using View_by_Distance.Shared.Models.Stateless.Methods;

namespace View_by_Distance.Shared.Models.Stateless;

internal abstract class Id
{

    internal static bool NameWithoutExtensionIsIdFormat(string fileNameWithoutExtension)
    {
        bool result;
        int intMinValueLength = int.MinValue.ToString().Length;
        if (fileNameWithoutExtension.Length < 5 || fileNameWithoutExtension.Length > intMinValueLength)
            result = false;
        else
        {
            bool skipOneAllAreNumbers = fileNameWithoutExtension[1..].All(l => char.IsNumber(l));
            result = (skipOneAllAreNumbers && fileNameWithoutExtension[0] == '-') || (skipOneAllAreNumbers && char.IsNumber(fileNameWithoutExtension[0]));
        }
        return result;
    }

    internal static FilePath GetFilePath(FilePath filePath, string file)
    {
        FilePath result;
        string fileName = Path.GetFileName(file);
        string fileExtensionLowered = Path.GetExtension(file).ToLower();
        result = new(filePath.DirectoryName, fileExtensionLowered, file, filePath.Id, filePath.IsIdFormat, filePath.IsPaddedIdFormat, fileName, filePath.NameWithoutExtension);
        return result;
    }

    internal static FilePath GetFilePath(MetadataConfiguration metadataConfiguration, string file)
    {
        FilePath result;
        int? id;
        short? multiplier;
        char negativeMarker;
        int absoluteValueOfId;
        string fileName = Path.GetFileName(file);
        string fileExtensionLowered = Path.GetExtension(file).ToLower();
        string fileNameWithoutExtension = Path.GetFileNameWithoutExtension(file);
        string fileDirectoryName = Path.GetDirectoryName(file) ?? throw new NullReferenceException();
        short sortOrderOnlyLengthIndex = IId.GetSortOrderOnlyLengthIndex(metadataConfiguration.Offset);
        bool nameWithoutExtensionIsIdFormat = IId.NameWithoutExtensionIsIdFormat(fileNameWithoutExtension);
        bool nameWithoutExtensionIsPaddedIdFormat = IId.NameWithoutExtensionIsPaddedIdFormat(fileNameWithoutExtension, sortOrderOnlyLengthIndex);
        if (!nameWithoutExtensionIsIdFormat && !nameWithoutExtensionIsPaddedIdFormat)
            id = null;
        else if (nameWithoutExtensionIsIdFormat)
        {
            if (!int.TryParse(fileNameWithoutExtension, out absoluteValueOfId))
                id = null;
            else
                id = absoluteValueOfId;
        }
        else
        {
            negativeMarker = fileNameWithoutExtension[sortOrderOnlyLengthIndex - 2];
            if (negativeMarker == '7')
                multiplier = 1;
            else if (negativeMarker == '3')
                multiplier = -1;
            else
                multiplier = null;
            if (!int.TryParse(fileNameWithoutExtension[sortOrderOnlyLengthIndex..], out absoluteValueOfId))
                id = null;
            else
            {
                id = absoluteValueOfId * multiplier;
                if (id is null || !fileNameWithoutExtension.EndsWith(id.Value.ToString()[1..]))
                    id = null;
            }
        }
        result = new(fileDirectoryName, fileExtensionLowered, file, id, nameWithoutExtensionIsIdFormat, nameWithoutExtensionIsPaddedIdFormat, fileName, fileNameWithoutExtension);
        return result;
    }

    internal static int GetDeterministicHashCode(byte[] value)
    {
        int result;
        unchecked
        {
            int hash1 = (5381 << 16) + 5381;
            int hash2 = hash1;
            for (int i = 0; i < value.Length; i += 2)
            {
                hash1 = ((hash1 << 5) + hash1) ^ value[i];
                if (i == value.Length - 1)
                    break;
                hash2 = ((hash2 << 5) + hash2) ^ value[i + 1];
            }
            result = hash1 + (hash2 * 1566083941);
        }
        return result;
    }

}