# frozen-string-literal: true
#
# These are refinements to core classes that allow the Sequel
# DSL to be used without modifying the core classes directly.
# After loading the extension via:
#
#   Sequel.extension :core_refinements
#
# you can enable the refinements for particular files:
#
#   using Sequel::CoreRefinements

raise(Sequel::Error, "Refinements require ruby 2.0.0 or greater") unless RUBY_VERSION >= '2.0.0'

module Sequel::CoreRefinements
  refine Array do
    # Return a <tt>Sequel::SQL::BooleanExpression</tt> created from this array, not matching all of the
    # conditions.
    #
    #   ~[[:a, true]] # SQL: (a IS NOT TRUE)
    #   ~[[:a, 1], [:b, [2, 3]]] # SQL: ((a != 1) OR (b NOT IN (2, 3)))
    def ~
      Sequel.~(self)
    end

    # Return a <tt>Sequel::SQL::CaseExpression</tt> with this array as the conditions and the given
    # default value and expression.
    #
    #   [[{a: [2,3]}, 1]].case(0) # SQL: CASE WHEN (a IN (2, 3)) THEN 1 ELSE 0 END
    #   [[:a, 1], [:b, 2]].case(:d, :c) # SQL: CASE c WHEN a THEN 1 WHEN b THEN 2 ELSE d END
    def case(*args)
      ::Sequel::SQL::CaseExpression.new(self, *args)
    end

    # Return a <tt>Sequel::SQL::ValueList</tt> created from this array.  Used if this array contains
    # all two element arrays and you want it treated as an SQL value list (IN predicate) 
    # instead of as a conditions specifier (similar to a hash).  This is not necessary if you are using
    # this array as a value in a filter, but may be necessary if you are using it as a
    # value with placeholder SQL:
    #
    #   DB[:a].where([:a, :b]=>[[1, 2], [3, 4]]) # SQL: ((a, b) IN ((1, 2), (3, 4)))
    #   DB[:a].where('(a, b) IN ?', [[1, 2], [3, 4]]) # SQL: ((a, b) IN ((1 = 2) AND (3 = 4)))
    #   DB[:a].where('(a, b) IN ?', [[1, 2], [3, 4]].sql_value_list) # SQL: ((a, b) IN ((1, 2), (3, 4)))
    def sql_value_list
      ::Sequel::SQL::ValueList.new(self)
    end
    
    # Return a <tt>Sequel::SQL::BooleanExpression</tt> created from this array, matching all of the
    # conditions.  Rarely do you need to call this explicitly, as Sequel generally
    # assumes that arrays of two element arrays specify this type of condition.  One case where
    # it can be necessary to use this is if you are using the object as a value in a filter hash
    # and want to use the = operator instead of the IN operator (which is used by default for
    # arrays of two element arrays).
    #
    #   [[:a, true]].sql_expr # SQL: (a IS TRUE)
    #   [[:a, 1], [:b, [2, 3]]].sql_expr # SQL: ((a = 1) AND (b IN (2, 3)))
    def sql_expr
      Sequel[self]
    end

    # Return a <tt>Sequel::SQL::BooleanExpression</tt> created from this array, matching none
    # of the conditions.
    #
    #   [[:a, true]].sql_negate # SQL: (a IS NOT TRUE)
    #   [[:a, 1], [:b, [2, 3]]].sql_negate # SQL: ((a != 1) AND (b NOT IN (2, 3)))
    def sql_negate
      Sequel.negate(self)
    end

    # Return a <tt>Sequel::SQL::BooleanExpression</tt> created from this array, matching any of the
    # conditions.
    #
    #   [[:a, true]].sql_or # SQL: (a IS TRUE)
    #   [[:a, 1], [:b, [2, 3]]].sql_or # SQL: ((a = 1) OR (b IN (2, 3)))
    def sql_or
      Sequel.or(self)
    end

    # Return a <tt>Sequel::SQL::StringExpression</tt> representing an SQL string made up of the
    # concatenation of this array's elements.  If an argument is passed
    # it is used in between each element of the array in the SQL
    # concatenation.
    #
    #   [:a].sql_string_join # SQL: a
    #   [:a, :b].sql_string_join # SQL: (a || b)
    #   [:a, 'b'].sql_string_join # SQL: (a || 'b')
    #   ['a', :b].sql_string_join(' ') # SQL: ('a' || ' ' || b)
    def sql_string_join(joiner=nil)
      Sequel.join(self, joiner)
    end
  end

  refine Hash do
    # Return a <tt>Sequel::SQL::BooleanExpression</tt> created from this hash, matching
    # all of the conditions in this hash and the condition specified by
    # the given argument.
    #
    #   {a: 1} & :b # SQL: ((a = 1) AND b)
    #   {a: true} & ~:b # SQL: ((a IS TRUE) AND NOT b)
    def &(ce)
      ::Sequel::SQL::BooleanExpression.new(:AND, self, ce)
    end

    # Return a <tt>Sequel::SQL::BooleanExpression</tt> created from this hash, matching
    # all of the conditions in this hash or the condition specified by
    # the given argument.
    #
    #   {a: 1} | :b # SQL: ((a = 1) OR b)
    #   {a: true} | ~:b # SQL: ((a IS TRUE) OR NOT b)
    def |(ce)
      ::Sequel::SQL::BooleanExpression.new(:OR, self, ce)
    end

    # Return a <tt>Sequel::SQL::BooleanExpression</tt> created from this hash, not matching all of the
    # conditions.
    #
    #   ~{a: true} # SQL: (a IS NOT TRUE)
    #   ~{a: 1, b: [2, 3]} # SQL: ((a != 1) OR (b NOT IN (2, 3)))
    def ~
      ::Sequel::SQL::BooleanExpression.from_value_pairs(self, :OR, true)
    end

    # Return a <tt>Sequel::SQL::CaseExpression</tt> with this hash as the conditions and the given
    # default value.
    #
    #   {{a: [2,3]}=>1}.case(0) # SQL: CASE WHEN (a IN (2, 3)) THEN 1 ELSE 0 END
    #   {a: 1, b: 2}.case(:d, :c) # SQL: CASE c WHEN a THEN 1 WHEN b THEN 2 ELSE d END
    def case(*args)
      ::Sequel::SQL::CaseExpression.new(to_a, *args)
    end

    # Return a <tt>Sequel::SQL::BooleanExpression</tt> created from this hash, matching all of the
    # conditions.  Rarely do you need to call this explicitly, as Sequel generally
    # assumes that hashes specify this type of condition.
    #
    #   {a: true}.sql_expr # SQL: (a IS TRUE)
    #   {a: 1, b: [2, 3]}.sql_expr # SQL: ((a = 1) AND (b IN (2, 3)))
    def sql_expr
      ::Sequel::SQL::BooleanExpression.from_value_pairs(self)
    end

    # Return a <tt>Sequel::SQL::BooleanExpression</tt> created from this hash, matching none
    # of the conditions.
    #
    #   {a: true}.sql_negate # SQL: (a IS NOT TRUE)
    #   {a: 1, b: [2, 3]}.sql_negate # SQL: ((a != 1) AND (b NOT IN (2, 3)))
    def sql_negate
      ::Sequel::SQL::BooleanExpression.from_value_pairs(self, :AND, true)
    end

    # Return a <tt>Sequel::SQL::BooleanExpression</tt> created from this hash, matching any of the
    # conditions.
    #
    #   {a: true}.sql_or # SQL: (a IS TRUE)
    #   {a: 1, b: [2, 3]}.sql_or # SQL: ((a = 1) OR (b IN (2, 3)))
    def sql_or
      ::Sequel::SQL::BooleanExpression.from_value_pairs(self, :OR)
    end
  end

  refine String do
    include Sequel::SQL::AliasMethods
    include Sequel::SQL::CastMethods

    # Converts a string into a <tt>Sequel::LiteralString</tt>, in order to override string
    # literalization, e.g.:
    #
    #   DB[:items].where(abc: 'def')
    #   # "SELECT * FROM items WHERE (abc = 'def')"
    #
    #   DB[:items].where(abc: 'def'.lit)
    #   # "SELECT * FROM items WHERE (abc = def)"
    #
    # You can also provide arguments, to create a <tt>Sequel::SQL::PlaceholderLiteralString</tt>:
    #
    #   DB[:items].select{|o| o.count('DISTINCT ?'.lit(:a))}
    #   # "SELECT count(DISTINCT a) FROM items"
    def lit(*args)
      args.empty? ? Sequel::LiteralString.new(self) : Sequel::SQL::PlaceholderLiteralString.new(self, args)
    end
    
    # Returns a <tt>Sequel::SQL::Blob</tt> that holds the same data as this string. Blobs provide proper
    # escaping of binary data.
    def to_sequel_blob
      ::Sequel::SQL::Blob.new(self)
    end
  end

  refine Symbol do
    include Sequel::SQL::AliasMethods
    include Sequel::SQL::CastMethods
    include Sequel::SQL::OrderMethods
    include Sequel::SQL::BooleanMethods
    include Sequel::SQL::NumericMethods
    include Sequel::SQL::QualifyingMethods
    include Sequel::SQL::StringMethods
    include Sequel::SQL::SubscriptMethods
    include Sequel::SQL::ComplexExpressionMethods

    # Returns receiver wrapped in an <tt>Sequel::SQL::Identifier</tt>.
    #
    #   :ab.identifier # SQL: "a"
    def identifier
      Sequel::SQL::Identifier.new(self)
    end

    # Returns a <tt>Sequel::SQL::Function</tt> with this as the function name,
    # and the given arguments.
    #
    #   :now.sql_function # SQL: now()
    #   :sum.sql_function(:a) # SQL: sum(a)
    #   :concat.sql_function(:a, :b) # SQL: concat(a, b)
    def sql_function(*args)
      Sequel::SQL::Function.new(self, *args)
    end
  end
end
