require_relative './gitlab_client.rb'
require_relative './highline_cli.rb'

module GitHelper
  class GitLabMergeRequest
    def create
      begin
        # Ask these questions right away
        base_branch
        new_mr_title
        options = {
          source_branch: local_branch,
          target_branch: base_branch,
          description: new_mr_body
        }

        puts "Creating merge request: #{new_mr_title}"
        mr = gitlab_client.create_merge_request(local_repo, new_mr_title, options)

        if mr.diff_refs.base_sha == mr.diff_refs.head_sha
          puts "Merge request was created, but no commits have been pushed to GitLab: #{mr.web_url}"
        else
          puts "Merge request successfully created: #{mr.web_url}"
        end
      rescue Gitlab::Error::Conflict => e
        puts 'Could not create merge request:'
        puts '  A merge request already exists for this branch'
      rescue Exception => e
        puts 'Could not create merge request:'
        puts e.message
      end
    end

    def merge
      begin
        # Ask these questions right away
        mr_id
        options = {}
        options[:should_remove_source_branch] = remove_source_branch?
        options[:squash] = squash_merge_request?
        options[:squash_commit_message] = existing_mr_title

        puts "Merging merge request: #{mr_id}"
        merge = gitlab_client.accept_merge_request(local_repo, mr_id, options)
        puts "Merge request successfully merged: #{merge.merge_commit_sha}"
      rescue Gitlab::Error::MethodNotAllowed => e
        puts 'Could not merge merge request:'
        puts '  The merge request is not mergeable'
      rescue Gitlab::Error::NotFound => e
        puts 'Could not merge merge request:'
        puts "  Could not a locate a merge request to merge with ID #{mr_id}"
      rescue Exception => e
        puts 'Could not merge merge request:'
        puts e.message
      end
    end

    private def local_repo
      # Get the repository by looking in the remote URLs for the full repository name
      remotes = `git remote -v`
      return remotes.scan(/\S[\s]*[\S]+.com[\S]{1}([\S]*).git/).first.first
    end

    private def local_branch
      # Get the current branch by looking in the list of branches for the *
      branches = `git branch`
      return branches.scan(/\*\s([\S]*)/).first.first
    end

    private def read_template
      if mr_template_options.count == 1
        apply_template?(mr_template_options.first) ? File.open(mr_template_options.first).read : ''
      else
        template_file_name_to_apply = template_to_apply
        template_file_name_to_apply == "None" ? '' : File.open(template_file_name_to_apply).read
      end
    end

    private def mr_id
      @mr_id ||= cli.ask('Merge Request ID?')
    end

    private def existing_mr_title
      @existing_mr_title ||= gitlab_client.merge_request(local_repo, mr_id).title
    end

    private def new_mr_title
      @new_mr_title ||= accept_autogenerated_title? ? autogenerated_title : cli.ask('Title?')
    end

    private def new_mr_body
      @new_mr_body ||= mr_template_options.empty? ? '' : read_template
    end

    private def base_branch
      @base_branch ||= base_branch_default? ? default_branch : cli.ask('Base branch?')
    end

    private def autogenerated_title
      @autogenerated_title ||= local_branch.split('_')[0..-1].join(' ').capitalize
    end

    private def default_branch
      @default_branch ||= gitlab_client.branches(local_repo).select { |branch| branch.default }.first.name
    end

    private def template_to_apply
      return @template_to_apply if @template_to_apply
      complete_options = mr_template_options << 'None'
      index = cli.ask_options("Which merge request template should be applied?", complete_options)
      @template_to_apply = complete_options[index]
    end

    private def mr_template_options
      return @mr_template_options if @mr_template_options
      nested_templates = Dir.glob(File.join("**/merge_request_templates", "*.md"), File::FNM_DOTMATCH | File::FNM_CASEFOLD)
      non_nested_templates = Dir.glob(File.join("**", "merge_request_template.md"), File::FNM_DOTMATCH | File::FNM_CASEFOLD)
      @mr_template_options = nested_templates.concat(non_nested_templates)
    end

    private def base_branch_default?
      answer = cli.ask("Is '#{default_branch}' the correct base branch for your new merge request? (y/n)")
      !!(answer =~ /^y/i)
    end

    private def accept_autogenerated_title?
      answer = cli.ask("Accept the autogenerated merge request title '#{autogenerated_title}'? (y/n)")
      !!(answer =~ /^y/i)
    end

    private def squash_merge_request?
      answer = cli.ask('Squash merge request? (y/n)')
      !!(answer =~ /^y/i)
    end

    private def remove_source_branch?
      answer = cli.ask('Remove source branch after merging? (y/n)')
      !!(answer =~ /^y/i)
    end

    private def apply_template?(template_file_name)
      answer = cli.ask("Apply the merge request template from #{template_file_name}? (y/n)")
      !!(answer =~ /^y/i)
    end

    private def gitlab_client
      @gitlab_client ||= GitHelper::GitLabClient.new.client
    end

    private def cli
      @cli ||= GitHelper::HighlineCli.new
    end
  end
end