# frozen_string_literal: true

require 'sitediff'
require 'sitediff/diff'
require 'sitediff/report'
require 'digest/sha1'
require 'fileutils'

class SiteDiff
  # SiteDiff Result Object.
  class Result < Struct.new(
    :path,
    :before,
    :after,
    :before_encoding,
    :after_encoding,
    :error,
    :verbose
  )
    STATUS_SUCCESS  = 0   # Identical before and after
    STATUS_FAILURE  = 1   # Different before and after
    STATUS_ERROR    = 2   # Couldn't fetch page
    STATUS_TEXT = %w[unchanged changed error].freeze

    attr_reader :status, :diff

    ##
    # Creates a Result.
    def initialize(*args)
      super
      if error
        @status = STATUS_ERROR
      else
        if !before_encoding || !after_encoding
          @diff = Diff.binary_diffy(
            before,
            after,
            before_encoding,
            after_encoding
          )
        else
          @diff = Diff.html_diffy(before, after)
        end
        @status = @diff ? STATUS_FAILURE : STATUS_SUCCESS
      end
    end

    ##
    # Whether the result has no diff.
    #
    # If there is a diff, it is not a success.
    #
    # TODO: Change "Success" to unchanged.
    def success?
      status == STATUS_SUCCESS
    end

    ##
    # Whether the result has an error.
    def error?
      status == STATUS_ERROR
    end

    # Textual representation of the status
    def status_text
      STATUS_TEXT[status]
    end

    # Printable URL
    def url(tag, prefix, cache)
      return unless prefix

      base = cache.read_tags.include?(tag) ? "/cache/#{tag}" : prefix
      base.to_s + path
    end

    # Filename to store diff
    def filename
      File.join(Report::DIFFS_DIR, "#{Digest::SHA1.hexdigest(path)}.html")
    end

    # Returns a URL to the result diff.
    #
    # Returns nil if the result has no diffs.
    def diff_url(relative: false)
      prefix = relative ? 'files/' : '/files/'
      return prefix + filename if status == STATUS_FAILURE
    end

    # Log the result to the terminal
    def log(verbose: true)
      case status
      when STATUS_SUCCESS
        SiteDiff.log path, :success, 'UNCHANGED'
      when STATUS_ERROR
        SiteDiff.log path + " (#{error})", :warning, 'ERROR'
      when STATUS_FAILURE
        SiteDiff.log path, :error, 'CHANGED'
        puts Diff.terminal_diffy(before, after) if verbose
      end
    end

    # Dump the result to a file
    def dump(dir, relative: false)
      dump_path = File.join(dir, filename)
      base = File.dirname(dump_path)
      FileUtils.mkdir_p(base) unless File.exist?(base)
      File.open(dump_path, 'w') do |f|
        f.write(Diff.generate_diff_output(self, relative:))
      end
    end
  end
end