# Controller for viewing a file's blame
class Projects::BlobController < Projects::ApplicationController
  include ExtractsPath
  include CreatesMergeRequestForCommit
  include ActionView::Helpers::SanitizeHelper

  # Raised when given an invalid file path
  class InvalidPathError < StandardError; end

  before_action :require_non_empty_project, except: [:new, :create]
  before_action :authorize_download_code!
  before_action :authorize_push_code!, only: [:destroy, :create]
  before_action :assign_blob_vars
  before_action :commit, except: [:new, :create]
  before_action :blob, except: [:new, :create]
  before_action :from_merge_request, only: [:edit, :update]
  before_action :require_branch_head, only: [:edit, :update]
  before_action :editor_variables, except: [:show, :preview, :diff]
  before_action :after_edit_path, only: [:edit, :update]

  def new
    commit unless @repository.empty?
  end

  def create
    create_commit(Files::CreateService, success_path: after_create_path,
                                        failure_view: :new,
                                        failure_path: namespace_project_new_blob_path(@project.namespace, @project, @ref))
  end

  def show
  end

  def edit
    @last_commit = Gitlab::Git::Commit.last_for_path(@repository, @ref, @path).sha
  end

  def update
    create_commit(Files::UpdateService, success_path: after_edit_path,
                                        failure_view: :edit,
                                        failure_path: namespace_project_blob_path(@project.namespace, @project, @id))
  end

  def preview
    @content = params[:content]
    diffy = Diffy::Diff.new(@blob.data, @content, diff: '-U 3', include_diff_info: true)
    @diff_lines = Gitlab::Diff::Parser.new.parse(diffy.diff.scan(/.*\n/))

    render layout: false
  end

  def destroy
    result = Files::DeleteService.new(@project, current_user, @commit_params).execute

    if result[:status] == :success
      flash[:notice] = "Your changes have been successfully committed"
      redirect_to after_destroy_path
    else
      flash[:alert] = result[:message]
      render :show
    end
  end

  def diff
    @form = UnfoldForm.new(params)
    @lines = @blob.data.lines[@form.since - 1..@form.to - 1]

    if @form.bottom?
      @match_line = ''
    else
      lines_length = @lines.length - 1
      line = [@form.since, lines_length].join(',')
      @match_line = "@@ -#{line}+#{line} @@"
    end

    render layout: false
  end

  private

  def blob
    @blob ||= @repository.blob_at(@commit.id, @path)

    if @blob
      @blob
    else
      if tree = @repository.tree(@commit.id, @path)
        if tree.entries.any?
          redirect_to namespace_project_tree_path(@project.namespace, @project, File.join(@ref, @path)) and return
        end
      end

      return render_404
    end
  end

  def commit
    @commit = @repository.commit(@ref)

    return render_404 unless @commit
  end

  def assign_blob_vars
    @id = params[:id]
    @ref, @path = extract_ref(@id)

  rescue InvalidPathError
    render_404
  end

  def create_commit(service, success_path:, failure_view:, failure_path:)
    result = service.new(@project, current_user, @commit_params).execute

    if result[:status] == :success
      flash[:notice] = "Your changes have been successfully committed"
      respond_to do |format|
        format.html { redirect_to success_path }
        format.json { render json: { message: "success", filePath: success_path } }
      end
    else
      flash[:alert] = result[:message]
      respond_to do |format|
        format.html { render failure_view }
        format.json { render json: { message: "failed", filePath: failure_path } }
      end
    end
  end

  def after_create_path
    @after_create_path ||=
      if create_merge_request?
        new_merge_request_path
      else
        namespace_project_blob_path(@project.namespace, @project, File.join(@new_branch, @file_path))
      end
  end

  def after_edit_path
    @after_edit_path ||=
      if create_merge_request?
        new_merge_request_path
      elsif from_merge_request && @new_branch == @ref
        diffs_namespace_project_merge_request_path(from_merge_request.target_project.namespace, from_merge_request.target_project, from_merge_request) +
          "#file-path-#{hexdigest(@path)}"
      else
        namespace_project_blob_path(@project.namespace, @project, File.join(@new_branch, @path))
      end
  end

  def after_destroy_path
    @after_destroy_path ||=
      if create_merge_request?
        new_merge_request_path
      else
        namespace_project_tree_path(@project.namespace, @project, @new_branch)
      end
  end

  def from_merge_request
    # If blob edit was initiated from merge request page
    @from_merge_request ||= MergeRequest.find_by(id: params[:from_merge_request_id])
  end

  def sanitized_new_branch_name
    @new_branch ||= sanitize(strip_tags(params[:new_branch]))
  end

  def editor_variables
    @current_branch = @ref
    @new_branch = params[:new_branch].present? ? sanitized_new_branch_name : @ref

    @file_path =
      if action_name.to_s == 'create'
        if params[:file].present?
          params[:file_name] = params[:file].original_filename
        end
        File.join(@path, params[:file_name])
      else
        @path
      end

    if params[:file].present?
      params[:content] = Base64.encode64(params[:file].read)
      params[:encoding] = 'base64'
    end

    @commit_params = {
      file_path: @file_path,
      current_branch: @current_branch,
      target_branch: @new_branch,
      commit_message: params[:commit_message],
      file_content: params[:content],
      file_content_encoding: params[:encoding]
    }
  end
end
