fix mutation activation EoC once again (#71445)

* fix mutation activation EoC once again

* Apply suggestions from code review

data/json/effects_on_condition/mutation_eocs/mutation_activation_eocs.json

@@ -3,7 +3,7 @@
     "type": "effect_on_condition",
     "id": "EOC_GENERIC_SPELL_MUTATION",
     "//energy_amount": "optional, how much stamina you spend on activation of the mutation - EoC works exclusively with stamina, to consume calories, fatigue or thirst use corresponding booleans in mutation; default zero if you don't need to consume stamina",
-    "//prep_time": "time you spend to prepare the activation, in seconds. Use 0 to make activation instant",
+    "//prep_time": "time you spend to prepare the activation, in seconds. Use 0 to make activation instant.  Decimals are allowed, 0.5 means 50 moves",
     "//spell_to_cast": "spell that would be casted if activation is successful",
     "//message_success": "message that would be printed if activation is successful",
     "//message_fail": "message, that would be printed, if you have less stamina than required",
@@ -14,21 +14,15 @@
       ]
     },
     "effect": [
-      { "u_assign_activity": "ACT_GENERIC_EOC", "duration": { "context_val": "prep_time" } },
+      { "turn_cost": { "context_val": "prep_time" } },
       { "math": [ "u_val('stamina')", "-=", "_energy_amount" ] },
-      {
-        "if": { "math": [ "_prep_time", ">", "1" ] },
-        "then": { "queue_eocs": [ "EOC_GENERIC_SPELL_MUTATION_ACT" ], "time_in_future": { "math": [ "_prep_time - 1" ] } },
-        "else": { "run_eocs": [ "EOC_GENERIC_SPELL_MUTATION_ACT" ] }
-      }
+      { "run_eocs": [ "EOC_GENERIC_SPELL_MUTATION_ACT" ] }
     ],
     "false_effect": [ { "u_message": { "context_val": "message_fail" }, "type": "bad" } ]
   },
   {
     "type": "effect_on_condition",
     "id": "EOC_GENERIC_SPELL_MUTATION_ACT",
-    "//": "no proper way to check activity type to ensure player still prepare the mutation, so only level is checked for now (if spell is not instant)",
-    "condition": { "or": [ { "math": [ "u_val('activity_level')", "==", "0" ] }, { "math": [ "_prep_time", "==", "0" ] } ] },
     "effect": [
       {
         "u_cast_spell": { "id": { "context_val": "spell_to_cast" }, "message": { "context_val": "message_success" } },

doc/EFFECT_ON_CONDITION.md

@@ -3695,7 +3695,7 @@ Subtract this many turns from the alpha talker's moves.
 
 | Syntax | Optionality | Value  | Info |
 | --- | --- | --- | --- |
-| "turn_cost" | **mandatory** | number, duration, [variable object](##variable-object) or value between two | how long the action takes (can be specified in number of turns, or as a duration) |
+| "turn_cost" | **mandatory** | number, duration, [variable object](##variable-object) or value between two | how long the action takes (can be specified in number of turns (as decimal), or as a duration) |
 
 ##### Examples
 
@@ -3707,6 +3707,14 @@ Subtract this many turns from the alpha talker's moves.
 }
 ```
 
+```json
+{
+  "effect": [
+    { "turn_cost": 0.6 }
+  ]
+}
+```
+
 ##### Valid talkers:
 
 | Avatar | Character | NPC | Monster |  Furniture | Item |