sprints work

src/__Libraries/StellaOps.Resolver/EdgeId.cs

@@ -0,0 +1,92 @@
+/**
+ * EdgeId - Content-Addressed Edge Identifier
+ * Sprint: SPRINT_9100_0001_0003 (Content-Addressed EdgeId)
+ * Task: EDGEID-9100-001, EDGEID-9100-002, EDGEID-9100-003
+ *
+ * A content-addressed identifier for graph edges.
+ * EdgeId = sha256(srcId + "->" + kind + "->" + dstId)
+ * 
+ * Enables:
+ * - Edge-level attestations
+ * - Delta detection between graphs
+ * - Merkle tree inclusion for proof chains
+ */
+
+using System.Security.Cryptography;
+using System.Text;
+
+namespace StellaOps.Resolver;
+
+/// <summary>
+/// Content-addressed edge identifier computed as SHA256 of src->kind->dst.
+/// Immutable value type for deterministic graph operations.
+/// </summary>
+public readonly record struct EdgeId : IComparable<EdgeId>, IEquatable<EdgeId>
+{
+    private readonly string _value;
+
+    /// <summary>
+    /// The SHA256 hex digest (lowercase, 64 characters).
+    /// </summary>
+    public string Value => _value ?? string.Empty;
+
+    private EdgeId(string value) => _value = value;
+
+    /// <summary>
+    /// Creates an EdgeId from a pre-computed digest value.
+    /// Use <see cref="From(NodeId, string, NodeId)"/> for computing from components.
+    /// </summary>
+    /// <param name="digest">A valid SHA256 hex digest (64 lowercase hex chars).</param>
+    public static EdgeId FromDigest(string digest)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(digest);
+        if (digest.Length != 64)
+            throw new ArgumentException("EdgeId digest must be 64 hex characters", nameof(digest));
+
+        return new EdgeId(digest.ToLowerInvariant());
+    }
+
+    /// <summary>
+    /// Computes an EdgeId from source, kind, and destination.
+    /// Format: sha256(srcId->kind->dstId)
+    /// </summary>
+    /// <param name="src">Source node identifier.</param>
+    /// <param name="kind">Edge kind (e.g., "depends_on", "calls", "imports").</param>
+    /// <param name="dst">Destination node identifier.</param>
+    /// <returns>Content-addressed EdgeId.</returns>
+    public static EdgeId From(NodeId src, string kind, NodeId dst)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(kind);
+
+        // NFC normalize kind for Unicode consistency
+        var normalizedKind = kind.Normalize(NormalizationForm.FormC);
+
+        var input = $"{src.Value}->{normalizedKind}->{dst.Value}";
+        var hash = SHA256.HashData(Encoding.UTF8.GetBytes(input));
+        var digest = Convert.ToHexString(hash).ToLowerInvariant();
+
+        return new EdgeId(digest);
+    }
+
+    /// <summary>
+    /// Ordinal comparison for deterministic ordering.
+    /// </summary>
+    public int CompareTo(EdgeId other)
+        => string.Compare(Value, other.Value, StringComparison.Ordinal);
+
+    /// <summary>
+    /// Equality is based on digest value.
+    /// </summary>
+    public bool Equals(EdgeId other)
+        => string.Equals(Value, other.Value, StringComparison.Ordinal);
+
+    public override int GetHashCode()
+        => Value.GetHashCode(StringComparison.Ordinal);
+
+    public override string ToString() => Value;
+
+    public static bool operator <(EdgeId left, EdgeId right) => left.CompareTo(right) < 0;
+    public static bool operator >(EdgeId left, EdgeId right) => left.CompareTo(right) > 0;
+    public static bool operator <=(EdgeId left, EdgeId right) => left.CompareTo(right) <= 0;
+    public static bool operator >=(EdgeId left, EdgeId right) => left.CompareTo(right) >= 0;
+}