using System;
using System.Collections.Generic;
using System.Linq;
using System.Security;
using Microsoft.SharePoint.Client;
using Microsoft.SharePoint.Client.Utilities;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            ConsoleColor defaultForeground = Console.ForegroundColor;

            Console.ForegroundColor = ConsoleColor.Green;
            Console.WriteLine("Enter the URL of the SharePoint Online site:");

            Console.ForegroundColor = defaultForeground;
            var webUrl = Console.ReadLine();
            if (string.IsNullOrWhiteSpace(webUrl)) webUrl = null;

            Console.ForegroundColor = ConsoleColor.Green;
            Console.WriteLine("Enter your user name (ex: user@tenant):");
            Console.ForegroundColor = defaultForeground;
            var userName = Console.ReadLine();
            if (string.IsNullOrWhiteSpace(userName)) userName = null;

            Console.ForegroundColor = ConsoleColor.Green;
            Console.WriteLine("Enter your password.");
            Console.ForegroundColor = defaultForeground;
            var password = GetPasswordFromConsoleInput();

            using (var context = new ClientContext(webUrl ?? "default_url"))
            {
                context.Credentials = new SharePointOnlineCredentials(userName ?? "default_username", password);
                var web = context.Web;

                var permissions = new BasePermissions();
                permissions.Set(PermissionKind.EditListItems);

                var result = new List<string>();
                result.Add("User|Url");
                ScanWeb(context, web, ref result, true);
                result.ForEach(Console.WriteLine);

                System.IO.File.WriteAllLines(string.Format(@"C:\\Contributors_{0}.txt",
                    DateTime.Now.ToString("yyyy-MM-dd-ssfff")), result.ToArray());

                Console.WriteLine("Done!");
                Console.Read();
            }
        }

        private const string LineFormat = @"{0}|{1}";

        private static void ScanWeb(ClientContext ctx, Web web, ref List<string> result, bool rootweb)
        {
            ctx.Load(web, w => w.HasUniqueRoleAssignments, w => w.Url);
            ctx.Load(web.Webs);
            ctx.Load(web.RoleAssignments);
            ctx.Load(web.SiteGroups);
            ctx.ExecuteQuery();

            if (rootweb || web.HasUniqueRoleAssignments)
            {
                var roles = web.RoleAssignments;
                foreach (var role in roles)
                {
                    ctx.Load(role.Member);
                    ctx.Load(role.RoleDefinitionBindings);
                    ctx.ExecuteQuery();
                    ScanRole(ctx, web, role, ref result);
                }
            }

            foreach (var w in web.Webs)
                ScanWeb(ctx, w, ref result, false);
        }

        private static void ScanRole(ClientContext ctx, Web web, RoleAssignment role, ref List<string> result)
        {
            var groups = web.SiteGroups;

            if (!role.RoleDefinitionBindings.Any(r => r.BasePermissions.Has(PermissionKind.EditListItems)))
                return;

            if (role.Member.PrincipalType == PrincipalType.User)
                result.Add(string.Format(LineFormat, role.Member.Title, web.Url));
            else if (role.Member.PrincipalType == PrincipalType.SharePointGroup)
            {
                var g = groups.GetByName(role.Member.LoginName);
                ctx.Load(g);
                ctx.Load(g.Users);
                ctx.ExecuteQuery();

                foreach (var user in g.Users)
                    result.Add(string.Format(LineFormat, user.Title, web.Url));
            }
        }

        private static SecureString GetPasswordFromConsoleInput()
        {
            ConsoleKeyInfo info;

            //Get the user's password as a SecureString
            SecureString securePassword = new SecureString();
            do
            {
                info = Console.ReadKey(true);
                if (info.Key != ConsoleKey.Enter)
                {
                    securePassword.AppendChar(info.KeyChar);
                }
            }
            while (info.Key != ConsoleKey.Enter);
            return securePassword;
        }
    }
}