Heads-I-Lose

-module(headsilose).
-export([get_locations/0, get_locations/1, headsilose/1]).
-include_lib("xmerl/include/xmerl.hrl").
-import(weather_types, [weather_type/1]).
-import(polyline, [decode/1]).
-import(osrm, [read_route/0]).

%Supply a direction and location and work out if head wind or not
%For now "know the location id" upfront, but ideally need to search for it at some point or present a choice.

	%Need to do this recursively
	[ #xmlAttribute{value=Location} ] = xmerl_xpath:string("@name", Node),
	[ #xmlAttribute{value=ID} ] = xmerl_xpath:string("@id", Node),
	io:format(Location++", "++ID++"~n"),
	print_locations(Rest).


get_weather(Location, { Date_formatted, Rep }) ->
	inets:start(),
	Key = readapikey(),
	URL = ?BASE_URL ++ ?WXFCS_LOCATIONID ++ Location ++ "?key=" ++ Key ++ "&res=3hourly",


	try
		{ ok, {_Status, _Headers, Body }} = httpc:request(get, {URL, []}, [{timeout, timer:seconds(10)}], []),
		{ Xml, _Rest } = xmerl_scan:string(Body),
		[ [ #xmlAttribute{value=Direction} ],
		  [ #xmlAttribute{value=Speed} ],
		  [ #xmlAttribute{value=Gust} ],
		  [ #xmlAttribute{value=Weather} ],

	Heading_signed = math:atan2(Lon, Lat),
	%Need to convert heading into a 2π value
	Heading = if Heading_signed < 0 ->
				Heading_signed + 2*math:pi();
			true ->
				Heading_signed
			end,

	convert_lats_longs_to_distance_heading_(Rest, [{Distance, Heading}]++Distance_headings_list);
convert_lats_longs_to_distance_heading_([], Distance_headings_list) ->
	lists:reverse(Distance_headings_list).


journey(Distance_headings_list) ->
	lists:map(
		fun({Distance, Heading}) ->
			Compass_direction = get_compass_direction_for(Heading),
			{Distance, Compass_direction}
		end,
		Distance_headings_list).


reverse_journey(Distance_headings_list) ->
	%Don't actually need a correctly ordered reverse route, as long as we have directions and distances.
	lists:map(
		fun({Distance, Compass_direction}) ->
			Reverse_direction = Compass_direction + math:pi(),
			{Distance, Reverse_direction}
		end,
		Distance_headings_list).


get_compass_direction_for(Heading) ->
	%In a way this is a waste of time as could just do headwind, etc based on angles, but since already have some code, why not?
	Segment = 2*math:pi()/16,
	Segments = erlang:round(Heading/Segment),
	Compass = ["N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE", "S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW"],
	lists:nth(Segments, Compass).

	Tailwind ->
		tailwind
	end.
%Something like that?
	

headsilose(Location) ->
	Date_today = erlang:localtime(),
	{ Date_formatted, Rep } = date_and_rep(Date_today),
	{Direction, Speed, Gust, Weather, Temperature} = get_weather(Location,  { Date_formatted, Rep }),
	Weather_type = weather_types:weather_type(erlang:list_to_integer(Weather)),
	[Headwinds, Sidewinds, Tailwinds] = build_list_of_wind_directions(Direction),


	{_Checksum, Polyline} = osrm:read_route(),
	Polyline_decoded = polyline:decode(Polyline),
	Distances_and_headings_list = convert_lats_longs_to_distance_heading(Polyline_decoded),
	%A better representation than 360 or 1080 would be better now this is used here as well.
	Journey = if Rep =:= "360" ->
		journey(Distances_and_headings_list);
	Rep =:= "1080" ->
		reverse_journey(Distances_and_headings_list)
	end,
	%If now have a set of co-ords need to figure out distances and directions
	Distances_and_wind_type_list = lists:map(
		fun({Distance, Compass}) ->
			Wind_type = head_side_or_tail_wind(Compass, [Headwinds, Sidewinds, Tailwinds]),
			{Distance, Wind_type}
		end,
		Journey),
	[Headwind_distances, Sidewind_distances, Tailwind_distances] = lists:map(
		fun(Wind_type_filter) ->
			lists:filter(
				fun({_Distance, Wind_type}) ->
					Wind_type == Wind_type_filter
				end,
				Distances_and_wind_type_list)