state.prevCPU[key] = cur
		target, ok := cpuBarTargetPcts(cur, prev)
		s := state.smoothedCPU[key]
		if s == nil {
			s = &[9]float64{}
			state.smoothedCPU[key] = s
			if ok {
				*s = target
			}
		} else if ok {
			for i := 0; i < 9; i++ {
				(*s)[i] += (target[i] - (*s)[i]) * smoothFactor
			}
			normalizePcts9(s)
		}
		peakPct := peakPctForBar(state, key, cfg.CPUAverage, s)
		drawCPUBarFromPcts(renderer, s, barWidth, x, winH, state.extended, peakPct)
	}
	if state.showMem {
		if state.smoothedMem[host] == nil {
			state.smoothedMem[host] = &struct{ ramUsed, swapUsed float64 }{}
		}
		drawMemBarSmoothed(renderer, h, state.smoothedMem[host], smoothFactor, barWidth, x, winH)
	}
	if state.showNet {
		if state.smoothedNet[host] == nil {
			state.smoothedNet[host] = &struct{ rxPct, txPct float64 }{}
		}
		state.prevNet[host] = drawNetBarSmoothed(renderer, h, cfg, state.smoothedNet[host], state.prevNet[host], state.netIntIndex, host, smoothFactor, barWidth, x, winH)
	}
}

func peakPctForBar(state *runState, key string, cpuAvg int, s *[9]float64) float64 {
	if !state.extended || s == nil {
		return 0
	}
	userSys := (*s)[0] + (*s)[1]
	hist := state.peakHistory[key]
	hist = append(hist, userSys)
	n := cpuAvg
	if n < 1 {
		n = 1
	}
	for len(hist) > n {
		hist = hist[1:]
	}
	state.peakHistory[key] = hist
	var max float64
	for _, v := range hist {
		if v > max {
			max = v
		}
	}
	return max
}

func sortedHosts(snap map[string]*stats.HostStats) []string {
	out := make([]string, 0, len(snap))
	for h := range snap {
		out = append(out, h)
	}
	sort.Strings(out)
	return out
}

func sortedCPUNames(cpu map[string]collector.CPULine, showCores bool) []string {
	var names []string
	for name := range cpu {
		if name == "cpu" {
			names = append(names, "cpu")
			continue
		}
		if showCores {
			names = append(names, name)
		}
	}
	sort.Slice(names, func(i, j int) bool {
		if names[i] == "cpu" {
			return true
		}
		if names[j] == "cpu" {
			return false
		}
		return names[i] < names[j]
	})
	return names
}

// cpuBarTargetPcts returns the 9 segment percentages (system, user, nice, idle, iowait, irq, softirq, guest, steal) from cur/prev delta. ok is false if no valid sample.
func cpuBarTargetPcts(cur, prev collector.CPULine) (out [9]float64, ok bool) {
	totalCur := cur.Total()
	totalPrev := prev.Total()
	if totalPrev == 0 || totalCur <= totalPrev {
		return out, false
	}
	scale := float64(totalCur-totalPrev) / 100.0
	if scale <= 0 {
		return out, false
	}
	out[0] = float64(cur.System-prev.System) / scale
	out[1] = float64(cur.User-prev.User) / scale
	out[2] = float64(cur.Nice-prev.Nice) / scale
	out[3] = float64(cur.Idle-prev.Idle) / scale
	out[4] = float64(cur.Iowait-prev.Iowait) / scale
	out[5] = float64(cur.IRQ-prev.IRQ) / scale
	out[6] = float64(cur.SoftIRQ-prev.SoftIRQ) / scale
	out[7] = float64(cur.Guest-prev.Guest) / scale
	out[8] = float64(cur.Steal-prev.Steal) / scale
	for i := range out {
		if out[i] < 0 {
			out[i] = 0
		}
		if out[i] > 100 {
			out[i] = 100
		}
	}
	return out, true
}

func normalizePcts9(s *[9]float64) {
	var sum float64
	for i := 0; i < 9; i++ {
		sum += (*s)[i]
	}
	if sum <= 0 {
		return
	}
	for i := 0; i < 9; i++ {
		(*s)[i] = (*s)[i] * 100 / sum
	}
}

// drawCPUBarFromPcts draws one CPU bar from 9 smoothed segment percentages. If s is nil, advances x only.
// When extended is true and peakPct > 0, draws a 1px peak line (max system+user over history).
func drawCPUBarFromPcts(renderer *sdl.Renderer, s *[9]float64, barW int32, x *int32, winH int32, extended bool, peakPct float64) {
	defer func() { *x += barW }()
	// Clear this slot so we never leave previous (e.g. mem/net) content visible
	renderer.SetDrawColor(constants.Black.R, constants.Black.G, constants.Black.B, 255)
	renderer.FillRect(&sdl.Rect{X: *x, Y: 0, W: barW, H: winH})
	if s == nil {
		return
	}
	barH := float64(winH) / 100.0
	y := float64(winH)
	fill := func(r, g, b uint8, pct float64) {
		hh := int32(pct * barH)
		if hh < 1 && pct > 0 {
			hh = 1
		}
		y -= float64(hh)
		renderer.SetDrawColor(r, g, b, 255)
		renderer.FillRect(&sdl.Rect{X: *x, Y: int32(y), W: barW, H: hh})
	}
	fill(constants.Blue.R, constants.Blue.G, constants.Blue.B, (*s)[0])       // system
	fill(constants.Yellow.R, constants.Yellow.G, constants.Yellow.B, (*s)[1]) // user
	fill(constants.Green.R, constants.Green.G, constants.Green.B, (*s)[2])    // nice
	fill(constants.Black.R, constants.Black.G, constants.Black.B, (*s)[3])    // idle
	fill(constants.Purple.R, constants.Purple.G, constants.Purple.B, (*s)[4]) // iowait
	fill(constants.White.R, constants.White.G, constants.White.B, (*s)[5])    // irq
	fill(constants.White.R, constants.White.G, constants.White.B, (*s)[6])    // softirq
	fill(constants.Red.R, constants.Red.G, constants.Red.B, (*s)[7])          // guest
	fill(constants.Red.R, constants.Red.G, constants.Red.B, (*s)[8])          // steal
	// Extended: 1px peak line at max (system+user) over history
	if extended && peakPct > 0 {
		peakY := winH - int32(peakPct*barH)
		if peakY < 0 {
			peakY = 0
		}
		if peakY >= winH {
			peakY = winH - 1
		}
		if peakPct > float64(constants.UserOrangeThreshold) {
			renderer.SetDrawColor(constants.Orange.R, constants.Orange.G, constants.Orange.B, 255)
		} else if peakPct > float64(constants.UserYellowThreshold) {
			renderer.SetDrawColor(constants.Yellow0.R, constants.Yellow0.G, constants.Yellow0.B, 255)
		} else {
			renderer.SetDrawColor(constants.Yellow.R, constants.Yellow.G, constants.Yellow.B, 255)
		}
		renderer.FillRect(&sdl.Rect{X: *x, Y: peakY, W: barW, H: 1})
	}
}

// drawMemBarSmoothed blends mem stats toward target and draws one memory bar (RAM left, Swap right).
func drawMemBarSmoothed(renderer *sdl.Renderer, h *stats.HostStats, smoothed *struct{ ramUsed, swapUsed float64 }, factor float64, barW int32, x *int32, winH int32) {
	defer func() { *x += barW }()
	// Clear this slot so we never leave previous (e.g. CPU/net) content visible
	renderer.SetDrawColor(constants.Black.R, constants.Black.G, constants.Black.B, 255)
	renderer.FillRect(&sdl.Rect{X: *x, Y: 0, W: barW, H: winH})
	if h.Mem == nil {
		return
	}
	var targetRam, targetSwap float64
	if memTotal := h.Mem["MemTotal"]; memTotal > 0 {
		targetRam = 100 - 100*float64(h.Mem["MemFree"])/float64(memTotal)
		if targetRam < 0 {
			targetRam = 0
		}
		if targetRam > 100 {
			targetRam = 100
		}
	}
	if swapTotal := h.Mem["SwapTotal"]; swapTotal > 0 {
		targetSwap = 100 - 100*float64(h.Mem["SwapFree"])/float64(swapTotal)
		if targetSwap < 0 {
			targetSwap = 0
		}
		if targetSwap > 100 {
			targetSwap = 100
		}
	}
	smoothed.ramUsed += (targetRam - smoothed.ramUsed) * factor
	smoothed.swapUsed += (targetSwap - smoothed.swapUsed) * factor

	halfW := barW / 2
	barH := float64(winH) / 100.0

	// RAM: used (dark grey) from bottom, free (black) on top
	ramUsedH := int32(smoothed.ramUsed * barH)
	if ramUsedH > 0 {
		renderer.SetDrawColor(constants.DarkGrey.R, constants.DarkGrey.G, constants.DarkGrey.B, 255)
		renderer.FillRect(&sdl.Rect{X: *x, Y: winH - ramUsedH, W: halfW, H: ramUsedH})
	}
	if ramFreeH := winH - ramUsedH; ramFreeH > 0 {
		renderer.SetDrawColor(constants.Black.R, constants.Black.G, constants.Black.B, 255)
		renderer.FillRect(&sdl.Rect{X: *x, Y: 0, W: halfW, H: ramFreeH})
	}

	// Swap: used (grey) from bottom, free (black) on top
	swapUsedH := int32(smoothed.swapUsed * barH)
	if swapUsedH > 0 {
		renderer.SetDrawColor(constants.Grey.R, constants.Grey.G, constants.Grey.B, 255)
		renderer.FillRect(&sdl.Rect{X: *x + halfW, Y: winH - swapUsedH, W: halfW, H: swapUsedH})
	}
	if swapFreeH := winH - swapUsedH; swapFreeH > 0 {
		renderer.SetDrawColor(constants.Black.R, constants.Black.G, constants.Black.B, 255)
		renderer.FillRect(&sdl.Rect{X: *x + halfW, Y: 0, W: halfW, H: swapFreeH})
	}
}

func printHotkeys() {
	fmt.Println("=> Hotkeys: 1=cores 2=mem 3=net e=extended h=help n=next net q=quit w=write config a/y=cpu avg d/c=net avg f/v=link scale arrows=resize")
}

// printNetInterfaceHelp prints which interface is used per host and how to set netint (when net view is toggled on).
func printNetInterfaceHelp(snap map[string]*stats.HostStats, cfg *config.Config, netIntIndex map[string]int) {
	for _, host := range sortedHosts(snap) {
		h := snap[host]
		if h == nil || h.Net == nil || len(h.Net) == 0 {
			fmt.Printf("Net: %s => (no interfaces yet, wait for data)\n", host)
			continue
		}
		iface := chooseNetIface(h, cfg, host, netIntIndex)
		all := make([]string, 0, len(h.Net))
		for name := range h.Net {
			all = append(all, name)
		}
		sort.Strings(all)
		if iface == "" {
			fmt.Printf("Net: %s => (no non-lo interface; seen: %s)\n", host, strings.Join(all, ", "))
			continue
		}
		hint := "set netint=IFACE in ~/.loadbarsrc or --netint IFACE"
		if cfg.NetInt != "" {
			hint = "using netint=" + cfg.NetInt + " from config"
		}
		fmt.Printf("Net: %s => %s (all: %s). %s\n", host, iface, strings.Join(all, ", "), hint)
	}
	fmt.Println("=> Link speed: netlink=" + cfg.NetLink + " (gbit/mbit/10mbit/100mbit/10gbit or number). Change in ~/.loadbarsrc or --netlink")
}

// netLinkBytesPerSec returns link speed in bytes/sec from cfg.NetLink (e.g. "gbit", "10gbit", "100mbit", or numeric mbit).
func netLinkBytesPerSec(cfg *config.Config) int64 {
	s := strings.ToLower(strings.TrimSpace(cfg.NetLink))
	switch s {
	case "gbit", "1gbit":
		return int64(constants.BytesGbit)
	case "10gbit":
		return int64(constants.Bytes10Gbit)
	case "mbit", "1mbit":
		return int64(constants.BytesMbit)
	case "10mbit":
		return int64(constants.Bytes10Mbit)
	case "100mbit":
		return int64(constants.Bytes100Mbit)
	case "":
		return int64(constants.BytesGbit)
	}
	if n, err := strconv.ParseInt(s, 10, 64); err == nil {
		return n * int64(constants.BytesMbit)
	}
	return int64(constants.BytesGbit)
}

// chooseNetIface returns the interface name to use for this host: cfg.NetInt if set and present, else first non-lo, cycling with n key.
func chooseNetIface(h *stats.HostStats, cfg *config.Config, host string, netIntIndex map[string]int) string {
	if h.Net == nil || len(h.Net) == 0 {
		return ""
	}
	if cfg.NetInt != "" {
		if _, ok := h.Net[cfg.NetInt]; ok {
			return cfg.NetInt
		}
	}
	names := make([]string, 0, len(h.Net))
	for iface := range h.Net {
		if iface == "lo" {
			continue
		}
		names = append(names, iface)
	}
	sort.Strings(names)
	if len(names) == 0 {
		return ""
	}
	idx := netIntIndex[host] % len(names)
	if idx < 0 {
		idx += len(names)
	}
	return names[idx]
}

func drawNetBarSmoothed(renderer *sdl.Renderer, h *stats.HostStats, cfg *config.Config, smoothed *struct{ rxPct, txPct float64 }, prev stats.NetStamp, netIntIndex map[string]int, host string, factor float64, barW int32, x *int32, winH int32) stats.NetStamp {
	defer func() { *x += barW }()
	// Clear this slot so we never leave previous (e.g. CPU/mem) content visible
	renderer.SetDrawColor(constants.Black.R, constants.Black.G, constants.Black.B, 255)
	renderer.FillRect(&sdl.Rect{X: *x, Y: 0, W: barW, H: winH})
	iface := chooseNetIface(h, cfg, host, netIntIndex)
	if iface == "" {
		renderer.SetDrawColor(constants.Red.R, constants.Red.G, constants.Red.B, 255)
		renderer.FillRect(&sdl.Rect{X: *x, Y: 0, W: barW, H: winH})
		return prev
	}
	cur, ok := h.Net[iface]
	if !ok {
		renderer.SetDrawColor(constants.Red.R, constants.Red.G, constants.Red.B, 255)
		renderer.FillRect(&sdl.Rect{X: *x, Y: 0, W: barW, H: winH})
		return prev
	}
	linkBps := netLinkBytesPerSec(cfg)
	if linkBps <= 0 {
		linkBps = int64(constants.BytesGbit)
	}
	var targetRx, targetTx float64
	if prev.Stamp > 0 && cur.Stamp > prev.Stamp {
		dt := float64(cur.Stamp-prev.Stamp) / 1e9
		if dt > 0 {
			deltaB := cur.B - prev.B
			deltaTb := cur.Tb - prev.Tb
			if deltaB < 0 {
				deltaB = 0
			}
			if deltaTb < 0 {
				deltaTb = 0
			}
			targetRx = 100 * float64(deltaB) / (float64(linkBps) * dt)
			targetTx = 100 * float64(deltaTb) / (float64(linkBps) * dt)
		}
	}
	smoothed.rxPct += (targetRx - smoothed.rxPct) * factor
	smoothed.txPct += (targetTx - smoothed.txPct) * factor

	halfW := barW / 2
	barH := float64(winH) / 100.0
	// Left half: RX from top (light green = used)
	rxH := int32(smoothed.rxPct * barH)
	if rxH > winH/2 {
		rxH = winH / 2
	}
	if rxH > 0 {
		renderer.SetDrawColor(constants.LightGreen.R, constants.LightGreen.G, constants.LightGreen.B, 255)
		renderer.FillRect(&sdl.Rect{X: *x, Y: 0, W: halfW, H: rxH})
	}
	if halfW > 0 && winH/2-rxH > 0 {
		renderer.SetDrawColor(constants.Black.R, constants.Black.G, constants.Black.B, 255)
		renderer.FillRect(&sdl.Rect{X: *x, Y: rxH, W: halfW, H: winH/2 - rxH})
	}
	// Right half: TX from bottom (light green = used)
	txH := int32(smoothed.txPct * barH)
	if txH > winH/2 {
		txH = winH / 2
	}
	if txH > 0 {
		renderer.SetDrawColor(constants.LightGreen.R, constants.LightGreen.G, constants.LightGreen.B, 255)
		renderer.FillRect(&sdl.Rect{X: *x + halfW, Y: winH - txH, W: halfW, H: txH})
	}
	if halfW > 0 && (winH-txH) > 0 {
		renderer.SetDrawColor(constants.Black.R, constants.Black.G, constants.Black.B, 255)
		renderer.FillRect(&sdl.Rect{X: *x + halfW, Y: 0, W: halfW, H: winH - txH})
	}
	return cur
}