#!/usr/bin/env julia

using Test

function string_start_index(s, width=4)
  delta = width - 1
  for i in 1:length(s)-delta
    if length(Set(s[i:i+delta])) == width
      println(i, " ", s[i:i+delta])
      return i + delta
    end
  end
end

function file_start_index(infile, width=4)
  io = open(infile, "r")
  data = readchomp(io)
  close(io)
  return string_start_index(data, width)
end

function test()
  @testset "elf signal start ex" verbose=true begin
    @test string_start_index("mjqjpqmgbljsphdztnvjfqwrcgsmlb") == 7
    @test string_start_index("bvwbjplbgvbhsrlpgdmjqwftvncz") == 5
    @test string_start_index("nppdvjthqldpwncqszvftbrmjlhg") == 6
    @test string_start_index("nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg") == 10
    @test string_start_index("zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw") == 11
    @test string_start_index("wewewewewewewewewewewewewebo") == 28
  end
  @testset "elf signal start in" verbose=true begin
    @test file_start_index("input.txt") == 1142
  end
  @testset "elf signal msg ex" verbose=true begin
    @test string_start_index("mjqjpqmgbljsphdztnvjfqwrcgsmlb", 14) == 19
    @test string_start_index("bvwbjplbgvbhsrlpgdmjqwftvncz", 14) == 23
    @test string_start_index("nppdvjthqldpwncqszvftbrmjlhg", 14) == 23
    @test string_start_index("nznrnfrfntjfmvfwmzdfjlvtqnbhcprsg", 14) == 29
    @test string_start_index("zcfzfwzzqfrljwzlrfnpqdbhtmscgvjw", 14) == 26
  end
  @testset "elf signal msg in" verbose=true begin
    @test file_start_index("input.txt", 14) == 2803
  end

end

function main()
  if size(ARGS, 1) == 0
    test()
  else
    infile = ARGS[1]
    println("infile = ", infile)
    println("start index: ", file_start_index(infile))
  end
end

main()