# Authors chinmay_dd, skarthik

# Clears global bit arrays
def clear_bit_arrays
	$a_bit = []
	$b_bit = []
	$c_bit = []
	$d_bit = []
	$e_bit = []
	$f_bit = []
	$g_bit = []
end

# Prints out seven segment equivalent of characters(26) present in global arrays
def print_led
	$a_bit.each do |i|
		print ' '
		print i=='1'? '_':' '
		print '  '
	end
	puts 
	for i in 0..$a_bit.size-1
		print $f_bit[i]=='1'? '|':' '
		print $g_bit[i]=='1'? '_':' '
		print $b_bit[i]=='1'? '|':' '
		print ' '
	end
	puts
	for i in 0..$a_bit.size-1
		print $e_bit[i]=='1'? '|':' '
		print $d_bit[i]=='1'? '_':' '
		print $c_bit[i]=='1'? '|':' '
		print ' '
	end
	print "\n\n"
end

# Appends binary representation of a number to global arrays
# Params:
# +bin+:: binary representation of a number
def append_to_arrays(bin)
	$a_bit << bin[0]
	$b_bit << bin[1]
	$c_bit << bin[2]
	$d_bit << bin[3]
	$e_bit << bin[4]
	$f_bit << bin[5]
	$g_bit << bin[6]	
end

# Encrypts string in seven segment display form
# Params:
# +string+:: string of characters read from file to be encrypted
def encrypt(string)
	string_chars = string.scan(/.{1,26}/)

	string_chars.each do |str|
		str.each_char do |i|
			bin = i.unpack("B*")[0][1..-1]
			append_to_arrays(bin)
		end
		print_led
		clear_bit_arrays	
	end
end

# Returns file object of the file from which the flag is to be read
def read_file
	File.new('flag.txt', 'r')
end

#################
# Main function #
#################

f = read_file
clear_bit_arrays
while (line = f.gets)
	
	# Encrypt each line
    encrypt(line)
end

# Author @skarthik, @chinmay_dd

# Clears global bit arrays
def clear_bit_arrays
	$a_bit = []
	$b_bit = []
	$c_bit = []
	$d_bit = []
	$e_bit = []
	$f_bit = []
	$g_bit = []	
end

# Computes equivalent value of the ASCII as per encryption and prints character
def print_equivalent_chr
	for idx in 0..$a_bit.size-1
		num = (2**6 * $a_bit[idx]) + (2**5 * $b_bit[idx]) + (2**4 * $c_bit[idx]) + (2**3 * $d_bit[idx]) + (2**2 * $e_bit[idx]) + (2**1 * $f_bit[idx]) + (2**0 * $g_bit[idx])
		print num.chr
	end
	clear_bit_arrays
end

# Takes an input and line counter as a parameter and decrypts given text into plaintext ASCII and prints it using print_equivalent_chr
# Params:
# +string+:: String to be decrypted. It may consist of '|', '_' and ' '
# +counter+:: Counter used to recognize the which level of the 7 segment display is to be decrypted
def decrypt(string, counter)
	# Take 4 characters, equivalent to width of a an ASCII character
	string_div = string.scan(/.{4}/)

	mod = counter%4
	case mod
	when 0
		string_div.each do |read|
			if read[1] == '_' then $a_bit << 1 else $a_bit << 0 end
		end
	when 1
		string_div.each do |read|
			if read[0] == '|' then $f_bit << 1 else $f_bit << 0 end
			if read[1] == '_' then $g_bit << 1 else $g_bit << 0 end
			if read[2] == '|' then $b_bit << 1 else $b_bit << 0 end
		end
	when 2
		string_div.each do |read|
			if read[0] == '|' then $e_bit << 1 else $e_bit << 0 end
			if read[1] == '_' then $d_bit << 1 else $d_bit << 0 end
			if read[2] == '|' then $c_bit << 1 else $c_bit << 0 end			
		end
	when 3
		print_equivalent_chr
	end
end

# Returns a file object from which encrypted text is to be read
def read_file
	File.new('ans.txt', 'r')
end

#################
# Main function #
#################

f = read_file
clear_bit_arrays
counter = 0

while (line = f.gets)

	# Decrypt each line
    decrypt(line, counter)
    counter+=1
end