# frozen_string_literal: true

class CopyPersonaTablesToAgent < ActiveRecord::Migration[7.0]
  def up
    # Copy the main table structure and data
    if table_exists?(:ai_personas) && !table_exists?(:ai_agents)
      execute <<~SQL
        CREATE TABLE ai_agents AS
        SELECT * FROM ai_personas
      SQL

      # Copy indexes from ai_personas to ai_agents
      execute <<~SQL
        CREATE UNIQUE INDEX index_ai_agents_on_id
        ON ai_agents USING btree (id)
      SQL

      # Copy any other indexes that exist on ai_personas
      indexes = execute(<<~SQL).to_a
        SELECT indexname, indexdef
        FROM pg_indexes
        WHERE tablename = 'ai_personas'
        AND indexname != 'ai_personas_pkey'
      SQL

      indexes.each do |index|
        new_index_def = index['indexdef'].gsub('ai_personas', 'ai_agents')
        new_index_name = index['indexname'].gsub('ai_personas', 'ai_agents')
        new_index_def = new_index_def.gsub(index['indexname'], new_index_name)
        execute(new_index_def)
      end
    end

    # Update polymorphic associations to point to new table
    execute <<~SQL
      UPDATE rag_document_fragments
      SET target_type = 'AiAgent'
      WHERE target_type = 'AiPersona'
    SQL

    execute <<~SQL
      UPDATE upload_references
      SET target_type = 'AiAgent'
      WHERE target_type = 'AiPersona'
    SQL

    # Migrate persona-related site settings to agent equivalents
    migrate_site_setting('ai_summarization_persona', 'ai_summarization_agent')
    migrate_site_setting('ai_summary_gists_persona', 'ai_summary_gists_agent')
    migrate_site_setting('ai_bot_discover_persona', 'ai_bot_discover_agent')
    migrate_site_setting('ai_discord_search_persona', 'ai_discord_search_agent')
  end

  def down
    drop_table :ai_agents if table_exists?(:ai_agents)

    # Revert polymorphic associations
    execute <<~SQL
      UPDATE rag_document_fragments
      SET target_type = 'AiPersona'
      WHERE target_type = 'AiAgent'
    SQL

    execute <<~SQL
      UPDATE upload_references
      SET target_type = 'AiPersona'
      WHERE target_type = 'AiAgent'
    SQL

    # Remove the new agent settings (keep the old persona ones)
    ['ai_summarization_agent', 'ai_summary_gists_agent', 'ai_bot_discover_agent', 'ai_discord_search_agent'].each do |setting|
      execute "DELETE FROM site_settings WHERE name = '#{setting}'"
    end
  end

  private

  def migrate_site_setting(old_name, new_name)
    execute <<~SQL
      INSERT INTO site_settings (name, value, data_type, created_at, updated_at)
      SELECT '#{new_name}', value, data_type, NOW(), NOW()
      FROM site_settings
      WHERE name = '#{old_name}'
      AND NOT EXISTS (SELECT 1 FROM site_settings WHERE name = '#{new_name}')
    SQL
  end
end