A 40-year-old woman presents with a 2-month history of low-grade fever, abdominal distension, oliguria, and lower extremity edema. She has a history of hepatitis B. Physical examination: no scleral icterus, abdominal distension, liver and spleen not clearly palpable, shifting dullness present, mild lower extremity edema. Laboratory tests: TBil 21 μmol/L, CB 7.2 μmol/L, ALT 50 U/L, albumin 2.6 g/L, globulin 3.5 g/L, AFP 100 ng/mL. Ascitic fluid analysis: light red, specific gravity 1.018, WBC 0.3×10^9/L (300/mm^3), RBC 3×10^9/L (3000/mm^3), polymorphonuclear cells (PMNs) 22%, monocytes 78%. The most likely diagnosis is: