Add filtering and search methods

[cardmagic]

Summary

Add methods to filter and search items by common criteria.

Proposed Features

items_since(time)

Filter items published after a given time:

def items_since(time)
  items.select do |item|
    date = item[:pubDate] || item[:updated] || item[:published]
    date && date > time
  end
end

Usage:

rss.items_since(1.day.ago)
rss.items_since(Time.parse('2024-01-01'))

items_by_category(name)

Filter items by category:

def items_by_category(name)
  items.select do |item|
    cat = item[:category]
    case cat
    when Array then cat.any? { |c| c.to_s.downcase.include?(name.downcase) }
    when String then cat.downcase.include?(name.downcase)
    end
  end
end

Usage:

rss.items_by_category('technology')

search(query)

Simple text search across title and description:

def search(query)
  pattern = Regexp.new(Regexp.escape(query), Regexp::IGNORECASE)
  items.select do |item|
    [item[:title], item[:description], item[:summary], item[:content]].any? do |field|
      field.to_s =~ pattern
    end
  end
end

Usage:

rss.search('ruby')
rss.search('breaking news')

Benefits

• Common operations without manual filtering
• Consistent date handling across RSS/Atom formats
• Case-insensitive matching by default