using System.ComponentModel.Design;
using SzCore.DataObjects;

namespace SzCore;

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

    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))
        {
            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;
    }

    public bool SaveTemplate(ISzTemplate template)
    {
        var templatePath = Path.Combine(SZ.LocalFileManager.TemplatesPath, template.Id, "template.json");
        try
        {
            return SZ.LocalFileManager.SaveFile(templatePath, SZ.SzParser.SerializeTemplateToJson(template));
        }
        catch (Exception e)
        {
            SZ.Logger.LogError("Error saving template: " + e.Message);
            return false;
        }
    }

    public T? LoadTemplate<T>(string templateId) where T : ISzTemplate
    {
        if (_loadedTemplates.TryGetValue(templateId, out ISzTemplate? existing))
        {
            return (T)existing;
        }

        var templatePah = Path.Combine(SZ.LocalFileManager.TemplatesPath, templateId, "template.json");
        
        var json = SZ.LocalFileManager.LoadFile(templatePah);
        if (json is null) 
        {
            SZ.Logger.LogWarning($"Could not load tetmplate with ID '{templateId}'");
            return default;  
        }

        var parsedTemplate = SZ.SzParser.DeserializeTemplate<T>(json);
        if (parsedTemplate is null)
        {
            SZ.Logger.LogWarning($"Could not load template with ID '{templateId}'");
            return default;  
        }

        _loadedTemplates.TryAdd(parsedTemplate.Id, parsedTemplate);

        return parsedTemplate;
    }

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

    // Only use these two methods for test purposes, we probably don't want to load all datasets and templates to memory in production
    private void LoadAllDatasets()
    {
        _loadedDatasets.Clear();
        if (!Directory.Exists(SZ.LocalFileManager.DatasetsPath))
        {
            throw new Exception("Could not load datasets, the dataset 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);
        }
    }

    private void LoadAllTemplates()
    {
        _loadedTemplates.Clear();
        if (!Directory.Exists(SZ.LocalFileManager.TemplatesPath))
        {
            throw new Exception("Could not load templates, the template directory does not exist.");
        }

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

            var templateJson = SZ.LocalFileManager.LoadFile(templateFilePath);
            if (templateJson == null) continue;

            var parsedTemplate = SZ.SzParser.DeserializeTemplate<ISzTemplate>(templateJson);
            if (parsedTemplate == null)
            {
                SZ.Logger.LogWarning($"Parse error: Could not parse file {templateFilePath} as an ISzTemplate");
                continue;
            }

            _loadedTemplates.Add(parsedTemplate.Id, parsedTemplate);
        }
    }
}