import random
BLOCK_NUM = 7
LAST_BLOCK = "FF"
FIRST_BLOCK = 8  # 第一块fat位置


def generate_chain_structure():
  sim_fat = ["0"] * BLOCK_NUM  # 文件块的大小
  used_blocks = {"00", FIRST_BLOCK}  # 用于存储已经被占用的块位置,且预置00块和第一块为已占用状态

  for i in range(len(sim_fat) - 1):
    while True:
      location = random.randint(0, 99)
      if location not in used_blocks:  # 防止已经被占用的快被重新占用
        sim_fat[i] = location
        used_blocks.add(location) # 添加到已占用块集合
        break

  sim_fat[-1] = LAST_BLOCK
  chain_structure = []  # 链结构  
  for i, value in enumerate(sim_fat): 
    if i == 0:
      print(f"SimFAT[{FIRST_BLOCK}] -> {value}")
      item = {FIRST_BLOCK: value}  # 构建链结构
    else:
      print(f"SimFAT[{sim_fat[i - 1]}] -> {value}")
      item = {sim_fat[i - 1]: value}  # 构建链结构
    chain_structure.append(item)  # 
  return chain_structure




if __name__ == "__main__":
  print(generate_chain_structure())