Make purifying water take a reasonable amount of time

data/json/items/tool/cooking.json

@@ -128,6 +128,7 @@
     "max_charges": 150,
     "charges_per_use": 1,
     "use_action": [ "WATER_PURIFIER" ],
+    "purification_factor": 2,
     "flags": [ "ALLOWS_REMOTE_USE" ]
   },
   {

data/json/items/tool/misc.json

@@ -428,6 +428,7 @@
     "max_charges": 4000,
     "charges_per_use": 1,
     "use_action": [ "WATER_PURIFIER" ]
+    "purification_factor": 4
   },
   {
     "id": "makeshift_halberd",

data/json/player_activities.json

@@ -860,6 +860,15 @@
     "based_on": "neither",
     "no_resume": true
   },
+  {
+    "id": "ACT_PURIFY_WATER",
+    "type": "activity_type",
+    "activity_level": "NO_EXERCISE",
+    "verb": "purifying the water",
+    "rooted": true,
+    "based_on": "time",
+    "auto_needs": true
+  },
   {
     "id": "ACT_CONSUME",
     "type": "activity_type",

doc/JSON_INFO.md

@@ -1999,6 +1999,7 @@ CBMs can be defined like this:
 "cooks_like": "meat_cooked" // (Optional) If the item is used in a recipe, replaces it with its cooks_like
 "parasites": 10,            // (Optional) Probability of becoming parasitised when eating
 "contamination": [ { "disease": "bad_food", "probability": 5 } ],         // (Optional) List of diseases carried by this comestible and their associated probability. Values must be in the [0, 100] range.
+"purification_factor": 0,   // (Optional) If item is used to purify water, additional multiplicative factor to the time taken. 0 results in a constant time.
 ```
 
 ### Containers
@@ -2166,6 +2167,7 @@ Alternately, every item (book, tool, armor, even food) can be used as a gunmod i
 "ammo": [ "NULL" ],       // Ammo types used for reloading
 "revert_to": "torch_done", // Transforms into item when charges are expended
 "use_action": [ "firestarter" ] // Action performed when tool is used, see special definition below
+"purification_factor": 1    // (OPTIONAL) If item is used to purify water, additional multiplicative factor to the time taken. 0 results in a constant time.
 ```
 
 ### Seed Data

src/activity_actor.cpp

@@ -1292,7 +1292,46 @@ std::unique_ptr<activity_actor> try_sleep_activity_actor::deserialize( JsonIn &j
 
     return actor.clone();
 }
+
+void purify_water_activity_actor::start( player_activity &act, Character & )
+{
+    act.moves_total = moves;
+    act.moves_left = moves;
+}
+
+void purify_water_activity_actor::finish( player_activity &act, Character & )
+{
+    if( liquid ) {
+        liquid->convert( "water_clean" ).poison = 0;
+    } else {
+        debugmsg( "Lost target item of ACT_PURIFY_WATER" );
+    }
 
+    act.set_to_null();
+}
+
+void purify_water_activity_actor::serialize( JsonOut &jsout ) const
+{
+    jsout.start_object();
+
+    jsout.member( "moves", moves );
+    jsout.member( "liquid", liquid );
+
+    jsout.end_object();
+}
+
+std::unique_ptr<activity_actor> purify_water_activity_actor::deserialize( JsonIn &jsin )
+{
+    purify_water_activity_actor actor( item_location(), 1 );
+
+    JsonObject data = jsin.get_object();
+
+    data.read( "moves", actor.moves );
+    data.read( "liquid", actor.liquid );
+
+    return actor.clone();
+}
+
 namespace activity_actors
 {
 
@@ -1310,6 +1349,7 @@ deserialize_functions = {
     { activity_id( "ACT_MOVE_ITEMS" ), &move_items_activity_actor::deserialize },
     { activity_id( "ACT_OPEN_GATE" ), &open_gate_activity_actor::deserialize },
     { activity_id( "ACT_PICKUP" ), &pickup_activity_actor::deserialize },
+    { activity_id( "ACT_PURIFY_WATER" ), &purify_water_activity_actor::deserialize },
     { activity_id( "ACT_TRY_SLEEP" ), &try_sleep_activity_actor::deserialize },
 };
 } // namespace activity_actors

src/activity_actor.h

@@ -550,6 +550,32 @@ class consume_activity_actor : public activity_actor
         static std::unique_ptr<activity_actor> deserialize( JsonIn &jsin );
 };
 
+class purify_water_activity_actor : public activity_actor
+{
+    private:
+        item_location liquid;
+        int moves;
+
+    public:
+        purify_water_activity_actor( item_location liquid, int moves = 1 ) : liquid( liquid ),
+            moves( moves ) {}
+
+        activity_id get_type() const override {
+            return activity_id( "ACT_PURIFY_WATER" );
+        }
+
+        void start( player_activity &act, Character & ) override;
+        void do_turn( player_activity &, Character & ) override {};
+        void finish( player_activity &, Character & ) override;
+
+        std::unique_ptr<activity_actor> clone() const override {
+            return std::make_unique<purify_water_activity_actor>( *this );
+        }
+
+        void serialize( JsonOut &jsout ) const override;
+        static std::unique_ptr<activity_actor> deserialize( JsonIn &jsin );
+};
+
 class try_sleep_activity_actor : public activity_actor
 {
     private:

src/item_factory.cpp

@@ -1835,6 +1835,7 @@ void Item_factory::load( islot_tool &slot, const JsonObject &jo, const std::stri
     assign( jo, "revert_to", slot.revert_to, strict );
     assign( jo, "revert_msg", slot.revert_msg, strict );
     assign( jo, "sub", slot.subtype, strict );
+    assign( jo, "purification_factor", slot.purification_factor, strict );
 
     if( jo.has_array( "rand_charges" ) ) {
         if( jo.has_member( "initial_charges" ) ) {
@@ -1997,6 +1998,7 @@ void Item_factory::load( islot_comestible &slot, const JsonObject &jo, const std
     assign( jo, "spoils_in", slot.spoils, strict, 1_hours );
     assign( jo, "cooks_like", slot.cooks_like, strict );
     assign( jo, "smoking_result", slot.smoking_result, strict );
+    assign( jo, "purification_factor", slot.purification_factor, strict );
 
     for( const JsonObject &jsobj : jo.get_array( "contamination" ) ) {
         slot.contamination.emplace( diseasetype_id( jsobj.get_string( "disease" ) ),

src/itype.h

@@ -104,6 +104,7 @@ struct islot_tool {
     int charges_per_use = 0;
     int turns_per_charge = 0;
     int power_draw = 0;
+    int purification_factor = 1;
 
     std::vector<int> rand_charges;
 };
@@ -189,6 +190,9 @@ struct islot_comestible {
         /** Chance the above monster group spawns*/
         int rot_spawn_chance = 10;
 
+        /** Additional multiplicative time factor for purifying water. 0 means a constant time */
+        int purification_factor = 0;
+
     private:
         /** effect on morale when consuming */
         int fun = 0;

src/iuse.cpp

@@ -2212,7 +2212,26 @@ int iuse::water_purifier( player *p, item *it, bool, const tripoint & )
         return 0;
     }
 
-    p->moves -= to_moves<int>( 2_seconds );
+    int factor;
+    if( it->type->tool ) {
+        factor = it->type->tool->purification_factor;
+    } else if( it->type->comestible ) {
+        factor = it->type->comestible->purification_factor;
+    } else {
+        debugmsg( "ERROR: Water purifier not a tool or comestible" );
+        return 0;
+    }
+
+    /** A factor of 0 represents a constant time to purify, such as with water purification tablets. */
+    if( factor == 0 ) {
+        p->assign_activity( player_activity( purify_water_activity_actor( item_location( *p,
+                                             &obj->contents.front() ),
+                                             to_moves<int>( 30_minutes ) ) ) );
+    } else {
+        p->assign_activity( player_activity( purify_water_activity_actor( item_location( *p,
+                                             &obj->contents.front() ),
+                                             to_moves<int>( 2_minutes * liquid.charges * factor ) ) ) );
+    }
 
     for( item *water : liquids ) {
         water->convert( itype_water_clean ).poison = 0;