@page "/meeting-schedule"
@attribute [Authorize]
@using System.Text
@using Core.Calculation
@using Microsoft.EntityFrameworkCore
@using WebApp.Components.Shared.Components
@using Core.Utility
@inject IConfiguration Configuration
@inject AppDbContext Context
@inject ClipboardService ClipboardService
@inject LocalStorageService LocalStorage

<PageHeader Title="@($"{Configuration["ChapterSettings:Shortname"]} TSA Schedule {Configuration["ChapterSettings:CompetitionYear"]}")" />

<MudPaper Elevation="2" Class="pa-3 pa-md-6 mt-4">
    <MudGrid>
        <MudItem xs="12" sm="8" lg="9">
            <MudText Typo="Typo.h4">Time Slots</MudText>
            <MudPaper Class="pa-2 ma-2" Elevation="3">
                <MudGrid>
                    <MudItem xs="6" sm="3" lg="2">
                        <MudNumericField Value="_parameters.TimeSlots"
                                         ValueChanged="async (int val) => await OnTimeSlotCountChanged(val)"
                                         Label="Time Slots" Min="1" Max="4">
                        </MudNumericField>
                    </MudItem>
                    <MudFlexBreak/>
                    <MudItem xs="12" sm="6" lg="4">
                        <MudTooltip Text="Schedule teams with Level of Effort >= 3" Inline="false">
                            <MudButton Variant="Variant.Outlined" OnClick="AddHighLevelOfEffort" FullWidth="true">Add High Effort</MudButton>
                        </MudTooltip>
                    </MudItem>
                    <MudItem xs="12" sm="6" lg="4">
                        <MudButton Variant="Variant.Outlined" OnClick="AddRegionals" FullWidth="true">Add Regionals</MudButton>
                    </MudItem>
                    <MudItem xs="12" sm="6" lg="4">
                        <MudButton Variant="Variant.Outlined" OnClick="RemoveIndividual" FullWidth="true">Remove Individual</MudButton>
                    </MudItem>
                    <MudItem xs="12" sm="6" lg="4">
                        <MudButton Variant="Variant.Outlined" OnClick="RemoveLowLevelOfEffort" FullWidth="true">Remove Low Effort</MudButton>
                    </MudItem>
                    <MudItem xs="12" sm="6" lg="4">
                        <MudButton Variant="Variant.Outlined" OnClick="Invert" FullWidth="true">Invert</MudButton>
                    </MudItem>
                    <MudItem xs="12" sm="6" lg="4">
                        <MudButton Variant="Variant.Outlined" Color="Color.Warning" OnClick="Reset" FullWidth="true">Reset</MudButton>
                    </MudItem>
                    <MudItem xs="12">
                        <MudButton Variant="Variant.Filled" Class="ma-3" OnClick="Solve" Color="Color.Primary" Disabled="@_isSolving">Solve</MudButton>
                        <MudTooltip Text="Copy to Clipboard">
                            <MudIconButton OnClick="CopyToClipboard" Icon="@Icons.Material.Filled.ContentCopy"></MudIconButton>
                        </MudTooltip>
                    </MudItem>

                </MudGrid>
            </MudPaper>

            <MudTable T="TeamScheduleTimeSlot" ServerData="SolveSchedule" @ref="_solutionData">
                <HeaderContent>
                </HeaderContent>
                <RowTemplate>
                    <MudTd>
                        <MudGrid>
                            <MudItem xs="12" lg="6">
                                <ScheduledTeamsList TimeSlotName="@context.Name"
                                                   Teams="@context.Teams"
                                                   ScheduledTeams="@_scheduledTeams"
                                                   AbsentStudents="@_absentStudents"
                                                   StudentHasOverlaps="@context.StudentHasOverlaps"
                                                   OnToggleTeam="@ToggleRequiredTeam" />
                            </MudItem>
                            <MudItem xs="12" lg="6">
                                <UnscheduledStudentsList UnscheduledStudents="@context.UnscheduledStudents"
                                                        AbsentStudents="@_absentStudents"
                                                        ScheduledTeams="@_scheduledTeams"
                                                        PossibleAdditions="@_possibleAdditions"
                                                        UnassignedTeams="@_solution.StudentUnassignedTeams"
                                                        OnToggleTeam="@ToggleRequiredTeam" />
                            </MudItem>
                        </MudGrid>
                    </MudTd>
                </RowTemplate>
            </MudTable>
        </MudItem>
        <MudItem xs="12" sm="4" lg="3">
            <MudStack>
                <StudentTextBoxSelector Students="@_students"
                                        SelectedStudents="_absentStudents"
                                        SelectedStudentsChanged="OnAbsentStudentsChanged"
                                        Title="Absent Students"
                                        Label="Search for absent students"
                                        ShowFullName="true"/>
                <MudDivider Class="my-4"/>
                <TeamMeetingToggleSelector Teams="@_teams"
                                          SelectedTeams="_scheduledTeams"
                                          SelectedTeamsChanged="OnScheduledTeamsChanged"
                                          ExtendedTeams="_extendedTeams"
                                          ExtendedTeamsChanged="OnExtendedTeamsChanged"
                                          Title="Scheduled Teams"
                                          ShowEventAttributes="false" />
            </MudStack>
        </MudItem>

    </MudGrid>
</MudPaper>

@code {
    private Team[] _teams = null!;
    private Student[] _students = null!;
    MudTable<TeamScheduleTimeSlot> _solutionData = null!;
    private TeamSchedulerSolution _solution = null!;
    private TeamSchedulerOptions _parameters = null!;
    bool _isSolving;
    private IEnumerable<Team> _scheduledTeams = [];
    private IEnumerable<Student> _absentStudents = [];
    private IEnumerable<Team> _possibleAdditions = [];
    private IEnumerable<Team> _extendedTeams = [];

    private async Task OnScheduledTeamsChanged(IEnumerable<Team> teams)
    {
        _scheduledTeams = teams;
        await SaveScheduledTeams();
    }

    private async Task OnAbsentStudentsChanged(IEnumerable<Student> students)
    {
        _absentStudents = students;
        await SaveAbsentStudents();
    }

    private async Task OnTimeSlotCountChanged(int timeSlots)
    {
        _parameters.TimeSlots = timeSlots;
        await SaveTimeSlotCount();
    }

    private async Task OnExtendedTeamsChanged(IEnumerable<Team> teams)
    {
        _extendedTeams = teams;
        await SaveExtendedTeams();
    }

    private async void AddRegionals()
    {
        _scheduledTeams
            = _teams.Where(e => e.Event.RegionalEvent).Concat(_scheduledTeams).Distinct();
        await SaveScheduledTeams();
    }

    private async void AddHighLevelOfEffort()
    {
        _scheduledTeams
            = _teams.Where(e => e.Event.LevelOfEffort >= 3).Concat(_scheduledTeams).Distinct();
        await SaveScheduledTeams();
    }

    private async void RemoveIndividual()
    {
        _scheduledTeams
            = _scheduledTeams.Where(t => t.Event.EventFormat != EventFormat.Individual);
        await SaveScheduledTeams();
    }

    private async void RemoveLowLevelOfEffort()
    {
        _scheduledTeams
            = _scheduledTeams.Where(t => t.Event.LevelOfEffort > 1);
        await SaveScheduledTeams();
    }

    private async void Invert()
    {
        var rt = _scheduledTeams.ToArray();
        _scheduledTeams
            = _teams.Where(t => !rt.Contains(t));
        await SaveScheduledTeams();
    }

    private async void Reset()
    {
        _scheduledTeams = [];
        await SaveScheduledTeams();
    }

    private async void ToggleRequiredTeam(Team unassignedTeam)
    {
        var scheduledTeamIds = _scheduledTeams.Select(t => t.Id).ToHashSet();
        if (scheduledTeamIds.Contains(unassignedTeam.Id))
            _scheduledTeams = _scheduledTeams.Where(t => t.Id != unassignedTeam.Id);
        else
        {
            _scheduledTeams = _scheduledTeams.Concat([unassignedTeam]);
        }
        await SaveScheduledTeams();
    }

    protected override async Task OnInitializedAsync()
    {
        _parameters =
            new TeamSchedulerOptions(
                2,
                mustIncludeEvents:
                [
                    // "Medical Technology", "Electrical Applications"  , "RegionalTeam",
                    // ,"Dragster", "Flight"
                ],
                extended:
                [
                    // "Invention", "Construction Challenge",  "Mechanical", "Mass", "Micro"
                    //"STEM"
                    //"Community", "Vlogging"// "Microcontroller"
                ],
                omittedEvents:
                [
                    // "Vlogging", "Junior", "Community Service Video", "Digital Photography",
                    // "STEM"

                    //"Leadership",// "Electrical", //"Construction"
                    // "Forensic",
                    //"CAD"
                    //"I&I Team 1", "I&I Team 2"//, "Website Design",
                ],
                absentStudents:
                [
                ]
            );

        _teams
            = await Context.Teams
                .AsNoTracking()
                .Include(e => e.Event)
                .Include(e => e.Students)
                .OrderBy(e => e.Event.Name)
                .ThenBy(e => e.Identifier)
                .ToArrayAsync();

        _students =
            await Context.Students
                .AsNoTracking()
                .Include(e => e.Teams)
                    .ThenInclude(t => t.Event)
                .Include(e => e.Teams)
                    .ThenInclude(t => t.Captain)
                .Include(e => e.EventRankings)
                    .ThenInclude(e => e.EventDefinition)
                .OrderBy(e => e.FirstName).ToArrayAsync();

        // Load saved selections from localStorage
        await LoadScheduledTeams();
        await LoadAbsentStudents();
        await LoadTimeSlotCount();
        await LoadExtendedTeams();
    }

    private async Task SaveScheduledTeams()
    {
        var teamIds = _scheduledTeams.Select(t => t.Id).ToArray();
        await LocalStorage.SetIntArrayAsync("MeetingSchedule_ScheduledTeams", teamIds);
    }

    private async Task LoadScheduledTeams()
    {
        var teamIds = await LocalStorage.GetIntArrayAsync("MeetingSchedule_ScheduledTeams");
        if (teamIds.Length > 0)
        {
            _scheduledTeams = _teams.Where(t => teamIds.Contains(t.Id)).ToArray();
        }
    }

    private async Task SaveAbsentStudents()
    {
        var studentIds = _absentStudents.Select(s => s.Id).ToArray();
        await LocalStorage.SetIntArrayAsync("MeetingSchedule_AbsentStudents", studentIds);
    }

    private async Task LoadAbsentStudents()
    {
        var studentIds = await LocalStorage.GetIntArrayAsync("MeetingSchedule_AbsentStudents");
        if (studentIds.Length > 0)
        {
            _absentStudents = _students.Where(s => studentIds.Contains(s.Id)).ToArray();
        }
    }

    private async Task SaveTimeSlotCount()
    {
        await LocalStorage.SetIntAsync("MeetingSchedule_TimeSlotCount", _parameters.TimeSlots);
    }

    private async Task LoadTimeSlotCount()
    {
        var timeSlots = await LocalStorage.GetIntAsync("MeetingSchedule_TimeSlotCount", defaultValue: 2);
        if (timeSlots > 0)
        {
            _parameters.TimeSlots = timeSlots;
        }
    }

    private async Task SaveExtendedTeams()
    {
        var teamIds = _extendedTeams.Select(t => t.Id).ToArray();
        await LocalStorage.SetIntArrayAsync("MeetingSchedule_ExtendedTeams", teamIds);
    }

    private async Task LoadExtendedTeams()
    {
        var teamIds = await LocalStorage.GetIntArrayAsync("MeetingSchedule_ExtendedTeams");
        if (teamIds.Length > 0)
        {
            _extendedTeams = _teams.Where(t => teamIds.Contains(t.Id)).ToArray();
        }
    }

    private async Task<TableData<TeamScheduleTimeSlot>> SolveSchedule(TableState arg1, CancellationToken arg2)
    {
        _isSolving = true;

        // Check if there are any teams to schedule
        if (!_scheduledTeams.Any())
        {
            _isSolving = false;
            _solution = new TeamSchedulerSolution([], [], "No teams selected");
            return new TableData<TeamScheduleTimeSlot> { Items = [] };
        }

        // Filter out absent students
        var availableStudents = _students.Where(s => !_absentStudents.Contains(s)).ToArray();

        // Check if there are any available students
        if (availableStudents.Length == 0)
        {
            _isSolving = false;
            _solution = new TeamSchedulerSolution([], [], "No available students");
            return new TableData<TeamScheduleTimeSlot> { Items = [] };
        }

        // Update parameters with absent student names
        _parameters.AbsentStudents = _absentStudents.Select(s => s.FirstNameLastName).ToArray();
        
        // Update parameters with extended team event names
        _parameters.ExtendedTeams = _extendedTeams
            .Where(t => t.Event != null)
            .Select(t => t.Event!.Name)
            .ToArray();

        var teamScheduler = new TeamScheduler(_scheduledTeams, _parameters.TimeSlots, availableStudents);
        _solution = teamScheduler.Solve();

        // Post-process: extend teams to next consecutive time slot
        if (_extendedTeams.Any())
        {
            ExtendTeamsInSolution(_solution, _extendedTeams, availableStudents);
        }

        // Try recommendation strategies in priority order
        var scheduler = new UnassignedStudentScheduler(_teams, _solution.TimeSlots);
        UnassignedScheduleStrategy[] strategies =
        [
            UnassignedScheduleStrategy.LevelOfEffort,
            UnassignedScheduleStrategy.BiggestGroup,
            UnassignedScheduleStrategy.AnyNotMeetingAlready,
            UnassignedScheduleStrategy.IndividualEvents
        ];

        _possibleAdditions = strategies
            .Select(strategy => scheduler.ScheduleStrategy(strategy))
            .FirstOrDefault(result => result.Any()) ?? [];

        await InvokeAsync(StateHasChanged); // let the UI know that the solution has been found

        _isSolving = false;
        return new TableData<TeamScheduleTimeSlot> { Items = _solution.TimeSlots };
    }

    private void Solve()
    {
        _solutionData.ReloadServerData();
    }

    // TODO: Move team extension logic into Core.Calculation.TeamScheduler to handle extended teams
    // as part of the constraint programming model rather than post-processing
    private void ExtendTeamsInSolution(TeamSchedulerSolution solution, IEnumerable<Team> extendedTeams, Student[] allStudents)
    {
        if (solution.TimeSlots == null || !solution.TimeSlots.Any())
            return;

        var extendedTeamsList = extendedTeams.ToList();
        if (!extendedTeamsList.Any())
            return;

        var extendedTeamIds = extendedTeamsList.Select(t => t.Id).ToHashSet();

        // Find which time slot each extended team is in and extend both forward and backward
        for (int slotIndex = 0; slotIndex < solution.TimeSlots.Length; slotIndex++)
        {
            var currentSlot = solution.TimeSlots[slotIndex];
            var teamsToExtend = currentSlot.Teams.Where(t => extendedTeamIds.Contains(t.Id)).ToList();

            if (!teamsToExtend.Any())
                continue;

            // Extend forward: add to next time slot (if exists)
            if (slotIndex + 1 < solution.TimeSlots.Length)
            {
                var nextSlot = solution.TimeSlots[slotIndex + 1];
                var nextSlotTeamsList = nextSlot.Teams.ToList();
                var nextSlotTeamIds = nextSlotTeamsList.Select(t => t.Id).ToHashSet();
                
                foreach (var team in teamsToExtend)
                {
                    if (!nextSlotTeamIds.Contains(team.Id))
                    {
                        nextSlotTeamsList.Add(team);
                        nextSlotTeamIds.Add(team.Id);
                    }
                }

                nextSlot.Teams = nextSlotTeamsList.ToArray();
                nextSlot.StudentOverlaps = TeamSchedulerSolution.GetStudentTeamOverlaps(nextSlot.Teams);
                nextSlot.UnscheduledStudents = TeamSchedulerSolution.GetStudentsNotInTimSlot(nextSlot.Teams, allStudents);
            }

            // Extend backward: add to previous time slot (if exists)
            if (slotIndex > 0)
            {
                var previousSlot = solution.TimeSlots[slotIndex - 1];
                var previousSlotTeamsList = previousSlot.Teams.ToList();
                var previousSlotTeamIds = previousSlotTeamsList.Select(t => t.Id).ToHashSet();
                
                foreach (var team in teamsToExtend)
                {
                    if (!previousSlotTeamIds.Contains(team.Id))
                    {
                        previousSlotTeamsList.Add(team);
                        previousSlotTeamIds.Add(team.Id);
                    }
                }

                previousSlot.Teams = previousSlotTeamsList.ToArray();
                previousSlot.StudentOverlaps = TeamSchedulerSolution.GetStudentTeamOverlaps(previousSlot.Teams);
                previousSlot.UnscheduledStudents = TeamSchedulerSolution.GetStudentsNotInTimSlot(previousSlot.Teams, allStudents);
            }
        }
    }

    async Task CopyToClipboard()
    {
        var sb = new StringBuilder();
        foreach (var timeslot in _solution.TimeSlots)
        {
            AppendScheduledTeams(sb, timeslot);
            AppendUnscheduledStudents(sb, timeslot);
            sb.Append(Environment.NewLine);
        }

        try
        {
            await ClipboardService.WriteTextAsync(sb.ToString());
        }
        catch
        {
            Console.WriteLine("Cannot write text to clipboard");
        }
    }

    private void AppendScheduledTeams(StringBuilder sb, TeamScheduleTimeSlot timeslot)
    {
        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);
                sb.Append($"{teamName} - {studentsList}");
            }
            sb.Append(Environment.NewLine);
        }
    }

    private string FormatStudentList(Team team, TeamScheduleTimeSlot timeslot)
    {
        return TeamStudentNameFormatter.FormatStudentList(
            team,
            new TeamStudentNameFormatter.FormatOptions
            {
                Ordering = TeamStudentNameFormatter.OrderingStyle.CaptainFirst,
                MarkOverlaps = true,
                HasOverlaps = timeslot.StudentHasOverlaps,
                MarkAbsent = true,
                AbsentStudents = _absentStudents.ToList()
            });
    }

    private string FormatStudentName(Student student, TeamScheduleTimeSlot timeslot)
    {
        // Find the team this student belongs to for formatting context
        var team = _teams.FirstOrDefault(t => t.Students.Contains(student));
        if (team == null)
        {
            // No team context, use StudentNameFormatter directly
            return StudentNameFormatter.FormatStudentName(
                student,
                new StudentNameFormatter.FormatOptions
                {
                    HasOverlap = timeslot.StudentHasOverlaps(student),
                    IsAbsent = _absentStudents.Contains(student)
                });
        }

        return TeamStudentNameFormatter.FormatStudentName(
            student,
            team,
            new TeamStudentNameFormatter.FormatOptions
            {
                MarkOverlaps = true,
                HasOverlaps = timeslot.StudentHasOverlaps,
                MarkAbsent = true,
                AbsentStudents = _absentStudents.ToList()
            });
    }

    private void AppendUnscheduledStudents(StringBuilder sb, TeamScheduleTimeSlot timeslot)
    {
        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);
        }
    }

}