@page "/clusters/{ClusterId}/draft/{GenerationId:long}/diff"
@using ZB.MOM.WW.OtOpcUa.Admin.Services
@using ZB.MOM.WW.OtOpcUa.Configuration.Entities
@using ZB.MOM.WW.OtOpcUa.Configuration.Enums
@inject GenerationService GenerationSvc

<div class="d-flex justify-content-between align-items-center mb-3">
    <div>
        <h1 class="mb-0">Draft diff</h1>
        <small class="text-muted">
            Cluster <code>@ClusterId</code> — from last published (@(_fromLabel)) → to draft @GenerationId
        </small>
    </div>
    <a class="btn btn-outline-secondary" href="/clusters/@ClusterId/draft/@GenerationId">Back to editor</a>
</div>

@if (_rows is null)
{
    <p>Computing diff…</p>
}
else if (_error is not null)
{
    <div class="alert alert-danger">@_error</div>
}
else if (_rows.Count == 0)
{
    <p class="text-muted">No differences — draft is structurally identical to the last published generation.</p>
}
else
{
    <table class="table table-hover table-sm">
        <thead><tr><th>Table</th><th>LogicalId</th><th>ChangeKind</th></tr></thead>
        <tbody>
        @foreach (var r in _rows)
        {
            <tr>
                <td>@r.TableName</td>
                <td><code>@r.LogicalId</code></td>
                <td>
                    @switch (r.ChangeKind)
                    {
                        case "Added":    <span class="badge bg-success">@r.ChangeKind</span> break;
                        case "Removed":  <span class="badge bg-danger">@r.ChangeKind</span> break;
                        case "Modified": <span class="badge bg-warning text-dark">@r.ChangeKind</span> break;
                        default:         <span class="badge bg-secondary">@r.ChangeKind</span> break;
                    }
                </td>
            </tr>
        }
        </tbody>
    </table>
}

@code {
    [Parameter] public string ClusterId { get; set; } = string.Empty;
    [Parameter] public long GenerationId { get; set; }

    private List<DiffRow>? _rows;
    private string _fromLabel = "(empty)";
    private string? _error;

    protected override async Task OnParametersSetAsync()
    {
        try
        {
            var all = await GenerationSvc.ListRecentAsync(ClusterId, 50, CancellationToken.None);
            var from = all.FirstOrDefault(g => g.Status == GenerationStatus.Published);
            _fromLabel = from is null ? "(empty)" : $"gen {from.GenerationId}";
            _rows = await GenerationSvc.ComputeDiffAsync(from?.GenerationId ?? 0, GenerationId, CancellationToken.None);
        }
        catch (Exception ex) { _error = ex.Message; }
    }
}