require 'commander'
require 'yaml'
require 'highline'
require_relative 'buildpaths'
require_relative 'terraform'
require_relative 'cleaner'
require_relative 'version'
require_relative 'git'

module Terragov
  class Cli
    include Commander::Methods

    def initialize
      program :name, 'terragov'
      program :version, Terragov::VERSION
      program :description, 'Wrapper for GOV.UK Terraform deployments.'

      global_option('-c', "--config-file FILE", 'Specify a config file. Has less precedence than environment variables, which in turn have less precedence than CLI options') do |config_file|
        $config_file = config_file
      end

      global_option('-d', "--data-dir DIRECTORY", String, 'Location of the data directory') do |data_dir|
        $data_dir = data_dir
      end

      global_option( '-e', '--environment STRING', String, 'Select environment') do |environment|
        $environment = environment
      end

      global_option(  '-p', '--project STRING', String, 'Name of the project') do |project|
        $project = project
      end

      global_option( '-r', '--repo-dir DIRECTORY', String, 'Location of the main terraform repository') do |repo_dir|
        $repo_dir = repo_dir
      end

      global_option( '-s', '--stack STRING', String, 'Name of the stack') do |stack|
        $stack = stack
      end

      global_option('--extra STRING', String, 'Any additional arguments to pass in the following format: --extra \\\\-target resource.foo.') do |extra|
        $extra = extra
      end

      global_option('--verbose', 'Verbose mode') do |verbose|
        $verbose = verbose
      end

      global_option('--dry-run', 'Dry run mode', 'Output the commands to run, but do not run them') do |dryrun|
        $dryrun = dryrun
      end

      global_option('--skip-git-check', 'Skip git check', 'Do not check the status of git repositories') do |skip_git_check|
        $skip_git_check = skip_git_check
      end
    end

    def data_dir
      return $data_dir ? $data_dir : false
    end

    def environment
      return $environment ? $environment : false
    end

    def project
      return $project ? $project : false
    end

    def repo_dir
      return $repo_dir ? $repo_dir : false
    end

    def stack
      return $stack ? $stack : false
    end

    def extra
      return $extra if $extra
    end

    def verbose
      return true ? $verbose : false
    end

    def dryrun
      return true ? $dryrun : false
    end

    def skip_git_check
      return true ? $skip_git_check : false
    end

    def load_config_file
      if $config_file || ENV['TERRAGOV_CONFIG_FILE']
        file = $config_file || ENV['TERRAGOV_CONFIG_FILE']
        $values = YAML.load_file(File.expand_path(file))
        return $values
      end
    end

    def config(option, file=false, required=true)
      env_var = "TERRAGOV_#{option.upcase}"
      error_message = "Must set #{option}. Use --help for details."
      if public_send(option)
        if file
          return File.expand_path(public_send(option))
        else
          return public_send(option)
        end
      elsif ENV[env_var]
        if file
          return File.expand_path(ENV[env_var])
        else
          return ENV[env_var]
        end
      elsif !load_config_file.nil?
        unless load_config_file[option].nil?
          if file
            return File.expand_path(load_config_file[option])
          else
            return load_config_file[option]
          end
        else
          if required
            abort(error_message)
          else
            return false
          end
        end
      else
        if required
          abort(error_message)
        else
          return false
        end
      end
    end

    def cmd_options
      cmd_options_hash = {
        "environment" => config('environment'),
        "data_dir"    => config('data_dir', true),
        "project"     => config('project'),
        "stack"       => config('stack'),
        "repo_dir"    => config('repo_dir', true),
        "extra"       => extra,
      }
      return cmd_options_hash
    end

    def git_compare_repo_and_data(skip=false)
      git_helper = Terragov::Git.new
      # FIXME this is confusing as we want to check the repository git status from
      # the root, but the "data" directory is one level down in the repository
      repo_dir_root = cmd_options['repo_dir']
      data_dir_root = File.expand_path(File.join(cmd_options['data_dir'], '../'))

      repo_dir_branch = git_helper.branch_name(repo_dir_root)
      data_dir_branch = git_helper.branch_name(data_dir_root)

      branches = {
        "repo_dir" => repo_dir_branch,
        "data_dir" => data_dir_branch,
      }

      unless skip
        branches.each do |name, branch|
          unless branch =~ /^master$/
            exit unless HighLine.agree("#{name} not on 'master' branch, continue on branch '#{branch}'?")
          end
        end

        unless git_helper.compare_branch(repo_dir_root, data_dir_root)
          puts "Warning: repo_dir(#{repo_dir_branch}) and data_dir(#{data_dir_branch}) on different branches"
          exit unless HighLine.agree("Do you wish to continue?")
        end
      end
    end

    def run_terraform_cmd(cmd, opt = nil)
      paths = Terragov::BuildPaths.new.base(cmd_options)
      varfiles = Terragov::BuildPaths.new.build_command(cmd_options)
      backend  = paths[:backend_file]
      project_dir = paths[:project_dir]

      be_verbose = config('verbose', false, false)

      do_dryrun = config('dryrun', false, false)

      skip_check =  config('skip_git_check', false, false)
      git_compare_repo_and_data(skip_check)

      if be_verbose
        puts cmd_options.to_yaml
      end

      if opt
        cmd = "#{cmd} #{opt}"
      end
      Terragov::Terraform.new.execute(cmd, varfiles, backend, project_dir, do_dryrun, be_verbose)
    end

    def run
      command :plan do |c|
        c.syntax = 'terragov plan'
        c.description = 'Runs a plan of your code'
        c.action do |args, options|

          run_terraform_cmd(c.name)
        end
      end

      command :apply do |c|
        c.syntax = 'terragov apply'
        c.description = 'Apply your code'
        c.action do |args, options|

          run_terraform_cmd(c.name)
        end
      end

      command :destroy do |c|
        c.syntax = 'terragov destroy'
        c.description = 'Destroy your selected project'
        c.option '--force', 'Force destroy'
        c.action do |args, options|
          if options.force
            run_terraform_cmd("#{c.name} -force")
          else
            run_terraform_cmd(c.name)
          end
        end
      end

      command :clean do |c|
        c.syntax = 'terragov clean'
        c.description = 'Clean your directory of any files terraform may have left lying around'
        c.option '--force', 'Force removal of files'
        c.action do |args, options|
          if config('verbose', false, false)
            puts "Selecting directory #{repo_dir}"
          end

          Terragov::Cleaner.new.delete(repo_dir, /terraform\.tfstate\.backup/, options.force)
        end
      end

      run!
    end
  end
end