module Tilt

# File lib/tilt.rb, line 69
def self.[](file)
  pattern = file.to_s.downcase
  until pattern.empty? || registered?(pattern)
    pattern = File.basename(pattern)
    pattern.sub!(/^[^.]*\.?/, '')
  end

  # Try to find a preferred engine.
  preferred_klass = @preferred_mappings[pattern]
  return preferred_klass if preferred_klass

  # Fall back to the general list of mappings.
  klasses = @template_mappings[pattern]

  # Try to find an engine which is already loaded.
  template = klasses.detect do |klass|
    if klass.respond_to?(:engine_initialized?)
      klass.engine_initialized?
    end
  end

  return template if template

  # Try each of the classes until one succeeds. If all of them fails,
  # we'll raise the error of the first class.
  first_failure = nil

  klasses.each do |klass|
    begin
      klass.new { '' }
    rescue Exception => ex
      first_failure ||= ex
      next
    else
      return klass
    end
  end

  raise first_failure if first_failure
end

# File lib/tilt.rb, line 8
def self.mappings
  @template_mappings
end

# File lib/tilt.rb, line 59
def self.new(file, line=nil, options={}, &block)
  if template_class = self[file]
    template_class.new(file, line, options, &block)
  else
    fail "No template engine registered for #{File.basename(file)}"
  end
end

# File lib/tilt.rb, line 12
def self.normalize(ext)
  ext.to_s.downcase.sub(/^\./, '')
end

# File lib/tilt.rb, line 38
def self.prefer(template_class, *extensions)
  if extensions.empty?
    mappings.each do |ext, klasses|
      @preferred_mappings[ext] = template_class if klasses.include? template_class
    end
  else
    extensions.each do |ext|
      ext = normalize(ext)
      register(template_class, ext)
      @preferred_mappings[ext] = template_class
    end
  end
end

# File lib/tilt.rb, line 17
def self.register(template_class, *extensions)
  if template_class.respond_to?(:to_str)
    # Support register(ext, template_class) too
    extensions, template_class = [template_class], extensions[0]
  end

  extensions.each do |ext|
    ext = normalize(ext)
    mappings[ext].unshift(template_class).uniq!
  end
end

# File lib/tilt.rb, line 53
def self.registered?(ext)
  mappings.key?(ext.downcase) && !mappings[ext.downcase].empty?
end