using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using Outlook = Microsoft.Office.Interop.Outlook;

namespace BulkArchiveMailer.AddIn
{
    /// <summary>Read-only snapshot of one Outlook.Account, taken once while the COM object was still alive - safe to hold onto and display after the Account RCW itself has been released.</summary>
    public sealed class OutlookAccountInfo
    {
        public string DisplayName { get; set; } = "";
        public string SmtpAddress { get; set; } = "";
    }

    /// <summary>
    /// Enumerates Outlook.Application.Session.Accounts for UI purposes
    /// (the "Отправлять от:" picker in SettingsForm) without leaking any
    /// COM references - mirrors the release-what-you-touch convention used
    /// in MailSender/SignatureReader. Never throws: on any failure it
    /// returns an empty list so a picker can simply fall back to "default
    /// account only" instead of crashing the Settings window.
    /// </summary>
    public static class OutlookAccounts
    {
        public static List<OutlookAccountInfo> ListAccounts(Outlook.Application application)
        {
            var result = new List<OutlookAccountInfo>();
            if (application == null)
            {
                return result;
            }

            Outlook.Accounts accounts = null;
            try
            {
                accounts = application.Session.Accounts;
                foreach (Outlook.Account account in accounts)
                {
                    try
                    {
                        result.Add(new OutlookAccountInfo
                        {
                            DisplayName = account.DisplayName ?? "",
                            SmtpAddress = account.SmtpAddress ?? "",
                        });
                    }
                    catch
                    {
                        // Skip an individual account we couldn't read
                        // rather than losing the rest of the list.
                    }
                    finally
                    {
                        Marshal.ReleaseComObject(account);
                    }
                }
            }
            catch
            {
                return new List<OutlookAccountInfo>();
            }
            finally
            {
                if (accounts != null)
                {
                    Marshal.ReleaseComObject(accounts);
                }

                // application.Session (NameSpace) is a long-lived object
                // owned by Outlook itself - never released here, same as
                // in MailSender.
            }

            return result;
        }
    }
}