1 files changed, 142 insertions, 0 deletions
diff --git a/learn-you-some-erlang/mafiapp-1.0.1/src/mafiapp.erl b/learn-you-some-erlang/mafiapp-1.0.1/src/mafiapp.erl
new file mode 100644
index 0000000..f40ebce
--- /dev/null
+++ b/learn-you-some-erlang/mafiapp-1.0.1/src/mafiapp.erl
@@ -0,0 +1,142 @@
+-module(mafiapp).
+-behaviour(application).
+-include_lib("stdlib/include/ms_transform.hrl").
+-include_lib("stdlib/include/qlc.hrl").
+-export([start/2, stop/1]).
+-export([install/1]).
+-export([add_friend/4, friend_by_name/1, friend_by_expertise/1,
+         add_service/4, debts/1]).
+-export([add_enemy/2, find_enemy/1, enemy_killed/1]).
+
+
+-record(mafiapp_friends, {name,
+                          contact=[],
+                          info=[],
+                          expertise}).
+-record(mafiapp_services, {from,
+                           to,
+                           date,
+                           description}).
+-record(mafiapp_enemies, {name,
+                          info=[]}).
+
+start(normal, []) ->
+    mnesia:wait_for_tables([mafiapp_friends,
+                            mafiapp_services,
+                            mafiapp_enemies], 5000),
+    mafiapp_sup:start_link().
+
+stop(_) -> ok.
+
+install(Nodes) ->
+    ok = mnesia:create_schema(Nodes),
+    rpc:multicall(Nodes, application, start, [mnesia]),
+    mnesia:create_table(mafiapp_friends,
+                        [{attributes, record_info(fields, mafiapp_friends)},
+                         {index, [#mafiapp_friends.expertise]},
+                         {disc_copies, Nodes}]),
+    mnesia:create_table(mafiapp_services,
+                        [{attributes, record_info(fields, mafiapp_services)},
+                         {index, [#mafiapp_services.to]},
+                         {disc_copies, Nodes},
+                         {type, bag}]),
+    mnesia:create_table(mafiapp_enemies,
+                        [{attributes, record_info(fields, mafiapp_enemies)},
+                         {disc_copies, Nodes},
+                         {local_content, true}]),
+    rpc:multicall(Nodes, application, stop, [mnesia]).
+
+add_friend(Name, Contact, Info, Expertise) ->
+    F = fun() ->
+        mnesia:write(#mafiapp_friends{name=Name,
+                                      contact=Contact,
+                                      info=Info,
+                                      expertise=Expertise})
+    end,
+    mnesia:activity(transaction, F).
+
+friend_by_name(Name) ->
+    F = fun() ->
+        case mnesia:read({mafiapp_friends, Name}) of
+            [#mafiapp_friends{contact=C, info=I, expertise=E}] ->
+                {Name,C,I,E,find_services(Name)};
+            [] ->
+                undefined
+        end
+    end,
+    mnesia:activity(transaction, F).
+
+friend_by_expertise(Expertise) ->
+    F = fun() ->
+        qlc:eval(qlc:q(
+            [{Name,C,I,E,find_services(Name)} ||
+             #mafiapp_friends{name=Name,
+                              contact=C,
+                              info=I,
+                              expertise=E} <- mnesia:table(mafiapp_friends),
+             E =:= Expertise]))
+    end,
+    mnesia:activity(transaction, F).
+
+%% Adding validation is left to the reader
+add_service(From, To, Date, Description) ->
+    F = fun() ->
+            case mnesia:read({mafiapp_friends, From}) =:= [] orelse
+                 mnesia:read({mafiapp_friends, To}) =:= [] of
+                true ->
+                    {error, unknown_friend};
+                false ->
+                    mnesia:write(#mafiapp_services{from=From,
+                                                   to=To,
+                                                   date=Date,
+                                                   description=Description})
+            end
+    end,
+    mnesia:activity(transaction,F).
+
+debts(Name) ->
+    F = fun() ->
+        QH = qlc:q(
+            [if Name =:= To -> {From,1};
+                Name =:= From -> {To,-1}
+             end || #mafiapp_services{from=From, to=To} <-
+                      mnesia:table(mafiapp_services),
+                   Name =:= To orelse Name =:= From]),
+        qlc:fold(fun({Person,N}, Dict) ->
+                  dict:update(Person, fun(X) -> X + N end, N, Dict)
+                 end,
+                 dict:new(),
+                 QH)
+    end,
+    lists:sort([{V,K} || {K,V} <- dict:to_list(mnesia:activity(transaction, F))]).
+
+add_enemy(Name, Info) ->
+    F = fun() -> mnesia:write(#mafiapp_enemies{name=Name, info=Info}) end,
+    mnesia:activity(transaction, F).
+
+find_enemy(Name) ->
+    F = fun() -> mnesia:read({mafiapp_enemies, Name}) end,
+    case mnesia:activity(transaction, F) of
+        [] -> undefined;
+        [#mafiapp_enemies{name=N, info=I}] -> {N,I}
+    end.
+
+enemy_killed(Name) ->
+    F = fun() -> mnesia:delete({mafiapp_enemies, Name}) end,
+    mnesia:activity(transaction, F).
+
+%%%%%%%%%%%%%%%
+%%% PRIVATE %%%
+%%%%%%%%%%%%%%%
+
+find_services(Name) ->
+    Match = ets:fun2ms(
+            fun(#mafiapp_services{from=From, to=To, date=D, description=Desc})
+                when From =:= Name ->
+                    {to, To, D, Desc};
+               (#mafiapp_services{from=From, to=To, date=D, description=Desc})
+                when To =:= Name ->
+                    {from, From, D, Desc}
+            end
+    ),
+    mnesia:select(mafiapp_services, Match).