說來話長 [说来话长]

Jyutping syut3 loi4 waa6 coeng4
Pinyin shuō lái huà cháng

Definitions (CC-CEDICT)
  1. start explaining and it's a long story (idiom); complicated and not easy to express succinctly
Definitions (Wiktionary)
  1. phrase, idiomatic
    it's a long story
    (syn.) 一言难尽, 一言難盡