using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net.Http;
using System.Xml;

namespace GoogleRandomSuggestions
{
    static class GoogleSuggestions
    {
        private const string url = "http://google.com/complete/search?q={0}&output=toolbar";
        static HttpClient http;

        static GoogleSuggestions()
        {
            http = new HttpClient();
        }

        public static IEnumerable<string> GetSuggestions(string search)
        {
            string xml = http.GetAsync(String.Format(url, Uri.EscapeUriString(search))).Result.Content.ReadAsStringAsync().Result;
            XmlDocument xdoc = new XmlDocument();
            bool stop = false;
            int attemptsLeft = 10;
            List<string> suggestions = new List<string>();
            while (!stop) {
                try {
                    xdoc.LoadXml(xml);
                    foreach (XmlNode node in xdoc.DocumentElement.ChildNodes) {
                        XmlNode suggestion = node.ChildNodes[0];
                        suggestions.Add(suggestion.Attributes["data"].Value);
                    }
                    stop = true;
                } catch (XmlException ex) {
                    if (xml.Contains("automated")) {
                        attemptsLeft--;
                        if (attemptsLeft == 0) stop = true;
                        Console.ForegroundColor = ConsoleColor.Red;
                        Console.WriteLine(String.Format("Automated query error - {0} attempts remaining", attemptsLeft));
                        Console.ForegroundColor = ConsoleColor.Gray;
                        http.Dispose();
                        System.Threading.Thread.Sleep(500);
                        http = new HttpClient();
                    } else {
                        stop = true;
                        throw ex;
                    }
                }
            }
            return suggestions;
        }
    }
}

namespace GoogleRandomSuggestions
{
    class Program
    {
        static Random rng;
        
        static Program()
        {
            rng = new Random();
        }

        static bool StringBeginsWith(string str, string beginning)
        {
            if (str.Length < beginning.Length) return false;
            return str.Substring(0, beginning.Length).Equals(beginning);
        }

        static string RandomPhrase(string start)
        {
            string phrase = start;
            bool stop = false;
            while (!stop) {
                string[] suggestions = GoogleSuggestions.GetSuggestions(phrase).Where(s => StringBeginsWith(s, phrase) && !s.Equals(phrase)).ToArray();

                if (suggestions.Length == 0) {
                    stop = true;
                } else if (suggestions.Length == 1) {
                    phrase = suggestions[0];
                    stop = true;
                } else {
                    string choice = suggestions[rng.Next(suggestions.Length)];
                    if (phrase.Length + 1 > choice.Length) {
                        phrase = choice;
                        stop = true;
                    } else {
                        phrase = choice.Substring(0, phrase.Length + 1);
                        Console.ForegroundColor = ConsoleColor.White;
                        Console.Write(phrase);
                        Console.ForegroundColor = ConsoleColor.Gray;
                        Console.WriteLine(choice.Substring(phrase.Length));
                    }
                }
            }
            return phrase;
        }

        static string RandomPhrase()
        {
            return RandomPhrase(Char.ConvertFromUtf32(rng.Next(65, 91)));
        }

        static void Main(string[] args)
        {
            string input = "";
            while (true) {
                Console.Write("> ");
                string last = input;
                input = Console.ReadLine();
                if (input.Length == 0) input = last;
                Console.WriteLine();
                string phrase = RandomPhrase(input);
                Console.ForegroundColor = ConsoleColor.White;
                Console.WriteLine(phrase);
                Console.ForegroundColor = ConsoleColor.Gray;
                Console.WriteLine();
            }
        }
    }
}