Earlier version with changes mostly to use Sequences (#1993)

* Fixes Issue #1697 by adding information to the special production constructions.

* Get rid of extra $ sign in the SpecialConstruction tooltips

* Major refactor to use Sequences instead of List to try to improve logic whenever getting a list of tiles at a distance.

* Get rid of extraneous parameter

* get rid of extra exception. slight refactor placeUnitNearTile for readability

* Fix bug of doing intersection instead of union

* Add an extra method to get tiles in distance range

* Update based on comments

core/src/com/unciv/logic/GameInfo.kt

@@ -164,11 +164,12 @@ class GameInfo {
         // Barbarians will only spawn in places that no one can see
         val allViewableTiles = civilizations.filterNot { it.isBarbarian() }
                 .flatMap { it.viewableTiles }.toHashSet()
-        val tilesWithin3ofExistingEncampment = existingEncampments.flatMap { it.getTilesInDistance(3) }
+        val tilesWithin3ofExistingEncampment = existingEncampments.asSequence()
+                .flatMap { it.getTilesInDistance(3) }.toSet()
         val viableTiles = tileMap.values.filter {
             !it.getBaseTerrain().impassable && it.isLand
-                    && it.terrainFeature==null
+                    && it.terrainFeature == null
-                    && it.naturalWonder==null
+                    && it.naturalWonder == null
                     && it !in tilesWithin3ofExistingEncampment
                     && it !in allViewableTiles
         }

core/src/com/unciv/logic/automation/Automation.kt

@@ -14,14 +14,6 @@ import kotlin.math.sqrt
 
 class Automation {
 
-    internal fun rankTile(tile: TileInfo?, civInfo: CivilizationInfo): Float {
-        if (tile == null) return 0f
-        val stats = tile.getTileStats(null, civInfo)
-        var rank = rankStatsValue(stats, civInfo)
-        if (tile.improvement == null) rank += 0.5f // improvement potential!
-        if (tile.hasViewableResource(civInfo)) rank += 1.0f
-        return rank
-    }
 
     fun rankTileForCityWork(tile:TileInfo, city: CityInfo, foodWeight: Float = 1f): Float {
         val stats = tile.getTileStats(city, city.civInfo)
@@ -63,20 +55,6 @@ class Automation {
         return rank
     }
 
-    fun rankStatsValue(stats: Stats, civInfo: CivilizationInfo): Float {
-        var rank = 0.0f
-        if (stats.food <= 2) rank += (stats.food * 1.2f) //food get more value to keep city growing
-        else rank += (2.4f + (stats.food - 2) / 2) // 1.2 point for each food up to 2, from there on half a point
-
-        if (civInfo.gold < 0 && civInfo.statsForNextTurn.gold <= 0) rank += stats.gold
-        else rank += stats.gold / 3 // 3 gold is much worse than 2 production
-
-        rank += stats.production
-        rank += stats.science
-        rank += stats.culture
-        return rank
-    }
-
     fun trainMilitaryUnit(city: CityInfo) {
         val name = chooseMilitaryUnit(city)
         city.cityConstructions.currentConstruction = name
@@ -128,6 +106,32 @@ class Automation {
         }
     }
 
+    companion object {
+
+        internal fun rankTile(tile: TileInfo?, civInfo: CivilizationInfo): Float {
+            if (tile == null) return 0f
+            val stats = tile.getTileStats(null, civInfo)
+            var rank = rankStatsValue(stats, civInfo)
+            if (tile.improvement == null) rank += 0.5f // improvement potential!
+            if (tile.hasViewableResource(civInfo)) rank += 1.0f
+            return rank
+        }
+
+        @JvmStatic
+        fun rankStatsValue(stats: Stats, civInfo: CivilizationInfo): Float {
+            var rank = 0.0f
+            if (stats.food <= 2) rank += (stats.food * 1.2f) //food get more value to keep city growing
+            else rank += (2.4f + (stats.food - 2) / 2) // 1.2 point for each food up to 2, from there on half a point
+
+            if (civInfo.gold < 0 && civInfo.statsForNextTurn.gold <= 0) rank += stats.gold
+            else rank += stats.gold / 3 // 3 gold is much worse than 2 production
+
+            rank += stats.production
+            rank += stats.science
+            rank += stats.culture
+            return rank
+        }
+    }
 }
 
 enum class ThreatLevel{

core/src/com/unciv/logic/automation/BarbarianAutomation.kt

@@ -86,7 +86,7 @@ class BarbarianAutomation(val civInfo: CivilizationInfo) {
         if (unit.health < 100 && UnitAutomation().tryHealUnit(unit, unitDistanceToTiles)) return
 
         // 6 - wander
-        UnitAutomation().wander(unit, unitDistanceToTiles)
+        UnitAutomation.wander(unit, unitDistanceToTiles)
     }
 
     private fun automateScout(unit: MapUnit) {
@@ -114,7 +114,7 @@ class BarbarianAutomation(val civInfo: CivilizationInfo) {
         if (unit.health < 100 && UnitAutomation().tryHealUnit(unit, unitDistanceToTiles)) return
 
         // 5 - wander
-        UnitAutomation().wander(unit, unitDistanceToTiles)
+        UnitAutomation.wander(unit, unitDistanceToTiles)
     }
 
     private fun findFurthestTileCanMoveTo(

core/src/com/unciv/logic/automation/BattleHelper.kt

@@ -63,9 +63,10 @@ class BattleHelper {
             val tilesInAttackRange =
                     if (unit.hasUnique("Ranged attacks may be performed over obstacles") || unit.type.isAirUnit())
                         reachableTile.getTilesInDistance(rangeOfAttack)
-                    else reachableTile.getViewableTiles(rangeOfAttack, unit.type.isWaterUnit())
+                    else reachableTile.getViewableTilesList(rangeOfAttack, unit.type.isWaterUnit())
+                            .asSequence()
 
-            attackableTiles += tilesInAttackRange.asSequence().filter { it in tilesWithEnemies }
+            attackableTiles += tilesInAttackRange.filter { it in tilesWithEnemies }
                     .map { AttackableTile(reachableTile, it) }
         }
         return attackableTiles

core/src/com/unciv/logic/automation/SpecificUnitAutomation.kt

@@ -37,7 +37,7 @@ class SpecificUnitAutomation{
                     return createImprovementAction()
             }
         }
-        else UnitAutomation().tryExplore(unit, unit.movement.getDistanceToTiles())
+        else UnitAutomation.tryExplore(unit, unit.movement.getDistanceToTiles())
     }
 
     fun automateGreatGeneral(unit: MapUnit){
@@ -72,14 +72,13 @@ class SpecificUnitAutomation{
     fun rankTileAsCityCenter(tileInfo: TileInfo, nearbyTileRankings: Map<TileInfo, Float>,
                              luxuryResourcesInCivArea: Sequence<TileResource>): Float {
         val bestTilesFromOuterLayer = tileInfo.getTilesAtDistance(2)
-                .asSequence()
                 .sortedByDescending { nearbyTileRankings[it] }.take(2)
                 .toList()
         val top5Tiles = tileInfo.neighbors.union(bestTilesFromOuterLayer)
                 .asSequence()
                 .sortedByDescending { nearbyTileRankings[it] }
                 .take(5)
-        var rank = top5Tiles.map { nearbyTileRankings[it]!! }.sum()
+        var rank = top5Tiles.map { nearbyTileRankings.getValue(it) }.sum()
         if (tileInfo.isCoastalTile()) rank += 5
 
         val luxuryResourcesInCityArea = tileInfo.getTilesAtDistance(2).filter { it.resource!=null }
@@ -94,9 +93,9 @@ class SpecificUnitAutomation{
 
 
     fun automateSettlerActions(unit: MapUnit) {
-        if(unit.getTile().militaryUnit==null) return // Don't move until you're accompanied by a military unit
+        if (unit.getTile().militaryUnit == null) return // Don't move until you're accompanied by a military unit
 
-        val tilesNearCities = unit.civInfo.gameInfo.getCities()
+        val tilesNearCities = unit.civInfo.gameInfo.getCities().asSequence()
                 .flatMap {
                     val distanceAwayFromCity =
                             if (unit.civInfo.knows(it.civInfo)
@@ -106,34 +105,36 @@ class SpecificUnitAutomation{
                             else 3
                     it.getCenterTile().getTilesInDistance(distanceAwayFromCity)
                 }
-                .toHashSet()
+                .toSet()
 
         // This is to improve performance - instead of ranking each tile in the area up to 19 times, do it once.
         val nearbyTileRankings = unit.getTile().getTilesInDistance(7)
-                .associateBy ( {it},{ Automation().rankTile(it,unit.civInfo) })
+                .associateBy({ it }, { Automation.rankTile(it, unit.civInfo) })
 
         val possibleCityLocations = unit.getTile().getTilesInDistance(5)
-                .filter { val tileOwner=it.getOwner()
+                .filter {
-                        it.isLand && (tileOwner==null || tileOwner==unit.civInfo) && // don't allow settler to settle inside other civ's territory
+                    val tileOwner = it.getOwner()
-                    (unit.movement.canMoveTo(it) || unit.currentTile==it)
+                    it.isLand && (tileOwner == null || tileOwner == unit.civInfo) && // don't allow settler to settle inside other civ's territory
-                            && it !in tilesNearCities }
+                            (unit.movement.canMoveTo(it) || unit.currentTile == it)
+                            && it !in tilesNearCities
+                }
 
         val luxuryResourcesInCivArea = unit.civInfo.cities.asSequence()
-                .flatMap { it.getTiles().asSequence() }.filter { it.resource!=null }
+                .flatMap { it.getTiles().asSequence() }.filter { it.resource != null }
-                .map { it.getTileResource() }.filter { it.resourceType==ResourceType.Luxury }
+                .map { it.getTileResource() }.filter { it.resourceType == ResourceType.Luxury }
                 .distinct()
         val bestCityLocation: TileInfo? = possibleCityLocations
-                .asSequence()
                 .sortedByDescending { rankTileAsCityCenter(it, nearbyTileRankings, luxuryResourcesInCivArea) }
                 .firstOrNull { unit.movement.canReach(it) }
 
-        if(bestCityLocation==null) { // We got a badass over here, all tiles within 5 are taken? Screw it, random walk.
+        if (bestCityLocation == null) { // We got a badass over here, all tiles within 5 are taken? Screw it, random walk.
-            if (UnitAutomation().tryExplore(unit, unit.movement.getDistanceToTiles())) return // try to find new areas
+            val unitDistanceToTiles = unit.movement.getDistanceToTiles()
-            UnitAutomation().wander(unit, unit.movement.getDistanceToTiles()) // go around aimlessly
+            if (UnitAutomation.tryExplore(unit, unitDistanceToTiles)) return // try to find new areas
+            UnitAutomation.wander(unit, unitDistanceToTiles) // go around aimlessly
             return
         }
 
-        if(bestCityLocation.getTilesInDistance(3).any { it.isCityCenter() })
+        if (bestCityLocation.getTilesInDistance(3).any { it.isCityCenter() })
             throw Exception("City within distance")
 
         if (unit.getTile() == bestCityLocation)
@@ -169,9 +170,9 @@ class SpecificUnitAutomation{
                             && it.isLand
                             && !it.isCityCenter()
                             && it.resource==null }
-                    .sortedByDescending { Automation().rankTile(it,unit.civInfo) }.toList()
+                    .sortedByDescending { Automation.rankTile(it,unit.civInfo) }.toList()
-            val chosenTile = tiles.firstOrNull { unit.movement.canReach(it) }
+            val chosenTile = tiles.firstOrNull { unit.movement.canReach(it) } ?: continue // to another city
-            if(chosenTile==null) continue // to another city
+
 
             unit.movement.headTowards(chosenTile)
             if(unit.currentTile==chosenTile && unit.currentMovement > 0)
@@ -185,35 +186,41 @@ class SpecificUnitAutomation{
     fun automateFighter(unit: MapUnit) {
         val tilesInRange = unit.currentTile.getTilesInDistance(unit.getRange())
         val enemyAirUnitsInRange = tilesInRange
-                .flatMap { it.airUnits }.filter { it.civInfo.isAtWarWith(unit.civInfo) }
+                .flatMap { it.airUnits.asSequence() }.filter { it.civInfo.isAtWarWith(unit.civInfo) }
 
-        if(enemyAirUnitsInRange.isNotEmpty()) return // we need to be on standby in case they attack
+        if (enemyAirUnitsInRange.any()) return // we need to be on standby in case they attack
-        if(battleHelper.tryAttackNearbyEnemy(unit)) return
+        if (battleHelper.tryAttackNearbyEnemy(unit)) return
 
         // TODO Implement consideration for landing on aircraft carrier
 
         val immediatelyReachableCities = tilesInRange
-                .filter { it.isCityCenter() && it.getOwner()==unit.civInfo && unit.movement.canMoveTo(it)}
+                .filter { it.isCityCenter() && it.getOwner() == unit.civInfo && unit.movement.canMoveTo(it) }
 
-        for(city in immediatelyReachableCities){
+        for (city in immediatelyReachableCities) {
-            if(city.getTilesInDistance(unit.getRange())
+            if (city.getTilesInDistance(unit.getRange())
-                            .any { battleHelper.containsAttackableEnemy(it,MapUnitCombatant(unit)) }) {
+                            .any { battleHelper.containsAttackableEnemy(it, MapUnitCombatant(unit)) }) {
                 unit.movement.moveToTile(city)
                 return
             }
         }
 
         val pathsToCities = unit.movement.getArialPathsToCities()
-        if(pathsToCities.isEmpty()) return // can't actually move anywhere else
+        if (pathsToCities.isEmpty()) return // can't actually move anywhere else
 
         val citiesByNearbyAirUnits = pathsToCities.keys
-                .groupBy { it.getTilesInDistance(unit.getRange())
+                .groupBy { key ->
-                        .count{it.airUnits.size>0 && it.airUnits.first().civInfo.isAtWarWith(unit.civInfo)} }
+                    key.getTilesInDistance(unit.getRange())
+                            .count {
+                                val firstAirUnit = it.airUnits.firstOrNull()
+                                firstAirUnit != null && firstAirUnit.civInfo.isAtWarWith(unit.civInfo)
+                            }
+                }
 
-        if(citiesByNearbyAirUnits.keys.any { it!=0 }){
+        if (citiesByNearbyAirUnits.keys.any { it != 0 }) {
             val citiesWithMostNeedOfAirUnits = citiesByNearbyAirUnits.maxBy { it.key }!!.value
-            val chosenCity = citiesWithMostNeedOfAirUnits.minBy { pathsToCities[it]!!.size }!! // city with min path = least turns to get there
+            //todo: maybe groupby size and choose highest priority within the same size turns
-            val firstStepInPath = pathsToCities[chosenCity]!!.first()
+            val chosenCity = citiesWithMostNeedOfAirUnits.minBy { pathsToCities.getValue(it).size }!! // city with min path = least turns to get there
+            val firstStepInPath = pathsToCities.getValue(chosenCity).first()
             unit.movement.moveToTile(firstStepInPath)
             return
         }
@@ -255,6 +262,8 @@ class SpecificUnitAutomation{
                 }
         if (citiesThatCanAttackFrom.isEmpty()) return
 
+        //todo: this logic looks similar to some parts of automateFighter, maybe pull out common code
+        //todo: maybe groupby size and choose highest priority within the same size turns
         val closestCityThatCanAttackFrom = citiesThatCanAttackFrom.minBy { pathsToCities[it]!!.size }!!
         val firstStepInPath = pathsToCities[closestCityThatCanAttackFrom]!!.first()
         airUnit.movement.moveToTile(firstStepInPath)

core/src/com/unciv/logic/automation/UnitAutomation.kt

@@ -3,10 +3,7 @@ package com.unciv.logic.automation
 import com.badlogic.gdx.graphics.Color
 import com.unciv.Constants
 import com.unciv.UncivGame
-import com.unciv.logic.battle.Battle
+import com.unciv.logic.battle.*
-import com.unciv.logic.battle.BattleDamage
-import com.unciv.logic.battle.CityCombatant
-import com.unciv.logic.battle.MapUnitCombatant
 import com.unciv.logic.city.CityInfo
 import com.unciv.logic.civilization.GreatPersonManager
 import com.unciv.logic.civilization.diplomacy.DiplomaticStatus
@@ -23,6 +20,41 @@ class UnitAutomation {
     companion object {
         const val CLOSE_ENEMY_TILES_AWAY_LIMIT = 5
         const val CLOSE_ENEMY_TURNS_AWAY_LIMIT = 3f
+
+        internal fun tryExplore(unit: MapUnit, unitDistanceToTiles: PathsToTilesWithinTurn): Boolean {
+            if (tryGoToRuin(unit, unitDistanceToTiles) && unit.currentMovement == 0f) return true
+
+            for (tile in unit.currentTile.getTilesInDistance(10))
+                if (unit.movement.canMoveTo(tile) && tile.position !in unit.civInfo.exploredTiles
+                        && unit.movement.canReach(tile)
+                        && (tile.getOwner() == null || !tile.getOwner()!!.isCityState())) {
+                    unit.movement.headTowards(tile)
+                    return true
+                }
+            return false
+        }
+
+        private fun tryGoToRuin(unit: MapUnit, unitDistanceToTiles: PathsToTilesWithinTurn): Boolean {
+            if (!unit.civInfo.isMajorCiv()) return false // barbs don't have anything to do in ruins
+            val tileWithRuin = unitDistanceToTiles.keys
+                    .firstOrNull {
+                        it.improvement == Constants.ancientRuins && unit.movement.canMoveTo(it)
+                    }
+            if (tileWithRuin == null)
+                return false
+            unit.movement.moveToTile(tileWithRuin)
+            return true
+        }
+
+        @JvmStatic
+        fun wander(unit: MapUnit, unitDistanceToTiles: PathsToTilesWithinTurn) {
+            val reachableTiles = unitDistanceToTiles
+                    .filter { unit.movement.canMoveTo(it.key) && unit.movement.canReach(it.key) }
+
+            val reachableTilesMaxWalkingDistance = reachableTiles.filter { it.value.totalDistance == unit.currentMovement }
+            if (reachableTilesMaxWalkingDistance.any()) unit.movement.moveToTile(reachableTilesMaxWalkingDistance.toList().random().first)
+            else if (reachableTiles.any()) unit.movement.moveToTile(reachableTiles.keys.random())
+        }
     }
 
     private val battleHelper = BattleHelper()
@@ -162,10 +194,9 @@ class UnitAutomation {
         return true
     }
 
-    fun getBombardTargets(city: CityInfo): List<TileInfo> {
+    fun getBombardTargets(city: CityInfo): Sequence<TileInfo> =
-        return city.getCenterTile().getViewableTiles(city.range, true)
+            city.getCenterTile().getTilesInDistance(city.range)
                     .filter { battleHelper.containsAttackableEnemy(it, CityCombatant(city)) }
-    }
 
     /** Move towards the closest attackable enemy of the [unit].
      *
@@ -180,7 +211,7 @@ class UnitAutomation {
         var closeEnemies = battleHelper.getAttackableEnemies(
                 unit,
                 unitDistanceToTiles,
-                tilesToCheck = unit.getTile().getTilesInDistance(CLOSE_ENEMY_TILES_AWAY_LIMIT)
+                tilesToCheck = unit.getTile().getTilesInDistance(CLOSE_ENEMY_TILES_AWAY_LIMIT).toList()
         ).filter {
             // Ignore units that would 1-shot you if you attacked
             BattleDamage().calculateDamageToAttacker(MapUnitCombatant(unit),
@@ -246,16 +277,13 @@ class UnitAutomation {
 
         if (closestReachableEnemyCity != null) {
             val unitDistanceToTiles = unit.movement.getDistanceToTiles()
-            val tilesInBombardRange = closestReachableEnemyCity.getTilesInDistance(2)
+            val tilesInBombardRange = closestReachableEnemyCity.getTilesInDistance(2).toSet()
-            val reachableTilesNotInBombardRange = unitDistanceToTiles.keys.filter { it !in tilesInBombardRange }
 
-            val suitableGatheringGroundTiles = closestReachableEnemyCity.getTilesAtDistance(4)
-                    .union(closestReachableEnemyCity.getTilesAtDistance(3))
-                    .filter { it.isLand }
 
             // don't head straight to the city, try to head to landing grounds -
             // this is against tha AI's brilliant plan of having everyone embarked and attacking via sea when unnecessary.
-            val tileToHeadTo = suitableGatheringGroundTiles
+            val tileToHeadTo = closestReachableEnemyCity.getTilesInDistanceRange(3..4)
+                    .filter { it.isLand }
                     .sortedBy { it.arialDistanceTo(unit.currentTile) }
                     .firstOrNull { unit.movement.canReach(it) } ?: closestReachableEnemyCity
 
@@ -263,17 +291,21 @@ class UnitAutomation {
                 unit.movement.headTowards(tileToHeadTo)
             else {
                 if (unit.getRange() > 2) { // should never be in a bombardable position
-                    val tilesCanAttackFromButNotInBombardRange =
+                    val tileToMoveTo =
-                            reachableTilesNotInBombardRange.filter { it.arialDistanceTo(closestReachableEnemyCity) <= unit.getRange() }
+                            unitDistanceToTiles.asSequence()
+                                    .filter { it.key !in tilesInBombardRange
+                                            && it.key.arialDistanceTo(closestReachableEnemyCity) <=
+                                            unit.getRange() }
+                                    .minBy { it.value.totalDistance }?.key
 
                     // move into position far away enough that the bombard doesn't hurt
-                    if (tilesCanAttackFromButNotInBombardRange.any())
+                    if (tileToMoveTo != null)
-                        unit.movement.headTowards(tilesCanAttackFromButNotInBombardRange.minBy { unitDistanceToTiles[it]!!.totalDistance }!!)
+                        unit.movement.headTowards(tileToMoveTo)
                 } else {
                     // calculate total damage of units in surrounding 4-spaces from enemy city (so we can attack a city from 2 directions at once)
                     val militaryUnitsAroundEnemyCity = closestReachableEnemyCity.getTilesInDistance(3)
                             .filter { it.militaryUnit != null && it.militaryUnit!!.civInfo == unit.civInfo }
-                            .map { it.militaryUnit!! }
+                            .map { it.militaryUnit }.filterNotNull()
                     var totalAttackOnCityPerTurn = -20 // cities heal 20 per turn, so anything below that its useless
                     val enemyCityCombatant = CityCombatant(closestReachableEnemyCity.getCity()!!)
                     for (militaryUnit in militaryUnitsAroundEnemyCity) {
@@ -290,28 +322,29 @@ class UnitAutomation {
     }
 
     fun tryBombardEnemy(city: CityInfo): Boolean {
-        if (!city.attackedThisTurn) {
+        return when {
-            val target = chooseBombardTarget(city)
+            city.attackedThisTurn -> false
-            if (target == null) return false
+            else -> {
-            val enemy = Battle.getMapCombatantOfTile(target)!!
+                val enemy = chooseBombardTarget(city) ?: return false
                 Battle.attack(CityCombatant(city), enemy)
-            return true
+                true
+            }
         }
-        return false
     }
 
-    private fun chooseBombardTarget(city: CityInfo): TileInfo? {
+    private fun chooseBombardTarget(city: CityInfo): ICombatant? {
-        var targets = getBombardTargets(city)
+        val mappedTargets = getBombardTargets(city).map { Battle.getMapCombatantOfTile(it)!! }
-        if (targets.isEmpty()) return null
+                .filter {
-        val siegeUnits = targets
+                    val unitType = it.getUnitType()
-                .filter { Battle.getMapCombatantOfTile(it)!!.getUnitType() == UnitType.Siege }
+                    unitType == UnitType.Siege || unitType.isRanged()
-        if (siegeUnits.any()) targets = siegeUnits
-        else {
-            val rangedUnits = targets
-                    .filter { Battle.getMapCombatantOfTile(it)!!.getUnitType().isRanged() }
-            if (rangedUnits.any()) targets = rangedUnits
                 }
-        return targets.minBy { Battle.getMapCombatantOfTile(it)!!.getHealth() }
+                .groupByTo(LinkedHashMap()) { it.getUnitType() }
+
+        var targets = mappedTargets[UnitType.Siege]?.asSequence()
+        if (targets == null)
+            targets = mappedTargets.values.asSequence().flatMap { it.asSequence() }
+
+        return targets.minBy { it.getHealth() }
     }
 
     private fun tryGarrisoningUnit(unit: MapUnit): Boolean {
@@ -352,28 +385,6 @@ class UnitAutomation {
         return true
     }
 
-    private fun tryGoToRuin(unit: MapUnit, unitDistanceToTiles: PathsToTilesWithinTurn): Boolean {
-        if (!unit.civInfo.isMajorCiv()) return false // barbs don't have anything to do in ruins
-        val tileWithRuin = unitDistanceToTiles.keys
-                .firstOrNull { it.improvement == Constants.ancientRuins && unit.movement.canMoveTo(it) }
-        if (tileWithRuin == null) return false
-        unit.movement.moveToTile(tileWithRuin)
-        return true
-    }
-
-    internal fun tryExplore(unit: MapUnit, unitDistanceToTiles: PathsToTilesWithinTurn): Boolean {
-        if (tryGoToRuin(unit, unitDistanceToTiles) && unit.currentMovement == 0f) return true
-
-        for (tile in unit.currentTile.getTilesInDistance(10))
-            if (unit.movement.canMoveTo(tile) && tile.position !in unit.civInfo.exploredTiles
-                && unit.movement.canReach(tile)
-                    && (tile.getOwner()==null || !tile.getOwner()!!.isCityState())) {
-                unit.movement.headTowards(tile)
-                return true
-            }
-        return false
-    }
-
     /** This is what a unit with the 'explore' action does.
      It also explores, but also has other functions, like healing if necessary. */
     fun automatedExplore(unit: MapUnit) {
@@ -383,13 +394,4 @@ class UnitAutomation {
         if (tryExplore(unit, unit.movement.getDistanceToTiles())) return
         unit.civInfo.addNotification("[${unit.name}] finished exploring.", unit.currentTile.position, Color.GRAY)
     }
-
-    fun wander(unit: MapUnit, unitDistanceToTiles: PathsToTilesWithinTurn) {
-        val reachableTiles = unitDistanceToTiles
-                .filter { unit.movement.canMoveTo(it.key) && unit.movement.canReach(it.key) }
-
-        val reachableTilesMaxWalkingDistance = reachableTiles.filter { it.value.totalDistance == unit.currentMovement }
-        if (reachableTilesMaxWalkingDistance.any()) unit.movement.moveToTile(reachableTilesMaxWalkingDistance.toList().random().first)
-        else if (reachableTiles.any()) unit.movement.moveToTile(reachableTiles.toList().random().first)
-    }
 }

core/src/com/unciv/logic/automation/WorkerAutomation.kt

@@ -14,8 +14,7 @@ class WorkerAutomation(val unit: MapUnit) {
     fun automateWorkerAction() {
         val enemyUnitsInWalkingDistance = unit.movement.getDistanceToTiles().keys
                 .filter {
-                    it.militaryUnit != null && it.militaryUnit!!.civInfo != unit.civInfo
+                    it.militaryUnit != null && it.militaryUnit!!.civInfo.isAtWarWith(unit.civInfo)
-                            && unit.civInfo.isAtWarWith(it.militaryUnit!!.civInfo)
                 }
 
         if (enemyUnitsInWalkingDistance.isNotEmpty()) return  // Don't you dare move.
@@ -118,24 +117,25 @@ class WorkerAutomation(val unit: MapUnit) {
      * Returns the current tile if no tile to work was found
      */
     private fun findTileToWork(): TileInfo {
-        val currentTile=unit.getTile()
+        val currentTile = unit.getTile()
         val workableTiles = currentTile.getTilesInDistance(4)
                 .filter {
-                    (it.civilianUnit== null || it == currentTile)
+                    (it.civilianUnit == null || it == currentTile)
-                            && tileCanBeImproved(it, unit.civInfo) }
+                            && tileCanBeImproved(it, unit.civInfo)
-                .sortedByDescending { getPriority(it, unit.civInfo) }.toMutableList()
+                }
+                .sortedByDescending { getPriority(it, unit.civInfo) }
 
         // the tile needs to be actually reachable - more difficult than it seems,
         // which is why we DON'T calculate this for every possible tile in the radius,
         // but only for the tile that's about to be chosen.
-        val selectedTile = workableTiles.firstOrNull{unit.movement.canReach(it) }
+        val selectedTile = workableTiles.firstOrNull { unit.movement.canReach(it) }
 
-        if (selectedTile != null
+        return if (selectedTile != null
-                && getPriority(selectedTile, unit.civInfo)>1
+                && getPriority(selectedTile, unit.civInfo) > 1
                 && (!workableTiles.contains(currentTile)
                         || getPriority(selectedTile, unit.civInfo) > getPriority(currentTile, unit.civInfo)))
-            return selectedTile
+            selectedTile
-        else return currentTile
+        else currentTile
     }
 
     private fun tileCanBeImproved(tile: TileInfo, civInfo: CivilizationInfo): Boolean {

core/src/com/unciv/logic/city/CityExpansionManager.kt

@@ -62,9 +62,10 @@ class CityExpansionManager {
     fun chooseNewTileToOwn(): TileInfo? {
         for (i in 2..5) {
             val tiles = cityInfo.getCenterTile().getTilesInDistance(i)
-                    .filter {it.getOwner() == null && it.neighbors.any { tile->tile.getOwner()==cityInfo.civInfo }}
+                    .filter { it.getOwner() == null
-            if (tiles.isEmpty()) continue
+                            && it.neighbors.any { tile -> tile.getOwner() == cityInfo.civInfo } }
-            val chosenTile = tiles.maxBy { Automation().rankTile(it,cityInfo.civInfo) }
+            val chosenTile = tiles.maxBy { Automation.rankTile(it, cityInfo.civInfo) }
+            if (chosenTile != null)
                 return chosenTile
         }
         return null
@@ -72,7 +73,7 @@ class CityExpansionManager {
 
     //region state-changing functions
     fun reset() {
-        for(tile in cityInfo.getTiles())
+        for (tile in cityInfo.getTiles())
             relinquishOwnership(tile)
 
         // The only way to create a city inside an owned tile is if it's in your territory
@@ -80,10 +81,9 @@ class CityExpansionManager {
         // It becomes an invisible city and weird shit starts happening
         takeOwnership(cityInfo.getCenterTile())
 
-        cityInfo.getCenterTile().getTilesInDistance(1)
+        for (tile in cityInfo.getCenterTile().getTilesInDistance(1)
-                .filter { it.getCity()==null } // can't take ownership of owned tiles (by other cities)
+                .filter { it.getCity() == null }) // can't take ownership of owned tiles (by other cities)
-                .forEach { takeOwnership(it) }
+            takeOwnership(tile)
-
     }
 
     private fun addNewTileWithCulture() {

core/src/com/unciv/logic/city/CityInfo.kt

@@ -277,7 +277,7 @@ class CityInfo {
     fun setTransients() {
         tileMap = civInfo.gameInfo.tileMap
         centerTileInfo = tileMap[location]
-        tilesInRange = getCenterTile().getTilesInDistance( 3).toHashSet()
+        tilesInRange = getCenterTile().getTilesInDistance(3).toHashSet()
         population.cityInfo = this
         expansion.cityInfo = this
         expansion.setTransients()

core/src/com/unciv/logic/civilization/CivilizationInfo.kt

@@ -292,8 +292,9 @@ class CivilizationInfo {
     }
 
     fun isAtWarWith(otherCiv:CivilizationInfo): Boolean {
-        if(otherCiv.isBarbarian() || isBarbarian()) return true
+        if (otherCiv.civName == civName) return false // never at war with itself
-        if(!diplomacy.containsKey(otherCiv.civName)) // not encountered yet
+        if (otherCiv.isBarbarian() || isBarbarian()) return true
+        if (!diplomacy.containsKey(otherCiv.civName)) // not encountered yet
             return false
         return getDiplomacyManager(otherCiv).diplomaticStatus == DiplomaticStatus.War
     }

core/src/com/unciv/logic/map/MapUnit.kt

@@ -141,10 +141,10 @@ class MapUnit {
     }
 
     fun updateVisibleTiles() {
-        if(type.isAirUnit()){
+        if(type.isAirUnit()) {
-            if(hasUnique("6 tiles in every direction always visible"))
+            viewableTiles = if (hasUnique("6 tiles in every direction always visible"))
-                viewableTiles = getTile().getTilesInDistance(6)  // it's that simple
+                getTile().getTilesInDistance(6).toList()  // it's that simple
-            else viewableTiles = listOf() // bomber units don't do recon
+            else listOf() // bomber units don't do recon
         }
         else {
             var visibilityRange = 2
@@ -161,7 +161,7 @@ class MapUnit {
             val tile = getTile()
             if (tile.baseTerrain == Constants.hill && type.isLandUnit()) visibilityRange += 1
 
-            viewableTiles = tile.getViewableTiles(visibilityRange, type.isWaterUnit())
+            viewableTiles = tile.getViewableTilesList(visibilityRange, type.isWaterUnit())
         }
         civInfo.updateViewableTiles() // for the civ
     }
@@ -388,9 +388,10 @@ class MapUnit {
         if (amountToHealBy == 0) return
 
         if (hasUnique("+10 HP when healing")) amountToHealBy += 10
-        val adjacentUnits = currentTile.getTilesInDistance(1).flatMap { it.getUnits() }
+        val maxAdjacentHealingBonus = currentTile.getTilesInDistance(1)
-        if (adjacentUnits.isNotEmpty())
+                .flatMap { it.getUnits().asSequence() }.map { it.adjacentHealingBonus() }.max()
-            amountToHealBy += adjacentUnits.map { it.adjacentHealingBonus() }.max()!!
+        if (maxAdjacentHealingBonus != null)
+            amountToHealBy += maxAdjacentHealingBonus
         if (hasUnique("All healing effects doubled"))
             amountToHealBy *= 2
         healBy(amountToHealBy)
@@ -441,19 +442,19 @@ class MapUnit {
             }
     }
 
-    fun startTurn(){
+    fun startTurn() {
         currentMovement = getMaxMovement().toFloat()
-        attacksThisTurn=0
+        attacksThisTurn = 0
         due = true
 
         // Wake sleeping units if there's an enemy nearby
-        if(isSleeping() && currentTile.getTilesInDistance(2).any {
+        if (isSleeping() && currentTile.getTilesInDistance(2).any {
-                    it.militaryUnit!=null && it.militaryUnit!!.civInfo.isAtWarWith(civInfo)
+                    it.militaryUnit != null && it.militaryUnit!!.civInfo.isAtWarWith(civInfo)
                 })
-            action=null
+            action = null
 
         val tileOwner = getTile().getOwner()
-        if(tileOwner!=null && !civInfo.canEnterTiles(tileOwner) && !tileOwner.isCityState()) // if an enemy city expanded onto this tile while I was in it
+        if (tileOwner != null && !civInfo.canEnterTiles(tileOwner) && !tileOwner.isCityState()) // if an enemy city expanded onto this tile while I was in it
             movement.teleportToClosestMoveableTile()
         doPreTurnAction()
     }
@@ -520,7 +521,7 @@ class MapUnit {
         civInfo.addNotification("We have captured a barbarian encampment and recovered [${goldGained.toInt()}] gold!", tile.position, Color.RED)
     }
 
-    fun disband(){
+    fun disband() {
         // evacuation of transported units before disbanding, if possible
         if (type.isAircraftCarrierUnit() || type.isMissileCarrierUnit()) {
             for(unit in currentTile.getUnits().filter { it.type.isAirUnit() && it.isTransported }) {
@@ -539,11 +540,17 @@ class MapUnit {
                     unit.disband()
             }
         }
-
         destroy()
-        if(currentTile.getOwner()==civInfo)
+        if (currentTile.getOwner() == civInfo)
             civInfo.gold += baseUnit.getDisbandGold()
         if (civInfo.isDefeated()) civInfo.destroy()
+        for (unit in currentTile.getUnits().filter { it.type.isAirUnit() && it.isTransported }) {
+            if (unit.movement.canMoveTo(currentTile)) continue // we disbanded a carrier in a city, it can still stay in the city
+            val tileCanMoveTo = unit.currentTile.getTilesInDistance(unit.getRange())
+                    .firstOrNull { unit.movement.canMoveTo(it) }
+            if (tileCanMoveTo != null) unit.movement.moveToTile(tileCanMoveTo)
+            else unit.disband()
+        }
     }
 
     private fun getAncientRuinBonus(tile: TileInfo) {
@@ -591,7 +598,7 @@ class MapUnit {
 
         // Map of the surrounding area
         actions.add {
-            val revealCenter = tile.getTilesAtDistance(ANCIENT_RUIN_MAP_REVEAL_OFFSET).random(tileBasedRandom)
+            val revealCenter = tile.getTilesAtDistance(ANCIENT_RUIN_MAP_REVEAL_OFFSET).toList().random(tileBasedRandom)
             val tilesToReveal = revealCenter
                 .getTilesInDistance(ANCIENT_RUIN_MAP_REVEAL_RANGE)
                 .filter { Random.nextFloat() < ANCIENT_RUIN_MAP_REVEAL_CHANCE }

core/src/com/unciv/logic/map/TileInfo.kt

@@ -68,9 +68,8 @@ open class TileInfo {
         return false
     }
 
-    fun containsUnique(unique: String): Boolean {
+    fun containsUnique(unique: String): Boolean =
-        return isNaturalWonder() && getNaturalWonder().uniques.contains(unique)
+            isNaturalWonder() && getNaturalWonder().uniques.contains(unique)
-    }
     //region pure functions
 
     /** Returns military, civilian and air units in tile */
@@ -104,13 +103,8 @@ open class TileInfo {
 
     // This is for performance - since we access the neighbors of a tile ALL THE TIME,
     // and the neighbors of a tile never change, it's much more efficient to save the list once and for all!
-    @Transient private var internalNeighbors : List<TileInfo>?=null
+    @delegate:Transient
-    val neighbors: List<TileInfo>
+    val neighbors: List<TileInfo> by lazy { getTilesAtDistance(1).toList() }
-        get(){
-            if(internalNeighbors==null)
-                internalNeighbors = getTilesAtDistance(1)
-            return internalNeighbors!!
-        }
 
     fun getHeight(): Int {
         if (baseTerrain == Constants.mountain) return 4
@@ -127,18 +121,15 @@ open class TileInfo {
         return containingCity.civInfo
     }
 
-    fun getTerrainFeature(): Terrain? {
+    fun getTerrainFeature(): Terrain? =
-        return if (terrainFeature == null) null else ruleset.terrains[terrainFeature!!]
+            if (terrainFeature == null) null else ruleset.terrains[terrainFeature!!]
-    }
 
     fun isWorked(): Boolean {
         val city = getCity()
         return city!=null && city.workedTiles.contains(position)
     }
 
-    fun getTileStats(observingCiv: CivilizationInfo): Stats {
+    fun getTileStats(observingCiv: CivilizationInfo): Stats = getTileStats(getCity(), observingCiv)
-        return getTileStats(getCity(), observingCiv)
-    }
 
     fun getTileStats(city: CityInfo?, observingCiv: CivilizationInfo): Stats {
         var stats = getBaseTerrain().clone()
@@ -264,21 +255,20 @@ open class TileInfo {
 
     fun isCoastalTile() = neighbors.any { it.baseTerrain==Constants.coast }
 
-    fun hasViewableResource(civInfo: CivilizationInfo): Boolean {
+    fun hasViewableResource(civInfo: CivilizationInfo): Boolean =
-        return resource != null && (getTileResource().revealedBy == null || civInfo.tech.isResearched(getTileResource().revealedBy!!))
+            resource != null && (getTileResource().revealedBy == null || civInfo.tech.isResearched(getTileResource().revealedBy!!))
-    }
 
-    fun getViewableTiles(distance:Int, ignoreCurrentTileHeight:Boolean = false): List<TileInfo> {
+    fun getViewableTilesList(distance:Int, ignoreCurrentTileHeight: Boolean): List<TileInfo> =
-        return tileMap.getViewableTiles(this.position,distance,ignoreCurrentTileHeight)
+            tileMap.getViewableTiles(position, distance, ignoreCurrentTileHeight)
-    }
 
-    fun getTilesInDistance(distance:Int): List<TileInfo> {
+    fun getTilesInDistance(distance: Int): Sequence<TileInfo> =
-        return tileMap.getTilesInDistance(position,distance)
+            tileMap.getTilesInDistance(position,distance)
-    }
 
-    fun getTilesAtDistance(distance:Int): List<TileInfo> {
+    fun getTilesInDistanceRange(range: IntRange): Sequence<TileInfo> =
-        return tileMap.getTilesAtDistance(position,distance)
+            tileMap.getTilesInDistanceRange(position, range)
-    }
+
+    fun getTilesAtDistance(distance:Int): Sequence<TileInfo> =
+            tileMap.getTilesAtDistance(position, distance)
 
     fun getDefensiveBonus(): Float {
         var bonus = getBaseTerrain().defenceBonus

core/src/com/unciv/logic/map/TileMap.kt

@@ -73,22 +73,21 @@ class TileMap {
         return get(vector.x.toInt(), vector.y.toInt())
     }
 
-    fun getTilesInDistance(origin: Vector2, distance: Int): List<TileInfo> {
+    fun getTilesInDistance(origin: Vector2, distance: Int): Sequence<TileInfo> =
-        val tilesToReturn = mutableListOf<TileInfo>()
+            getTilesInDistanceRange(origin, 0..distance)
-        for (i in 0 .. distance) {
-            tilesToReturn += getTilesAtDistance(origin, i)
-        }
-        return tilesToReturn
-    }
 
-    fun getTilesAtDistance(origin: Vector2, distance: Int): List<TileInfo> {
+    fun getTilesInDistanceRange(origin: Vector2, range: IntRange): Sequence<TileInfo> =
-        if(distance==0) return listOf(get(origin))
+            sequence {
-        val tilesToReturn = ArrayList<TileInfo>()
+                for (i in range)
+                    yield(getTilesAtDistance(origin, i))
+            }.flatMap { it }
 
-        fun addIfTileExists(x:Int,y:Int){
+    fun getTilesAtDistance(origin: Vector2, distance: Int): Sequence<TileInfo> =
-            if(contains(x,y))
+            if (distance <= 0) // silently take negatives.
-                tilesToReturn += get(x,y)
+                sequenceOf(get(origin))
-        }
+            else
+                sequence {
+                    fun getIfTileExistsOrNull(x: Int, y: Int) = if (contains(x, y)) get(x, y) else null
 
                     val centerX = origin.x.toInt()
                     val centerY = origin.y.toInt()
@@ -98,26 +97,25 @@ class TileMap {
                     var currentY = centerY - distance
 
                     for (i in 0 until distance) { // From 6 to 8
-            addIfTileExists(currentX,currentY)
+                        yield(getIfTileExistsOrNull(currentX, currentY))
                         // We want to get the tile on the other side of the clock,
                         // so if we're at current = origin-delta we want to get to origin+delta.
                         // The simplest way to do this is 2*origin - current = 2*origin- (origin - delta) = origin+delta
-            addIfTileExists(2*centerX - currentX, 2*centerY - currentY)
+                        yield(getIfTileExistsOrNull(2 * centerX - currentX, 2 * centerY - currentY))
                         currentX += 1 // we're going upwards to the left, towards 8 o'clock
                     }
                     for (i in 0 until distance) { // 8 to 10
-            addIfTileExists(currentX,currentY)
+                        yield(getIfTileExistsOrNull(currentX, currentY))
-            addIfTileExists(2*centerX - currentX, 2*centerY - currentY)
+                        yield(getIfTileExistsOrNull(2 * centerX - currentX, 2 * centerY - currentY))
                         currentX += 1
                         currentY += 1 // we're going up the left side of the hexagon so we're going "up" - +1,+1
                     }
                     for (i in 0 until distance) { // 10 to 12
-            addIfTileExists(currentX,currentY)
+                        yield(getIfTileExistsOrNull(currentX, currentY))
-            addIfTileExists(2*centerX - currentX, 2*centerY - currentY)
+                        yield(getIfTileExistsOrNull(2 * centerX - currentX, 2 * centerY - currentY))
                         currentY += 1 // we're going up the top left side of the hexagon so we're heading "up and to the right"
                     }
-        return tilesToReturn
+                }.filterNotNull()
-    }
 
     /** Tries to place the [unitName] into the [TileInfo] closest to the given the [position]
      *
@@ -134,24 +132,32 @@ class TileMap {
     ): MapUnit? {
         val unit = gameInfo.ruleSet.units[unitName]!!.getMapUnit(gameInfo.ruleSet)
 
-        fun isTileMovePotential(tileInfo:TileInfo): Boolean {
+        fun isTileMovePotential(tileInfo: TileInfo): Boolean =
-            if(unit.type.isAirUnit()) return true
+                when {
-            if(unit.type.isWaterUnit()) return tileInfo.isWater || tileInfo.isCityCenter()
+                    unit.type.isAirUnit() -> true
-            else return tileInfo.isLand
+                    unit.type.isWaterUnit() -> tileInfo.isWater || tileInfo.isCityCenter()
+                    else -> tileInfo.isLand
                 }
 
-        val viableTilesToPlaceUnitInAtDistance1 = getTilesInDistance(position, 1).filter { isTileMovePotential(it) }
+        val viableTilesToPlaceUnitInAtDistance1 = getTilesAtDistance(position, 1)
+                .filter { isTileMovePotential(it) }.toSet()
         // This is so that units don't skip over non-potential tiles to go elsewhere -
         // e.g. a city 2 tiles away from a lake could spawn water units in the lake...Or spawn beyond a mountain range...
-        val viableTilesToPlaceUnitInAtDistance2 = getTilesAtDistance(position, 2)
+        val viableTilesToPlaceUnitIn = getTilesAtDistance(position, 2)
-                .filter { isTileMovePotential(it) && it.neighbors.any { n->n in viableTilesToPlaceUnitInAtDistance1 } }
+                .filter {
+                    isTileMovePotential(it)
+                            && it.neighbors.any { n -> n in viableTilesToPlaceUnitInAtDistance1 }
+                } + viableTilesToPlaceUnitInAtDistance1
 
-        val viableTilesToPlaceUnitIn = viableTilesToPlaceUnitInAtDistance1.union(viableTilesToPlaceUnitInAtDistance2)
 
-        unit.assignOwner(civInfo,false)  // both the civ name and actual civ need to be in here in order to calculate the canMoveTo...Darn
+        unit.assignOwner(civInfo, false)  // both the civ name and actual civ need to be in here in order to calculate the canMoveTo...Darn
         val unitToPlaceTile = viableTilesToPlaceUnitIn.firstOrNull { unit.movement.canMoveTo(it) }
 
-        if(unitToPlaceTile!=null) {
+        if (unitToPlaceTile == null) {
+            civInfo.removeUnit(unit) // since we added it to the civ units in the previous assignOwner
+            return null // we didn't actually create a unit...
+        }
+
         // Remove the tile improvement, e.g. when placing the starter units (so they don't spawn on ruins/encampments)
         if (removeImprovement) unitToPlaceTile.improvement = null
         // only once we know the unit can be placed do we add it to the civ's unit list
@@ -159,24 +165,20 @@ class TileMap {
         unit.currentMovement = unit.getMaxMovement().toFloat()
 
         // Only once we add the unit to the civ we can activate addPromotion, because it will try to update civ viewable tiles
-            for(promotion in unit.baseUnit.promotions)
+        for (promotion in unit.baseUnit.promotions)
             unit.promotions.addPromotion(promotion, true)
 
         // And update civ stats, since the new unit changes both unit upkeep and resource consumption
         civInfo.updateStatsForNextTurn()
         civInfo.updateDetailedCivResources()
-        }
-        else {
-            civInfo.removeUnit(unit) // since we added it to the civ units in the previous assignOwner
-            return null // we didn't actually create a unit...
-        }
 
         return unit
     }
 
 
-    fun getViewableTiles(position: Vector2, sightDistance: Int, ignoreCurrentTileHeight: Boolean = false): List<TileInfo> {
+    fun getViewableTiles(position: Vector2, sightDistance: Int, ignoreCurrentTileHeight: Boolean)
-        if (ignoreCurrentTileHeight) return getTilesInDistance(position, sightDistance)
+            : List<TileInfo> {
+        if (ignoreCurrentTileHeight) return getTilesInDistance(position, sightDistance).toList()
 
         val viewableTiles = getTilesInDistance(position, 1).toMutableList()
         val currentTileHeight = get(position).getHeight()

core/src/com/unciv/logic/map/UnitMovementAlgorithms.kt

@@ -43,9 +43,9 @@ class UnitMovementAlgorithms(val unit:MapUnit) {
     class ParentTileAndTotalDistance(val parentTile:TileInfo, val totalDistance: Float)
 
     fun getDistanceToTilesWithinTurn(origin: Vector2, unitMovement: Float): PathsToTilesWithinTurn {
-        if(unitMovement==0f) return PathsToTilesWithinTurn()
-
         val distanceToTiles = PathsToTilesWithinTurn()
+        if(unitMovement==0f) return distanceToTiles
+
         val unitTile = unit.getTile().tileMap[origin]
         distanceToTiles[unitTile] = ParentTileAndTotalDistance(unitTile,0f)
         var tilesToCheck = listOf(unitTile)
@@ -344,7 +344,8 @@ class UnitMovementAlgorithms(val unit:MapUnit) {
         return true
     }
 
-    fun getDistanceToTiles() = getDistanceToTilesWithinTurn(unit.currentTile.position,unit.currentMovement)
+    fun getDistanceToTiles(): PathsToTilesWithinTurn
+            = getDistanceToTilesWithinTurn(unit.currentTile.position,unit.currentMovement)
 
     fun getArialPathsToCities(): HashMap<TileInfo, ArrayList<TileInfo>> {
         var tilesToCheck = ArrayList<TileInfo>()

core/src/com/unciv/ui/cityscreen/CityScreen.kt

@@ -98,7 +98,7 @@ class CityScreen(internal val city: CityInfo): CameraStageBaseScreen() {
         updateAnnexAndRazeCityButton()
         updateTileGroups()
 
-        if (city.getCenterTile().getTilesAtDistance(4).isNotEmpty())
+        if (city.getCenterTile().getTilesAtDistance(4).any())
             displayTutorial(Tutorial.CityRange)
     }
 

core/src/com/unciv/ui/worldscreen/WorldMapHolder.kt

@@ -251,18 +251,20 @@ class WorldMapHolder(internal val worldScreen: WorldScreen, internal val tileMap
         tileGroups[unit.getTile()]!!.selectUnit(unit)
 
         val isAirUnit = unit.type.isAirUnit()
-        val tilesInMoveRange = if(isAirUnit) unit.getTile().getTilesInDistance(unit.getRange())
+        val tilesInMoveRange =
-        else unit.movement.getDistanceToTiles().keys
+                if (isAirUnit)
+                    unit.getTile().getTilesInDistance(unit.getRange())
+                else
+                    unit.movement.getDistanceToTiles().keys.asSequence()
 
-        if(isAirUnit)
+        for (tile in tilesInMoveRange) {
-            for(tile in tilesInMoveRange)
+            val tileToColor = tileGroups.getValue(tile)
-                tileGroups[tile]!!.showCircle(Color.BLUE,0.3f)
+            if (isAirUnit)
-
+                tileToColor.showCircle(Color.BLUE, 0.3f)
-        for (tile: TileInfo in tilesInMoveRange)
             if (unit.movement.canMoveTo(tile))
-                tileGroups[tile]!!.showCircle(Color.WHITE,
+                tileToColor.showCircle(Color.WHITE,
                         if (UncivGame.Current.settings.singleTapMove || isAirUnit) 0.7f else 0.3f)
-
+        }
 
         val unitType = unit.type
         val attackableTiles: List<TileInfo> = if (unitType.isCivilian()) listOf()
@@ -281,15 +283,15 @@ class WorldMapHolder(internal val worldScreen: WorldScreen, internal val tileMap
         else 0.5f
         for (tile in tileGroups.values) {
             if (tile.icons.populationIcon != null) tile.icons.populationIcon!!.color.a = fadeout
-            if (tile.icons.improvementIcon != null && tile.tileInfo.improvement!=Constants.barbarianEncampment
+            if (tile.icons.improvementIcon != null && tile.tileInfo.improvement != Constants.barbarianEncampment
-                    && tile.tileInfo.improvement!=Constants.ancientRuins)
+                    && tile.tileInfo.improvement != Constants.ancientRuins)
                 tile.icons.improvementIcon!!.color.a = fadeout
             if (tile.resourceImage != null) tile.resourceImage!!.color.a = fadeout
         }
     }
 
     private fun updateTilegroupsForSelectedCity(city: CityInfo, playerViewableTilePositions: HashSet<Vector2>) {
-        val attackableTiles: List<TileInfo> = UnitAutomation().getBombardTargets(city)
+        val attackableTiles = UnitAutomation().getBombardTargets(city)
                 .filter { (UncivGame.Current.viewEntireMapForDebug || playerViewableTilePositions.contains(it.position)) }
         for (attackableTile in attackableTiles) {
             tileGroups[attackableTile]!!.showCircle(colorFromRGB(237, 41, 57))