51 lines
1.9 KiB
Ruby
51 lines
1.9 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
# Calculate a diff between two sets of strings. Used to calculate diffs between
|
|
# artist URLs and between other names. Tries to compare each set to detect which
|
|
# strings were added, which were removed, and which were changed.
|
|
class SetDiff
|
|
attr_reader :additions, :removals, :added, :removed, :changed, :unchanged
|
|
|
|
# Initialize a diff between two sets of strings.
|
|
# @param this_list [Array<String>] the new list of strings
|
|
# @param other_list [Array<String>] the old list of strings
|
|
def initialize(this_list, other_list)
|
|
this, other = this_list.to_a, other_list.to_a
|
|
|
|
@additions = this - other
|
|
@removals = other - this
|
|
@unchanged = this & other
|
|
@added, @removed, @changed = changes(additions, removals)
|
|
end
|
|
|
|
# Returns the strings that were either completely newly added, completely
|
|
# removed, or simply updated.
|
|
# @param added [Array<String>] the strings that were added to this_list
|
|
# @param removed [Array<String>] the strings that were removed from other_list
|
|
# @return [Array<(Array<String>, Array<String>, Array<String>)>] the list of
|
|
# additions, removals, and changed strings.
|
|
def changes(added, removed)
|
|
changed = []
|
|
|
|
removed.each do |removal|
|
|
if addition = find_similar(removal, added)
|
|
changed << [removal, addition]
|
|
added -= [addition]
|
|
removed -= [removal]
|
|
end
|
|
end
|
|
|
|
[added, removed, changed]
|
|
end
|
|
|
|
# Finds the strings most similar to the `candidate` string among the `candidates` set.
|
|
# @param string [String] the string to find closest matches with in the `candidates` set.
|
|
# @param candidates [Array<String>] the set of candidate strings
|
|
def find_similar(string, candidates, max_dissimilarity: 0.70)
|
|
distance = ->(other) { ::DidYouMean::Levenshtein.distance(string, other) }
|
|
max_distance = string.size * max_dissimilarity
|
|
|
|
candidates.select { |candidate| distance[candidate] <= max_distance }.min_by(&distance)
|
|
end
|
|
end
|