require 'openssl'
require 'base64'

module Instagram
  # Defines HTTP request methods
  module Request
    # Perform an HTTP GET request
    def get(path, options={}, signature=false, raw=false, unformatted=false, no_response_wrapper=no_response_wrapper(), signed=sign_requests)
      ret = nil
      ntry = 0
      max_try = 5
      begin
        ntry += 1
        sleep 1 if ntry > 1
        ret = request(:get, path, options, signature, raw, unformatted, no_response_wrapper, signed)
      rescue Zlib::BufError => e
        retry if ntry < max_try
        raise e
      rescue Faraday::ConnectionFailed => e
        retry if ntry < max_try
        raise e
      end
      ret
    end

    # Perform an HTTP POST request
    def post(path, options={}, signature=false, raw=false, unformatted=false, no_response_wrapper=no_response_wrapper(), signed=sign_requests)
      request(:post, path, options, signature, raw, unformatted, no_response_wrapper, signed)
    end

    # Perform an HTTP PUT request
    def put(path, options={},  signature=false, raw=false, unformatted=false, no_response_wrapper=no_response_wrapper(), signed=sign_requests)
      request(:put, path, options, signature, raw, unformatted, no_response_wrapper, signed)
    end

    # Perform an HTTP DELETE request
    def delete(path, options={}, signature=false, raw=false, unformatted=false, no_response_wrapper=no_response_wrapper(), signed=sign_requests)
      request(:delete, path, options, signature, raw, unformatted, no_response_wrapper, signed)
    end

    private

    # Perform an HTTP request
    def request(method, path, options, signature=false, raw=false, unformatted=false, no_response_wrapper=false, signed=sign_requests)
      response = connection(raw).send(method) do |request|
        path = formatted_path(path) unless unformatted

        if signed == true
          if client_id != nil
            sig_options = options.merge({:client_id => client_id})
          end
          if access_token != nil
            sig_options = options.merge({:access_token => access_token})
          end
          sig = generate_sig("/"+path, sig_options, client_secret)
          options[:sig] = sig
        end

        case method
        when :get, :delete
          request.url(URI.encode(path), options)
        when :post, :put
          request.path = URI.encode(path)
          request.body = options unless options.empty?
        end
        if signature && client_ips != nil
          request.headers["X-Insta-Forwarded-For"] = get_insta_fowarded_for(client_ips, client_secret)
        end
      end
      return response if raw
      return response.body if no_response_wrapper
      return Response.create( response.body, {:limit => response.headers['x-ratelimit-limit'].to_i,
                                              :remaining => response.headers['x-ratelimit-remaining'].to_i} )
    end

    def formatted_path(path)
      [path, format].compact.join('.')
    end

    def get_insta_fowarded_for(ips, secret)
        digest = OpenSSL::Digest.new('sha256')
        signature = OpenSSL::HMAC.hexdigest(digest, secret, ips)
        return [ips, signature].join('|')
    end

    def generate_sig(endpoint, params, secret)
      sig = endpoint
      params = params.sort_by{|c|c[0].to_s}
      params.map do |key, val|
        sig += '|%s=%s' % [key, val]
      end
      digest = OpenSSL::Digest.new('sha256')
      return OpenSSL::HMAC.hexdigest(digest, secret, sig)
    end

  end
end