using System.Text.Json;
using System.Text.Json.Nodes;
using FluentAssertions;
using StellaOps.Graph.Indexer.Schema;
using Xunit;

namespace StellaOps.Graph.Indexer.Tests;

public sealed class GraphIdentityTests
{
    private static readonly string FixturesRoot =
        Path.Combine(AppContext.BaseDirectory, "Fixtures", "v1");

    [Fact]
    public void NodeIds_are_stable()
    {
        var nodes = LoadArray("nodes.json");

        foreach (var node in nodes.Cast<JsonObject>())
        {
            var tenant = node["tenant"]!.GetValue<string>();
            var kind = node["kind"]!.GetValue<string>();
            var canonicalKey = (JsonObject)node["canonical_key"]!;
            var tuple = GraphIdentity.ExtractIdentityTuple(canonicalKey);

            var expectedId = node["id"]!.GetValue<string>();
            var actualId = GraphIdentity.ComputeNodeId(tenant, kind, tuple);

            actualId.Should()
                .Be(expectedId, $"node {kind} with canonical tuple {canonicalKey.ToJsonString()} must have deterministic id");

            var documentClone = JsonNode.Parse(node.ToJsonString())!.AsObject();
            documentClone.Remove("hash");

            var expectedHash = node["hash"]!.GetValue<string>();
            var actualHash = GraphIdentity.ComputeDocumentHash(documentClone);

            actualHash.Should()
                .Be(expectedHash, $"node {kind}:{expectedId} must have deterministic document hash");
        }
    }

    [Fact]
    public void EdgeIds_are_stable()
    {
        var edges = LoadArray("edges.json");

        foreach (var edge in edges.Cast<JsonObject>())
        {
            var tenant = edge["tenant"]!.GetValue<string>();
            var kind = edge["kind"]!.GetValue<string>();
            var canonicalKey = (JsonObject)edge["canonical_key"]!;
            var tuple = GraphIdentity.ExtractIdentityTuple(canonicalKey);

        var expectedId = edge["id"]!.GetValue<string>();
        var actualId = GraphIdentity.ComputeEdgeId(tenant, kind, tuple);

        actualId.Should()
            .Be(expectedId, $"edge {kind} with canonical tuple {canonicalKey.ToJsonString()} must have deterministic id");

        var documentClone = JsonNode.Parse(edge.ToJsonString())!.AsObject();
        documentClone.Remove("hash");

        var expectedHash = edge["hash"]!.GetValue<string>();
        var actualHash = GraphIdentity.ComputeDocumentHash(documentClone);

        actualHash.Should()
            .Be(expectedHash, $"edge {kind}:{expectedId} must have deterministic document hash");
        }
    }

    [Fact]
    public void AttributeCoverage_matches_matrix()
    {
        var matrix = LoadObject("schema-matrix.json");
        var nodeExpectations = (JsonObject)matrix["nodes"]!;
        var edgeExpectations = (JsonObject)matrix["edges"]!;

        var nodes = LoadArray("nodes.json");
        foreach (var node in nodes.Cast<JsonObject>())
        {
            var kind = node["kind"]!.GetValue<string>();
            var expectedAttributes = nodeExpectations[kind]!.AsArray().Select(x => x!.GetValue<string>()).OrderBy(x => x, StringComparer.Ordinal).ToArray();
            var actualAttributes = ((JsonObject)node["attributes"]!).Select(pair => pair.Key).OrderBy(x => x, StringComparer.Ordinal).ToArray();

            actualAttributes.Should()
                .Equal(expectedAttributes, $"node kind {kind} must align with schema matrix");
        }

        var edges = LoadArray("edges.json");
        foreach (var edge in edges.Cast<JsonObject>())
        {
            var kind = edge["kind"]!.GetValue<string>();
            var expectedAttributes = edgeExpectations[kind]!.AsArray().Select(x => x!.GetValue<string>()).OrderBy(x => x, StringComparer.Ordinal).ToArray();
            var actualAttributes = ((JsonObject)edge["attributes"]!).Select(pair => pair.Key).OrderBy(x => x, StringComparer.Ordinal).ToArray();

            actualAttributes.Should()
                .Equal(expectedAttributes, $"edge kind {kind} must align with schema matrix");
        }
    }

    private static JsonArray LoadArray(string fileName)
        => (JsonArray)JsonNode.Parse(File.ReadAllText(GetFixturePath(fileName)))!;

    private static JsonObject LoadObject(string fileName)
        => (JsonObject)JsonNode.Parse(File.ReadAllText(GetFixturePath(fileName)))!;

    private static string GetFixturePath(string fileName)
        => Path.Combine(FixturesRoot, fileName);
}