aa/Metadata/Models/A_Metadata.cs

using System.Collections.ObjectModel;
using System.Text.Json;
using View_by_Distance.Metadata.Models.Stateless;
using View_by_Distance.Shared.Models;
using View_by_Distance.Shared.Models.Stateless;

namespace View_by_Distance.Metadata.Models;

public class A_Metadata
{

    private readonly ResultSettings _ResultSettings;
    private readonly MetadataSettings _MetadataSettings;
    private readonly ReadOnlyDictionary<int, ReadOnlyDictionary<string, string[]>> _FileGroups;

    public A_Metadata(ResultSettings resultSettings, MetadataSettings metadataSettings)
    {
        _ResultSettings = resultSettings;
        _MetadataSettings = metadataSettings;
        string aResultsFullGroupDirectory = IResult.GetResultsFullGroupDirectory(resultSettings,
                                                                                 nameof(A_Metadata),
                                                                                 string.Empty,
                                                                                 includeResizeGroup: false,
                                                                                 includeModel: false,
                                                                                 includePredictorModel: false);
        _FileGroups = IPath.GetKeyValuePairs(resultSettings, aResultsFullGroupDirectory, [resultSettings.ResultSingleton]);
    }

    private (int, FileInfo) GetFileInfo(ResultSettings resultSettings, FilePath filePath)
    {
        FileInfo result;
        FileInfo fileInfo = new(filePath.FullName);
        (_, int directoryIndex) = IPath.GetDirectoryNameAndIndex(resultSettings, filePath);
        DateTime minimumDateTime = fileInfo.CreationTime < fileInfo.LastWriteTime ? fileInfo.CreationTime : fileInfo.LastWriteTime;
        int fileInfoMinimumYear = minimumDateTime.Year < resultSettings.EpicYear ? resultSettings.EpicYear : minimumDateTime.Year;
        result = new(Path.Combine(_FileGroups[fileInfoMinimumYear][_ResultSettings.ResultSingleton][directoryIndex], $"{filePath.NameWithoutExtension}{filePath.ExtensionLowered}.json"));
        return (fileInfoMinimumYear, result);
    }

    private (int, string) GetJsonFile(ResultSettings resultSettings, FilePath filePath, ExifDirectory exifDirectory)
    {
        string? result;
        DateTime? dateTime;
        dateTime = IDate.GetDateTimeOriginal(exifDirectory);
        dateTime ??= IDate.GetMinimum(exifDirectory);
        (_, int directoryIndex) = IPath.GetDirectoryNameAndIndex(resultSettings, filePath);
        int exifYear = dateTime.Value.Year < resultSettings.EpicYear ? resultSettings.EpicYear : dateTime.Value.Year;
        result = Path.Combine(_FileGroups[exifYear][_ResultSettings.ResultSingleton][directoryIndex], $"{filePath.NameWithoutExtension}{filePath.ExtensionLowered}.json");
        return (exifYear, result);
    }

    private static (string, ExifDirectory?) Get(string jsonFile)
    {
        ExifDirectory? result;
        string json = File.ReadAllText(jsonFile);
        try
        {
            result = JsonSerializer.Deserialize(json, ExifDirectorySourceGenerationContext.Default.ExifDirectory);
            if (result is null)
                throw new Exception();
        }
        catch (Exception)
        {
            result = null;
        }
        return (json, result);
    }

    public (FileInfo, ExifDirectory) GetMetadataCollection(ResultSettings resultSettings, MetadataSettings metadataSettings, FilePath filePath)
    {
        ExifDirectory? result;
        (int fileInfoMinimumYear, FileInfo fileInfo) = GetFileInfo(resultSettings, filePath);
        if (_MetadataSettings.ForceMetadataLastWriteTimeToCreationTime && !fileInfo.Exists && File.Exists(Path.ChangeExtension(fileInfo.FullName, ".delete")))
        {
            File.Move(Path.ChangeExtension(fileInfo.FullName, ".delete"), fileInfo.FullName);
            fileInfo.Refresh();
        }
        if (_MetadataSettings.ForceMetadataLastWriteTimeToCreationTime && fileInfo.Exists && fileInfo.LastWriteTime != fileInfo.CreationTime)
        {
            File.SetLastWriteTime(fileInfo.FullName, fileInfo.CreationTime);
            fileInfo.Refresh();
        }
        if (_MetadataSettings.PropertiesChangedForMetadata)
            result = null;
        else if (!fileInfo.Exists)
            result = null;
        else if (!fileInfo.FullName.EndsWith(".json") && !fileInfo.FullName.EndsWith(".old"))
            throw new ArgumentException("must be a *.json file");
        else
        {
            string json = File.ReadAllText(fileInfo.FullName);
            try
            {
                result = JsonSerializer.Deserialize(json, ExifDirectorySourceGenerationContext.Default.ExifDirectory);
                if (result is null)
                    throw new Exception();
            }
            catch (Exception)
            {
                result = null;
            }
        }
        if (result is null)
        {
            string json;
            const PersonKeyFormattedAndKeyTicksAndDisplayDirectoryName? personKeyFormattedAndKeyTicksAndDisplayDirectoryName = null;
            result = Exif.GetExifDirectory(filePath, personKeyFormattedAndKeyTicksAndDisplayDirectoryName);
            (int exifYear, string jsonFile) = GetJsonFile(_ResultSettings, filePath, result);
            if (exifYear == fileInfoMinimumYear)
                json = JsonSerializer.Serialize(result, ExifDirectorySourceGenerationContext.Default.ExifDirectory);
            else
            {
                fileInfo = new(jsonFile);
                if (!File.Exists(jsonFile))
                    json = JsonSerializer.Serialize(result, ExifDirectorySourceGenerationContext.Default.ExifDirectory);
                else
                {
                    (string checkJson, ExifDirectory? exifDirectory) = Get(jsonFile);
                    if (exifDirectory is null)
                        json = JsonSerializer.Serialize(result, ExifDirectorySourceGenerationContext.Default.ExifDirectory);
                    else
                    {
                        json = checkJson;
                        result = exifDirectory;
                    }
                }
            }
            if (IPath.WriteAllText(fileInfo.FullName, json, updateDateWhenMatches: false, compareBeforeWrite: true, updateToWhenMatches: null) && _MetadataSettings.ForceMetadataLastWriteTimeToCreationTime)
            {
                File.SetLastWriteTime(fileInfo.FullName, fileInfo.CreationTime);
                fileInfo.Refresh();
            }
        }
        return (fileInfo, result);
    }

}