From 343e6316337e33275fa482318454f2277df3fdab Mon Sep 17 00:00:00 2001
From: Davide Cappellini <signorsasso@gmail.com>
Date: Sun, 20 Sep 2026 22:07:49 +0200
Subject: [PATCH] fix(gun_harness): random tiebreak + drop AntiSurfer + raise
 MinObsBeforeCompete

- bestGun: replace first-index-wins argmax with random pick among guns
  within TieMargin (2%) of best rate. HeadOn at index 0 was silently
  winning every tie, starving Tsetlin/Linear/etc.
- MinObsBeforeCompete 15 -> 50 (Pattern entered competition on noise)
- add MinHitRateFloor 0.10: if no gun clears it, fall back to HeadOn
  instead of selecting the best of a bad field
- ModularBot: remove AntiSurfer gun (0% virtual hit rate everywhere),
  14 -> 13 guns, renumber ids and selection counters
---
 ModularBot_garage/src/ModularBot.nim        | 77 +++++++++------------
 common_libs/gun_harness/virtual_bullets.nim | 26 +++++--
 2 files changed, 55 insertions(+), 48 deletions(-)

diff --git a/ModularBot_garage/src/ModularBot.nim b/ModularBot_garage/src/ModularBot.nim
index 458b9c7..c633fc0 100644
--- a/ModularBot_garage/src/ModularBot.nim
+++ b/ModularBot_garage/src/ModularBot.nim
@@ -1,5 +1,5 @@
 ## ModularBot — plugin gun architecture tracer bullet.
-## Guns: HeadOnGun (0), LinearGun (1), TsetlinGun (2), CircularGun (3), GFGun (4), PatternMatcherGun (5), AntiSurferGun (6), WallBounceGun (7), AccelGun (8), StopShotGun (9), DisplacementGun (10), AveragedLeadGun (11), DecayGFGun (12) via GunHarness.
+## Guns: HeadOnGun (0), LinearGun (1), TsetlinGun (2), CircularGun (3), GFGun (4), PatternMatcherGun (5), WallBounceGun (6), AccelGun (7), StopShotGun (8), DisplacementGun (9), AveragedLeadGun (10), DecayGFGun (11), KNNGun (12) via GunHarness.
 ## Radar: RadarLockModule (1v1) / MeleeScanModule (2+ enemies), auto-switched per tick.
 ## Movement: OscillatorModule (perpendicular strafing).
 
@@ -17,7 +17,6 @@ import guns/circular
 import guns/tsetlin
 import guns/guess_factor
 import guns/pattern_matcher
-import guns/anti_surfer
 import guns/wall_bounce
 import guns/accel_predictor
 import guns/stop_shot
@@ -36,7 +35,7 @@ import targeting/target_selector
 const botJsonPath = currentSourcePath().parentDir / "ModularBot.json"
 const DebugVBullets = false
 const DebugCircular = false
-const GunNames = ["HeadOn", "Linear", "Tsetlin", "Circular", "GuessFactor", "Pattern", "AntiSurf", "WallBounce", "Accel", "StopShot", "Displace", "AvgLead", "DecayGF", "KNN"]
+const GunNames = ["HeadOn", "Linear", "Tsetlin", "Circular", "GuessFactor", "Pattern", "WallBounce", "Accel", "StopShot", "Displace", "AvgLead", "DecayGF", "KNN"]
 
 const
   CLR_GUN = "\e[33m"    # yellow
@@ -64,7 +63,6 @@ type
     tsetlin:      TsetlinGun
     guessFactor:  GFGun
     patternMatcher: PatternMatcherGun
-    antiSurfer:   AntiSurferGun
     wallBounce:   WallBounceGun
     accelGun:     AccelGun
     stopShot:     StopShotGun
@@ -92,7 +90,7 @@ type
     roundNumber:  int
     realShotsFired: int
     realHits:     int
-    gunSelectionCount: array[14, int]
+    gunSelectionCount: array[13, int]
     lastKnownTargetId: int  ## persists through death, used for round-end stats
 
 proc printConfig(bot: ModularBot, changed: string = "") =
@@ -184,7 +182,7 @@ method onRoundEnded*(bot: ModularBot, e: RoundEndedEventForBot) =
     f
 
   var gunsArr = newJArray()
-  for gid in 0..<14:
+  for gid in 0..<13:
     var totalShots = 0
     var totalHits  = 0
     for binIdx in 0..<len(vb.PowerBins):
@@ -221,7 +219,7 @@ method onRoundStarted*(bot: ModularBot, e: RoundStartedEvent) =
   bot.realShotsFired = 0
   bot.realHits = 0
   bot.lastKnownTargetId = -1
-  for i in 0..<14: bot.gunSelectionCount[i] = 0
+  for i in 0..<13: bot.gunSelectionCount[i] = 0
   setAdjustGunForBodyTurn(true)
   setAdjustRadarForBodyTurn(true)
   setAdjustRadarForGunTurn(true)
@@ -409,7 +407,6 @@ method run*(bot: ModularBot) =
       var circPreds: array[len(PowerBins), GunPrediction]
       var gfPreds:   array[len(PowerBins), GunPrediction]
       var pmPreds:   array[len(PowerBins), GunPrediction]
-      var asPreds:   array[len(PowerBins), GunPrediction]
       var wbPreds:   array[len(PowerBins), GunPrediction]
       var acPreds:   array[len(PowerBins), GunPrediction]
       var ssPreds:   array[len(PowerBins), GunPrediction]
@@ -424,7 +421,6 @@ method run*(bot: ModularBot) =
         circPreds[i] = bot.circular.predict(bot.lastState, bulletSpeed(PowerBins[i]))
         gfPreds[i]   = bot.guessFactor.predict(bot.lastState, bulletSpeed(PowerBins[i]))
         pmPreds[i]   = bot.patternMatcher.predict(bot.lastState, bulletSpeed(PowerBins[i]))
-        asPreds[i]   = bot.antiSurfer.predict(bot.lastState, bulletSpeed(PowerBins[i]))
         wbPreds[i]   = bot.wallBounce.predict(bot.lastState, bulletSpeed(PowerBins[i]))
         acPreds[i]   = bot.accelGun.predict(bot.lastState, bulletSpeed(PowerBins[i]))
         ssPreds[i]   = bot.stopShot.predict(bot.lastState, bulletSpeed(PowerBins[i]))
@@ -440,14 +436,13 @@ method run*(bot: ModularBot) =
       bot.tracker.spawnBullets(3, circPreds, bot.lastState, tid)
       bot.tracker.spawnBullets(4, gfPreds,   bot.lastState, tid)
       bot.tracker.spawnBullets(5, pmPreds,   bot.lastState, tid)
-      bot.tracker.spawnBullets(6, asPreds,   bot.lastState, tid)
-      bot.tracker.spawnBullets(7, wbPreds,   bot.lastState, tid)
-      bot.tracker.spawnBullets(8, acPreds,   bot.lastState, tid)
-      bot.tracker.spawnBullets(9, ssPreds,   bot.lastState, tid)
-      bot.tracker.spawnBullets(10, dsPreds,  bot.lastState, tid)
-      bot.tracker.spawnBullets(11, alPreds,  bot.lastState, tid)
-      bot.tracker.spawnBullets(12, dgPreds,  bot.lastState, tid)
-      bot.tracker.spawnBullets(13, knnPreds, bot.lastState, tid)
+      bot.tracker.spawnBullets(6, wbPreds,   bot.lastState, tid)
+      bot.tracker.spawnBullets(7, acPreds,   bot.lastState, tid)
+      bot.tracker.spawnBullets(8, ssPreds,   bot.lastState, tid)
+      bot.tracker.spawnBullets(9, dsPreds,   bot.lastState, tid)
+      bot.tracker.spawnBullets(10, alPreds,  bot.lastState, tid)
+      bot.tracker.spawnBullets(11, dgPreds,  bot.lastState, tid)
+      bot.tracker.spawnBullets(12, knnPreds, bot.lastState, tid)
 
       # Build slim enemy table for tickBullets
       var enemyPositions: Table[int, tuple[x, y: float, lastSeenTick: int, alive: bool]]
@@ -468,14 +463,13 @@ method run*(bot: ModularBot) =
             echo fmt"[circ-vb] predicted=({fe.prediction.x:.0f},{fe.prediction.y:.0f}) actual=({ax:.0f},{ay:.0f}) miss={fe.missDistance:.1f}px hit={fe.hit}"
         of 4: bot.guessFactor.onResult(fe)
         of 5: bot.patternMatcher.onResult(fe)
-        of 6: bot.antiSurfer.onResult(fe)
-        of 7: bot.wallBounce.onResult(fe)
-        of 8: bot.accelGun.onResult(fe)
-        of 9: bot.stopShot.onResult(fe)
-        of 10: bot.displace.onResult(fe)
-        of 11: bot.avgLead.onResult(fe)
-        of 12: bot.decayGF.onResult(fe)
-        of 13: bot.knnGun.onResult(fe)
+        of 6: bot.wallBounce.onResult(fe)
+        of 7: bot.accelGun.onResult(fe)
+        of 8: bot.stopShot.onResult(fe)
+        of 9: bot.displace.onResult(fe)
+        of 10: bot.avgLead.onResult(fe)
+        of 11: bot.decayGF.onResult(fe)
+        of 12: bot.knnGun.onResult(fe)
         else: discard
         if fe.hit: inc bot.virtualHits else: inc bot.virtualMiss
         when DebugVBullets:
@@ -496,14 +490,13 @@ method run*(bot: ModularBot) =
         of 3: setTurretColor("#33CC33"); setBulletColor("#66FF66")
         of 4: setTurretColor("#FFCC00"); setBulletColor("#FFE066")
         of 5: setTurretColor("#FF6600"); setBulletColor("#FF9944")
-        of 6: setTurretColor("#00CCFF"); setBulletColor("#66DDFF")
-        of 7: setTurretColor("#CCCCCC"); setBulletColor("#EEEEEE")
-        of 8: setTurretColor("#FF00FF"); setBulletColor("#FF66FF")
-        of 9: setTurretColor("#990000"); setBulletColor("#CC3333")
-        of 10: setTurretColor("#006600"); setBulletColor("#009900")
-        of 11: setTurretColor("#996633"); setBulletColor("#CC9966")
-        of 12: setTurretColor("#008888"); setBulletColor("#00AAAA")
-        of 13: setTurretColor("#CC00CC"); setBulletColor("#FF44FF")
+        of 6: setTurretColor("#CCCCCC"); setBulletColor("#EEEEEE")
+        of 7: setTurretColor("#FF00FF"); setBulletColor("#FF66FF")
+        of 8: setTurretColor("#990000"); setBulletColor("#CC3333")
+        of 9: setTurretColor("#006600"); setBulletColor("#009900")
+        of 10: setTurretColor("#996633"); setBulletColor("#CC9966")
+        of 11: setTurretColor("#008888"); setBulletColor("#00AAAA")
+        of 12: setTurretColor("#CC00CC"); setBulletColor("#FF44FF")
         else: discard
 
       let pred = case selectedGun
@@ -512,14 +505,13 @@ method run*(bot: ModularBot) =
         of 3: bot.circular.predict(bot.lastState, bulletSpeed(power))
         of 4: bot.guessFactor.predict(bot.lastState, bulletSpeed(power))
         of 5: bot.patternMatcher.predict(bot.lastState, bulletSpeed(power))
-        of 6: bot.antiSurfer.predict(bot.lastState, bulletSpeed(power))
-        of 7: bot.wallBounce.predict(bot.lastState, bulletSpeed(power))
-        of 8: bot.accelGun.predict(bot.lastState, bulletSpeed(power))
-        of 9: bot.stopShot.predict(bot.lastState, bulletSpeed(power))
-        of 10: bot.displace.predict(bot.lastState, bulletSpeed(power))
-        of 11: bot.avgLead.predict(bot.lastState, bulletSpeed(power))
-        of 12: bot.decayGF.predict(bot.lastState, bulletSpeed(power))
-        of 13: bot.knnGun.predict(bot.lastState, bulletSpeed(power))
+        of 6: bot.wallBounce.predict(bot.lastState, bulletSpeed(power))
+        of 7: bot.accelGun.predict(bot.lastState, bulletSpeed(power))
+        of 8: bot.stopShot.predict(bot.lastState, bulletSpeed(power))
+        of 9: bot.displace.predict(bot.lastState, bulletSpeed(power))
+        of 10: bot.avgLead.predict(bot.lastState, bulletSpeed(power))
+        of 11: bot.decayGF.predict(bot.lastState, bulletSpeed(power))
+        of 12: bot.knnGun.predict(bot.lastState, bulletSpeed(power))
         else: bot.headOn.predict(bot.lastState, bulletSpeed(power))
       let aimTarget = aimAngle(getX(), getY(), pred.x, pred.y)
 
@@ -537,14 +529,13 @@ method run*(bot: ModularBot) =
 
 when isMainModule:
   var bot = ModularBot(
-    tracker:    vb.initTracker(14),  # 0: HeadOn, 1: Linear, 2: Tsetlin, 3: Circular, 4: GuessFactor, 5: Pattern, 6: AntiSurf, 7: WallBounce, 8: Accel, 9: StopShot, 10: Displace, 11: AvgLead, 12: DecayGF, 13: KNN
+    tracker:    vb.initTracker(13),  # 0: HeadOn, 1: Linear, 2: Tsetlin, 3: Circular, 4: GuessFactor, 5: Pattern, 6: WallBounce, 7: Accel, 8: StopShot, 9: Displace, 10: AvgLead, 11: DecayGF, 12: KNN
     headOn:     HeadOnGun(),
     linear:     LinearGun(),
     circular:   CircularGun(),
     tsetlin:    initTsetlinGun(),
     guessFactor: initGFGun(),
     patternMatcher: PatternMatcherGun(),
-    antiSurfer:  initAntiSurferGun(),
     wallBounce:  initWallBounceGun(),
     accelGun:    initAccelGun(),
     stopShot:    initStopShotGun(),
diff --git a/common_libs/gun_harness/virtual_bullets.nim b/common_libs/gun_harness/virtual_bullets.nim
index 81842d3..682057e 100644
--- a/common_libs/gun_harness/virtual_bullets.nim
+++ b/common_libs/gun_harness/virtual_bullets.nim
@@ -5,6 +5,7 @@
 
 import std/math
 import std/tables
+import std/random
 import gun_interface
 
 const
@@ -12,7 +13,9 @@ const
   WindowSize*   = 100                     ## rolling window ticks for fitness
   MaxBullets*   = 2048                    ## hard cap; ponytail: ring buffer, resize if more guns added
   MinHitRate*          = 0.40   ## 40% threshold for acceptable power selection
-  MinObsBeforeCompete* = 15    ## min observations before a gun×bin enters competition
+  MinObsBeforeCompete* = 50    ## min observations before a gun×bin enters competition
+  TieMargin*           = 0.02  ## guns within this hit-rate margin of best are tied
+  MinHitRateFloor*     = 0.10  ## if best gun < this, fall back to gun 0 (HeadOn)
 
 type
   GunId*   = int  ## index into the guns seq
@@ -168,11 +171,11 @@ proc bestGun*(t: VirtualTracker, targetId: int = -1): GunId =
   ## Guns with fewer than MinObsBeforeCompete observations are skipped
   ## unless every gun is below threshold (then fall back to best of all).
   ## Uses per-enemy fitness when targetId >= 0 and data exists; else aggregate.
+  ## Ties (within TieMargin) are broken randomly to avoid index-0 bias.
   ## ponytail: O(n*bins), fine for small gun counts
   let fit = t.fitnessFor(targetId)
   proc bestAmong(fit: seq[GunFitness], requireMin: bool): GunId =
     var bestRate = -1.0
-    result = 0
     for gunId in 0..<fit.len:
       var maxCount = 0
       for binIdx in 0..<len(PowerBins):
@@ -180,9 +183,22 @@ proc bestGun*(t: VirtualTracker, targetId: int = -1): GunId =
       if requireMin and maxCount < MinObsBeforeCompete: continue
       for binIdx in 0..<len(PowerBins):
         let r = fit[gunId].bins[binIdx].hitRate()
-        if r > bestRate:
-          bestRate = r
-          result = gunId
+        if r > bestRate: bestRate = r
+    # Floor check: if nothing hits well enough, HeadOn is the safe default
+    if bestRate < MinHitRateFloor: return 0
+    var tied: seq[GunId]
+    for gunId in 0..<fit.len:
+      var maxCount = 0
+      for binIdx in 0..<len(PowerBins):
+        maxCount = max(maxCount, fit[gunId].bins[binIdx].count)
+      if requireMin and maxCount < MinObsBeforeCompete: continue
+      for binIdx in 0..<len(PowerBins):
+        let r = fit[gunId].bins[binIdx].hitRate()
+        if r >= bestRate - TieMargin:
+          tied.add(gunId)
+          break
+    if tied.len == 0: return 0
+    return tied[rand(tied.len - 1)]
 
   var anyQualifies = false
   for gunId in 0..<fit.len: