using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using Outlook = Microsoft.Office.Interop.Outlook;

namespace OutlookCaseHelper
{
    public class OutlookHelper
    {
        private Outlook.Application outlookApp;
        private Outlook.NameSpace outlookNamespace;

        public OutlookHelper()
        {
            outlookApp = new Outlook.Application();
            outlookNamespace = outlookApp.GetNamespace("MAPI");
        }

        // Get Tracking ID from selected email subject
        public string? GetSelectedEmailTrackingId()
        {
            try
            {
                Outlook.Explorer activeExplorer = outlookApp.ActiveExplorer();
                if (activeExplorer == null)
                    return null;

                Outlook.Selection selection = activeExplorer.Selection;
                if (selection.Count == 0)
                    return null;

                Outlook.MailItem email = selection[1] as Outlook.MailItem;
                if (email == null)
                    return null;

                // Subject pattern: "Something - TrackingID1234567890123456"
                string pattern = @"TrackingID(\d+)";
                Match match = Regex.Match(email.Subject, pattern);

                if (match.Success)
                    return match.Groups[1].Value;

                return null;
            }
            catch
            {
                return null;
            }
        }

        // Create folder and move all emails with this tracking id
        public bool CreateFolderAndMoveEmails(string trackingId)
        {
            try
            {
                Outlook.Folder inboxFolder =
                    outlookNamespace.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderInbox) as Outlook.Folder;

                Outlook.Folder casesFolder = GetOrCreateFolder(inboxFolder, "Cases");
                Outlook.Folder activeFolder = GetOrCreateFolder(casesFolder, "Active");
                Outlook.Folder trackingFolder = GetOrCreateFolder(activeFolder, trackingId);

                MoveEmailsWithTrackingId(inboxFolder, trackingId, trackingFolder);

                Outlook.Folder sentFolder =
                    outlookNamespace.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderSentMail) as Outlook.Folder;
                if (sentFolder != null)
                    MoveEmailsWithTrackingId(sentFolder, trackingId, trackingFolder);

                return true;
            }
            catch
            {
                return false;
            }
        }

        // Remove rule: move folder from Active to Closed
        public bool RemoveRuleAndMoveToClosed(string trackingId)
        {
            try
            {
                Outlook.Folder inboxFolder =
                    outlookNamespace.GetDefaultFolder(Outlook.OlDefaultFolders.olFolderInbox) as Outlook.Folder;

                Outlook.Folder casesFolder = GetFolder(inboxFolder, "Cases");
                if (casesFolder == null) return false;

                Outlook.Folder activeFolder = GetFolder(casesFolder, "Active");
                if (activeFolder == null) return false;

                Outlook.Folder trackingFolder = GetFolder(activeFolder, trackingId);
                if (trackingFolder == null) return false;

                Outlook.Folder closedFolder = GetOrCreateFolder(casesFolder, "Closed");
                MoveAllItemsFromFolder(trackingFolder, closedFolder);

                try
                {
                    activeFolder.Folders.Remove(trackingId);
                }
                catch { }

                return true;
            }
            catch
            {
                return false;
            }
        }

        private Outlook.Folder GetOrCreateFolder(Outlook.Folder parent, string name)
        {
            foreach (Outlook.Folder folder in parent.Folders)
            {
                if (folder.Name == name)
                    return folder;
            }

            return parent.Folders.Add(name) as Outlook.Folder;
        }

        private Outlook.Folder? GetFolder(Outlook.Folder parent, string name)
        {
            foreach (Outlook.Folder folder in parent.Folders)
            {
                if (folder.Name == name)
                    return folder;
            }
            return null;
        }

        private void MoveEmailsWithTrackingId(Outlook.Folder source, string trackingId, Outlook.Folder dest)
        {
            var toMove = new List<Outlook.MailItem>();

            foreach (object item in source.Items)
            {
                Outlook.MailItem mail = item as Outlook.MailItem;
                if (mail != null && mail.Subject.Contains($"TrackingID{trackingId}"))
                    toMove.Add(mail);
            }

            foreach (var mail in toMove)
                mail.Move(dest);
        }

        private void MoveAllItemsFromFolder(Outlook.Folder source, Outlook.Folder dest)
        {
            var toMove = new List<Outlook.MailItem>();

            foreach (object item in source.Items)
            {
                Outlook.MailItem mail = item as Outlook.MailItem;
                if (mail != null)
                    toMove.Add(mail);
            }

            foreach (var mail in toMove)
                mail.Move(dest);
        }
    }
}