-module(pollution).
-author("Arkadiusz Cwikla").

%% API
-export([createMonitor/0,
  addStation/3, addValue/5, removeValue/4,
  getOneValue/4, getStationMean/3, getDailyMean/3,
  getDailyMaxMean/3, getDailyMinMean/3, getMinimumDistanceStations/3]).
%% records
-record(measurement, {type, value, date}).
-record(monitor, {stations, measurements}).

%%createMonitor/0 - tworzy i zwraca nowy monitor zanieczyszczeń;
%%addStation/3 - dodaje do monitora wpis o nowej stacji pomiarowej (nazwa i współrzędne geograficzne), zwraca zaktualizowany monitor;
%%addValue/5 - dodaje odczyt ze stacji (współrzędne geograficzne lub nazwa stacji, data, typ pomiaru, wartość), zwraca zaktualizowany monitor;
%%removeValue/4 - usuwa odczyt ze stacji (współrzędne geograficzne lub nazwa stacji, data, typ pomiaru), zwraca zaktualizowany monitor;
%%getOneValue/4 - zwraca wartość pomiaru o zadanym typie, z zadanej daty i stacji;
%%getStationMean/3 - zwraca średnią wartość parametru danego typu z zadanej stacji;
%%getDailyMean/3 - zwraca średnią wartość parametru danego typu, danego dnia na wszystkich stacjach;

%% monitor to krotka slownikow coordinates - name oraz name - lista measurement
createMonitor() -> #monitor{stations = dict:new(), measurements = dict:new()}.
%% funkcje pomocnicze do sprawdzania warunkow
coordinatesUsed(Coordinates, #monitor{stations = Stations}) -> dict:is_key(Coordinates, Stations).
nameUsed(StationName, #monitor{measurements = Measurements}) -> dict:is_key(StationName, Measurements).
%% sprawdzanie spojnosci danych i ewentualne dodawanie stacji
addStation(StationName, Coordinates, Monitor) ->
  case {coordinatesUsed(Coordinates, Monitor), nameUsed(StationName, Monitor)} of
    {true, true} ->
%%      io:format("~p ~n", ["Coordinates and station name are already used"]),
      Monitor;
    {true, false} ->
%%      io:format("~p ~n", ["Coordinates are already used"]),
      Monitor;
    {false, true} ->
%%      io:format("~p ~n", ["Station name is already used"]),
      Monitor;
    {false, false} -> addNewStation(StationName, Coordinates, Monitor)
  end
.
%% dodawanie stacji
addNewStation(StationName, Coordinates, #monitor{stations = Stations, measurements = Measurements}) ->
  NewStations = dict:store(Coordinates, StationName, Stations),
  NewMeasurements = dict:append_list(StationName, [], Measurements),
%%  io:format("~p ~n", ["Added new station"]),
  #monitor{stations = NewStations, measurements = NewMeasurements}
.
%% obsluga dodawania wartosci w zaleznosci od tego, czy podano nazwe czy wspolrzedne
addValue(StationName, Date, Type, Value, Monitor) when is_list(StationName) ->
  case nameUsed(StationName, Monitor) of
    false ->
%%      io:format("~p ~n", ["Incorrect station name"]),
      Monitor;
    true -> addNewValueUsingName(StationName, Date, Type, Value, Monitor)
  end;
addValue(StationCoords, Date, Type, Value, Monitor) when is_tuple(StationCoords) ->
  case coordinatesUsed(StationCoords, Monitor) of
    false ->
%%      io:format("~p ~n", ["Incorrect coordinates"]),
      Monitor;
    true -> addNewValueUsingCoords(StationCoords, Date, Type, Value, Monitor)
  end
.
%% funkcja pomocnicza
getStationName(StationCoords, #monitor{stations = Stations}) ->
  dict:fetch(StationCoords, Stations)
.
%% owijka dla przypadku uzycia wspolrzednych
addNewValueUsingCoords(StationCoords, Date, Type, Value, Monitor) ->
  StationName = getStationName(StationCoords, Monitor),
  addNewValueUsingName(StationName, Date, Type, Value, Monitor)
.
%% dodawanie wartosci
addNewValueUsingName(StationName, Date, Type, Value, Monitor) ->
  #monitor{measurements = Measurements} = Monitor,
  StoredMeasurements = dict:fetch(StationName, Measurements),
  case checkMeasurement(Date, Type, StoredMeasurements) of
    {_, true} ->
%%      io:format("~p ~n", ["Added new measurement"]),
      Measurement = #measurement{type = Type, value = Value, date = Date},
      NewMeasurements = dict:append(StationName, Measurement, Measurements),
      Monitor#monitor{measurements = NewMeasurements};
    {_, false} ->
%%      io:format("~p ~n", ["You cannot add the same measurement twice"]),
      Monitor
  end
.
%% wazna funkcja pomocnicza, sprawdza czy pomiar o danej dacie i typie juz istnieje w danej stacji
%% zwraca pusta tablice i true, gdy nie istnieje
%% zwraca tablice z istniejacym pomiarem i false, gdy istnieje
checkMeasurement(Date, Type, StoredMeasurements) ->
  EqualDateAndType =
    fun(#measurement{date = StoredDate, type = StoredType}) ->
      (StoredDate == Date) and (StoredType == Type)
    end,
  FilteredMeasurements = lists:filter(EqualDateAndType, StoredMeasurements),
  case FilteredMeasurements of
    [] -> {[], true};
    [Measurement] -> {[Measurement], false}
  end
.
%% obsluga usuwania wartosci, w zaleznosci od tego, czy podano nazwe czy wspolrzedne
removeValue(StationName, Date, Type, Monitor) when is_list(StationName) ->
  case nameUsed(StationName, Monitor) of
    false ->
%%      io:format("~p ~n", ["Incorrect station name"]),
      Monitor;
    true -> removeValueUsingName(StationName, Date, Type, Monitor)
  end;
removeValue(StationCoords, Date, Type, Monitor) when is_tuple(StationCoords) ->
  case coordinatesUsed(StationCoords, Monitor) of
    false ->
%%      io:format("~p ~n", ["Incorrect coordinates"]),
      Monitor;
    true -> removeValueUsingCoords(StationCoords, Date, Type, Monitor)
  end
.
%% owijka dla przypadku uzycia wspolrzednych
removeValueUsingCoords(StationCoords, Date, Type, Monitor) ->
  StationName = getStationName(StationCoords, Monitor),
  removeValueUsingName(StationName, Date, Type, Monitor)
.
%% usuwanie pomiaru z danej stacji
removeValueUsingName(StationName, Date, Type, Monitor) ->
  #monitor{measurements = Measurements} = Monitor,
  StoredMeasurements = dict:fetch(StationName, Measurements),
  {Measurement, _} = checkMeasurement(Date, Type, StoredMeasurements),
  NewMeasurements = dict:store(StationName, StoredMeasurements -- Measurement, Measurements),
%%  io:format("~p ~n", ["Removed measurement"]),
  Monitor#monitor{measurements = NewMeasurements}
.
%% obsluga czytania wartosci, w zaleznosci od tego, czy podano nazwe czy wspolrzedne
getOneValue(StationName, Date, Type, Monitor) when is_list(StationName) ->
  case nameUsed(StationName, Monitor) of
    false ->
%%      io:format("~p ~n", ["Incorrect station name"]),
      Monitor;
    true -> getValueUsingName(StationName, Date, Type, Monitor)
  end;
getOneValue(StationCoords, Date, Type, Monitor) when is_tuple(StationCoords) ->
  case coordinatesUsed(StationCoords, Monitor) of
    false ->
%%      io:format("~p ~n", ["Incorrect coordinates"]),
      Monitor;
    true -> getValueUsingCoords(StationCoords, Date, Type, Monitor)
  end
.
%% owijka dla przypadku uzycia wspolrzednych
getValueUsingCoords(StationCoords, Date, Type, Monitor) ->
  StationName = getStationName(StationCoords, Monitor),
  getValueUsingName(StationName, Date, Type, Monitor)
.
%% czytanie wartosci
getValueUsingName(StationName, Date, Type, Monitor) ->
  #monitor{measurements = Measurements} = Monitor,
  StoredMeasurements = dict:fetch(StationName, Measurements),
  case checkMeasurement(Date, Type, StoredMeasurements) of
    {[], true} ->
%%      io:format("~p ~n", ["No such value"]),
      no_value;
    {[Measurement], false} ->
      #measurement{value = Value} = Measurement,
      Value
  end
.
%% obliczanie sredniej dla stacji, w zaleznosci od tego, czy podano nazwe czy wspolrzedne
getStationMean(StationName, Type, Monitor) when is_list(StationName) ->
  case nameUsed(StationName, Monitor) of
    false ->
%%      io:format("~p ~n", ["Incorrect station name"]),
      Monitor;
    true -> getStationMeanUsingName(StationName, Type, Monitor)
  end;
getStationMean(StationCoords, Type, Monitor) when is_tuple(StationCoords) ->
  case coordinatesUsed(StationCoords, Monitor) of
    false ->
%%      io:format("~p ~n", ["Incorrect coordinates"]),
      Monitor;
    true -> getStationMeanUsingCoords(StationCoords, Type, Monitor)
  end
.
%% owijka dla przypadku uzycia wspolrzednych
getStationMeanUsingCoords(StationCoords, Type, Monitor) ->
  StationName = getStationName(StationCoords, Monitor),
  getStationMeanUsingName(StationName, Type, Monitor)
.
%% obliczenie sredniej dla stacji
getStationMeanUsingName(StationName, Type, Monitor) ->
  #monitor{measurements = Measurements} = Monitor,
  StoredMeasurements = dict:fetch(StationName, Measurements),
  MatchingTypes =
    fun(#measurement{type = StoredType}) ->
      (StoredType == Type)
    end,
  FilteredMeasurements = lists:filter(MatchingTypes, StoredMeasurements),
  getMean(FilteredMeasurements)
.
%% obliczanie sredniej dziennej dla typu
getDailyMean(Type, {Date, _Hour}, Monitor) ->
  #monitor{measurements = Measurements} = Monitor,
  Concat =
    fun(_, Measurement, Acc) ->
      Acc ++ Measurement
    end,
  ConcatenatedMeasurements = dict:fold(Concat, [], Measurements),
  MatchingTypesAndDates =
    fun(#measurement{type = StoredType, date = {StoredDate, _StoredHour}}) ->
      (StoredType == Type) and (StoredDate == Date)
    end,
  FilteredMeasurements = lists:filter(MatchingTypesAndDates, ConcatenatedMeasurements),
  getMean(FilteredMeasurements)
.
%% pomocnicza funkcja do obliczania srednich
getMean(Measurements) ->
  SumValuesAndOccurrences =
    fun(#measurement{value = Value}, {Sum, Occurrences}) ->
      {Sum + Value, Occurrences + 1}
    end,
  {Sum, Occurrences} = lists:foldl(SumValuesAndOccurrences, {0, 0}, Measurements),
%%  io:format("~w ~w ~n", [Sum, Occurrences]),
  Sum / Occurrences
.

%% dodatkowe funckje
%% getDailyMaxMean/3 - wyszukuje maksymalna srednia wartosc parametru dla danego dnia i zwraca krotke {nazwa, wartosc}
%% getDailyMinMean/3 - wyszukuje minimalna srednia wartosc parametru dla danego dnia i zwraca krotke {nazwa, wartosc}

getDailyMaxMean(Type, {Date, _Hour}, Monitor) ->
  Means = getDailyMeans(Type, Date, Monitor),
  MaxMean =
    fun(Name, Value, {_MaxName, MaxValue}) when (Value > MaxValue) -> {Name, Value};
      (_Name, Value, {MaxName, MaxValue}) when not(Value > MaxValue) -> {MaxName, MaxValue}
    end,
  dict:fold(MaxMean, {"", -999999999}, Means)
.

getDailyMinMean(Type, {Date, _Hour}, Monitor) ->
  Means = getDailyMeans(Type, Date, Monitor),
  MinMean =
    fun(Name, Value, {_MinName, MinValue}) when (Value < MinValue) -> {Name, Value};
      (_Name, Value, {MinName, MinValue}) when not(Value < MinValue) -> {MinName, MinValue}
    end,
  dict:fold(MinMean, {"", 999999999}, Means)
.
%% pomocnicza funkcja
getDailyMeans(Type, Date, Monitor) ->
  #monitor{measurements = StoredMeasurements} = Monitor,
%%  io:format("~s ~n ~w ~n", ["StoredMeasurements", StoredMeasurements]),
  MatchingTypesAndDates =
    fun(#measurement{type = StoredType, date = {StoredDate, _StoredHour}}) ->
      (StoredType == Type) and (StoredDate == Date)
    end,
  MapFilteredLists =
    fun(_, Measurements) ->
      length(lists:filter(MatchingTypesAndDates, Measurements)) > 0
    end,
  FilteredMeasurements = dict:filter(MapFilteredLists, StoredMeasurements),
  MapMeans =
    fun(_, Measurements) ->
      getMean(Measurements)
    end,
%%  io:format("~s ~n ~w ~n", ["FilteredMeasurements", FilteredMeasurements]),
  dict:map(MapMeans, FilteredMeasurements)
.
% trzecia dodatkowa funckja z excela
% zwraca liste koordynatów stacji które są w odpowiedniej odleglosci od danego punktu
getMinimumDistanceStations(Coords, Distance, #monitor{stations = Stations}) ->
  CoordsList = dict:to_list(Stations),
  InDistance =
    fun ({CurrentCoords, _Name}) -> distance(CurrentCoords, Coords) < Distance end,
  Filtered = lists:filter(InDistance, CoordsList),
  lists:map(fun ({CurrentCoords, _Name})-> CurrentCoords end, Filtered)
.

%% haversin zakoszony z forum
distance({Lng1, Lat1}, {Lng2, Lat2}) ->
  Deg2rad = fun(Deg) -> math:pi()*Deg/180 end,
  [RLng1, RLat1, RLng2, RLat2] = [Deg2rad(Deg) || Deg <- [Lng1, Lat1, Lng2, Lat2]],

  DLon = RLng2 - RLng1,
  DLat = RLat2 - RLat1,

  A = math:pow(math:sin(DLat/2), 2) + math:cos(RLat1) * math:cos(RLat2) * math:pow(math:sin(DLon/2), 2),

  C = 2 * math:asin(math:sqrt(A)),

  %% suppose radius of Earth is 6372.8 km
  Km = 6372.8 * C,
  Km.