Support for achievements hidden by other achievements

data/json/achievements.json

@@ -12,13 +12,63 @@
     "time_constraint": { "since": "game_start", "is": "<=", "target": "1 minute" },
     "requirements": [ { "event_statistic": "num_avatar_kills", "is": ">=", "target": 1 } ]
   },
+  {
+    "id": "achievement_kill_10_monsters",
+    "type": "achievement",
+    "name": "Decamate",
+    "requirements": [ { "event_statistic": "num_avatar_kills", "is": ">=", "target": 10 } ]
+  },
+  {
+    "id": "achievement_kill_100_monsters",
+    "type": "achievement",
+    "name": "Centinel",
+    "hidden_by": [ "achievement_kill_10_monsters" ],
+    "requirements": [ { "event_statistic": "num_avatar_kills", "is": ">=", "target": 100 } ]
+  },
   {
     "id": "achievement_survive_one_day",
     "type": "achievement",
     "name": "The first day of the rest of their unlives",
+    "description": "Survive for a day and find a safe place to sleep",
     "time_constraint": { "since": "game_start", "is": ">=", "target": "1 day" },
     "requirements": [ { "event_statistic": "num_avatar_wake_ups", "is": "anything" } ]
   },
+  {
+    "id": "achievement_survive_7_days",
+    "type": "achievement",
+    "name": "Thank God it's Friday",
+    "description": "Survive for a week",
+    "hidden_by": [ "achievement_survive_one_day" ],
+    "time_constraint": { "since": "game_start", "is": ">=", "target": "7 days" },
+    "requirements": [ { "event_statistic": "num_avatar_wake_ups", "is": "anything" } ]
+  },
+  {
+    "id": "achievement_survive_28_days",
+    "type": "achievement",
+    "name": "28 days later",
+    "description": "Survive for a month",
+    "hidden_by": [ "achievement_survive_7_days" ],
+    "time_constraint": { "since": "game_start", "is": ">=", "target": "28 days" },
+    "requirements": [ { "event_statistic": "num_avatar_wake_ups", "is": "anything" } ]
+  },
+  {
+    "id": "achievement_survive_91_days",
+    "type": "achievement",
+    "name": "A time to every purpose under heaven",
+    "description": "Survive for a season",
+    "hidden_by": [ "achievement_survive_28_days" ],
+    "time_constraint": { "since": "game_start", "is": ">=", "target": "91 days" },
+    "requirements": [ { "event_statistic": "num_avatar_wake_ups", "is": "anything" } ]
+  },
+  {
+    "id": "achievement_survive_365_days",
+    "type": "achievement",
+    "name": "Brighter days ahead?",
+    "description": "Survive for a year",
+    "hidden_by": [ "achievement_survive_91_days" ],
+    "time_constraint": { "since": "game_start", "is": ">=", "target": "365 days" },
+    "requirements": [ { "event_statistic": "num_avatar_wake_ups", "is": "anything" } ]
+  },
   {
     "id": "achievement_marathon",
     "type": "achievement",

doc/JSON_INFO.md

@@ -1288,7 +1288,17 @@ an `event_statistic`.  For example:
 The `"is"` field must be `">="`, `"<="` or `"anything"`.  When it is not
 `"anything"` the `"target"` must be present, and must be an integer.
 
-Another optional field is
+There are further optional fields:
+
+```C++
+"hidden_by": [ "other_achievement_id" ]
+```
+
+Give a list of other achievement ids.  This achievement will be hidden (i.e.
+not appear in the achievements UI) until all of the achievements listed have
+been completed.
+
+Use this to prevent spoilers or to reduce clutter in the list of achievements.
 
 ```C++
 "time_constraint": { "since": "game_start", "is": "<=", "target": "1 minute" }

src/achievement.cpp

@@ -50,6 +50,13 @@ const achievement &string_id<achievement>::obj() const
     return achievement_factory.obj( *this );
 }
 
+/** @relates string_id */
+template<>
+bool string_id<achievement>::is_valid() const
+{
+    return achievement_factory.is_valid( *this );
+}
+
 namespace io
 {
 
@@ -310,18 +317,25 @@ void achievement::load( const JsonObject &jo, const std::string & )
 {
     mandatory( jo, was_loaded, "name", name_ );
     optional( jo, was_loaded, "description", description_ );
+    optional( jo, was_loaded, "hidden_by", hidden_by_ );
     optional( jo, was_loaded, "time_constraint", time_constraint_ );
     mandatory( jo, was_loaded, "requirements", requirements_ );
 }
 
 void achievement::check() const
 {
-    for( const achievement_requirement &req : requirements_ ) {
-        req.check( id );
+    for( const string_id<achievement> &a : hidden_by_ ) {
+        if( !a.is_valid() ) {
+            debugmsg( "Achievement %s specifies hidden_by achievement %s, but the latter does not "
+                      "exist.", id.str(), a.str() );
+        }
     }
     if( time_constraint_ ) {
         time_constraint_->check( id );
     }
+    for( const achievement_requirement &req : requirements_ ) {
+        req.check( id );
+    }
 }
 
 static std::string text_for_requirement( const achievement_requirement &req,
@@ -599,6 +613,20 @@ achievement_completion achievements_tracker::is_completed( const string_id<achie
     return it->second.completion;
 }
 
+bool achievements_tracker::is_hidden( const achievement *ach ) const
+{
+    if( is_completed( ach->id ) == achievement_completion::completed ) {
+        return false;
+    }
+
+    for( const string_id<achievement> &hidden_by : ach->hidden_by() ) {
+        if( is_completed( hidden_by ) != achievement_completion::completed ) {
+            return true;
+        }
+    }
+    return false;
+}
+
 std::string achievements_tracker::ui_text_for( const achievement *ach ) const
 {
     auto state_it = achievements_status_.find( ach->id );

src/achievement.h

@@ -67,6 +67,10 @@ class achievement
             return description_;
         }
 
+        const std::vector<string_id<achievement>> &hidden_by() const {
+            return hidden_by_;
+        }
+
         class time_bound
         {
             public:
@@ -98,6 +102,7 @@ class achievement
     private:
         translation name_;
         translation description_;
+        std::vector<string_id<achievement>> hidden_by_;
         cata::optional<time_bound> time_constraint_;
         std::vector<achievement_requirement> requirements_;
 };
@@ -170,6 +175,7 @@ class achievements_tracker : public event_subscriber
         void report_achievement( const achievement *, achievement_completion );
 
         achievement_completion is_completed( const string_id<achievement> & ) const;
+        bool is_hidden( const achievement * ) const;
         std::string ui_text_for( const achievement * ) const;
 
         void clear();

src/scores_ui.cpp

@@ -22,6 +22,11 @@ static std::string get_achievements_text( const achievements_tracker &achievemen
 {
     std::string os;
     std::vector<const achievement *> valid_achievements = achievements.valid_achievements();
+    valid_achievements.erase(
+        std::remove_if( valid_achievements.begin(), valid_achievements.end(),
+    [&]( const achievement * a ) {
+        return achievements.is_hidden( a );
+    } ), valid_achievements.end() );
     using sortable_achievement =
         std::tuple<achievement_completion, std::string, const achievement *>;
     std::vector<sortable_achievement> sortable_achievements;

tests/stats_tracker_test.cpp

@@ -486,6 +486,26 @@ TEST_CASE( "achievments_tracker", "[stats]" )
         CHECK( achievements_completed.count( a_survive_one_day ) );
     }
 
+    SECTION( "hidden_kills" ) {
+        const character_id u_id = g->u.getID();
+        const mtype_id mon_zombie( "mon_zombie" );
+        const cata::event avatar_zombie_kill =
+            cata::event::make<event_type::character_kills_monster>( u_id, mon_zombie );
+
+        string_id<achievement> a_kill_10( "achievement_kill_10_monsters" );
+        string_id<achievement> a_kill_100( "achievement_kill_100_monsters" );
+
+        b.send<event_type::game_start>( u_id );
+
+        CHECK( !a.is_hidden( &*a_kill_10 ) );
+        CHECK( a.is_hidden( &*a_kill_100 ) );
+        for( int i = 0; i < 10; ++i ) {
+            b.send( avatar_zombie_kill );
+        }
+        CHECK( !a.is_hidden( &*a_kill_10 ) );
+        CHECK( !a.is_hidden( &*a_kill_100 ) );
+    }
+
     SECTION( "kills" ) {
         time_duration time_since_game_start = GENERATE( 30_seconds, 10_minutes );
         CAPTURE( time_since_game_start );