# frozen_string_literal: true

# https://docs.ruby-lang.org/en/3.2/ERB.html
require "erb"

$LERB_VERBOSE = ENV["LERB_VERBOSE"]

class LERB < ERB
  class Error < StandardError; end
  class BuildError < Error; end
  class ExecutionError < Error; end

  # output

  def self.puts string=nil
    super if $LERB_VERBOSE
  end

  # loaders

  DEFAULT_KEY = "inline.txt.erb"

  def self.load path_radical
    erbs = []

    "#{path_radical}.rb".tap do |filename|
      _load erbs, filename
    end

    Dir.glob("#{path_radical}.*.erb").each do |filename|
      _load erbs, filename
    end

    Dir.glob("#{path_radical}/*.*.erb").each do |filename|
      _load erbs, filename
    end

    #

    puts "#{erbs.size} erbs".on_red
    erbs.each do |h|
      puts "key: #{h.key}".on_green
    end

    erbs
  end

  def self._load erbs, filename
    is_erb = filename.end_with? ".erb"
    is_ignoring_ruby = !is_erb
    is_accepting_views = false
    
    puts
    puts "LERB filename: #{filename}".on_red
    
    puts "LERB is_erb: #{is_erb}".on_red
    puts "LERB is_ignoring_ruby: #{is_ignoring_ruby}".on_red
    puts "LERB is_accepting_views: #{is_accepting_views}".on_red

    current_lineno = 0
    current_content = ""
    current_key = is_erb ? filename.split("/").last : DEFAULT_KEY

    if current_key
      puts "LERB declare: #{current_key} | because not erb".green
    end

    File.readlines(filename).each.with_index do |line, lineno|
      is_line_end = line == "__END__\n"

      # stop ignoring ruby lines if line is __END__
      # move to next line if ignoring ruby lines

      if is_ignoring_ruby
        puts "LERB ignore: #{lineno}: #{line[0..-2]}".light_black
        if is_line_end
          is_ignoring_ruby = false
          is_accepting_views = true
          current_lineno = lineno + 1
          puts "LERB declare: #{current_key} | current".green if current_key
        end
        next
      end

      if is_accepting_views && line[0..6] == "# view "
        _load_into erbs, filename, current_lineno, current_key, current_content
        current_key = line[7..-1].strip
        current_lineno = lineno + 1
        current_content = ""
        puts "LERB declare: #{current_key} | #{lineno}: #{line[0..-2]}".green
      else
        current_content += line
        puts "LERB keeping: #{lineno}: #{line[0..-2]}".bold.white
      end

      if is_line_end
        puts "LERB warning: #{lineno}: #{line[0..-2]} found! No longer accepting views".light_yellow
        is_accepting_views = false
      end
    end

    _load_into erbs, filename, current_lineno, current_key, current_content

    erbs
  end

  def self._load_into erbs, filename, lineno, key, content
    return unless key
    return unless key.end_with? "erb"
    return if content.strip.empty?

    content += "\n" if content[-1] != "\n"

    erbs.push new filename, lineno, key, content
  end

  # format

  TAG_FORMATS = %w|xml html|

  def tags?
    TAG_FORMATS.include? format
  end

  # constructor

  TRIM_MODE = "<>-"

  attr_reader :key, :name, :format

  def initialize filename, lineno, key, content
    segments = key.split("/").last.split(".")
    name, format = segments[0..1]

    if format.gsub(/[^a-z0-9]/, "") != format
      raise BuildError, "key '#{key}' has an invalid format '#{format}'"
    end

    super content, trim_mode: TRIM_MODE
    self.filename, self.lineno, @key, @name, @format = filename, lineno, key, name, format
  end

  # result

  def result the_binding, receiver=:unset
    super the_binding
  rescue NameError => e
    raise unless e.receiver == receiver
    message = "ERB template for a #{e.receiver.class} instance could not find method '#{e.name}'"
    raise ExecutionError, message, [e.backtrace[0]]
  end
end