A 28-year-old man with history of recurrent productive cough for the last 10 years was admitted with a 3-day history of worsening cough, which produces blood-tinged purulent sputum. In the past one year he was admitted four times due to similar exacerbations. He was depressed due to the recurrent problems and had to quit his job as a soldier. He was otherwise generally fit. He smoked cigarettes one pack per day, for the last five years. No family or past history of tuberculosis On physical examination he was febrile 38.9C. Pulse: 100/min. Resp: 20/min. BP: 110/75mmHg. There was clubbing and the chest examination revealed coarse crackles over the left lower chest and bilateral wheeze. What is the most likely diagnosis which explains his chronic illness?