module Sprockets::HTTPUtils

def find_best_mime_type_match(q_value_header, available)

Returns the matched mime type String from available Array or nil.

Adapted from Rack::Utils#q_values.

options.
Internal: Find the best qvalue match from an Array of available mime type 
def find_best_mime_type_match(q_value_header, available)
  find_best_q_match(q_value_header, available) do |a, b|
    match_mime_type?(a, b)
  end
end

def find_best_q_match(q_values, available, &matcher)

Returns the matched String from available Array or nil.

Adapted from Rack::Utils#q_values.

Internal: Find the best qvalue match from an Array of available options. 
def find_best_q_match(q_values, available, &matcher)
  find_q_matches(q_values, available, &matcher).first
end

def find_mime_type_matches(q_value_header, available)

Returns Array of matched mime type Strings from available Array or [].

Adapted from Rack::Utils#q_values.

options.
Internal: Find the all qvalue match from an Array of available mime type 
def find_mime_type_matches(q_value_header, available)
  find_q_matches(q_value_header, available) do |a, b|
    match_mime_type?(a, b)
  end
end

def find_q_matches(q_values, available, &matcher)

Returns Array of matched Strings from available Array or [].

Adapted from Rack::Utils#q_values.

Internal: Find all qvalue matches from an Array of available options. 
def find_q_matches(q_values, available, &matcher)
  matcher ||= lambda { |a, b| a == b }
  matches = []
  case q_values
  when Array
  when String
    q_values = parse_q_values(q_values)
  when NilClass
    q_values = []
  else
    raise TypeError, "unknown q_values type: #{q_values.class}"
  end
  q_values.each do |accepted, quality|
    if match = available.find { |option| matcher.call(option, accepted) }
      matches << [match, quality]
    end
  end
  matches.sort_by { |match, quality| -quality }.map { |match, quality| match }
end

def match_mime_type?(value, matcher)

specification, false otherwise.
Returns true if the given value is a mime match for the given mime match

match_mime_type?('text/html', 'application/json') => false
match_mime_type?('text/plain', '*') => true
match_mime_type?('text/html', 'text/*') => true

Internal: Test mime type against mime range. 
def match_mime_type?(value, matcher)
  v1, v2 = value.split('/', 2)
  m1, m2 = matcher.split('/', 2)
  (m1 == '*' || v1 == m1) && (m2.nil? || m2 == '*' || m2 == v2)
end

def parse_q_values(values)

Returns an Array of [String, Float].

Adapted from Rack::Utils#q_values.

Internal: Parse Accept header quality values. 
def parse_q_values(values)
  values.to_s.split(/\s*,\s*/).map do |part|
    value, parameters = part.split(/\s*;\s*/, 2)
    quality = 1.0
    if md = /\Aq=([\d.]+)/.match(parameters)
      quality = md[1].to_f
    end
    [value, quality]
  end
end