using System.Text;
using System.Text.Json;

namespace DevJsonDB.IO;

public class LocalStore<T> : IStore<T>
{
    private static Encoding DefaultEncoding = Encoding.UTF8;
    private string filePath;
    private List<T> items;

    public LocalStore(string filePath)
    {
        this.filePath = filePath;
        this.items = new List<T>();

        this.InitDatabase();
    }

    public void Dispose()
    {
        this.Commit();
    }

    public void Commit()
    {
        try
        {
            using (FileStream fs = new FileStream(this.filePath, FileMode.OpenOrCreate))
            using (StreamWriter writer = new StreamWriter(fs, DefaultEncoding))
            {
                foreach (T item in this.items)
                {
                    string json = JsonSerializer.Serialize<T>(item);
                    writer.WriteLine(json);
                }
            }
        }
        catch (Exception ex)
        {
            throw new JsonDBException(ex.Message, ex);
        }
    }

    public bool Add(T item)
    {
        if (this.items.Contains(item))
        {
            return false;
        }

        this.items.Add(item);
        return true;
    }

    public IEnumerable<T> GetValues()
    {
        return this.items.ToList();
    }

    private void InitDatabase()
    {
        try
        {
            using (FileStream fs = new FileStream(this.filePath, FileMode.OpenOrCreate))
            using (StreamReader reader = new StreamReader(fs, DefaultEncoding))
            {
                string? line = null;
                while ((line = reader.ReadLine()) != null)
                {
                    T? value = JsonSerializer.Deserialize<T>(line);
                    if (value is object)
                    {
                        this.items.Add(value);
                    }
                }
            }
        }
        catch (Exception ex)
        {
            throw new JsonDBException(ex.Message, ex);
        }
    }
}