Traders have trading standards

src/item.cpp

@@ -6352,31 +6352,7 @@ int item::price( bool practical ) const
     int res = 0;
 
     visit_items( [&res, practical]( const item * e, item * ) {
-        if( e->rotten() ) {
-            // TODO: Special case things that stay useful when rotten
-            return VisitResponse::NEXT;
-        }
-
-        int child = units::to_cent( practical ? e->type->price_post : e->type->price );
-        if( e->damage() > 0 ) {
-            // maximal damage level is 4, maximal reduction is 40% of the value.
-            child -= child * static_cast<double>( e->damage_level() ) / 10;
-        }
-
-        if( e->count_by_charges() || e->made_of( phase_id::LIQUID ) ) {
-            // price from json data is for default-sized stack
-            child *= e->charges / static_cast<double>( e->type->stack_size );
-
-        } else if( e->magazine_integral() && e->ammo_remaining() && e->ammo_data() ) {
-            // items with integral magazines may contain ammunition which can affect the price
-            child += item( e->ammo_data(), calendar::turn, e->ammo_remaining() ).price( practical );
-
-        } else if( e->is_tool() && e->type->tool->max_charges != 0 ) {
-            // if tool has no ammo (e.g. spray can) reduce price proportional to remaining charges
-            child *= e->ammo_remaining() / static_cast<double>( std::max( e->type->charges_default(), 1 ) );
-        }
-
-        res += child;
+        res += e->price_no_contents( practical );
         return VisitResponse::NEXT;
     } );
 
@@ -6390,8 +6366,12 @@ int item::price_no_contents( bool practical ) const
     }
     int price = units::to_cent( practical ? type->price_post : type->price );
     if( damage() > 0 ) {
-        // maximal damage level is 4, maximal reduction is 40% of the value.
-        price -= price * static_cast< double >( damage_level() ) / 10;
+        // maximal damage level is 4, maximal reduction is 80% of the value.
+        price -= price * static_cast< double >( damage_level() ) / 5;
+    }
+
+    if( is_filthy() ) {
+        price *= 0.5;
     }
 
     if( count_by_charges() || made_of( phase_id::LIQUID ) ) {
@@ -6407,7 +6387,6 @@ int item::price_no_contents( bool practical ) const
         price *= ammo_remaining() / static_cast< double >( std::max( type->charges_default(), 1 ) );
 
     }
-
     return price;
 }
 

src/npc.cpp

@@ -1937,6 +1937,7 @@ bool npc::wants_to_sell( const item &it, int at_price, int /*market_price*/ ) co
     }
 
     // TODO: Base on inventory
+    // why should he sell things for free?
     return at_price >= 0;
 }
 
@@ -1956,8 +1957,9 @@ bool npc::wants_to_buy( const item &it, int at_price, int /*market_price*/ ) con
         return false;
     }
 
+    // Item sale refusal if worthless
     // TODO: Base on inventory
-    return at_price > 0;
+    return at_price > 1;
 }
 
 // Will the NPC freely exchange items with the player?

src/npctrade.cpp

@@ -136,16 +136,17 @@ double npc_trading::net_price_adjustment( const Character &buyer, const Characte
 {
     // Adjust the prices based on your social skill.
     // cap adjustment so nothing is ever sold below value
-    ///\EFFECT_INT_NPC slightly increases bartering price changes, relative to your INT
 
-    ///\EFFECT_BARTER_NPC increases bartering price changes, relative to your BARTER
+    // Boost the NPC selling/buying power
+    // average (a+b)/2;
 
-    ///\EFFECT_INT slightly increases bartering price changes, relative to NPC INT
-
-    ///\EFFECT_BARTER increases bartering price changes, relative to NPC BARTER
-    double adjust = 0.05 * ( seller.int_cur - buyer.int_cur ) +
-                    price_adjustment( seller.get_skill_level( skill_speech ) -
-                                      buyer.get_skill_level( skill_speech ) );
+    //    double average = ( seller.int_cur + buyer.int_cur ) / 2;
+    double selladjust = 0.05;
+    if( seller.is_npc() ) {
+        selladjust = 0.2;
+    }
+    double adjust = ( ( selladjust * seller.int_cur ) - ( 0.05 * buyer.int_cur ) ) +
+                    price_adjustment( seller.get_skill_level( skill_speech ) - buyer.get_skill_level( skill_speech ) );
     return std::max( adjust, 1.0 );
 }
 
@@ -202,6 +203,14 @@ int npc_trading::trading_price( Character const &buyer, Character const &seller,
                 return VisitResponse::SKIP;
             }
         }
+        // Prevent free items
+        if( price < 1 ) {
+            if( e->count_by_charges() ) {
+                ret = 1 * amount;
+            } else {
+                ret = 1;
+            }
+        }
         ret += price;
         return VisitResponse::NEXT;
     } );
@@ -221,6 +230,9 @@ void item_pricing::set_values( int ip_count )
         charges = i_p->count();
         if( charges > 0 ) {
             price /= charges;
+            if( price < 1 ) {
+                price = 1;
+            }
             vol /= charges;
             weight /= charges;
         } else {