require 'sawyer'
require 'octokit/authentication'
module Octokit

  # Network layer for API clients.
  module Connection

    include Octokit::Authentication

    # Header keys that can be passed in options hash to {#get},{#head}
    CONVENIENCE_HEADERS = Set.new([:accept, :content_type])

    # Make a HTTP GET request
    #
    # @param url [String] The path, relative to {#api_endpoint}
    # @param options [Hash] Query and header params for request
    # @return [Sawyer::Resource]
    def get(url, options = {})
      request :get, url, parse_query_and_convenience_headers(options)
    end

    # Make a HTTP POST request
    #
    # @param url [String] The path, relative to {#api_endpoint}
    # @param options [Hash] Body and header params for request
    # @return [Sawyer::Resource]
    def post(url, options = {})
      request :post, url, options
    end

    # Make a HTTP PUT request
    #
    # @param url [String] The path, relative to {#api_endpoint}
    # @param options [Hash] Body and header params for request
    # @return [Sawyer::Resource]
    def put(url, options = {})
      request :put, url, options
    end

    # Make a HTTP PATCH request
    #
    # @param url [String] The path, relative to {#api_endpoint}
    # @param options [Hash] Body and header params for request
    # @return [Sawyer::Resource]
    def patch(url, options = {})
      request :patch, url, options
    end

    # Make a HTTP DELETE request
    #
    # @param url [String] The path, relative to {#api_endpoint}
    # @param options [Hash] Query and header params for request
    # @return [Sawyer::Resource]
    def delete(url, options = {})
      request :delete, url, options
    end

    # Make a HTTP HEAD request
    #
    # @param url [String] The path, relative to {#api_endpoint}
    # @param options [Hash] Query and header params for request
    # @return [Sawyer::Resource]
    def head(url, options = {})
      request :head, url, parse_query_and_convenience_headers(options)
    end

    # Make one or more HTTP GET requests, optionally fetching
    # the next page of results from URL in Link response header based
    # on value in {#auto_paginate}.
    #
    # @param url [String] The path, relative to {#api_endpoint}
    # @param options [Hash] Query and header params for request
    # @param block [Block] Block to perform the data concatination of the
    #   multiple requests. The block is called with two parameters, the first
    #   contains the contents of the requests so far and the second parameter
    #   contains the latest response.
    # @return [Sawyer::Resource]
    def paginate(url, options = {}, &block)
      opts = parse_query_and_convenience_headers(options)
      if @auto_paginate || @per_page
        opts[:query][:per_page] ||=  @per_page || (@auto_paginate ? 100 : nil)
      end

      data = request(:get, url, opts.dup)

      if @auto_paginate
        while @last_response.rels[:next] && rate_limit.remaining > 0
          @last_response = @last_response.rels[:next].get(:headers => opts[:headers])
          if block_given?
            yield(data, @last_response)
          else
            data.concat(@last_response.data) if @last_response.data.is_a?(Array)
          end
        end

      end

      data
    end

    # Hypermedia agent for the GitHub API
    #
    # @return [Sawyer::Agent]
    def agent
      @agent ||= Sawyer::Agent.new(endpoint, sawyer_options) do |http|
        http.headers[:accept] = default_media_type
        http.headers[:content_type] = "application/json"
        http.headers[:user_agent] = user_agent
        if basic_authenticated?
          http.basic_auth(@login, @password)
        elsif token_authenticated?
          http.authorization 'token', @access_token
        elsif bearer_authenticated?
          http.authorization 'Bearer', @bearer_token
        elsif application_authenticated?
          http.params = http.params.merge application_authentication
        end
      end
    end

    # Fetch the root resource for the API
    #
    # @return [Sawyer::Resource]
    def root
      get "/"
    end

    # Response for last HTTP request
    #
    # @return [Sawyer::Response]
    def last_response
      @last_response if defined? @last_response
    end

    protected

    def endpoint
      api_endpoint
    end

    private

    def reset_agent
      @agent = nil
    end

    def request(method, path, data, options = {})
      if data.is_a?(Hash)
        options[:query]   = data.delete(:query) || {}
        options[:headers] = data.delete(:headers) || {}
        if accept = data.delete(:accept)
          options[:headers][:accept] = accept
        end
      end

      @last_response = response = agent.call(method, URI::Parser.new.escape(path.to_s), data, options)
      response.data
    end

    # Executes the request, checking if it was successful
    #
    # @return [Boolean] True on success, false otherwise
    def boolean_from_response(method, path, options = {})
      request(method, path, options)
      @last_response.status == 204
    rescue Octokit::NotFound
      false
    end


    def sawyer_options
      opts = {
        :links_parser => Sawyer::LinkParsers::Simple.new
      }
      conn_opts = @connection_options
      conn_opts[:builder] = @middleware if @middleware
      conn_opts[:proxy] = @proxy if @proxy
      opts[:faraday] = Faraday.new(conn_opts)

      opts
    end

    def parse_query_and_convenience_headers(options)
      options = options.dup
      headers = options.delete(:headers) { Hash.new }
      CONVENIENCE_HEADERS.each do |h|
        if header = options.delete(h)
          headers[h] = header
        end
      end
      query = options.delete(:query)
      opts = {:query => options}
      opts[:query].merge!(query) if query && query.is_a?(Hash)
      opts[:headers] = headers unless headers.empty?

      opts
    end
  end
end
