-module(btl_condition).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% TYPES %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-include("tacticians/conditions.hrl").

-type update_action() ::
   (
      none
      | remove
      | {update, type(), ataxic:basic()}
   ).

-record
(
   btl_cond,
   {
      category :: shr_condition:id(),
      triggers :: ordset:ordset(shr_condition:trigger()),
      occurrences :: (non_neg_integer() | -1),
      duration :: (non_neg_integer() | -1),
      parameters :: tuple()
   }
).

-opaque type() :: #btl_cond{}.

-export_type([type/0, update_action/0]).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% EXPORTS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-export
(
   [
      get_category/1,
      get_triggers/1,
      get_remaining_occurrences/1,
      get_duration/1,
      get_parameters/1,

      set_triggers/2,
      set_remaining_occurrences/2,
      set_duration/2,
      set_parameters/2,

      ataxia_set_triggers/2,
      ataxia_set_remaining_occurrences/2,
      ataxia_set_duration/2,
      ataxia_set_parameters/2,

      ataxia_set_triggers/3,
      ataxia_set_parameters/3,

      get_category_field/0,
      get_triggers_field/0,
      get_remaining_occurrences_field/0,
      get_duration_field/0,
      get_parameters_field/0
   ]
).

-export
(
   [
      triggers_on/2,
      apply/3,
      recursive_apply/3,
      apply_updates/2,
      ataxia_apply_updates/2
   ]
).

-export
(
   [
      encode/1
   ]
).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% LOCAL FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-spec encode_parameters
   (
      shr_condition:id(),
      tuple()
   )
   -> {list({binary(), any()})}.
encode_parameters (_Category, _Parameters) -> {[]}. % TODO.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% EXPORTED FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

-spec get_category (type()) -> shr_condition:id().
get_category (Condition) -> Condition#btl_cond.category.

-spec get_triggers (type()) -> ordset:ordset(shr_condition:trigger()).
get_triggers (Condition) -> Condition#btl_cond.triggers.

-spec get_remaining_occurrences (type()) -> (non_neg_integer() | -1).
get_remaining_occurrences (Condition) -> Condition#btl_cond.occurrences.

-spec get_duration (type()) -> (non_neg_integer() | -1).
get_duration (Condition) -> Condition#btl_cond.duration.

-spec get_parameters (type()) -> tuple().
get_parameters (Condition) -> Condition#btl_cond.parameters.

-spec set_triggers (ordset:ordset(shr_condition:trigger()), type()) -> type().
set_triggers (Triggers, Condition) -> Condition#btl_cond{ triggers = Triggers }.

-spec set_remaining_occurrences ((non_neg_integer() | -1), type()) -> type().
set_remaining_occurrences (Value, Condition) ->
   Condition#btl_cond{ occurrences = Value }.

-spec set_duration ((non_neg_integer() | -1), type()) -> type().
set_duration (Value, Condition) ->
   Condition#btl_cond{ duration = Value }.

-spec set_parameters (tuple(), type()) -> type().
set_parameters (Value, Condition) -> Condition#btl_cond{ parameters = Value }.

-spec ataxia_set_triggers
   (
      ordset:ordset(shr_condition:trigger()),
      type()
   )
   -> {type(), ataxic:basic()}.
ataxia_set_triggers (Triggers, Condition) ->
   {
      set_triggers(Triggers, Condition),
      ataxic:update_field
      (
         get_triggers_field(),
         ataxic:constant(Triggers)
      )
   }.

-spec ataxia_set_remaining_occurrences
   (
      (non_neg_integer() | -1),
      type()
   )
   -> {type(), ataxic:basic()}.
ataxia_set_remaining_occurrences (Value, Condition) ->
   {
      set_remaining_occurrences(Value, Condition),
      ataxic:update_field
      (
         get_remaining_occurrences_field(),
         ataxic:constant(Value)
      )
   }.


-spec ataxia_set_duration
   (
      (non_neg_integer() | -1),
      type()
   )
   -> {type(), ataxic:basic()}.
ataxia_set_duration (Value, Condition) ->
   {
      set_duration(Value, Condition),
      ataxic:update_field
      (
         get_duration_field(),
         ataxic:constant(Value)
      )
   }.

-spec ataxia_set_parameters (tuple(), type()) -> {type(), ataxic:basic()}.
ataxia_set_parameters (Value, Condition) ->
   {
      set_parameters(Value, Condition),
      ataxic:update_field
      (
         get_parameters_field(),
         ataxic:constant(Value)
      )
   }.

-spec ataxia_set_triggers
   (
      ordset:ordset(shr_condition:trigger()),
      ataxic:basic(),
      type()
   )
   -> {type(), ataxic:basic()}.
ataxia_set_triggers (Triggers, Update, Condition) ->
   {
      set_triggers(Triggers, Condition),
      ataxic:update_field
      (
         get_triggers_field(),
         Update
      )
   }.

-spec ataxia_set_parameters
   (
      tuple(),
      ataxic:basic(),
      type()
   )
   -> {type(), ataxic:basic()}.
ataxia_set_parameters (Value, Update, Condition) ->
   {
      set_parameters(Value, Condition),
      ataxic:update_field
      (
         get_parameters_field(),
         Update
      )
   }.

-spec triggers_on (shr_condition:trigger(), type()) -> boolean().
triggers_on (Trigger, Type) ->
   ordset:is_element(Trigger, Type#btl_cond.triggers).

-spec get_category_field () -> non_neg_integer().
get_category_field () -> #btl_cond.category.

-spec get_triggers_field () -> non_neg_integer().
get_triggers_field () -> #btl_cond.triggers.

-spec get_remaining_occurrences_field () -> non_neg_integer().
get_remaining_occurrences_field () -> #btl_cond.occurrences.

-spec get_duration_field () -> non_neg_integer().
get_duration_field () -> #btl_cond.duration.

-spec get_parameters_field () -> non_neg_integer().
get_parameters_field () -> #btl_cond.parameters.

-spec apply
   (
      type(),
      shr_condition:context(),
      btl_character_turn_update:type()
   )
   ->
   {
      shr_condition:context(),
      btl_character_turn_update:type(),
      update_action()
   }.
apply (Condition, S0Context, S0Update) ->
   Module = shr_condition_selector:get_module(get_category(Condition)),

   {S1Context, S1Update, UpdateAction} =
      erlang:apply(Module, apply, [S0Context, Condition, S0Update]),

   {S1Context, S1Update, UpdateAction}.


-spec recursive_apply
   (
      orddict:orddict(IndexType, type()),
      shr_condition:context(),
      btl_character_turn_update:type()
   )
   ->
   {
      shr_condition:context(),
      btl_character_turn_update:type(),
      list({IndexType, update_action()})
   }.
recursive_apply (Conditions, S0Context, S0Update) ->
   {[LastContext, LastUpdate], AllUpdateActions} =
      orddict:fold
      (
         fun (IX, Condition, {Parameters, UpdateActions}) ->
            {NextContext, NextUpdate, UpdateAction} =
               erlang:apply(btl_condition, apply, [Condition|Parameters]),

            {
               [NextContext, NextUpdate],
               case UpdateAction of
                  none -> UpdateActions;
                  _ -> [{IX, UpdateAction}|UpdateActions]
               end
            }
         end,
         [S0Context, S0Update, []],
         Conditions
      ),

   {LastContext, LastUpdate, AllUpdateActions}.

-spec apply_updates
   (
      list({IndexType, update_action()}),
      orddict:orddict(IndexType, type())
   )
   -> orddict:orddict(IndexType, type()).
apply_updates (Updates, Conditions) ->
   lists:foldl
   (
      fun ({IX, Update}, CurrentConditions) ->
         case Update of
            none -> CurrentConditions;
            remove -> orddict:erase(IX, CurrentConditions);
            {update, Val, _Ataxic} -> orddict:store(IX, Val, CurrentConditions)
         end
      end,
      Conditions,
      Updates
   ).

-spec ataxia_apply_updates
   (
      list({IndexType, update_action()}),
      orddict:orddict(IndexType, type())
   )
   -> {orddict:orddict(IndexType, type()), ataxic:basic()}.
ataxia_apply_updates (Updates, Conditions) ->
   {FinalConditions, AtaxicSequence} =
      lists:foldl
      (
         fun ({IX, Update}, {CurrentConditions, AtaxicUpdates}) ->
            case Update of
               none -> {CurrentConditions, AtaxicUpdates};
               remove ->
                  {
                     orddict:erase(IX, CurrentConditions),
                     [
                        ataxic:apply_function
                        (
                           orddict,
                           erase,
                           [ataxic:constant(IX), ataxic:current_value()]
                        )
                        |AtaxicUpdates
                     ]
                  };

               {update, Val, Ataxic} ->
                  {
                     orddict:store(IX, Val, CurrentConditions),
                     [
                        ataxic_sugar:update_orddict_element(IX, Ataxic)
                        |AtaxicUpdates
                     ]
                  }
            end
         end,
         Conditions,
         Updates
      ),

   {FinalConditions, ataxic:sequence(AtaxicSequence)}.

-spec encode (type()) -> {list({binary(), any()})}.
encode (Condition) -> {[]}. % TODO