"""list_imports.py <pe.exe>  — list all DLLs imported by a PE file."""
import struct, sys

with open(sys.argv[1], "rb") as f:
    data = f.read()
pe_off = struct.unpack_from("<I", data, 0x3c)[0]
opt_off = pe_off + 24
num_sec = struct.unpack_from("<H", data, pe_off + 6)[0]
size_opt = struct.unpack_from("<H", data, pe_off + 20)[0]
sec_off = opt_off + size_opt
imp_rva, imp_size = struct.unpack_from("<II", data, opt_off + 96 + 1*8)

# Build RVA->offset map
secs = []
for i in range(num_sec):
    sh = sec_off + i*40
    vaddr = struct.unpack_from("<I", data, sh+12)[0]
    vsize = struct.unpack_from("<I", data, sh+8)[0]
    rsize = struct.unpack_from("<I", data, sh+16)[0]
    roff  = struct.unpack_from("<I", data, sh+20)[0]
    secs.append((vaddr, max(vsize, rsize), roff, bytes(data[sh:sh+8]).rstrip(b"\0").decode()))

def rva2off(rva):
    for vaddr, vsize, roff, _ in secs:
        if vaddr <= rva < vaddr + vsize:
            return roff + (rva - vaddr)
    return None

print(f"IMPORT dir RVA=0x{imp_rva:08x} size={imp_size}")
print(f"sections:")
for v, sz, r, n in secs:
    print(f"  {n:>10}  vaddr=0x{v:08x}  vsize={sz:>8}  roff=0x{r:x}")

print("imports:")
pos = rva2off(imp_rva)
i = 0
while True:
    desc = data[pos:pos+20]
    if desc == b"\0"*20:
        print(f"  [{i}] (null terminator)")
        break
    ilt_rva, ts, fwc, name_rva, iat_rva = struct.unpack("<IIIII", desc)
    name_off = rva2off(name_rva)
    name = bytes(data[name_off:data.index(0, name_off)]).decode("ascii", "replace") if name_off else "?"
    print(f"  [{i}] {name}  (ILT=0x{ilt_rva:08x} IAT=0x{iat_rva:08x})")
    pos += 20
    i += 1