# frozen_string_literal: true
module SyntaxSuggest
# Scans up/down from the given block
#
# You can try out a change, stash it, or commit it to save for later
#
# Example:
#
# scanner = ScanHistory.new(code_lines: code_lines, block: block)
# scanner.scan(
# up: ->(_, _, _) { true },
# down: ->(_, _, _) { true }
# )
# scanner.changed? # => true
# expect(scanner.lines).to eq(code_lines)
#
# scanner.stash_changes
#
# expect(scanner.lines).to_not eq(code_lines)
class ScanHistory
attr_reader :before_index, :after_index
def initialize(code_lines:, block:)
@code_lines = code_lines
@history = [block]
refresh_index
end
def commit_if_changed
if changed?
@history << CodeBlock.new(lines: @code_lines[before_index..after_index])
end
self
end
# Discards any changes that have not been committed
def stash_changes
refresh_index
self
end
# Discard changes that have not been committed and revert the last commit
#
# Cannot revert the first commit
def revert_last_commit
if @history.length > 1
@history.pop
refresh_index
end
self
end
def changed?
@before_index != current.lines.first.index ||
@after_index != current.lines.last.index
end
# Iterates up and down
#
# Returns line, kw_count, end_count for each iteration
def scan(up:, down:)
kw_count = 0
end_count = 0
up_index = before_lines.reverse_each.take_while do |line|
kw_count += 1 if line.is_kw?
end_count += 1 if line.is_end?
up.call(line, kw_count, end_count)
end.last&.index
kw_count = 0
end_count = 0
down_index = after_lines.each.take_while do |line|
kw_count += 1 if line.is_kw?
end_count += 1 if line.is_end?
down.call(line, kw_count, end_count)
end.last&.index
@before_index = if up_index && up_index < @before_index
up_index
else
@before_index
end
@after_index = if down_index && down_index > @after_index
down_index
else
@after_index
end
self
end
def next_up
return nil if @before_index <= 0
@code_lines[@before_index - 1]
end
def next_down
return nil if @after_index >= @code_lines.length
@code_lines[@after_index + 1]
end
def lines
@code_lines[@before_index..@after_index]
end
private def before_lines
@code_lines[0...@before_index] || []
end
# Returns an array of all the CodeLines that exist after
# the currently scanned block
private def after_lines
@code_lines[@after_index.next..-1] || []
end
private def current
@history.last
end
private def refresh_index
@before_index = current.lines.first.index
@after_index = current.lines.last.index
self
end
end
end
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