// This file is auto-generated by alef — DO NOT EDIT.
// alef:hash:4e15143f4af1ae8bafbdb1506ef057da924484c66a19483966333558ad437e75
// To regenerate: alef generate
// To verify freshness: alef verify --exit-code
// Issues & docs: https://github.com/kreuzberg-dev/alef
#nullable enable

using System;
using System.Collections.Generic;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace Kreuzberg;

/// <summary>
/// A text chunk with optional embedding and metadata.
///
/// Chunks are created when chunking is enabled in `ExtractionConfig`. Each chunk
/// contains the text content, optional embedding vector (if embedding generation
/// is configured), and metadata about its position in the document.
/// </summary>
public sealed record Chunk
{
    /// <summary>
    /// The text content of this chunk.
    /// </summary>
    [JsonPropertyName("content")]
    public required string Content { get; init; }

    /// <summary>
    /// Semantic structural classification of this chunk.
    ///
    /// Assigned by the heuristic classifier based on content patterns and
    /// heading context. Defaults to `ChunkType.Unknown` when no rule matches.
    /// </summary>
    [JsonPropertyName("chunk_type")]
    public ChunkType? ChunkType { get; init; } = null;

    /// <summary>
    /// Optional embedding vector for this chunk.
    ///
    /// Only populated when `EmbeddingConfig` is provided in chunking configuration.
    /// The dimensionality depends on the chosen embedding model.
    /// </summary>
    [JsonPropertyName("embedding")]
    public List<float>? Embedding { get; init; } = null;

    /// <summary>
    /// Metadata about this chunk's position and properties.
    /// </summary>
    [JsonPropertyName("metadata")]
    public required ChunkMetadata Metadata { get; init; }


    /// <summary>
    /// Parse a <see cref="Chunk"/> from a JSON string.
    /// </summary>
    /// <exception cref="KreuzbergException">When the JSON cannot be deserialised.</exception>
    public static Chunk FromJson(string json)
    {
        try
        {
            return JsonSerializer.Deserialize<Chunk>(json, JsonOptions)
                ?? throw new KreuzbergException($"Failed to parse Chunk from JSON: deserializer returned null");
        }
        catch (KreuzbergException)
        {
            throw;
        }
        catch (Exception e)
        {
            throw new KreuzbergException($"Failed to parse Chunk from JSON: {e.Message}", e);
        }
    }

    private static readonly JsonSerializerOptions JsonOptions = new()
    {
        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingDefault,
        Converters = { new JsonStringEnumConverter(JsonNamingPolicy.SnakeCaseLower) },
    };

    /// <summary>Options for serializing config/input objects to FFI. Strips nulls
    /// (nullable C# fields default to null and would override required Rust fields with
    /// non-deserialisable nulls) but preserves explicit false/0 so caller intent is kept.</summary>
    private static readonly JsonSerializerOptions JsonSerializationOptions = new()
    {
        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
        Converters = { new JsonStringEnumConverter(JsonNamingPolicy.SnakeCaseLower) },
    };
}
