// Copyright (c) StellaOps. All rights reserved.
// Licensed under BUSL-1.1. See LICENSE in the project root.

using System.Text.Json.Serialization;

namespace StellaOps.BinaryIndex.DeltaSig;

/// <summary>
/// Source file pair used to compute semantic edit scripts.
/// </summary>
public sealed record SourceFileDiff
{
    /// <summary>
    /// Source file path (repository-relative).
    /// </summary>
    public required string Path { get; init; }

    /// <summary>
    /// Previous file content.
    /// </summary>
    public string? BeforeContent { get; init; }

    /// <summary>
    /// Current file content.
    /// </summary>
    public string? AfterContent { get; init; }
}

/// <summary>
/// Source line span.
/// </summary>
public sealed record SourceSpan
{
    /// <summary>
    /// 1-based start line.
    /// </summary>
    public required int StartLine { get; init; }

    /// <summary>
    /// 1-based end line.
    /// </summary>
    public required int EndLine { get; init; }
}

/// <summary>
/// Deterministic semantic edit script.
/// </summary>
public sealed record SemanticEditScript
{
    /// <summary>
    /// Schema version.
    /// </summary>
    public string SchemaVersion { get; init; } = "1.0.0";

    /// <summary>
    /// Digest of the full source tree diff input.
    /// </summary>
    public required string SourceTreeDigest { get; init; }

    /// <summary>
    /// Deterministic ordered edits.
    /// </summary>
    public required IReadOnlyList<SemanticEdit> Edits { get; init; }
}

/// <summary>
/// Single semantic edit entry.
/// </summary>
public sealed record SemanticEdit
{
    /// <summary>
    /// Stable digest-derived ID for dedupe and audit references.
    /// </summary>
    public required string StableId { get; init; }

    /// <summary>
    /// Edit type: add, remove, move, update, rename.
    /// </summary>
    public required string EditType { get; init; }

    /// <summary>
    /// Node kind: file, method, class, field, import, statement.
    /// </summary>
    public required string NodeKind { get; init; }

    /// <summary>
    /// Deterministic node path.
    /// </summary>
    public required string NodePath { get; init; }

    /// <summary>
    /// Symbol anchor used to link to binary symbols.
    /// </summary>
    public required string Anchor { get; init; }

    /// <summary>
    /// Pre-change source span.
    /// </summary>
    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
    public SourceSpan? PreSpan { get; init; }

    /// <summary>
    /// Post-change source span.
    /// </summary>
    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
    public SourceSpan? PostSpan { get; init; }

    /// <summary>
    /// Pre-change digest.
    /// </summary>
    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
    public string? PreDigest { get; init; }

    /// <summary>
    /// Post-change digest.
    /// </summary>
    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
    public string? PostDigest { get; init; }
}

/// <summary>
/// Build-stage symbol map linked to build identity.
/// </summary>
public sealed record SymbolMap
{
    /// <summary>
    /// Schema version.
    /// </summary>
    public string SchemaVersion { get; init; } = "1.0.0";

    /// <summary>
    /// Build ID (ELF build-id, PDB GUID, or equivalent).
    /// </summary>
    public required string BuildId { get; init; }

    /// <summary>
    /// Optional binary digest for traceability.
    /// </summary>
    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
    public string? BinaryDigest { get; init; }

    /// <summary>
    /// Address derivation source (manifest, synthetic-signature).
    /// </summary>
    public string AddressSource { get; init; } = "manifest";

    /// <summary>
    /// Ordered symbol entries.
    /// </summary>
    public required IReadOnlyList<SymbolMapEntry> Symbols { get; init; }
}

/// <summary>
/// Symbol map entry.
/// </summary>
public sealed record SymbolMapEntry
{
    /// <summary>
    /// Symbol name.
    /// </summary>
    public required string Name { get; init; }

    /// <summary>
    /// Symbol kind: function, object, section.
    /// </summary>
    public string Kind { get; init; } = "function";

    /// <summary>
    /// Start address.
    /// </summary>
    public required ulong AddressStart { get; init; }

    /// <summary>
    /// End address.
    /// </summary>
    public required ulong AddressEnd { get; init; }

    /// <summary>
    /// Containing section.
    /// </summary>
    public string Section { get; init; } = ".text";

    /// <summary>
    /// Source ranges for this symbol.
    /// </summary>
    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
    public IReadOnlyList<SourceRange>? SourceRanges { get; init; }

    /// <summary>
    /// Symbol size derived from address range.
    /// </summary>
    [JsonIgnore]
    public long Size => checked((long)(AddressEnd >= AddressStart ? AddressEnd - AddressStart + 1UL : 0UL));
}

/// <summary>
/// Source range metadata.
/// </summary>
public sealed record SourceRange
{
    /// <summary>
    /// Source file path.
    /// </summary>
    public required string File { get; init; }

    /// <summary>
    /// 1-based start line.
    /// </summary>
    public required int LineStart { get; init; }

    /// <summary>
    /// 1-based end line.
    /// </summary>
    public required int LineEnd { get; init; }
}

/// <summary>
/// Join artifact linking semantic edits to symbol changes.
/// </summary>
public sealed record SymbolPatchPlan
{
    /// <summary>
    /// Schema version.
    /// </summary>
    public string SchemaVersion { get; init; } = "1.0.0";

    /// <summary>
    /// Build ID before patch.
    /// </summary>
    public required string BuildIdBefore { get; init; }

    /// <summary>
    /// Build ID after patch.
    /// </summary>
    public required string BuildIdAfter { get; init; }

    /// <summary>
    /// Semantic script digest.
    /// </summary>
    public required string EditsDigest { get; init; }

    /// <summary>
    /// Old symbol map digest.
    /// </summary>
    public required string SymbolMapDigestBefore { get; init; }

    /// <summary>
    /// New symbol map digest.
    /// </summary>
    public required string SymbolMapDigestAfter { get; init; }

    /// <summary>
    /// Ordered symbol changes.
    /// </summary>
    public required IReadOnlyList<SymbolPatchChange> Changes { get; init; }
}

/// <summary>
/// Single symbol patch plan entry.
/// </summary>
public sealed record SymbolPatchChange
{
    /// <summary>
    /// Symbol name.
    /// </summary>
    public required string Symbol { get; init; }

    /// <summary>
    /// Change type: added, removed, modified, moved.
    /// </summary>
    public required string ChangeType { get; init; }

    /// <summary>
    /// Linked source anchors.
    /// </summary>
    public required IReadOnlyList<string> AstAnchors { get; init; }

    /// <summary>
    /// Hash before.
    /// </summary>
    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
    public string? PreHash { get; init; }

    /// <summary>
    /// Hash after.
    /// </summary>
    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
    public string? PostHash { get; init; }

    /// <summary>
    /// Delta reference digest.
    /// </summary>
    public required string DeltaRef { get; init; }
}

/// <summary>
/// Normalized patch manifest for per-symbol deltas.
/// </summary>
public sealed record PatchManifest
{
    /// <summary>
    /// Schema version.
    /// </summary>
    public string SchemaVersion { get; init; } = "1.0.0";

    /// <summary>
    /// Build ID.
    /// </summary>
    public required string BuildId { get; init; }

    /// <summary>
    /// Normalization recipe identifier.
    /// </summary>
    public required string NormalizationRecipeId { get; init; }

    /// <summary>
    /// Ordered patch entries.
    /// </summary>
    public required IReadOnlyList<SymbolPatchArtifact> Patches { get; init; }

    /// <summary>
    /// Total delta bytes across symbols.
    /// </summary>
    [JsonIgnore]
    public long TotalDeltaBytes => Patches.Sum(p => p.DeltaSizeBytes);
}

/// <summary>
/// Per-symbol patch artifact.
/// </summary>
public sealed record SymbolPatchArtifact
{
    /// <summary>
    /// Symbol name.
    /// </summary>
    public required string Symbol { get; init; }

    /// <summary>
    /// Address range in hex format.
    /// </summary>
    public required string AddressRange { get; init; }

    /// <summary>
    /// Digest of patch payload.
    /// </summary>
    public required string DeltaDigest { get; init; }

    /// <summary>
    /// Pre-patch metrics.
    /// </summary>
    public required PatchSizeHash Pre { get; init; }

    /// <summary>
    /// Post-patch metrics.
    /// </summary>
    public required PatchSizeHash Post { get; init; }

    /// <summary>
    /// Absolute byte delta.
    /// </summary>
    [JsonIgnore]
    public long DeltaSizeBytes => Math.Abs(Post.Size - Pre.Size);
}

/// <summary>
/// Size/hash tuple.
/// </summary>
public sealed record PatchSizeHash
{
    /// <summary>
    /// Size in bytes.
    /// </summary>
    public required long Size { get; init; }

    /// <summary>
    /// Hash digest.
    /// </summary>
    public required string Hash { get; init; }
}

/// <summary>
/// Full hybrid diff evidence bundle.
/// </summary>
public sealed record HybridDiffEvidence
{
    /// <summary>
    /// Semantic edit script.
    /// </summary>
    public required SemanticEditScript SemanticEditScript { get; init; }

    /// <summary>
    /// Old symbol map.
    /// </summary>
    public required SymbolMap OldSymbolMap { get; init; }

    /// <summary>
    /// New symbol map.
    /// </summary>
    public required SymbolMap NewSymbolMap { get; init; }

    /// <summary>
    /// Symbol patch plan.
    /// </summary>
    public required SymbolPatchPlan SymbolPatchPlan { get; init; }

    /// <summary>
    /// Normalized patch manifest.
    /// </summary>
    public required PatchManifest PatchManifest { get; init; }

    /// <summary>
    /// Semantic edit script digest.
    /// </summary>
    public required string SemanticEditScriptDigest { get; init; }

    /// <summary>
    /// Old symbol map digest.
    /// </summary>
    public required string OldSymbolMapDigest { get; init; }

    /// <summary>
    /// New symbol map digest.
    /// </summary>
    public required string NewSymbolMapDigest { get; init; }

    /// <summary>
    /// Symbol patch plan digest.
    /// </summary>
    public required string SymbolPatchPlanDigest { get; init; }

    /// <summary>
    /// Patch manifest digest.
    /// </summary>
    public required string PatchManifestDigest { get; init; }
}