using System.Text.Json;
using Models;

namespace Repository;

public class JsonRepository : IRepository, IDisposable
{
    private const string _appName = "Keychain";

    private uint _autoIncrementedId;
    private readonly string _filePath;
    private List<PasswordStore> _cache;
    private bool _cacheAhead;

    public JsonRepository(string fileName)
    {
        string? xdgDataHome = Environment.GetEnvironmentVariable("XDG_DATA_HOME");
        string dataHome;
        if (!string.IsNullOrEmpty(xdgDataHome))
        {
            dataHome = Path.Combine(xdgDataHome, _appName);
        }
        else
        {
            dataHome = Path.Combine(
                Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".local", "share"),
                _appName
            );
        }
        _filePath = Path.Combine(dataHome, fileName);

        ReadAllFromFile();

        var lastItem = _cache.OrderBy(item => item.ID).LastOrDefault();
        _autoIncrementedId = lastItem != null ? lastItem.ID : 0;
    }

    private void ReadAllFromFile()
    {
        var items = new List<PasswordStore>();

        if (File.Exists(_filePath))
        {
            try
            {
                string json = File.ReadAllText(_filePath);
                items = JsonSerializer.Deserialize<List<PasswordStore>>(json) ?? new List<PasswordStore>();
            }
            catch (JsonException e)
            {
                WriteToStdErr($"JSON error: {e.Message}");
            }
            catch (IOException e)
            {
                WriteToStdErr($"File I/O error: {e.Message}");
            }
            catch (Exception e)
            {
                WriteToStdErr($"Unexpected error: {e.Message}");
            }
        }

        _cache = items;
        _cacheAhead = false;
    }

    public List<PasswordStore> GetAll()
    {
        return _cache;
    }

    public PasswordStore? Get(uint id)
    {
        try
        {
            return _cache.First(item => item.ID.Equals(id));
        }
        catch (InvalidOperationException)
        {
            // Not found
            return null;
        }
        catch (Exception e)
        {
            WriteToStdErr($"Unexpected error: {e.Message}");
            return null;
        }
    }

    public void Dispose()
    {
        if (_cacheAhead)
        {
            try
            {
                string json = JsonSerializer.Serialize(_cache);
                string? directory = Path.GetDirectoryName(_filePath);
                if (!Directory.Exists(directory))
                {
                    Directory.CreateDirectory(directory!);
                }
                File.WriteAllText(_filePath, json);
            }
            catch (IOException e)
            {
                WriteToStdErr($"File I/O error: {e.Message}");
            }
            catch (Exception e)
            {
                WriteToStdErr($"Unexpected error: {e.Message}");
            }

            ReadAllFromFile();
        }
    }

    public void Edit(uint ID, PasswordStore newItem)
    {
        try
        {
            PasswordStore item = _cache.First(item => item.ID.Equals(ID));
            item.DisplayName = newItem.DisplayName;
            item.IconName = newItem.IconName;
            item.Path = newItem.Path;
            _cacheAhead = true;
        }
        catch (InvalidOperationException)
        {
            WriteToStdErr($"Edit error: Item with ID {ID} not found.");
        }
        catch (Exception e)
        {
            WriteToStdErr($"Unexpected error: {e.Message}");
        }
    }

    public void Create(PasswordStore item)
    {
        item.ID = ++_autoIncrementedId;
        _cache.Add(item);
        _cacheAhead = true;
    }

    public void Delete(PasswordStore item)
    {
        Delete(item.ID);
    }

    public void Delete(uint id)
    {
        try
        {
            var item = _cache.First(item => item.ID.Equals(id));
            _cache.Remove(item);
            _cacheAhead = true;
        }
        catch (InvalidOperationException)
        {
            WriteToStdErr($"Delete error: Item with ID {id} not found.");
        }
        catch (Exception e)
        {
            WriteToStdErr($"Unexpected error: {e.Message}");
        }
    }

    private void WriteToStdErr(string message)
    {
        using var sw = new StreamWriter(Console.OpenStandardError());
        sw.WriteLine(message);
    }
}