125 lines
3.7 KiB
Ruby
125 lines
3.7 KiB
Ruby
# frozen_string_literal: true
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module DiscourseAi
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class TopicSummarization
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def self.summarize(topic, user, opts = {}, &on_partial_blk)
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new(DiscourseAi::Summarization.default_strategy).summarize(topic, user, opts, &on_partial_blk)
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end
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def initialize(strategy)
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@strategy = strategy
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end
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def summarize(topic, user, opts = {}, &on_partial_blk)
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existing_summary = AiSummary.find_by(target: topic)
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# Existing summary shouldn't be nil in this scenario because the controller checks its existence.
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return if !user && !existing_summary
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targets_data = summary_targets(topic).pluck(:post_number, :raw, :username)
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current_topic_sha = build_sha(targets_data.map(&:first))
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can_summarize = Guardian.new(user).can_request_summary?
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if use_cached?(existing_summary, can_summarize, current_topic_sha, !!opts[:skip_age_check])
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# It's important that we signal a cached summary is outdated
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existing_summary.mark_as_outdated if new_targets?(existing_summary, current_topic_sha)
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return existing_summary
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end
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delete_cached_summaries_of(topic) if existing_summary
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content = {
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resource_path: "#{Discourse.base_path}/t/-/#{topic.id}",
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content_title: topic.title,
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contents: [],
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}
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targets_data.map do |(pn, raw, username)|
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raw_text = raw
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if pn == 1 && topic.topic_embed&.embed_content_cache.present?
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raw_text = topic.topic_embed&.embed_content_cache
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end
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content[:contents] << { poster: username, id: pn, text: raw_text }
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end
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summarization_result = strategy.summarize(content, user, &on_partial_blk)
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cache_summary(summarization_result, targets_data.map(&:first), topic)
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end
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def summary_targets(topic)
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topic.has_summary? ? best_replies(topic) : pick_selection(topic)
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end
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private
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attr_reader :strategy
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def best_replies(topic)
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Post
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.summary(topic.id)
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.where("post_type = ?", Post.types[:regular])
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.where("NOT hidden")
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.joins(:user)
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.order(:post_number)
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end
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def pick_selection(topic)
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posts =
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Post
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.where(topic_id: topic.id)
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.where("post_type = ?", Post.types[:regular])
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.where("NOT hidden")
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.order(:post_number)
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post_numbers = posts.limit(5).pluck(:post_number)
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post_numbers += posts.reorder("posts.score desc").limit(50).pluck(:post_number)
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post_numbers += posts.reorder("post_number desc").limit(5).pluck(:post_number)
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Post
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.where(topic_id: topic.id)
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.joins(:user)
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.where("post_number in (?)", post_numbers)
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.order(:post_number)
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end
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def delete_cached_summaries_of(topic)
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AiSummary.where(target: topic).destroy_all
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end
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# For users without permissions to generate a summary or fresh summaries, we return what we have cached.
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def use_cached?(existing_summary, can_summarize, current_sha, skip_age_check)
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existing_summary &&
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!(
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can_summarize && new_targets?(existing_summary, current_sha) &&
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(skip_age_check || existing_summary.created_at < 1.hour.ago)
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)
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end
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def new_targets?(summary, current_sha)
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summary.original_content_sha != current_sha
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end
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def cache_summary(result, post_numbers, topic)
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cached_summary =
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AiSummary.create!(
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target: topic,
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algorithm: strategy.display_name,
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content_range: (post_numbers.first..post_numbers.last),
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summarized_text: result[:summary],
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original_content_sha: build_sha(post_numbers),
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)
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cached_summary
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end
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def build_sha(ids)
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Digest::SHA256.hexdigest(ids.join)
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end
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end
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end
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