// 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>
/// Unified page structure for documents.
///
/// Supports different page types (PDF pages, PPTX slides, Excel sheets)
/// with character offset boundaries for chunk-to-page mapping.
/// </summary>
public sealed record PageStructure
{
    /// <summary>
    /// Total number of pages/slides/sheets
    /// </summary>
    [JsonPropertyName("total_count")]
    public uint TotalCount { get; init; } = 0;

    /// <summary>
    /// Type of paginated unit
    /// </summary>
    [JsonPropertyName("unit_type")]
    public required PageUnitType UnitType { get; init; }

    /// <summary>
    /// Character offset boundaries for each page
    ///
    /// Maps character ranges in the extracted content to page numbers.
    /// Used for chunk page range calculation.
    /// </summary>
    [JsonPropertyName("boundaries")]
    public List<PageBoundary>? Boundaries { get; init; } = null;

    /// <summary>
    /// Detailed per-page metadata (optional, only when needed)
    /// </summary>
    [JsonPropertyName("pages")]
    public List<PageInfo>? Pages { get; init; } = null;


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