@using System.Text.Json
@using MudBlazor

<MudDialog>
    <TitleContent>
        <MudText Typo="Typo.h6">Import Order JSON</MudText>
    </TitleContent>

    <DialogContent>

        @if (ShowWarning)
        {
            <MudAlert Severity="Severity.Warning"
                      Variant="Variant.Outlined"
                      Class="mb-4">
                Only valid <b>VDA 5050 Order JSON</b> is accepted.<br />
                Invalid structure will be rejected.
            </MudAlert>
        }

        <MudTextField @bind-Value="JsonText"
                      Label="Paste Order JSON"
                      Lines="20"
                      Variant="Variant.Filled"
                      Immediate
                      Style="font-family: monospace" />

        @if (!string.IsNullOrEmpty(ErrorMessage))
        {
            <MudAlert Severity="Severity.Error" Class="mt-3">
                @ErrorMessage
            </MudAlert>
        }

    </DialogContent>

    <DialogActions>
        <MudButton OnClick="Cancel">Cancel</MudButton>
        <MudButton Variant="Variant.Filled"
                   Color="Color.Primary"
                   OnClick="ValidateAndImport">
            Import
        </MudButton>
    </DialogActions>
</MudDialog>
@code {
    [CascadingParameter] public IMudDialogInstance MudDialog { get; set; } = default!;

    public string JsonText { get; set; } = "";
    public string? ErrorMessage;
    public bool ShowWarning { get; set; } = false;

    private void Cancel() => MudDialog.Cancel();

    private void ValidateAndImport()
    {
        ErrorMessage = null;
        ShowWarning = false;

        try
        {
            using var doc = JsonDocument.Parse(JsonText);
            var root = doc.RootElement;

            // ===== BASIC STRUCTURE CHECK =====
            if (!root.TryGetProperty("nodes", out _) ||
                !root.TryGetProperty("edges", out _))
                throw new Exception("Missing 'nodes' or 'edges' field.");

            var order = OrderMessage.FromSchemaObject(root);

            ValidateOrder(order);

            MudDialog.Close(DialogResult.Ok(order));
        }
        catch (JsonException)
        {
            ShowWarning = true;
            ErrorMessage = "Invalid JSON format.";
        }
        catch (Exception ex)
        {
            ShowWarning = true;
            ErrorMessage = ex.Message;
        }
    }

    private void ValidateOrder(OrderMessage order)
    {
        if (order.Nodes.Count == 0)
            throw new Exception("Order must contain at least one node.");

        var nodeIds = order.Nodes.Select(n => n.NodeId).ToHashSet();

        foreach (var e in order.Edges)
        {
            if (!nodeIds.Contains(e.StartNodeId) ||
                !nodeIds.Contains(e.EndNodeId))
                throw new Exception(
                    $"Edge '{e.EdgeId}' references unknown node."
                );
        }
    }
}