module Greencache

# File lib/greencache.rb, line 21
def cache(redis_key, config = {}, &block)
  config = merge_config(config)
  return block.call if config[:skip_cache] || !redis_up?
  read_from_cache!(redis_key, config)
rescue CacheMiss
  value = block.call
  write_into_cache(redis_key, value, config)
  value
end

# File lib/greencache.rb, line 91
def configuration
  @configuration ||= Configuration.new
end

# File lib/greencache.rb, line 17
def configure
  yield(configuration)
end

# File lib/greencache.rb, line 83
def decrypt(value, config)
  return nil if value.nil?
  return MultiJson.load(value) unless config[:encrypt]
  verifier = fernet.verifier(config[:secret], value)
  return MultiJson.load(verifier.message) if verifier.valid?
  return nil
end

# File lib/greencache.rb, line 78
def encrypt(value, config)
  return prep_value(value) unless config[:encrypt]
  fernet.generate(config[:secret], prep_value(value))
end

# File lib/greencache.rb, line 31
def expire(redis_key)
  redis.del(redis_key) if redis_up?
end

# File lib/greencache.rb, line 129
def fernet
  ::Fernet
end

# File lib/greencache.rb, line 64
def get_value(key, config)
  get_value!(key, config)
rescue CacheMiss
end

# File lib/greencache.rb, line 121
def log(str, key, config)
  config[:logger].log(log_prefix(str, config) => 1, :key => key) unless config[:silent]
end

# File lib/greencache.rb, line 125
def log_prefix(str, config)
  [config[:log_prefix], str].join(".")
end

# File lib/greencache.rb, line 133
def memory_cache
  @@memory_cache ||= MiniCache::Store.new
end

# File lib/greencache.rb, line 74
def merge_config(config)
  configuration.to_hash.merge(config)
end

# File lib/greencache.rb, line 117
def prep_value(value)
  MultiJson.encode(value)
end

# File lib/greencache.rb, line 44
def read_from_cache
  read_from_cache!(redis_key)
rescue CacheMiss
end

# File lib/greencache.rb, line 95
def redis
  configuration.redis
end

# File lib/greencache.rb, line 99
def redis_up?
  begin
    redis.ping
  rescue Redis::CannotConnectError, Timeout::Error
    puts "Redis is DOWN! :shitsonfire:"
    return false
  end
  return true
end

# File lib/greencache.rb, line 69
def set_value(key, value, config)
  redis.setex key, config[:cache_time], encrypt(value, config)
  memory_cache.set(key, value, expires_in: 1)
end

# File lib/greencache.rb, line 113
def test?
  ENV["RACK_ENV"] == 'test'
end

# File lib/greencache.rb, line 109
def with_redis(&block)
  block.call if redis_up?
end

# File lib/greencache.rb, line 49
def write_into_cache(redis_key, value, config)
  with_redis do
    log("cache.write", redis_key, config)
    set_value(redis_key, value, config)
  end
  value
end

# File lib/greencache.rb, line 57
        def get_value!(key, config)
  raise CacheMiss unless redis.exists(key)
  result = memory_cache.get(key)
  result = decrypt(redis.get(key), config) if result.nil?
  result
end

# File lib/greencache.rb, line 35
        def read_from_cache!(redis_key, config)
  value = get_value!(redis_key, config)
  log("cache.hit", redis_key, config)
  value
rescue CacheMiss
  log("cache.miss", redis_key, config)
  raise
end