Replicating the column first nonzero value while a condition is true, without loops

The example data goes like this, with prices of a stock, and buy indicating the possible buy points.

    Price   Buy
0   121385  0
1   121375  0
2   121375  0
3   121360  121360
4   121360  121360
5   121350  121350
6   121350  121350
7   121340  121340
8   121345  121345
9   121340  121340
10  121340  121340
11  121345  121345
12  121350  121350
13  121350  0
14  121340  121340
15  121345  121345
16  121345  121345
17  121350  0
18  121355  0
19  121255  0
20  121245  0
21  121245  0
22  121240  0
23  121240  0
24  121225  0
25  121235  0
26  121225  0
27  121220  0
28  121215  121215
29  121225  0
30  121230  0

After the first nonzero Buy, the output column should , repeate the same first buy value while price dont deviate 130 points below or above the first buy point. Like this:

Price   Buy     output
121385  0       0.0
121375  0       0.0
121375  0       0.0
121360  121360  121360.0
121360  121360  121360.0
121350  121350  121360.0
121350  121350  121360.0
121340  121340  121360.0
121345  121345  121360.0
121340  121340  121360.0
121340  121340  121360.0
121345  121345  121360.0
121350  121350  121360.0
121350  0       121360.0
121340  121340  121360.0
121345  121345  121360.0
121345  121345  121360.0
121350  0       121360.0
121355  0       121360.0
121255  0       121360.0
121245  0       121360.0
121245  0       121360.0
121240  0       121360.0
121240  0       121360.0
121225  0       0.0
121235  0       0.0
121225  0       0.0
121220  0       0.0
121215  121215  121215.0
121225  0       121215.0
121230  0       121215.0

The following loop does the work, though with a long computational time.

import pandas as pd
df=pd.read_csv('DataStack.CSV',delimiter=';')  

Poze=0            #0=waiting   1=buying
FirstBuy=0         #Buy
SL=130            #deviation

for index, row in df.iterrows():
      if (Poze==0):                        #check if already has a entry buy point
        if (row['Buy']!=0):                #assign entry buy point
          Poze=1
          FirstBuy=row['Price']    
      else:
        if (Poze==1):                      # stop replicating if deviation is enough
            if (row['Price']>=FirstBuy+SL):
              Poze=0   
            elif (row['Price']<=FirstBuy-SL):
              Poze=0  

      df.loc[index,'pose']=Poze
      df.loc[index,'first']=FirstBuy
      df['output']=df['pose']*df['first'] 

• Link to the CSV with data: https://drive.google.com/file/d/1uI3GDh2HTrqyubaLWw6hG3pxtbKdzqBl/view?usp=sharing
• Link to the code: https://colab.research.google.com/drive/11osytR5iC3TIC8gkQhZ3t307qozlItoe?usp=sharing

Anyone knows how can i find the same output column, avoiding loops? Tks!