// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using Aspire.Dashboard.Model.Otlp;
using Aspire.Dashboard.Otlp.Storage;
using Aspire.Dashboard.Utils;
 
namespace Aspire.Dashboard.Model;
 
public class TracesViewModel
{
    private readonly DashboardDataSource _dataSource;
    private readonly List<FieldTelemetryFilter> _filters = new();
 
    private PagedResult<TraceSummary>? _traces;
    private ResourceKey? _resourceKey;
    private string _filterText = string.Empty;
    private int _startIndex;
    private int _count;
    private SpanType? _spanType;
 
    public TracesViewModel(DashboardDataSource dataSource)
    {
        _dataSource = dataSource;
    }
 
    public ResourceKey? ResourceKey { get => _resourceKey; set => SetValue(ref _resourceKey, value); }
    public SpanType? SpanType { get => _spanType; set => SetValue(ref _spanType, value); }
    public string FilterText { get => _filterText; set => SetValue(ref _filterText, value); }
    public int StartIndex { get => _startIndex; set => SetValue(ref _startIndex, value); }
    public int Count { get => _count; set => SetValue(ref _count, value); }
    public TimeSpan MaxDuration { get; private set; }
    public IReadOnlyList<FieldTelemetryFilter> Filters => _filters;
 
    public void ClearFilters()
    {
        _filters.Clear();
        _traces = null;
    }
 
    public void AddFilter(FieldTelemetryFilter filter)
    {
        // Don't add duplicate filters.
        foreach (var existingFilter in _filters)
        {
            if (existingFilter.Equals(filter))
            {
                return;
            }
        }
 
        _filters.Add(filter);
        _traces = null;
    }
 
    public bool RemoveFilter(FieldTelemetryFilter filter)
    {
        if (_filters.Remove(filter))
        {
            _traces = null;
            return true;
        }
        return false;
    }
 
    private void SetValue<T>(ref T field, T value)
    {
        if (EqualityComparer<T>.Default.Equals(field, value))
        {
            return;
        }
 
        field = value;
        _traces = null;
    }
 
    public async Task<PagedResult<TraceSummary>> GetTracesAsync(CancellationToken cancellationToken)
    {
        var traces = _traces;
        if (traces == null)
        {
            var filters = GetFilters();
 
            var result = await _dataSource.TelemetryRepository.GetTraceSummariesAsync(new GetTracesRequest
            {
                ResourceKeys = ResourceKey is { } key ? [key] : [],
                StartIndex = StartIndex,
                Count = Count,
                Filters = filters,
                TraceNameFilterText = FilterText,
                LatestItemCount = DashboardUIHelpers.MaxVirtualizedItemCount
            }, cancellationToken).ConfigureAwait(false);
 
            traces = result.PagedResult;
            MaxDuration = result.MaxDuration;
        }
 
        return traces;
    }
 
    private List<TelemetryFilter> GetFilters()
    {
        var filters = Filters.Cast<TelemetryFilter>().ToList();
        if (SpanType?.Filter is { } typeFilter)
        {
            filters.Add(typeFilter);
        }
 
        return filters;
    }
 
    public void ClearData()
    {
        _traces = null;
    }
}