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%% Produces filters based on lookup params |
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-module(mam_filter). |
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-export([produce_filter/2]). |
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-include("mongoose_mam.hrl"). |
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-type column() :: atom(). |
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-type filter_field() :: {like, column(), binary()} |
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| {le, column(), integer()} |
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| {ge, column(), integer()} |
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| {equal, column(), integer() | binary()} |
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| {less, column(), integer()} |
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| {greater, column(), integer()}. |
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-type filter() :: [filter_field()]. |
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-type fields() :: [#lookup_field{}]. |
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-type params() :: map(). |
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-export_type([filter_field/0]). |
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-export_type([filter/0]). |
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-define(SEARCH_WORDS_LIMIT, 10). |
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-spec produce_filter(params(), fields()) -> list(filter_field()). |
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produce_filter(Params, Fields) -> |
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:-( |
[new_filter(Field, Value) |
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:-( |
|| Field <- Fields, |
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Value <- field_to_values(Field, Params)]. |
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field_to_values(#lookup_field{param = Param, value_maker = ValueMaker, required = Required} = Field, Params) -> |
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:-( |
case maps:find(Param, Params) of |
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{ok, Value} when Value =/= undefined -> |
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make_value(ValueMaker, Value); |
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Other when Required -> |
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error(#{reason => missing_required_field, field => Field, params => Params, result => Other}); |
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_ -> |
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:-( |
[] |
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end. |
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:-( |
make_value(search_words, Value) -> search_words(Value); |
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make_value(undefined, Value) -> [Value]. %% Default value_maker |
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new_filter(#lookup_field{op = Op, column = Column}, Value) -> |
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:-( |
{Op, Column, Value}. |
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%% Constructs a separate LIKE filter for each word. |
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%% SearchText example is "word1%word2%word3". |
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%% Order of words does not matter (they can go in any order). |
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-spec search_words(binary()) -> list(binary()). |
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search_words(SearchText) -> |
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Words = binary:split(SearchText, <<"%">>, [global]), |
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[<<"%", Word/binary, "%">> || Word <- lists:sublist(Words, ?SEARCH_WORDS_LIMIT)]. |