using SzCore.DataObjects;

namespace SzCore;

public class SzDataHandler
{
    private Dictionary<string, SzDataset> _loadedDatasets = [];

    public SzDataHandler(){}

    public bool SaveDataset(SzDataset dataset)
    {
        var datasetPath = Path.Combine(SZ.LocalFileManager.DatasetsPath, dataset.Id, "dataset.json");
        try
        {
            return SZ.LocalFileManager.SaveFile(datasetPath, SZ.SzParser.SerializeDatasetToJson(dataset));
        }
        catch (Exception e)
        {
            SZ.Logger.LogError("Error saving dataset: " + e.Message);
            return false;
        }
    }

    public SzDataset? LoadDataset(string datasetId)
    {
        if (_loadedDatasets.TryGetValue(datasetId, out SzDataset? value))
        {
            if (value is not null) return value;
        }

        var datasetPath = Path.Combine(SZ.LocalFileManager.DataPath, "datasets", datasetId, "dataset.json");
        
        var json = SZ.LocalFileManager.LoadFile(datasetPath);
        if (json is null) 
        {
            SZ.Logger.LogWarning($"Could not load dataset with ID '{datasetId}'");
            return null;  
        }

        var parsedDataset = SZ.SzParser.DeserializeDataset(json);
        if (parsedDataset is null)
        {
            SZ.Logger.LogWarning($"Could not load dataset with ID '{datasetId}'");
            return null;  
        }

        _loadedDatasets.Add(parsedDataset.Id, parsedDataset);
        return parsedDataset;
    }

    // The client should periodically call this to free memory, probably
    private void ClearLoadedDatasets()
    {
        _loadedDatasets.Clear();
    }

    // Only use this for test purposes, we probably don't want to load all datasets to memory in production
    private void LoadAllDatasets()
    {
        ClearLoadedDatasets();
        if (!Directory.Exists(SZ.LocalFileManager.DatasetsPath))
        {
            throw new Exception("Could not load datasets, the datase directory does not exist.");
        }

        foreach (var dir in Directory.GetDirectories(SZ.LocalFileManager.DatasetsPath))
        {
            var datasetFilePath = Path.Combine(dir, "dataset.json");
            if (!File.Exists(datasetFilePath)) continue;

            var datasetJson = SZ.LocalFileManager.LoadFile(datasetFilePath);
            if (datasetJson == null) continue;

            var parsedDataset = SZ.SzParser.DeserializeDataset(datasetJson);
            if (parsedDataset == null)
            {
                SZ.Logger.LogWarning($"Parse error: Could not parse file {datasetFilePath} as an SzDataset");
                continue;
            }

            _loadedDatasets.Add(parsedDataset.Id, parsedDataset);
        }
    }
}