#!/usr/bin/env python3

"""
Strip OOB/spare area from NAND dump
Converts 66 MB dump (with OOB) to 64 MB (without OOB)
"""

import sys
import os

INPUT = "W25N512GV_original_66MB.bin"
OUTPUT = "W25N512GV_stripped_64MB.bin"

PAGE_MAIN = 2048      # Main data
PAGE_SPARE = 64       # OOB/spare
PAGE_TOTAL = 2112     # Total per page

TOTAL_PAGES = 32768   # 512 blocks * 64 pages/block

def strip_oob():
    print("OOB Stripper for W25N512GV NAND dump")
    print("=" * 50)
    print()
    
    if not os.path.exists(INPUT):
        print(f"ERROR: {INPUT} not found!")
        print()
        print("Download from:")
        print("  https://drive.usercontent.google.com/download?id=1GufkkjU6tJbbC6E2G3SigHb8DhyCoQA8")
        print(f"  Save as: {INPUT}")
        sys.exit(1)
    
    input_size = os.path.getsize(INPUT)
    print(f"Input:  {INPUT} ({input_size / 1024 / 1024:.1f} MB)")
    
    if input_size == 67108864:
        print("Already 64 MB (no OOB)! Just copying...")
        with open(INPUT, 'rb') as f_in, open(OUTPUT, 'wb') as f_out:
            f_out.write(f_in.read())
        print(f"Done: {OUTPUT}")
        sys.exit(0)
    
    if input_size != 69206016:
        print(f"WARNING: Unexpected size (expected 66 MB)")
        print("Continuing anyway...")
    
    print(f"Output: {OUTPUT} (64 MB)")
    print()
    print(f"Processing {TOTAL_PAGES} pages...")
    print()
    
    with open(INPUT, 'rb') as f_in, open(OUTPUT, 'wb') as f_out:
        for page in range(TOTAL_PAGES):
            # Read page with OOB
            offset = page * PAGE_TOTAL
            f_in.seek(offset)
            
            # Read only main area (skip spare)
            data = f_in.read(PAGE_MAIN)
            f_out.write(data)
            
            # Progress
            if (page + 1) % 1024 == 0:
                percent = (page + 1) * 100 // TOTAL_PAGES
                print(f"  Progress: {percent}% ({page + 1} / {TOTAL_PAGES} pages)")
    
    print()
    output_size = os.path.getsize(OUTPUT)
    
    if output_size == 67108864:
        print(f"SUCCESS: {OUTPUT} is exactly 64 MB!")
        print()
        print("You can now use this with repair_nand_final.sh")
        return 0
    else:
        print(f"ERROR: Output is {output_size / 1024 / 1024:.1f} MB (expected 64 MB)")
        return 1

if __name__ == "__main__":
    sys.exit(strip_oob())