#!/usr/bin/env ruby

def color_code(color_name, background_color_name = nil)
  colors = %w[ black red green yellow blue pink cyan white ].map(&:to_sym)
  color = 30 + colors.index(color_name)
  if background_code = colors.index(background_color_name)
    background = 40 + background_code
    bold = 1
  end
  [ bold, color, background ].compact.join ';'
end

def colorize(text, color_name, background_color_name = nil)
  color_code = color_code(color_name, background_color_name)
  "\e[#{color_code}m#{text}\e[0m"
end

def header(text)
  puts colorize(text, :yellow, :blue), ''
end

def call_or_fail(command, return_output = false)
  puts colorize(command, :pink), ''
  if return_output
    result = `#{command}`.to_s.strip
    $?.success? or raise "Error while calling #{command}: #{$?}"
  else
    result = system(command) or raise "Error while calling #{command}: #{$?}"
    puts
  end
  result
end

def prompt(message, default)
  print "#{message}"
  print " [#{default}]" if default
  print ": "
  input = gets.strip
  if input.empty? && default
    input = default
  end
  puts
  input
end

def success(message)
  puts colorize(message, :green), ''
  exit 0
end

def error(message)
  puts colorize(message, :red), ''
  exit 1
end

puts

ENV['PAGER'] = 'cat'

master_branch = prompt('master branch', 'master')
production_branch = prompt('production branch', 'production')
production_stage = prompt('production capistrano stage', 'production')

header("Checking if your #{master_branch} is up to date")

diff_size = call_or_fail("git fetch && git diff #{master_branch} origin/#{master_branch} | wc -l", true)
changes_size = call_or_fail("git status -s | wc -l", true)

if diff_size == '0' and changes_size == '0'
  puts "All good.", ''
else
  error "Your #{master_branch} is not the same as on origin or holds uncommitted changes. Fix that first."
end

header("Checking what's on #{production_stage} right now...")

call_or_fail("git checkout #{production_branch} && git pull")

header("You are about to deploy the following commits from #{master_branch} to #{production_branch}:")

call_or_fail("git log #{production_branch}..#{master_branch} --oneline")

if prompt("Go ahead with the deployment? (y/n)", "n").downcase == 'y'
  puts("git merge #{master_branch} && git push && cap #{production_stage} deploy:migrations")
  call_or_fail("git merge #{master_branch} && git push && cap #{production_stage} deploy:migrations")
  success 'Deployment complete.'
else
  error 'Deployment cancelled.'
end