@page "/deco-templates/{Id:int}"
@using System.Globalization
@using ErsatzTV.Application.Scheduling
@implements IDisposable
@inject NavigationManager NavigationManager
@inject ILogger<DecoTemplateEditor> Logger
@inject ISnackbar Snackbar
@inject IMediator Mediator

<MudForm Style="max-height: 100%">
    <MudPaper Square="true" Style="display: flex; height: 64px; min-height: 64px; width: 100%; z-index: 100; align-items: center">
        <MudButton Variant="Variant.Filled" Color="Color.Primary" Class="ml-6" OnClick="@(_ => SaveChanges())" StartIcon="@Icons.Material.Filled.Save">
            Save Deco Template
        </MudButton>
    </MudPaper>
    <div class="d-flex flex-column" style="height: 100vh; overflow-x: auto">
        <MudContainer MaxWidth="MaxWidth.ExtraLarge" Class="pt-8">
            <MudText Typo="Typo.h5" Class="mb-2">General</MudText>
            <MudDivider Class="mb-6"/>
            <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                <div class="d-flex">
                    <MudText>Deco Template Group Name</MudText>
                </div>
                <MudTextField @bind-Value="_decoTemplate.GroupName" Disabled="true"/>
            </MudStack>
            <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                <div class="d-flex">
                    <MudText>Deco Template Name</MudText>
                </div>
                <MudTextField @bind-Value="_decoTemplate.Name" For="@(() => _decoTemplate.Name)"/>
            </MudStack>
            <MudText Typo="Typo.h5" Class="mt-10 mb-2">Add Content</MudText>
            <MudDivider Class="mb-6"/>
            <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                <div class="d-flex">
                    <MudText>Deco Group</MudText>
                </div>
                <MudSelect T="DecoGroupViewModel" ValueChanged="@(vm => UpdateDecoGroupItems(vm))">
                    @foreach (DecoGroupViewModel decoGroup in _decoGroups)
                    {
                        <MudSelectItem Value="@decoGroup">@decoGroup.Name</MudSelectItem>
                    }
                </MudSelect>
            </MudStack>
            <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                <div class="d-flex">
                    <MudText>Deco</MudText>
                </div>
                <MudSelect T="DecoViewModel" @bind-value="_selectedDeco">
                    @foreach (DecoViewModel deco in _decos)
                    {
                        <MudSelectItem Value="@deco">@deco.Name</MudSelectItem>
                    }
                </MudSelect>
            </MudStack>
            <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                <div class="d-flex">
                    <MudText>Start Time On Or After</MudText>
                </div>
                <MudSelect T="DateTime" @bind-value="_selectedDecoStart">
                    @foreach (DateTime startTime in _startTimes)
                    {
                        <MudSelectItem Value="@startTime">
                            @startTime.ToString(CultureInfo.CurrentCulture.DateTimeFormat.ShortTimePattern)
                        </MudSelectItem>
                    }
                </MudSelect>
            </MudStack>
            <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                <div class="d-flex">
                    <MudText>Duration</MudText>
                </div>
                <MudTextField T="int"
                              @bind-Value="_durationHours"
                              Adornment="Adornment.End"
                              AdornmentText="hours"/>
            </MudStack>
            <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                <div class="d-flex"></div>
                <MudSelect T="int" @bind-Value="_durationMinutes" Adornment="Adornment.End" AdornmentText="minutes">
                    <MudSelectItem Value="0"/>
                    <MudSelectItem Value="5"/>
                    <MudSelectItem Value="10"/>
                    <MudSelectItem Value="15"/>
                    <MudSelectItem Value="20"/>
                    <MudSelectItem Value="25"/>
                    <MudSelectItem Value="30"/>
                    <MudSelectItem Value="35"/>
                    <MudSelectItem Value="40"/>
                    <MudSelectItem Value="45"/>
                    <MudSelectItem Value="50"/>
                    <MudSelectItem Value="55"/>
                </MudSelect>
            </MudStack>
            <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                <div class="d-flex"></div>
                <MudButton Variant="Variant.Filled" Color="Color.Primary" OnClick="@(_ => AddDecoToDecoTemplate())" Disabled="@(_selectedDeco is null)" StartIcon="@Icons.Material.Filled.Add">
                    Add Deco To Template
                </MudButton>
            </MudStack>
            <MudText Typo="Typo.h5" Class="mt-10 mb-2">Remove Content</MudText>
            <MudDivider Class="mb-6"/>
            <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                <div class="d-flex">
                    <MudText>Deco To Remove</MudText>
                </div>
                <MudSelect T="DecoTemplateItemEditViewModel" @bind-Value="_decoToRemove">
                    <MudSelectItem Value="@((DecoTemplateItemEditViewModel)null)">(none)</MudSelectItem>
                    @foreach (DecoTemplateItemEditViewModel item in _decoTemplate.Items.OrderBy(i => i.Start))
                    {
                        <MudSelectItem Value="@item">@item.Start.ToShortTimeString() - @item.Text</MudSelectItem>
                    }
                </MudSelect>
            </MudStack>
            <MudStack Row="true" Breakpoint="Breakpoint.SmAndDown" Class="form-field-stack gap-md-8 mb-5">
                <div class="d-flex"></div>
                <MudButton Variant="Variant.Filled" Color="Color.Primary" OnClick="@(_ => RemoveDecoFromDecoTemplate())" Disabled="@(_decoToRemove is null)" StartIcon="@Icons.Material.Filled.Remove">
                    Remove Deco From Template
                </MudButton>
            </MudStack>
            <MudText Typo="Typo.h5" Class="mt-10 mb-2">Content</MudText>
            <MudDivider Class="mb-6"/>
            <MudCalendar T="CalendarItem"
                         Class="mb-6"
                         Items="@_decoTemplate.Items"
                         ShowMonth="false"
                         ShowWeek="false"
                         ShowPrevNextButtons="false"
                         ShowDatePicker="false"
                         ShowTodayButton="false"
                         DayTimeInterval="CalendarTimeInterval.Minutes10"
                         Use24HourClock="@(CultureInfo.CurrentCulture.DateTimeFormat.ShortTimePattern.Contains("H"))"
                         EnableDragItems="true"
                         EnableResizeItems="false"
                         ItemChanged="@(ci => CalendarItemChanged(ci))"/>
        </MudContainer>
    </div>
</MudForm>

@code {
    private CancellationTokenSource _cts;
    private readonly List<DecoGroupViewModel> _decoGroups = [];
    private readonly List<DecoViewModel> _decos = [];
    private readonly List<DateTime> _startTimes = [];

    [Parameter]
    public int Id { get; set; }

    private DecoTemplateItemsEditViewModel _decoTemplate = new();
    private DecoTemplateItemEditViewModel _decoToRemove;
    private DecoGroupViewModel _selectedDecoGroup;
    private DecoViewModel _selectedDeco;
    private DateTime _selectedDecoStart;
    private int _durationHours;
    private int _durationMinutes = 15;

    public void Dispose()
    {
        _cts?.Cancel();
        _cts?.Dispose();
    }

    protected override async Task OnParametersSetAsync()
    {
        _cts?.Cancel();
        _cts?.Dispose();
        _cts = new CancellationTokenSource();
        var token = _cts.Token;

        try
        {
            await LoadDecoTemplateItems(token);

            DateTime start = DateTime.Today;
            _selectedDecoStart = start;
            while (start.Date == DateTime.Today.Date)
            {
                _startTimes.Add(start);
                start = start.AddMinutes(5);
            }
        }
        catch (OperationCanceledException)
        {
            // do nothing
        }
    }

    private async Task LoadDecoTemplateItems(CancellationToken cancellationToken)
    {
        Option<DecoTemplateViewModel> maybeDecoTemplate = await Mediator.Send(new GetDecoTemplateById(Id), cancellationToken);
        if (maybeDecoTemplate.IsNone)
        {
            NavigationManager.NavigateTo("deco-templates");
            return;
        }

        foreach (DecoTemplateViewModel template in maybeDecoTemplate)
        {
            _decoTemplate = new DecoTemplateItemsEditViewModel
            {
                GroupId = template.DecoTemplateGroupId,
                GroupName = template.GroupName,
                Name = template.Name
            };
        }

        Option<IEnumerable<DecoTemplateItemViewModel>> maybeResults = await Mediator.Send(new GetDecoTemplateItems(Id), cancellationToken);
        foreach (IEnumerable<DecoTemplateItemViewModel> items in maybeResults)
        {
            _decoTemplate.Items.AddRange(items.Map(ProjectToEditViewModel));
        }

        _decoGroups.AddRange(await Mediator.Send(new GetAllDecoGroups(), cancellationToken));
    }

    private static DecoTemplateItemEditViewModel ProjectToEditViewModel(DecoTemplateItemViewModel item) =>
        new()
        {
            DecoId = item.DecoId,
            DecoName = item.DecoName,
            Start = item.StartTime,
            End = item.EndTime
        };

    private async Task UpdateDecoGroupItems(DecoGroupViewModel decoGroup)
    {
        _selectedDecoGroup = decoGroup;

        _decos.Clear();
        _decos.AddRange(await Mediator.Send(new GetDecosByDecoGroupId(_selectedDecoGroup.Id), _cts.Token));
    }

    private void AddDecoToDecoTemplate()
    {
        // find first time where this deco will fit
        DateTime maybeStart = _selectedDecoStart;
        while (maybeStart.Date == DateTime.Today)
        {
            DateTime maybeEnd = maybeStart.AddHours(_durationHours).AddMinutes(_durationMinutes);
            if (!IntersectsOthers(null, maybeStart, maybeEnd))
            {
                var item = new DecoTemplateItemEditViewModel
                {
                    DecoId = _selectedDeco.Id,
                    DecoName = _selectedDeco.Name,
                    Start = maybeStart,
                    End = maybeEnd,
                    LastStart = maybeStart,
                    LastEnd = maybeEnd
                };

                _decoTemplate.Items.Add(item);

                break;
            }

            maybeStart = maybeStart.AddMinutes(5);
        }
    }

    private async Task RemoveDecoFromDecoTemplate()
    {
        if (_decoToRemove is not null)
        {
            _decoTemplate.Items.Remove(_decoToRemove);
            _decoToRemove = null;

            await InvokeAsync(StateHasChanged);
        }
    }

    private void CalendarItemChanged(CalendarItem calendarItem)
    {
        // don't allow any overlap
        if (calendarItem is DecoTemplateItemEditViewModel item)
        {
            bool intersects = item.End.HasValue && IntersectsOthers(item, item.Start, item.End.Value);
            bool crossesMidnight = item.End.HasValue && item.End.Value.TimeOfDay > TimeSpan.Zero && item.End.Value.TimeOfDay < item.Start.TimeOfDay;
            if (intersects || crossesMidnight)
            {
                // roll back
                item.Start = item.LastStart;
                item.End = item.LastEnd;
            }
            else
            {
                // commit
                item.LastStart = item.Start;
                item.LastEnd = item.End;
            }
        }
    }

    private bool IntersectsOthers(DecoTemplateItemEditViewModel item, DateTime start, DateTime end)
    {
        var willFit = true;

        foreach (DecoTemplateItemEditViewModel existing in _decoTemplate.Items)
        {
            if (existing == item)
            {
                continue;
            }

            if (start < existing.End && existing.Start < end)
            {
                willFit = false;
                break;
            }
        }

        return !willFit;
    }

    // private void RemoveDecoTemplateItem(DecoTemplateItemEditViewModel item)
    // {
    //     _selectedItem = null;
    //     _decoTemplate.Items.Remove(item);
    // }

    private async Task SaveChanges()
    {
        if (_decoTemplate.Items.Any(i => i.End is null))
        {
            Snackbar.Add("Template item cannot end after midnight", Severity.Error);
            return;
        }

        var items = _decoTemplate.Items.Map(item => new ReplaceDecoTemplateItem(item.DecoId, item.Start.TimeOfDay, item.End!.Value.TimeOfDay)).ToList();

        Seq<BaseError> errorMessages = await Mediator.Send(new ReplaceDecoTemplateItems(Id, _decoTemplate.GroupId, _decoTemplate.Name, items), _cts.Token)
            .Map(e => e.LeftToSeq());

        errorMessages.HeadOrNone().Match(
            error =>
            {
                Snackbar.Add($"Unexpected error saving template: {error.Value}", Severity.Error);
                Logger.LogError("Unexpected error saving template: {Error}", error.Value);
            },
            () => NavigationManager.NavigateTo("deco-templates"));
    }

}