fix(balance): repair chance rebalancing

data/json/items/tool/tailoring.json

@@ -72,7 +72,7 @@
       "item_action_type": "repair_fabric",
       "materials": [ "cotton", "leather", "nylon", "wool", "fur", "faux_fur", "nomex", "kevlar", "gutskin" ],
       "skill": "tailor",
-      "tool_quality": -1,
+      "tool_quality": 1,
       "cost_scaling": 0.1,
       "move_cost": 1300
     },
@@ -101,7 +101,7 @@
       "item_action_type": "repair_fabric",
       "materials": [ "neoprene" ],
       "skill": "tailor",
-      "tool_quality": 0,
+      "tool_quality": 1,
       "cost_scaling": 0.1,
       "move_cost": 1200
     },
@@ -130,7 +130,7 @@
       "item_action_type": "repair_fabric",
       "materials": [ "cotton", "nylon", "leather", "wool", "fur", "faux_fur", "nomex", "gutskin" ],
       "skill": "tailor",
-      "tool_quality": -1,
+      "tool_quality": 0,
       "cost_scaling": 0.1,
       "move_cost": 1500
     },
@@ -160,7 +160,7 @@
       "item_action_type": "repair_fabric",
       "materials": [ "cotton", "leather", "nylon", "wool", "fur", "faux_fur", "nomex", "kevlar", "gutskin" ],
       "skill": "tailor",
-      "tool_quality": 0,
+      "tool_quality": 2,
       "cost_scaling": 0.1,
       "move_cost": 1000
     },
@@ -206,7 +206,7 @@
         "item_action_type": "repair_fabric",
         "materials": [ "cotton", "leather", "nylon", "wool", "fur", "faux_fur", "nomex", "kevlar", "neoprene", "gutskin" ],
         "skill": "tailor",
-        "tool_quality": 1,
+        "tool_quality": 3,
         "cost_scaling": 0.1,
         "move_cost": 800
       },

doc/src/content/docs/en/mod/json/reference/json_info.md

@@ -2414,7 +2414,29 @@ more structured function.
     "done_message": "Place the beartrap on the %s.", // The message that appears after the trap has been placed. %s is replaced with the terrain name of the place where the trap has been put.
     "practice": 4, // How much practice to the "traps" skill placing the trap gives.
     "moves": 10 // (optional, default is 100): the move points that are used by placing the trap.
-}
+},
+"use_action": {
+  {
+    "type": "repair_item",                // Repair items. Skill, tool quality, and dexterity is checked against how hard that item is to craft/dissemble (which may be modified with repairs_like).
+    "item_action_type": "repair_fabric",  // Points to an item_action JSON entry that determines the action's name in the use menu. Vanilla examples include repair_fabric and repair_metal.
+    "materials": [                        // What materials can be repaired by this item. Materials.json defines what item is consumed when repairing items of that material.
+      "cotton",
+      "leather",
+      "nylon",
+      "wool",
+      "fur",
+      "faux_fur",
+      "nomex",
+      "kevlar",
+      "neoprene",
+      "gutskin"
+    ],
+    "skill": "tailor",    // What skill determines chance of success vs. risk of damaging the item further.
+    "tool_quality": 3,    // Bonus from tool, 1.<X> times multiplier on skill.  With 8 Dex, 10 skill plus 2 or more tool_quality allows any item in the game to be fully reinforced.
+    "cost_scaling": 0.1,  // Reduces or increases how much raw material is needed per successful repair action, also affected by the item's volume.
+    "move_cost": 800      // How long between each roll for success or failure, 100 moves is 1 turn.
+  }
+},
 "use_action": {
     "type": "sew_advanced",  // Modify clothing
     "materials": [           // materials to deal with.

src/iuse_actor.cpp

@@ -3295,8 +3295,8 @@ std::pair<float, float> repair_item_actor::repair_chance(
             action_difficulty = fix.max_damage() / itype::damage_scale;
             break;
         case RT_REINFORCE:
-            // Reinforcing is at least as hard as refitting
-            action_difficulty = std::max( fix.max_damage() / itype::damage_scale, recipe_difficulty );
+            // Reinforcing is 50% harder than refitting
+            action_difficulty = ( fix.max_damage() / itype::damage_scale ) + 2;
             break;
         case RT_PRACTICE:
             // Skill gain scales with recipe difficulty, so practice difficulty should too
@@ -3306,18 +3306,11 @@ std::pair<float, float> repair_item_actor::repair_chance(
     }
 
     const int difficulty = recipe_difficulty + action_difficulty;
-    // Sample numbers:
-    // Item   | Damage | Skill | Dex | Success | Failure
-    // Hoodie |    2   |   3   |  10 |   6%    |   0%
-    // Hazmat |    1   |   10  |  10 |   8%    |   0%
-    // Hazmat |    1   |   5   |  20 |   0%    |   2%
-    // t-shirt|    4   |   1   |  5  |   2%    |   3%
-    // Duster |    2   |   5   |  5  |   10%   |   0%
-    // Duster |    2   |   2   |  10 |   4%    |   1%
-    // Duster | Refit  |   2   |  10 |   0%    |   N/A
-    float success_chance = ( 10 + 2 * skill - 2 * difficulty + tool_quality / 5.0f ) / 100.0f;
+    float success_chance = ( 10 + 2 * ( skill * ( 1 + tool_quality / 10.0f ) ) - 2 * difficulty ) /
+                           100.0f;
     /** @EFFECT_DEX reduces the chances of damaging an item when repairing */
-    float damage_chance = ( difficulty - skill - ( tool_quality + pl.dex_cur ) / 5.0f ) / 100.0f;
+    float damage_chance = ( difficulty - ( skill * ( 1 + tool_quality / 10.0f ) ) - pl.dex_cur /
+                            5.0f ) / 100.0f;
 
     damage_chance = std::max( 0.0f, std::min( 1.0f, damage_chance ) );
     success_chance = std::max( 0.0f, std::min( 1.0f - damage_chance, success_chance ) );