using System.Collections.Generic;
using System.Text.Json;
using Microsoft.Extensions.Caching.Memory;
using StellaOps.Graph.Api.Contracts;
using StellaOps.Graph.Api.Services;
using Xunit;


using StellaOps.TestKit;
namespace StellaOps.Graph.Api.Tests;

public class QueryServiceTests
{
    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public async Task QueryAsync_EmitsNodesEdgesStatsAndCursor()
    {
        var repo = new InMemoryGraphRepository();
        var service = CreateService(repo);

        var request = new GraphQueryRequest
        {
            Kinds = new[] { "component", "artifact" },
            Query = "component",
            Limit = 1,
            IncludeEdges = true,
            IncludeStats = true
        };

        var lines = new List<string>();
        await foreach (var line in service.QueryAsync("acme", request))
        {
            lines.Add(line);
        }

        Assert.Contains(lines, l => l.Contains("\"type\":\"node\""));
        Assert.Contains(lines, l => l.Contains("\"type\":\"edge\""));
        Assert.Contains(lines, l => l.Contains("\"type\":\"stats\""));
        Assert.Contains(lines, l => l.Contains("\"type\":\"cursor\""));
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public async Task QueryAsync_ReturnsBudgetExceededError()
    {
        var repo = new InMemoryGraphRepository();
        var service = CreateService(repo);

        var request = new GraphQueryRequest
        {
            Kinds = new[] { "component", "artifact" },
            Query = "component",
            Budget = new GraphQueryBudget { Nodes = 1, Edges = 0, Tiles = 2 },
            Limit = 10
        };

        var lines = new List<string>();
        await foreach (var line in service.QueryAsync("acme", request))
        {
            lines.Add(line);
        }

        Assert.Single(lines);
        Assert.Contains("GRAPH_BUDGET_EXCEEDED", lines[0]);
    }

    [Trait("Category", TestCategories.Unit)]
        [Fact]
    public async Task QueryAsync_IncludesOverlaysAndSamplesExplainOnce()
    {
        var repo = new InMemoryGraphRepository(new[]
        {
            new NodeTile { Id = "gn:acme:component:one", Kind = "component", Tenant = "acme" },
            new NodeTile { Id = "gn:acme:component:two", Kind = "component", Tenant = "acme" }
        }, Array.Empty<EdgeTile>());

        var cache = new MemoryCache(new MemoryCacheOptions());
        var metrics = new GraphMetrics();
        var overlays = new InMemoryOverlayService(cache, metrics);
        var service = new InMemoryGraphQueryService(repo, cache, overlays, metrics);
        var request = new GraphQueryRequest
        {
            Kinds = new[] { "component" },
            IncludeOverlays = true,
            Limit = 5
        };

        var overlayNodes = 0;
        var explainCount = 0;

        await foreach (var line in service.QueryAsync("acme", request))
        {
            if (!line.Contains("\"type\":\"node\"")) continue;
            using var doc = JsonDocument.Parse(line);
            var data = doc.RootElement.GetProperty("data");
            if (data.TryGetProperty("overlays", out var overlaysElement) && overlaysElement.ValueKind == JsonValueKind.Object)
            {
                overlayNodes++;
                foreach (var overlay in overlaysElement.EnumerateObject())
                {
                    if (overlay.Value.ValueKind != JsonValueKind.Object) continue;
                    if (overlay.Value.TryGetProperty("data", out var payload) && payload.TryGetProperty("explainTrace", out var trace) && trace.ValueKind == JsonValueKind.Array)
                    {
                        explainCount++;
                    }
                }
            }
        }

        Assert.True(overlayNodes >= 1);
        Assert.Equal(1, explainCount);
    }

    private static InMemoryGraphQueryService CreateService(InMemoryGraphRepository? repository = null)
    {
        var cache = new MemoryCache(new MemoryCacheOptions());
        var metrics = new GraphMetrics();
        var overlays = new InMemoryOverlayService(cache, metrics);
        return new InMemoryGraphQueryService(repository ?? new InMemoryGraphRepository(), cache, overlays, metrics);
    }
}