# frozen_string_literal: true

require 'i18n/tasks/scanners/file_scanner'
require 'i18n/tasks/scanners/relative_keys'
require 'i18n/tasks/scanners/occurrence_from_position'
require 'i18n/tasks/scanners/ruby_key_literals'

module I18n::Tasks::Scanners
  # Scan for I18n.t usages using a simple regular expression.
  class PatternScanner < FileScanner
    include RelativeKeys
    include OccurrenceFromPosition
    include RubyKeyLiterals

    TRANSLATE_CALL_RE = /(?<=^|[^\w'\-.]|[^\w'\-]I18n\.|I18n\.)t(?:!|ranslate!?)?/
    IGNORE_LINES = {
      'coffee' => /^\s*#(?!\si18n-tasks-use)/,
      'erb' => /^\s*<%\s*#(?!\si18n-tasks-use)/,
      'es6' => %r{^\s*//(?!\si18n-tasks-use)},
      'haml' => /^\s*-\s*#(?!\si18n-tasks-use)/,
      'js' => %r{^\s*//(?!\si18n-tasks-use)},
      'opal' => /^\s*#(?!\si18n-tasks-use)/,
      'slim' => %r{^\s*(?:-#|/)(?!\si18n-tasks-use)}
    }.freeze

    def initialize(**args)
      super
      @translate_call_re = config[:translate_call].present? ? Regexp.new(config[:translate_call]) : TRANSLATE_CALL_RE
      @pattern = config[:pattern].present? ? Regexp.new(config[:pattern]) : default_pattern
      @ignore_lines_res = (config[:ignore_lines] || IGNORE_LINES).each_with_object({}) do |(ext, re), h|
        h[ext.to_s] = Regexp.new(re)
      end
    end

    protected

    # Extract i18n keys from file based on the pattern which must capture the key literal.
    # @return [Array<[key, Results::Occurrence]>] each occurrence found in the file
    def scan_file(path)
      keys = []
      text = read_file(path)
      text.scan(@pattern) do |match|
        src_pos = Regexp.last_match.offset(0).first
        location = occurrence_from_position(path, text, src_pos, raw_key: strip_literal(match[0]))
        next if exclude_line?(location.line, path)
        key = match_to_key(match, path, location)
        next unless key
        key += ':' if key.end_with?('.')
        next unless valid_key?(key)
        keys << [key, location]
      end
      keys
    rescue Exception => e # rubocop:disable Lint/RescueException
      raise ::I18n::Tasks::CommandError.new(e, "Error scanning #{path}: #{e.message}")
    end

    # @param [MatchData] match
    # @param [String] path
    # @return [String] full absolute key name
    def match_to_key(match, path, location)
      absolute_key(strip_literal(match[0]), path,
                   calling_method: -> { closest_method(location) if key_relative_to_method?(path) })
    end

    def exclude_line?(line, path)
      re = @ignore_lines_res[File.extname(path)[1..-1]]
      re && re =~ line
    end

    VALID_KEY_RE_DYNAMIC = /^(#{VALID_KEY_CHARS}|[:\#{@}\[\]])+$/

    def valid_key?(key)
      if @config[:strict]
        super(key)
      else
        key =~ VALID_KEY_RE_DYNAMIC
      end
    end

    def key_relative_to_method?(path)
      /controllers|mailers/ =~ path
    end

    def closest_method(occurrence)
      method = File.readlines(occurrence.path, encoding: 'UTF-8')
                   .first(occurrence.line_num - 1).reverse_each.find { |x| x =~ /\bdef\b/ }
      method && method.strip.sub(/^def\s*/, '').sub(/[\(\s;].*$/, '')
    end

    # This method only exists for backwards compatibility with monkey-patches and plugins
    attr_reader :translate_call_re

    def default_pattern
      # capture only the first argument
      /
      #{translate_call_re} [\( ] \s* (?# fn call begin )
      (#{first_argument_re})         (?# capture the first argument)
      /x
    end

    def first_argument_re
      literal_re
    end
  end
end