#if WINDOWS
using MeetingAssistant.Calendar;

namespace MeetingAssistant.MeetingNotes;

internal static class OutlookClassicAppointmentMetadata
{
    public static MeetingMetadata CreateMetadata(object appointment, DateTime end)
    {
        var title = ReadSubject(appointment);
        return new MeetingMetadata(
            title,
            ReadAttendees(appointment),
            ExtractAgenda(Convert.ToString(OutlookClassicCom.GetProperty(appointment, "Body")) ?? ""),
            OutlookClassicCom.ToLocalOffset(end));
    }

    public static string ReadSubject(object appointment)
    {
        var subject = Convert.ToString(OutlookClassicCom.GetProperty(appointment, "Subject"))?.Trim();
        return string.IsNullOrWhiteSpace(subject) ? "Teams meeting" : subject;
    }

    public static bool IsTeamsAppointment(object appointment)
    {
        var subject = Convert.ToString(OutlookClassicCom.GetProperty(appointment, "Subject")) ?? "";
        var location = Convert.ToString(OutlookClassicCom.GetProperty(appointment, "Location")) ?? "";
        var body = Convert.ToString(OutlookClassicCom.GetProperty(appointment, "Body")) ?? "";
        return TeamsMeetingMarkerDetector.IsTeamsAppointment(subject, location, body);
    }

    public static string ExtractAgenda(string body)
    {
        if (string.IsNullOrWhiteSpace(body))
        {
            return "";
        }

        var lines = body.Replace("\r\n", "\n", StringComparison.Ordinal).Replace('\r', '\n').Split('\n');
        var agendaLines = new List<string>();
        foreach (var line in lines)
        {
            if (IsTeamsSeparator(line) || IsTeamsJoinLine(line))
            {
                break;
            }

            agendaLines.Add(line);
        }

        return string.Join(Environment.NewLine, agendaLines).Trim();
    }

    public static IReadOnlyList<string> ReadAttendees(object appointment)
    {
        var attendees = new List<string>();
        var organizer = Convert.ToString(OutlookClassicCom.GetProperty(appointment, "Organizer"));
        if (!string.IsNullOrWhiteSpace(organizer))
        {
            attendees.Add(organizer.Trim());
        }

        object? recipients = null;
        try
        {
            recipients = OutlookClassicCom.GetProperty(appointment, "Recipients");
            var count = Convert.ToInt32(OutlookClassicCom.GetProperty(recipients!, "Count"));
            for (var index = 1; index <= count; index++)
            {
                object? recipient = null;
                try
                {
                    recipient = OutlookClassicCom.Invoke(recipients!, "Item", index);
                    var formatted = FormatRecipient(recipient!);
                    if (!string.IsNullOrWhiteSpace(formatted))
                    {
                        attendees.Add(formatted);
                    }
                }
                finally
                {
                    OutlookClassicCom.ReleaseComObject(recipient);
                }
            }
        }
        finally
        {
            OutlookClassicCom.ReleaseComObject(recipients);
        }

        return NormalizeAttendees(attendees);
    }

    public static IReadOnlyList<string> NormalizeAttendees(IEnumerable<string> attendees)
    {
        return attendees
            .Select(NormalizeAttendee)
            .Where(attendee => !string.IsNullOrWhiteSpace(attendee))
            .GroupBy(GetAttendeeDeduplicationKey, StringComparer.OrdinalIgnoreCase)
            .Select(group => group
                .OrderByDescending(attendee => attendee.Contains('<', StringComparison.Ordinal))
                .ThenBy(attendee => attendee.Length)
                .First())
            .ToList();
    }

    private static bool IsTeamsSeparator(string line)
    {
        var trimmed = line.Trim();
        return trimmed.Length >= 8 &&
            trimmed.All(character => character is '_' or '-' or '*' or ' ');
    }

    private static bool IsTeamsJoinLine(string line)
    {
        return TeamsMeetingMarkerDetector.ContainsTeamsMarker(line);
    }

    private static string NormalizeAttendee(string attendee)
    {
        var normalized = attendee.Trim();
        var mailtoPrefix = "mailto:";
        normalized = normalized.Replace(mailtoPrefix, "", StringComparison.OrdinalIgnoreCase);
        while (normalized.Contains("  ", StringComparison.Ordinal))
        {
            normalized = normalized.Replace("  ", " ", StringComparison.Ordinal);
        }

        var emailStart = normalized.IndexOf('<', StringComparison.Ordinal);
        var emailEnd = normalized.LastIndexOf('>');
        if (emailStart > 0 && emailEnd > emailStart)
        {
            var name = normalized[..emailStart].Trim();
            var email = normalized[(emailStart + 1)..emailEnd].Trim();
            if (name.Equals(email, StringComparison.OrdinalIgnoreCase))
            {
                return email;
            }

            return $"{name} <{email}>";
        }

        return normalized;
    }

    private static string GetAttendeeDeduplicationKey(string attendee)
    {
        var emailStart = attendee.IndexOf('<', StringComparison.Ordinal);
        var emailEnd = attendee.LastIndexOf('>');
        if (emailStart > 0 && emailEnd > emailStart)
        {
            return attendee[(emailStart + 1)..emailEnd].Trim();
        }

        return attendee.Trim();
    }

    private static string FormatRecipient(object recipient)
    {
        var name = Convert.ToString(OutlookClassicCom.GetProperty(recipient, "Name"))?.Trim() ?? "";
        var email = Convert.ToString(OutlookClassicCom.GetProperty(recipient, "Address"))?.Trim() ?? "";
        if (string.IsNullOrWhiteSpace(name))
        {
            return email;
        }

        if (string.IsNullOrWhiteSpace(email) ||
            email.Contains('/'))
        {
            return name;
        }

        return $"{name} <{email}>";
    }
}
#endif