#!/usr/bin/python
import sys, os, math, linecache, re

# change numerator and denominator variables progressively to perform a proper bissection search manually
numerator = 1
denominator = 2

defconfig_file_name = "defconfig_clean"

def usage():
    print("""Usage: bissect_conf [<input_comparison_file> <config_in>]

Will output a defconfig file with the changes detected from the comparison_file to the config_in file
Example usage:
 $ bissect_conf comparison_file defconfig_not_working
""")
    sys.exit(0)

def main():
    global merge_style
    outup_f = open("defconfig", "w")


    # parse command line args
    if ("-h" in sys.argv or "--help" in sys.argv):
        usage()

    compare_file = open("compare.defconfig")
    compare_file_data = compare_file.readlines()
    compare_file_num = len(compare_file_data)

    defconfig_file = open(defconfig_file_name)
    defconfig_data = defconfig_file.readlines()

    # split into number of chunks equal to denominator
    denomi_lines = math.ceil(compare_file_num/denominator)

    for i in range(denomi_lines*(numerator-1), denomi_lines*(numerator)): # first line is at 1
        compare_file_line = compare_file_data[i]

##############################################################################################################
        # the comparison file describes a change which starts with a "-"
        if compare_file_line.startswith("-"):
            compare_file_line = compare_file_line[1:]
            current_config_name = "CONFIG_" + compare_file_line.split(" ")[0]

            # cycle through entire defconfig file and search for config_name
            for j in range(0, len(defconfig_data)):
                if current_config_name+" " in defconfig_data[j] or current_config_name+"=" in defconfig_data[j]:
                    defconfig_data[j] = current_config_name+"="+compare_file_line.split(" ")[1]

                if j == len(defconfig_data) - 1:
                    defconfig_data.append(current_config_name+"="+compare_file_line.split(" ")[1])

##############################################################################################################
        # the comparison file describes a change which starts with a "+"
        elif compare_file_line.startswith("+"): 
            compare_file_line = compare_file_line[1:]
            current_config_name = "CONFIG_" + compare_file_line.split(" ")[0]
            #current_config_name = current_config_name.strip()

            # cycle through entire defconfig file and search for config_name
            for j in range(0, len(defconfig_data)):
                if current_config_name in defconfig_data[j]:
                    defconfig_data[j] = ""

##############################################################################################################
        else:
            current_config_name = "CONFIG_" + compare_file_line.split(" ")[1]
            print(compare_file_line)
            for j in range(0, len(defconfig_data)):
                if current_config_name+" " in defconfig_data[j] or current_config_name+"=" in defconfig_data[j]:
                    defconfig_data[j] = current_config_name+"="+compare_file_line.split(" ")[2]+"\n"

    outup_f.writelines(defconfig_data)

main()