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# frozen_string_literal: true
class SearchQueryTransformer < Parslet::Transform
class Query
attr_reader :should_clauses, :must_not_clauses, :must_clauses
def initialize(clauses)
grouped = clauses.chunk(&:operator).to_h
@should_clauses = grouped.fetch(:should, [])
@must_not_clauses = grouped.fetch(:must_not, [])
@must_clauses = grouped.fetch(:must, [])
end
def apply(search)
should_clauses.each { |clause| search = search.query.should(clause_to_query(clause)) }
must_clauses.each { |clause| search = search.query.must(clause_to_query(clause)) }
must_not_clauses.each { |clause| search = search.query.must_not(clause_to_query(clause)) }
search.query.minimum_should_match(1)
end
private
def clause_to_query(clause)
case clause
when TermClause
{ multi_match: { type: 'most_fields', query: clause.term, fields: ['text', 'text.stemmed'] } }
when PhraseClause
{ match_phrase: { text: { query: clause.phrase } } }
else
raise "Unexpected clause type: #{clause}"
end
end
end
class Operator
class << self
def symbol(str)
case str
when '+'
:must
when '-'
:must_not
when nil
:should
else
raise "Unknown operator: #{str}"
end
end
end
end
class TermClause
attr_reader :prefix, :operator, :term
def initialize(prefix, operator, term)
@prefix = prefix
@operator = Operator.symbol(operator)
@term = term
end
end
class PhraseClause
attr_reader :prefix, :operator, :phrase
def initialize(prefix, operator, phrase)
@prefix = prefix
@operator = Operator.symbol(operator)
@phrase = phrase
end
end
rule(clause: subtree(:clause)) do
prefix = clause[:prefix][:term].to_s if clause[:prefix]
operator = clause[:operator]&.to_s
if clause[:term]
TermClause.new(prefix, operator, clause[:term].to_s)
elsif clause[:phrase]
PhraseClause.new(prefix, operator, clause[:phrase].map { |p| p[:term].to_s }.join(' '))
else
raise "Unexpected clause type: #{clause}"
end
end
rule(query: sequence(:clauses)) { Query.new(clauses) }
end
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