using System;
using System.IO;
using System.Runtime.Serialization;
using System.Xml;
using TelegramBotBase.Args;
using TelegramBotBase.Base;
using TelegramBotBase.Form;
using TelegramBotBase.Interfaces;

namespace TelegramBotBase.States;

public class XmlStateMachine : IStateMachine
{
    /// <summary>
    ///     Will initialize the state machine.
    /// </summary>
    /// <param name="file">Path of the file and name where to save the session details.</param>
    /// <param name="fallbackStateForm">
    ///     Type of Form which will be saved instead of Form which has
    ///     <seealso cref="Attributes.IgnoreState" /> attribute declared. Needs to be subclass of
    ///     <seealso cref="Form.FormBase" />.
    /// </param>
    /// <param name="overwrite">Declares of the file could be overwritten.</param>
    public XmlStateMachine(string file, Type fallbackStateForm = null, bool overwrite = true)
    {
        FallbackStateForm = fallbackStateForm;

        if (FallbackStateForm != null && !FallbackStateForm.IsSubclassOf(typeof(FormBase)))
        {
            throw new ArgumentException("FallbackStateForm is not a subclass of FormBase");
        }

        FilePath = file ?? throw new ArgumentNullException(nameof(file));
        Overwrite = overwrite;
    }

    public string FilePath { get; set; }

    public bool Overwrite { get; set; }

    public Type FallbackStateForm { get; }

    public StateContainer LoadFormStates()
    {
        try
        {
            var serializer = new DataContractSerializer(typeof(StateContainer));

            using (var reader = new StreamReader(FilePath))
            {
                using (var xml = new XmlTextReader(reader))
                {
                    var sc = serializer.ReadObject(xml) as StateContainer;
                    return sc;
                }
            }
        }
        catch
        {
        }

        return new StateContainer();
    }

    public void SaveFormStates(SaveStatesEventArgs e)
    {
        if (File.Exists(FilePath))
        {
            if (!Overwrite)
            {
                throw new Exception("File exists already.");
            }

            File.Delete(FilePath);
        }

        try
        {
            var serializer = new DataContractSerializer(typeof(StateContainer));

            using (var sw = new StreamWriter(FilePath))
            {
                using (var writer = new XmlTextWriter(sw))
                {
                    writer.Formatting = Formatting.Indented; // indent the Xml so it’s human readable
                    serializer.WriteObject(writer, e.States);
                    writer.Flush();
                }
            }
        }
        catch
        {
        }
    }
}