| % Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| % use this file except in compliance with the License. You may obtain a copy of |
| % the License at |
| % |
| % http://www.apache.org/licenses/LICENSE-2.0 |
| % |
| % Unless required by applicable law or agreed to in writing, software |
| % distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| % WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| % License for the specific language governing permissions and limitations under |
| % the License. |
| |
| -module(mango_sort). |
| |
| -export([ |
| new/1, |
| to_json/1, |
| fields/1, |
| directions/1 |
| ]). |
| |
| |
| -include("mango.hrl"). |
| |
| |
| new(Fields) when is_list(Fields) -> |
| Sort = {[sort_field(Field) || Field <- Fields]}, |
| validate(Sort), |
| {ok, Sort}; |
| new(Else) -> |
| ?MANGO_ERROR({invalid_sort_json, Else}). |
| |
| |
| to_json({Fields}) -> |
| to_json(Fields); |
| to_json([]) -> |
| []; |
| to_json([{Name, Dir} | Rest]) -> |
| [{[{Name, Dir}]} | to_json(Rest)]. |
| |
| |
| fields({Props}) -> |
| [Name || {Name, _Dir} <- Props]. |
| |
| |
| directions({Props}) -> |
| [Dir || {_Name, Dir} <- Props]. |
| |
| |
| sort_field(Field) when is_binary(Field) -> |
| {Field, <<"asc">>}; |
| sort_field({[{Name, <<"asc">>}]}) when is_binary(Name) -> |
| {Name, <<"asc">>}; |
| sort_field({[{Name, <<"desc">>}]}) when is_binary(Name) -> |
| {Name, <<"desc">>}; |
| sort_field({Name, BadDir}) when is_binary(Name) -> |
| ?MANGO_ERROR({invalid_sort_dir, BadDir}); |
| sort_field(Else) -> |
| ?MANGO_ERROR({invalid_sort_field, Else}). |
| |
| |
| validate({Props}) -> |
| % Assert each field is in the same direction |
| % until we support mixed direction sorts. |
| Dirs = [D || {_, D} <- Props], |
| case lists:usort(Dirs) of |
| [] -> |
| ok; |
| [_] -> |
| ok; |
| _ -> |
| ?MANGO_ERROR({unsupported, mixed_sort}) |
| end. |