@page "/students/teams"
@attribute [Authorize]
@using Microsoft.EntityFrameworkCore
@using WebApp.Models
@using WebApp.Components.Shared.Components
@using Core.Validation
@inject AppDbContext Context
@inject WebApp.LocalStorageService LocalStorage
@inject ValidationService ValidationService

<PageHeader Title="Registration" Icon="@AppIcons.Registration">
    <ActionButtons>
        <MudButton StartIcon="@Icons.Material.Filled.FilterAlt"
                   Variant="@(_showRegionalOnly ? Variant.Filled : Variant.Outlined)"
                   Color="Color.Primary"
                   OnClick="ToggleRegionalFilter">
            @(_showRegionalOnly ? "Showing Regional Only" : "Show Regional Only")
        </MudButton>
    </ActionButtons>
</PageHeader>

<MudPaper Elevation="2" Class="pa-3 pa-md-6">
    <MudText Typo="Typo.body2" Class="mb-2">
        <MudIcon Icon="@AppIcons.Captain" Size="Size.Small" /> = Team Captain
    </MudText>

    <MudText Typo="Typo.body2" Class="mb-3">
        <MudStack Row="true" AlignItems="AlignItems.Center" Justify="Justify.SpaceBetween" Spacing="1">
        <strong>Show Columns:</strong>
        <MudCheckBox Value="_showGrade" ValueChanged="async (bool val) => await OnColumnToggle(nameof(_showGrade), val, v => _showGrade = v)" Label="Grade" Dense="true" Size="Size.Small"/>
        <MudCheckBox Value="_showRegionalId" ValueChanged="async (bool val) => await OnColumnToggle(nameof(_showRegionalId), val, v => _showRegionalId = v)" Label="Regional ID" Dense="true" Size="Size.Small"/>
        <MudCheckBox Value="_showStateId" ValueChanged="async (bool val) => await OnColumnToggle(nameof(_showStateId), val, v => _showStateId = v)" Label="State ID" Dense="true" Size="Size.Small"/>
        <MudCheckBox Value="_showNationalId" ValueChanged="async (bool val) => await OnColumnToggle(nameof(_showNationalId), val, v => _showNationalId = v)" Label="National ID" Dense="true" Size="Size.Small"/>
        </MudStack>
    </MudText>

    <MudDataGrid T="StudentTeamInfo" ServerData="ServerReload" @ref="_dataGrid" @key="_gridKey" Filterable="true" RowsPerPage="35" Dense="true" Striped="true" Hover="true" Loading="@_isLoading" LoadingProgressColor="Color.Primary">
    <Columns>
        <PropertyColumn Property="@(e => e.Student.LastName)" Title="Student" Sortable="true">
            
            <CellTemplate>
                <MudStack Row="true" AlignItems="AlignItems.Center" Justify="Justify.SpaceBetween" Spacing="1">
                @context.Item.Student.LastNameFirstName
                <MudTooltip Text="Edit">
                    <MudIconButton Icon="@Icons.Material.Filled.Edit"
                                   Size="Size.Small"
                                   Href="@($"/students/edit?id={context.Item.Student.Id}&returnUrl=/students/teams")"
                                   Style="margin-left: 4px;"/>
                </MudTooltip>
                    </MudStack>
            </CellTemplate>
            
        </PropertyColumn>
        <TemplateColumn Title="Warnings" Sortable="false">
            <CellTemplate>
                <ValidationWarnings Warnings="@GetRegistrationWarnings(context.Item.Student)" />
            </CellTemplate>
        </TemplateColumn>
        @if (_showGrade)
        {
            <PropertyColumn Property="@(e => e.Student.Grade)" Title="Grade" Sortable="true" />
        }
        @if (_showRegionalId)
        {
            <PropertyColumn Property="@(e => e.Student.RegionalId)" Title="Regional ID" Sortable="true" />
        }
        @if (_showStateId)
        {
            <PropertyColumn Property="@(e => e.Student.StateId)" Title="State ID" Sortable="true" />
        }
        @if (_showNationalId)
        {
            <PropertyColumn Property="@(e => e.Student.NationalId)" Title="National ID" Sortable="true" />
        }
        <TemplateColumn Title="Events">
            <CellTemplate>
                @{
                    var teamsToDisplay = _showRegionalOnly
                        ? context.Item.Teams.Where(t => t?.Event is { RegionalEvent: true }).OrderBy(t => t.Event.Name)
                        : context.Item.Teams.Where(t => t?.Event != null).OrderBy(t => t.Event.Name);
                }
                <div class="d-flex flex-wrap" style="gap: 0.25rem;">
                    @foreach (var team in teamsToDisplay)
                    {
                        var isCaptain = team.Captain != null && team.Captain.Equals(context.Item.Student);
                        var teamMembers = string.Join(", ", team.Students.Select(s => s.FirstName));

                        <MudTooltip Text="@teamMembers">
                            <MudChip Size="Size.Small"
                                     Color="Color.Default"
                                     Href="@($"/teams/edit?id={team.Id}")"
                                     Style="cursor: pointer;">
                                @team
                                @if (isCaptain && team.Event.EventFormat != EventFormat.Individual)
                                {
                                    <MudIcon Icon="@AppIcons.Captain" Size="Size.Small" Style="margin-left: 4px;" />
                                }
                            </MudChip>
                        </MudTooltip>
                    }
                </div>
            </CellTemplate>
        </TemplateColumn>
    </Columns>
        <PagerContent>
            <MudDataGridPager T="StudentTeamInfo" PageSizeOptions="new int[] { 10, 25, 35, 50, 100 }"></MudDataGridPager>
        </PagerContent>
    </MudDataGrid>
</MudPaper>

@code {
    MudDataGrid<StudentTeamInfo> _dataGrid = null!;
    private bool _isLoading = true;
    private bool _showRegionalOnly;
    private bool _showGrade;
    private bool _showRegionalId;
    private bool _showStateId;
    private bool _showNationalId;
    private bool _preferencesLoaded = false;

    // TODO: Remove this workaround once MudBlazor fixes dynamic column ordering
    // https://dev.to/the_real_slim_janey/get-in-line-customizing-column-order-in-mudblazor-3ail
    // To remove:
    // 1. Delete this _gridKey field
    // 2. Remove "_gridKey++;" from all checkbox ValueChanged handlers (lines 26-29)
    // 3. Remove "@key="_gridKey"" attribute from MudDataGrid (line 32)
    private int _gridKey = 0;

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (!_preferencesLoaded)
        {
            await LoadColumnPreferences();
            _preferencesLoaded = true;
            _gridKey++; // Force grid recreation with loaded preferences
            StateHasChanged();
        }
    }

    protected override void OnInitialized()
    {
        // Reset flag when component is initialized/re-initialized
        _preferencesLoaded = false;
    }

    private async Task LoadColumnPreferences()
    {
        _showGrade = await LocalStorage.GetBoolAsync("Registration_ShowGrade", false);
        _showRegionalId = await LocalStorage.GetBoolAsync("Registration_ShowRegionalId", false);
        _showStateId = await LocalStorage.GetBoolAsync("Registration_ShowStateId", false);
        _showNationalId = await LocalStorage.GetBoolAsync("Registration_ShowNationalId", false);
    }

    private async Task OnColumnToggle(string columnName, bool value, Action<bool> setter)
    {
        setter(value);
        _gridKey++;
        await LocalStorage.SetBoolAsync($"Registration_{columnName}", value);
        StateHasChanged();
    }

    private async Task ToggleRegionalFilter()
    {
        _showRegionalOnly = !_showRegionalOnly;
        StateHasChanged();
        await Task.Delay(10);
        await _dataGrid.ReloadServerData();
    }

    private async Task<GridData<StudentTeamInfo>> ServerReload(GridState<StudentTeamInfo> state)
    {
        _isLoading = true;
        try
        {
            // Load all students with their teams
            var students = await Context.Students
                .Include(s => s.Teams)
                    .ThenInclude(t => t.Event)
                .Include(s => s.Teams)
                    .ThenInclude(t => t.Captain)
                .ToListAsync();

            // Filter to only students with teams
            var studentTeams = students
                .Where(s => s.Teams.Any(t => t?.Event != null && (!_showRegionalOnly || t.Event.RegionalEvent)))
                .Select(s => new StudentTeamInfo
                {
                    Student = s,
                    Teams = s.Teams?.Where(t => t?.Event != null).ToList() ?? []
                })
                .ToList();

            // Apply sorting
            var sortedData = ApplySorting(studentTeams, state.SortDefinitions);

            var totalItems = sortedData.Count();
            var pagedData = sortedData.Skip(state.Page * state.PageSize).Take(state.PageSize).ToArray();

            return new GridData<StudentTeamInfo>
            {
                TotalItems = totalItems,
                Items = pagedData
            };
        }
        finally
        {
            _isLoading = false;
        }
    }

    /// <summary>
    /// Dictionary mapping column property names to their corresponding sort expressions.
    /// Used to provide type-safe sorting for data grid columns.
    /// </summary>
    /// <remarks>
    /// Each entry maps a property path (e.g., "Student.LastName") to a function that
    /// extracts the comparable value from a StudentTeamInfo instance.
    /// Nullable strings are coalesced to empty strings to ensure consistent sorting behavior.
    /// </remarks>
    private static readonly Dictionary<string, Func<StudentTeamInfo, IComparable>> SortExpressions = new()
    {
        { "Student.LastName", s => s.Student.LastName },
        { "Student.Grade", s => s.Student.Grade },
        { "Student.RegionalId", s => s.Student.RegionalId ?? string.Empty },
        { "Student.StateId", s => s.Student.StateId ?? string.Empty },
        { "Student.NationalId", s => s.Student.NationalId ?? string.Empty }
    };

    /// <summary>
    /// Applies sorting to the student team data based on the provided sort definitions.
    /// </summary>
    /// <param name="data">The list of StudentTeamInfo records to sort.</param>
    /// <param name="sortDefinitions">Collection of sort definitions from the MudDataGrid state.</param>
    /// <returns>
    /// An IEnumerable of StudentTeamInfo sorted according to the first sort definition,
    /// or sorted by LastName if no valid sort definition is provided.
    /// </returns>
    /// <remarks>
    /// If no sort definitions are provided, or if the requested property is not found in SortExpressions,
    /// the data will default to sorting by Student.LastName in ascending order.
    /// Only the first sort definition is applied (multi-column sorting is not supported).
    /// </remarks>
    private IEnumerable<StudentTeamInfo> ApplySorting(
        List<StudentTeamInfo> data,
        ICollection<SortDefinition<StudentTeamInfo>> sortDefinitions)
    {
        if (!sortDefinitions.Any())
        {
            return data.OrderBy(s => s.Student.LastName);
        }

        var sortDef = sortDefinitions.First();
        var propertyName = sortDef.SortBy;

        if (!SortExpressions.TryGetValue(propertyName, out var sortExpression))
        {
            return data.OrderBy(s => s.Student.LastName);
        }

        return sortDef.Descending
            ? data.OrderByDescending(sortExpression)
            : data.OrderBy(sortExpression);
    }

    private List<ValidationWarning> GetRegistrationWarnings(Student student)
    {
        // Create StudentEventStatistics from the student's teams
        var stats = new StudentEventStatistics
        {
            Student = student,
            Events = student.Teams?.Where(t => t?.Event != null)
                                  .Select(t => t.Event)
                                  .ToList() ?? new List<EventDefinition>()
        };

        return ValidationService.ValidateStudentStatistics(stats, ValidationContext.StudentRegistration);
    }

    public class StudentTeamInfo
    {
        public required Student Student { get; init; }
        public List<Team> Teams { get; init; } = [];
    }
}