require "bundler/inline"
gemfile(true) do
  source "https://rubygems.org"
  gem "rails", "~> 7.2"
  gem "pg"
end

require "active_record"
require "logger"

class ActiveRecord::ConnectionAdapters::ConnectionPool::ConnectionLeasingQueue
  private
  def internal_poll(timeout)
    result = super
    result
  rescue ActiveRecord::ConnectionTimeoutError => e
    puts "\n=== Connection Pool Timeout ==="
    puts "\nPool size: #{ActiveRecord::Base.connection_pool.size}"
    puts "Checked out connections: #{ActiveRecord::Base.connection_pool.connections.count}"

    connection_owners = ActiveRecord::Base.connection_pool.connections.map(&:owner)
    puts "\nThread list:"
    Thread.list.each_with_index do |t, i|
      connection_mark = connection_owners.include?(t) ? "[HAS CONNECTION]" : "[NO CONNECTION]"
      connection_mark += "[CURRENT]" if t == Thread.current
      connection_mark += "[MAIN]" if t == Thread.main
      puts "---- #{connection_mark} : Thread #{i}, status: #{t.status.inspect}, thread_info: #{t.inspect.split(' ', 2)[1].chop}"
    end

    puts "\nCurrent thread: #{Thread.current.inspect}"
    puts "\n=== End Debug Info ===\n"
    raise e
  end
end

# Configure a very small connection pool
ActiveRecord::Base.establish_connection(
adapter: "postgresql",
database: "playground", # create a database named "playground" in your local PostgreSQL
pool: 2,
checkout_timeout: 2
)
ActiveRecord::Base.logger = Logger.new(STDOUT)

# Create a simple table
ActiveRecord::Schema.define do
  create_table :shipments, force: true do |t|
    t.string :status
  end
end

class Shipment < ActiveRecord::Base
end

def dangerous_threads
  threads = []
  # We duplicate code to report different lines in the stack trace
  threads << Thread.new do
    puts "Thread 1 starting..."
    ActiveRecord::Base.connection.execute("select pg_sleep(5)")
  end

  threads << Thread.new do
    puts "Thread 2 starting..."
    ActiveRecord::Base.connection.execute("select pg_sleep(5)")
  end

  threads << Thread.new do
    puts "Thread 2 starting..."
    ActiveRecord::Base.connection.execute("select pg_sleep(5)")
  end

  threads.each(&:join)
end

puts "Connection pool size: #{ActiveRecord::Base.connection_pool.size}"
puts "Starting threads..."
dangerous_threads