#!/usr/bin/env ruby

if ARGV.include?("-i")
  puts "*******************************************************"
  puts
  system("du -sh ~/dumps")
  puts
  puts "*******************************************************"

  exit
end

require 'erb'
require "yaml"

DB_CONFIG_PATH = 'config/database.yml'
DUMPS_DIR = "#{ENV['HOME']}/dumps"

def run(*args)
  if !!ENV['GEORDI_TESTING']
    puts "system #{args.join(', ')}"
    true # "Command succeeded"
  else
    system *args
  end
end

def cd_to_project_root(fail_gently)
  current = Dir.pwd
  until File.exist?(DB_CONFIG_PATH)
    Dir.chdir '..'
    if current == Dir.pwd
      if fail_gently
        puts "* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *"
        puts "*                                                             *"
        puts "*                                                             *"
        puts "*     Script is not called from inside a Rails project,       *"
        puts "*                                                             *"
        puts "*            THE DATABASE WILL NOT BE DUMPED.                 *"
        puts "*                                                             *"
        puts "*                                                             *"
        puts "* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *"
        sleep 5
        exit
      else
        raise "x Call me from inside a Rails project."
      end
    end
    current = Dir.pwd
  end
end

def dump_command(dump_file, config)
  host = config['host']
  port = config['port']

  case config['adapter']
  when /mysql/
    command = "mysqldump"
    command << " -u\"#{config['username']}\""
    command << " -p\"#{config['password']}\""
    command << " #{config['database']}"
    command << " -r #{dump_file}"
    # Using a transaction to allow concurrent request while creating a dump.
    # This works only reliable for InnoDB tables.
    # More details: https://dev.mysql.com/doc/refman/5.7/en/mysqldump.html#option_mysqldump_single-transaction
    command << ' --single-transaction'
    # Disable buffering in memory to avoid a memory overflow for large tables
    # More details https://dev.mysql.com/doc/refman/5.7/en/mysqldump.html#option_mysqldump_quick
    command << ' --quick'
    if port
      command << " -h#{host || '127.0.0.1'} -P#{port}"
    else
      command << " -h#{host || 'localhost'}"
    end
    command
  when /postgres/
    command = "PGPASSWORD=\"#{config['password']}\""
    command << " pg_dump #{config['database']}"
    command << " --clean"
    command << " --format=custom"
    command << " --file=#{dump_file}"
    command << " --username=\"#{config['username']}\""
    command << " --host=#{host}" if host
    command << " --port=#{port}" if port
    command
  else
    raise %(x Adapter "#{config['adapter']}" is not supported.)
  end
end

def find_database_config(config_path, environment, database)
  environment ||= 'production'
  database_yml = ERB.new(File.read(config_path)).result
  config = if Gem::Version.new(Psych::VERSION) >= Gem::Version.new('3.1.0')
    YAML.safe_load(database_yml, aliases: true)
  else
    YAML.safe_load(database_yml, [], [], true)
  end
  config = config[environment] or raise "x No #{environment} database found.\nUsage: dumple ENVIRONMENT [DATABASE]"

  if config.values[0].is_a? Hash # Multi-db setup
    if database # Explicitly requested
      config = config[database] or raise %(x Unknown #{environment} database "#{database}".)
    elsif config.key? 'primary'
      puts '> Multiple databases detected. Defaulting to primary database.'
      config = config['primary']
    else
      puts "> Multiple databases detected. Defaulting to first entry (#{config.keys[0]})."
      config = config.values[0]
    end
  else # Single-db setup
    if database
      raise %(x Could not select "#{database}" database in a single-db environment.)
    end
  end

  config
end

def prepare_dump_path(config)
  unless File.directory?(DUMPS_DIR)
    Dir.mkdir(DUMPS_DIR)
    run "chmod 700 #{DUMPS_DIR}"
  end

  if ARGV.include? '--for_download'
    "#{DUMPS_DIR}/dump_for_download.dump"
  else
    "#{DUMPS_DIR}/#{config['database']}_#{Time.now.strftime("%Y%m%d_%H%M%S")}.dump"
  end
end

begin
  fail_gently = ARGV.include?("--fail-gently")
  compress = ARGV.include?("--compress")
  environment, database = ARGV.reject { |arg| arg[0].chr == '-' }

  cd_to_project_root(fail_gently)
  config = find_database_config(DB_CONFIG_PATH, environment, database)
  dump_path = prepare_dump_path(config)

  # Dump!
  given_database = database ? %(#{database} ) : ""
  command = dump_command(dump_path, config)
  puts "> Dumping #{given_database}database for \"#{environment}\" environment ..."
  run command or raise "x Creating the dump failed."
  run "chmod 600 #{dump_path}"

  if compress
    puts "> Compressing the dump ..."
    # gzip compresses in place
    compress_success = run "gzip #{dump_path}"
    compress_success or raise "x Compressing the dump failed."
    dump_path << ".gz"
  end

  dump_size_kb = (File.size(dump_path) / 1024).round

  puts "> Dumped to #{dump_path} (#{dump_size_kb} KB)"
rescue StandardError => e
  $stderr.puts e.message
  exit 1
end