-module(json_validate).
-export([validate_activity/1, load_schema/1]).

load_schema(SchemaName) ->
    Filename = "priv/" ++ SchemaName ++ ".json",
    {ok, Bin} = file:read_file(Filename),
    jsx:decode(Bin, [return_maps]).

validate_activity(JsonBin) ->
    case catch jsx:decode(JsonBin, [return_maps]) of
        {'EXIT', _} ->
            {error, malformed_json};
        JsonMap when is_map(JsonMap) ->
            case maps:get(<<"type">>, JsonMap, undefined) of
                undefined ->
                    {error, missing_type};
                TypeBin when is_binary(TypeBin) ->
                    TypeLower = string:lowercase(binary_to_list(TypeBin)),
                    case TypeLower of
                        "note" ->
                            Schema = load_schema("note"),
                            case jesse:validate_with_schema(Schema, JsonMap) of
                                {ok, _} -> ok;
                                {error, Errors} -> {error, Errors}
                            end;
                        OtherType ->
                            {error, {unsupported_type, TypeBin}}
                    end;
                _ ->
                    {error, invalid_type_field}
            end
    end.