require_relative './octokit_client.rb'
require_relative './highline_cli.rb'

module GitHelper
  class GitHubPullRequest
    def create
      begin
        # Ask these questions right away
        base_branch
        new_pr_title
        new_pr_body

        puts "Creating pull request: #{new_pr_title}"
        pr = octokit_client.create_pull_request(local_repo, base_branch, local_branch, new_pr_title, new_pr_body)
        puts "Pull request successfully created: #{pr.html_url}"
      rescue Octokit::UnprocessableEntity => e
        puts 'Could not create pull request:'
        if e.message.include?('pull request already exists')
          puts '  A pull request already exists for this branch'
        elsif e.message.include?('No commits between')
          puts '  No commits have been pushed to GitHub'
        else
          puts e.message
        end
      rescue Exception => e
        puts 'Could not create pull request:'
        puts e.message
      end
    end

    def merge
      begin
        # Ask these questions right away
        pr_id
        merge_method

        puts "Merging pull request: #{pr_id}"
        merge = octokit_client.merge_pull_request(local_repo, pr_id, existing_pr_title, { merge_method: merge_method })
        puts "Pull request successfully merged: #{merge.sha}"
      rescue Octokit::UnprocessableEntity => e
        puts 'Could not merge pull request:'
        puts e.message
      rescue Octokit::NotFound => e
        puts 'Could not merge pull request:'
        puts "  Could not a locate a pull request to merge with ID #{pr_id}"
      rescue Octokit::MethodNotAllowed => e
        puts 'Could not merge pull request:'
        if e.message.include?('405 - Required status check')
          puts '  A required status check has not passed'
        elsif e.message.include?('405 - Base branch was modified')
          puts '  The base branch has been modified'
        elsif e.message.include?('405 - Pull Request is not mergeable')
          puts '  The pull request is not mergeable'
        elsif e.message.include?('405 - Rebase merges are not allowed on this repository')
          puts '  Rebase merges are not allowed on this repository'
        elsif e.message.include?('405 - Merge commits are not allowed on this repository')
          puts '  Merge commits are not allowed on this repository'
        elsif e.message.include?('405 - Squash commits are not allowed on this repository')
          puts '  Squash merges are not allowed on this repository'
        else
          puts e.message
        end
      rescue Exception => e
        puts 'Could not merge pull 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 pr_template_options.count == 1
        apply_template?(pr_template_options.first) ? File.open(pr_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 merge_options
      [ 'merge', 'squash', 'rebase' ]
    end

    private def pr_id
      @pr_id ||= cli.ask('Pull Request ID?')
    end

    private def existing_pr_title
      @existing_pr_title ||= octokit_client.pull_request(local_repo, pr_id).title
    end

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

    private def new_pr_body
      @new_pr_body ||= pr_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 ||= octokit_client.repository(local_repo).default_branch
    end

    private def merge_method
      return @merge_method if @merge_method
      index = cli.ask_options("Merge method?", merge_options)
      @merge_method = merge_options[index]
    end

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

    private def pr_template_options
      return @pr_template_options if @pr_template_options
      nested_templates = Dir.glob(File.join("**/PULL_REQUEST_TEMPLATE", "*.md"), File::FNM_DOTMATCH | File::FNM_CASEFOLD)
      non_nested_templates = Dir.glob(File.join("**", "pull_request_template.md"), File::FNM_DOTMATCH | File::FNM_CASEFOLD)
      @pr_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 pull request? (y/n)")
      !!(answer =~ /^y/i)
    end

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

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

    private def octokit_client
      @octokit_client ||= GitHelper::OctokitClient.new.client
    end

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