using System.Text;
using Core.Calculation;
using Core.Entities;
using Core.Utility;

namespace WebApp.Services;

/// <summary>
/// Service for formatting meeting schedule data for clipboard operations.
/// </summary>
public class MeetingScheduleClipboardService : IMeetingScheduleClipboardService
{
    public string FormatScheduleForClipboard(
        TeamSchedulerSolution solution,
        Team[] allTeams,
        IEnumerable<Student> absentStudents,
        Dictionary<(int teamId, int timeSlotIndex, int studentId), bool> excludedStudents,
        Func<string, int> getTimeSlotIndex)
    {
        var sb = new StringBuilder();
        foreach (var timeslot in solution.TimeSlots)
        {
            AppendScheduledTeams(sb, timeslot, allTeams, absentStudents, excludedStudents, getTimeSlotIndex);
            AppendUnscheduledStudents(sb, timeslot, solution, absentStudents);
            sb.Append(Environment.NewLine);
        }
        return sb.ToString();
    }

    private void AppendScheduledTeams(
        StringBuilder sb,
        TeamScheduleTimeSlot timeslot,
        Team[] allTeams,
        IEnumerable<Student> absentStudents,
        Dictionary<(int teamId, int timeSlotIndex, int studentId), bool> excludedStudents,
        Func<string, int> getTimeSlotIndex)
    {
        var timeSlotIndex = getTimeSlotIndex(timeslot.Name);
        foreach (var scheduledTeam in timeslot.Teams.OrderBy(e => e.ToString()))
        {
            var teamName = scheduledTeam.ToString();

            if (scheduledTeam.Event.EventFormat is EventFormat.Individual)
            {
                sb.Append(teamName);
            }
            else
            {
                var studentsList = FormatStudentList(scheduledTeam, timeslot, timeSlotIndex, absentStudents, excludedStudents);
                sb.Append($"{teamName} - {studentsList}");
            }
            sb.Append(Environment.NewLine);
        }
    }

    private string FormatStudentList(
        Team team,
        TeamScheduleTimeSlot timeslot,
        int timeSlotIndex,
        IEnumerable<Student> absentStudents,
        Dictionary<(int teamId, int timeSlotIndex, int studentId), bool> excludedStudents)
    {
        // Filter out excluded students for this team and time slot
        var excludedStudentIds = excludedStudents.Keys
            .Where(k => k.teamId == team.Id && k.timeSlotIndex == timeSlotIndex && excludedStudents[k])
            .Select(k => k.studentId)
            .ToHashSet();

        var includedStudents = team.Students
            .Where(s => !excludedStudentIds.Contains(s.Id))
            .ToList();

        // Create a temporary team with only included students for formatting
        var teamForFormatting = new Team
        {
            Id = team.Id,
            Event = team.Event,
            Students = includedStudents,
            Captain = team.Captain,
            Identifier = team.Identifier
        };

        return TeamStudentNameFormatter.FormatStudentList(
            teamForFormatting,
            new TeamStudentNameFormatter.FormatOptions
            {
                Ordering = TeamStudentNameFormatter.OrderingStyle.CaptainFirst,
                MarkOverlaps = true,
                HasOverlaps = timeslot.StudentHasOverlaps,
                MarkAbsent = true,
                AbsentStudents = absentStudents.ToList()
            });
    }

    private void AppendUnscheduledStudents(
        StringBuilder sb,
        TeamScheduleTimeSlot timeslot,
        TeamSchedulerSolution solution,
        IEnumerable<Student> absentStudents)
    {
        if (!timeslot.UnscheduledStudents.Any())
            return;

        sb.Append("--Unscheduled");
        sb.Append(Environment.NewLine);

        foreach (var student in timeslot.UnscheduledStudents)
        {
            var studentName = StudentNameFormatter.FormatStudentName(
                student,
                new StudentNameFormatter.FormatOptions
                {
                    IsAbsent = absentStudents.Contains(student)
                });

            var unassignedTeams = solution.StudentUnassignedTeams(student);
            var teamsList = string.Join(", ", unassignedTeams.Select(e => e.ToString()));

            sb.Append($"{studentName} - {teamsList}");
            sb.Append(Environment.NewLine);
        }
    }
}