#!/bin/bash

if [ $# -ne 2 ]; then
    echo "Usage: $0 <file1> <file2>"
    exit 1
fi

file1="$1"
file2="$2"

if [ ! -f "$file1" ] || [ ! -f "$file2" ]; then
    echo "Error: Both input files must exist."
    exit 1
fi

data1=()
data2=()

while read line; do
    if [[ "$line" == "BS Search"* ]]; then
        parts=($line)
        y="${parts[4]}"
        y_err="${parts[6]#±}"
        data1+=("$y,$y_err")
    fi
done < "$file1"

while read line; do
    if [[ "$line" == "BS Search"* ]]; then
        parts=($line)
        y="${parts[4]}"
        y_err="${parts[6]#±}"
        data2+=("$y,$y_err")
    fi
done < "$file2"

if [ ${#data1[@]} -ne ${#data2[@]} ]; then
    echo "Error: The two files do not have the same number of data points."
    exit 1
fi

echo "Data point y_sum y_err_sum"
for i in "${!data1[@]}"; do
    IFS=',' read -ra data1_parts <<< "${data1[i]}"
    IFS=',' read -ra data2_parts <<< "${data2[i]}"
    
    y_sum=$(echo "${data1_parts[0]} + ${data2_parts[0]}" | bc -l)
    y_err_sum=$(echo "scale=4; sqrt(${data1_parts[1]}^2 + ${data2_parts[1]}^2)" | bc -l)
    
    echo "$((i+1)) $y_sum $y_err_sum"
done