// 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 detected layout region on a page.
///
/// When layout detection is enabled, each page may have layout regions
/// identifying different content types (text, pictures, tables, etc.)
/// with confidence scores and spatial positions.
/// </summary>
public sealed record LayoutRegion
{
    /// <summary>
    /// Layout class name (e.g. "picture", "table", "text", "section_header").
    /// </summary>
    [JsonPropertyName("class_name")]
    public string ClassName { get; init; } = "";

    /// <summary>
    /// Confidence score from the layout detection model (0.0 to 1.0).
    /// </summary>
    [JsonPropertyName("confidence")]
    public double Confidence { get; init; } = 0.0;

    /// <summary>
    /// Bounding box in document coordinate space.
    /// </summary>
    [JsonPropertyName("bounding_box")]
    public BoundingBox BoundingBox { get; init; } = default!;

    /// <summary>
    /// Fraction of the page area covered by this region (0.0 to 1.0).
    /// </summary>
    [JsonPropertyName("area_fraction")]
    public double AreaFraction { get; init; } = 0.0;


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