// 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>
/// Image preprocessing configuration for OCR.
///
/// These settings control how images are preprocessed before OCR to improve
/// text recognition quality. Different preprocessing strategies work better
/// for different document types.
/// </summary>
public sealed record ImagePreprocessingConfig
{
    /// <summary>
    /// Target DPI for the image (300 is standard, 600 for small text).
    /// </summary>
    [JsonPropertyName("target_dpi")]
    public int TargetDpi { get; init; } = 300;

    /// <summary>
    /// Auto-detect and correct image rotation.
    /// </summary>
    [JsonPropertyName("auto_rotate")]
    public bool AutoRotate { get; init; } = true;

    /// <summary>
    /// Correct skew (tilted images).
    /// </summary>
    [JsonPropertyName("deskew")]
    public bool Deskew { get; init; } = true;

    /// <summary>
    /// Remove noise from the image.
    /// </summary>
    [JsonPropertyName("denoise")]
    public bool Denoise { get; init; } = false;

    /// <summary>
    /// Enhance contrast for better text visibility.
    /// </summary>
    [JsonPropertyName("contrast_enhance")]
    public bool ContrastEnhance { get; init; } = false;

    /// <summary>
    /// Binarization method: "otsu", "sauvola", "adaptive".
    /// </summary>
    [JsonPropertyName("binarization_method")]
    public string BinarizationMethod { get; init; } = "otsu";

    /// <summary>
    /// Invert colors (white text on black → black on white).
    /// </summary>
    [JsonPropertyName("invert_colors")]
    public bool InvertColors { get; init; } = false;


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

    public static ImagePreprocessingConfig Default()
    {
        var nativeResult = NativeMethods.ImagePreprocessingConfigDefault();
        var jsonPtr = NativeMethods.ImagePreprocessingConfigToJson(nativeResult);
        var json = global::System.Runtime.InteropServices.Marshal.PtrToStringUTF8(jsonPtr);
        NativeMethods.FreeString(jsonPtr);
        NativeMethods.ImagePreprocessingConfigFree(nativeResult);
        return JsonSerializer.Deserialize<ImagePreprocessingConfig>(json ?? "null", JsonOptions)!;
    }
}
