import argparse
import sys

def hexdump(data, base=0, width=16):
    for i in range(0, len(data), width):
        chunk = data[i:i+width]
        hex_bytes = ' '.join(f"{b:02x}" for b in chunk)
        ascii_repr = ''.join((chr(b) if 32 <= b < 127 else '.') for b in chunk)
        print(f"{base+i:08x}: {hex_bytes:<48}  {ascii_repr}")

def main():
    p = argparse.ArgumentParser()
    p.add_argument('--file', required=True)
    p.add_argument('--addr', required=True, help='PSX virtual address (e.g. 0x80064355)')
    p.add_argument('--before', type=int, default=64)
    p.add_argument('--after', type=int, default=256)
    p.add_argument('--base', type=lambda x: int(x,0), default=0x80000000, help='PSX RAM base address used for dump offset')
    args = p.parse_args()

    addr = int(args.addr, 0)
    base = args.base
    offset = addr - base
    if offset < 0:
        print(f"Computed negative offset {offset} for addr {hex(addr)} base {hex(base)}", file=sys.stderr)
        sys.exit(2)

    try:
        with open(args.file, 'rb') as f:
            f.seek(0, 2)
            size = f.tell()
            if offset >= size:
                print(f"Offset {offset:#x} beyond file size {size:#x}")
                sys.exit(3)
            start = max(0, offset - args.before)
            f.seek(start)
            data = f.read(args.before + args.after)
            print(f"File: {args.file}")
            print(f"PSX addr: {hex(addr)}, file offset: {hex(offset)}, dump start: {hex(start)}, len: {len(data)}")
            hexdump(data, base=start)
    except FileNotFoundError:
        print(f"File not found: {args.file}")
        sys.exit(4)

if __name__ == '__main__':
    main()