module Ethon::Easy::Queryable

def self.included(base)
  base.send(:attr_accessor, :escape)
  base.send(:attr_accessor, :params_encoding)
end

def build_query_pairs(hash)
  return [hash] if hash.is_a?(String)
  pairs = []
  recursively_generate_pairs(hash, nil, pairs)
  pairs
end

def empty?
  @params.empty?
end

def encode_hash_pairs(h, prefix, pairs)
  h.each_pair do |k,v|
    key = prefix.nil? ? k : "#{prefix}[#{k}]"
    pairs_for(v, key, pairs)
  end
end

def encode_indexed_array_pairs(h, prefix, pairs)
  h.each_with_index do |v, i|
    key = "#{prefix}[#{i}]"
    pairs_for(v, key, pairs)
  end
end

def encode_multi_array_pairs(h, prefix, pairs)
  h.each_with_index do |v, i|
    key = prefix
    pairs_for(v, key, pairs)
  end
end

def encode_rack_array_pairs(h, prefix, pairs)
  h.each do |v|
    key = "#{prefix}[]"
    pairs_for(v, key, pairs)
  end
end

def file_info(file)
  filename = File.basename(file.path)
  [
    filename,
    mime_type(filename),
    File.expand_path(file.path)
  ]
end

def mime_type(filename)
  if defined?(MIME) && t = MIME::Types.type_for(filename).first
    t.to_s
  else
    'application/octet-stream'
  end
end

def pairs_for(v, key, pairs)
  case v
  when Hash, Array
    recursively_generate_pairs(v, key, pairs)
  when File, Tempfile
    pairs << [key, file_info(v)]
  else
    pairs << [key, v]
  end
end

def query_pairs
  @query_pairs ||= build_query_pairs(@params)
end

def recursively_generate_pairs(h, prefix, pairs)
  case h
  when Hash
    encode_hash_pairs(h, prefix, pairs)
  when Array
    if params_encoding == :rack
      encode_rack_array_pairs(h, prefix, pairs)
    elsif params_encoding == :multi
      encode_multi_array_pairs(h, prefix, pairs)
    elsif params_encoding == :none
      pairs << [prefix, h]
    else
      encode_indexed_array_pairs(h, prefix, pairs)
    end
  end
end

def to_s
  @to_s ||= query_pairs.map{ |pair|
    return pair if pair.is_a?(String)
    if escape && @easy
      pair.map{ |e| @easy.escape(e.to_s) }.join("=")
    else
      pair.join("=")
    end
  }.join('&')
end