84 lines
2.0 KiB
Ruby
84 lines
2.0 KiB
Ruby
class TopicFeaturedUsers
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attr_reader :topic
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def initialize(topic)
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@topic = topic
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end
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def self.count
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4
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end
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# Chooses which topic users to feature
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def choose(args={})
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self.class.ensure_consistency!(topic.id.to_i)
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update_participant_count
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end
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def user_ids
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[topic.featured_user1_id,
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topic.featured_user2_id,
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topic.featured_user3_id,
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topic.featured_user4_id].uniq.compact
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end
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def self.ensure_consistency!(topic_id=nil)
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sql = <<SQL
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WITH cte as (
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SELECT
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t.id,
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p.user_id,
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MAX(p.created_at) last_post_date,
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ROW_NUMBER() OVER(PARTITION BY t.id ORDER BY COUNT(*) DESC, MAX(p.created_at) DESC) as rank
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FROM topics t
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JOIN posts p ON p.topic_id = t.id
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WHERE p.deleted_at IS NULL AND
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NOT p.hidden AND
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p.user_id <> t.user_id AND
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p.user_id <> t.last_post_user_id
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GROUP BY t.id, p.user_id
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),
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cte2 as (
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SELECT id, user_id, ROW_NUMBER() OVER(PARTITION BY id ORDER BY last_post_date ASC) as rank
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FROM cte
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WHERE rank <= #{count}
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)
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UPDATE topics tt
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SET
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featured_user1_id = featured_user1,
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featured_user2_id = featured_user2,
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featured_user3_id = featured_user3,
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featured_user4_id = featured_user4
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FROM (
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SELECT
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c.id,
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MAX(case when c.rank = 1 then c.user_id end) featured_user1,
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MAX(case when c.rank = 2 then c.user_id end) featured_user2,
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MAX(case when c.rank = 3 then c.user_id end) featured_user3,
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MAX(case when c.rank = 4 then c.user_id end) featured_user4
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FROM cte2 as c
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GROUP BY c.id
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) x
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WHERE x.id = tt.id AND
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(
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COALESCE(featured_user1_id,-99) <> COALESCE(featured_user1,-99) OR
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COALESCE(featured_user2_id,-99) <> COALESCE(featured_user2,-99) OR
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COALESCE(featured_user3_id,-99) <> COALESCE(featured_user3,-99) OR
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COALESCE(featured_user4_id,-99) <> COALESCE(featured_user4,-99)
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) #{"AND x.id = #{topic_id.to_i}" if topic_id}
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SQL
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Topic.exec_sql(sql)
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end
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private
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def update_participant_count
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topic.update_columns(participant_count: topic.posts.count('distinct user_id'))
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end
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end
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