module Hizuke::DateKeywordMatcher

def check_compound_date_expressions(clean_text)
  compound_matches = find_compound_matches(clean_text)
  # If we found compound matches, handle them specially
  return nil if compound_matches.empty?
  # Use the first match (in case there are multiple)
  match_key, indices = compound_matches.min_by { |_, v| v[0] }
  process_compound_match(clean_text, match_key, indices)
end

def check_single_word_date_references(clean_text)
  # Split the text into words
  words = clean_text.split
  # Find the matching date keyword
  date_match = find_date_keyword_match(words)
  # If no reference was found, return nil
  return nil unless date_match
  # Calculate the date based on the keyword
  date = calculate_date(date_match[:value])
  # Create the clean text by removing the date keyword
  final_text = remove_date_keyword_from_text(words, date_match[:index])
  Result.new(final_text, date)
end

def find_compound_keywords
  DATE_KEYWORDS.keys.select { |k| k.include?(' ') }
end

def find_compound_matches(clean_text)
  compound_matches = {}
  find_compound_keywords.each do |compound_key|
    next unless clean_text.downcase.include?(compound_key)
    start_idx = clean_text.downcase.index(compound_key)
    end_idx = start_idx + compound_key.length - 1
    compound_matches[compound_key] = [start_idx, end_idx]
  end
  compound_matches
end

def find_date_keyword_match(words)
  words.each_with_index do |word, index|
    clean_word = word.downcase.gsub(/[^a-z]/, '')
    next unless DATE_KEYWORDS.key?(clean_word)
    return { index: index, value: DATE_KEYWORDS[clean_word] }
  end
  nil
end

def process_compound_match(clean_text, match_key, indices)
  # Calculate date based on the keyword
  date_value = DATE_KEYWORDS[match_key]
  date = calculate_date(date_value)
  # Remove the date expression from the text
  final_text = clean_text.dup
  final_text.slice!(indices[0]..indices[1])
  Result.new(final_text.strip, date)
end

def remove_date_keyword_from_text(words, index)
  clean_words = words.dup
  clean_words.delete_at(index)
  clean_words.join(' ').strip
end

def try_parsing_strategies(clean_text)
  # Check for dynamic patterns first (in X days, X days ago)
  result = check_dynamic_patterns(clean_text)
  return result if result
  # Check for day of week patterns (this Monday, next Tuesday, etc.)
  result = check_day_of_week_patterns(clean_text)
  return result if result
  # Try to find compound date expressions (like "next week")
  result = check_compound_date_expressions(clean_text)
  return result if result
  # Try to find single-word date references
  result = check_single_word_date_references(clean_text)
  return result if result
  # If no date reference was found, return nil instead of today's date
  nil
end