module FakeRedis::TransactionCommands

def self.in_multi
  @in_multi ||= Hash.new{|h,k| h[k] = false}
end

def self.included(klass)
  klass.class_eval do
    def self.queued_commands
      @queued_commands ||= Hash.new {|h,k| h[k] = [] }
    end
    def self.in_multi
      @in_multi ||= Hash.new{|h,k| h[k] = false}
    end
    def queued_commands
      self.class.queued_commands[database_instance_key]
    end
    def queued_commands=(cmds)
      self.class.queued_commands[database_instance_key] = cmds
    end
    def in_multi
      self.class.in_multi[database_instance_key]
    end
    def in_multi=(multi_state)
      self.class.in_multi[database_instance_key] = multi_state
    end
  end
end

def self.queued_commands
  @queued_commands ||= Hash.new {|h,k| h[k] = [] }
end

def discard
  unless in_multi
    raise Redis::CommandError, "ERR DISCARD without MULTI"
  end
  self.in_multi = false
  self.queued_commands = []
  'OK'
end

def exec
  unless in_multi
    raise Redis::CommandError, "ERR EXEC without MULTI"
  end
  responses  = queued_commands.map do |cmd|
    begin
      send(*cmd)
    rescue => e
      e
    end
  end
  self.queued_commands = [] # reset queued_commands
  self.in_multi = false     # reset in_multi state
  responses
end

def in_multi
  self.class.in_multi[database_instance_key]
end

def in_multi=(multi_state)
  self.class.in_multi[database_instance_key] = multi_state
end

def multi
  if in_multi
    raise Redis::CommandError, "ERR MULTI calls can not be nested"
  end
  self.in_multi = true
  yield(self) if block_given?
  "OK"
end

def queued_commands
  self.class.queued_commands[database_instance_key]
end

def queued_commands=(cmds)
  self.class.queued_commands[database_instance_key] = cmds
end

def unwatch
  "OK"
end

def watch(*_)
  "OK"
end