# encoding: utf-8

require 'redis-copy'
require 'optparse'

module RedisCopy
  class CLI
    REDIS_URI = (/\A(?:redis:\/\/)?([a-z0-9\-.]+)(:[0-9]{1,5})?(\/(?:(?:1[0-5])|[0-9]))?\z/i).freeze
    DEFAULTS = {
      ui:           :command_line,
      key_emitter:  :default,
      strategy:     :auto,
      fail_fast:    false,
      yes:          false,
    }.freeze unless defined?(DEFAULTS)

    def initialize(argv = ARGV)
      argv = argv.dup
      options = {}

      OptionParser.new do |opts|
        opts.banner = "Usage: #{opts.program_name} [options] <source> <destination>"
        opts.version = RedisCopy::VERSION

        indent_desc = proc do |desc|
          desc.split("\n").join("\n#{opts.summary_indent}#{' '*opts.summary_width} ")
        end

        opts.separator "    <source> and <destination> must be redis connection uris"
        opts.separator "    like [redis://]<hostname>[:<port>][/<db>]"
        opts.separator ''
        opts.separator "Specific options:"

        opts.on('--strategy STRATEGY', [:auto, :new, :classic],
          indent_desc.(
            "Select strategy (auto, new, classic) (default #{DEFAULTS[:strategy]})\n" +
            "  auto:    uses new if available, otherwise fallback\n" +
            "  new:     use redis DUMP and RESTORE commands (faster)\n" +
            "  classic: migrates via multiple type-specific commands"
          )
        ) do |strategy|
          options[:strategy] = strategy
        end

        opts.on('--[no-]dry-run', 'Output configuration and exit') do |d|
          options[:dry_run] = true
        end

        opts.on('-d', '--[no-]debug', 'Write debug output') do |debug|
          options[:debug] = debug
        end

        opts.on('-t', '--[no-]trace', 'Enable backtrace on failure') do |trace|
          options[:trace] = trace
        end

        opts.on('-f', '--[no-]fail-fast', 'Abort on first failure') do |ff|
          options[:fail_fast] = ff
        end

        opts.on('-y', '--yes', 'Automatically accept any prompts') do
          options[:yes] = true
        end

        opts.parse!(argv)
        unless argv.size == 2
          opts.abort "Source and Destination must be specified\n\n" +
                            opts.help
        end
        @source = argv.shift
        @destination = argv.shift

        opts.abort "source is not valid URI" unless @source =~ REDIS_URI
        opts.abort "destination is not valid URI" unless @destination =~ REDIS_URI
      end

      @config = DEFAULTS.merge(options)
    end

    def run!
      (puts self.inspect; exit 1) if @config.delete(:dry_run)

      RedisCopy::copy(@source, @destination, @config)
    rescue => exception
      $stderr.puts exception.message
      $stderr.puts exception.backtrace if @config[:trace]
      exit 1
    end
  end
end