using System;
using System.Xml.Serialization;
using Newtonsoft.Json;
using SabreTools.Core.Tools;

namespace SabreTools.Core
{
    /// <summary>
    /// Represents an item that's backed by a DictionaryBase item
    /// </summary>
    public abstract class ModelBackedItem : IEquatable<ModelBackedItem>
    {
        #region Comparision Methods

        /// <inheritdoc/>
        public abstract bool Equals(ModelBackedItem? other);

        #endregion
    }

    /// <summary>
    /// Represents an item that's backed by a DictionaryBase item
    /// </summary>
    public abstract class ModelBackedItem<T> : ModelBackedItem, IEquatable<ModelBackedItem<T>> where T : Models.Metadata.DictionaryBase
    {
        /// <summary>
        /// Internal model wrapped by this DatItem
        /// </summary>
        [JsonIgnore, XmlIgnore]
        protected T _internal;

        #region Constructors

        public ModelBackedItem()
        {
            _internal = (T)Activator.CreateInstance(typeof(T))!;
        }

        #endregion

        #region Accessors

        /// <summary>
        /// Get the value from a field based on the type provided
        /// </summary>
        /// <typeparam name="U">Type of the value to get from the internal model</typeparam>
        /// <param name="fieldName">Field to retrieve</param>
        /// <returns>Value from the field, if possible</returns>
        public U? GetFieldValue<U>(string? fieldName)
        {
            // Invalid field cannot be processed
            if (fieldName == null || !_internal.ContainsKey(fieldName))
                return default;

            // Get the value based on the type
            return _internal.Read<U>(fieldName);
        }

        /// <summary>
        /// Get the value from a field based on the type provided
        /// </summary>
        /// <param name="fieldName">Field to retrieve</param>
        /// <returns>Value from the field, if possible</returns>
        public bool? GetBoolFieldValue(string? fieldName)
        {
            // Invalid field cannot be processed
            if (fieldName == null || !_internal.ContainsKey(fieldName))
                return default;

            // Get the value based on the type
            return _internal.ReadBool(fieldName);
        }

        /// <summary>
        /// Get the value from a field based on the type provided
        /// </summary>
        /// <param name="fieldName">Field to retrieve</param>
        /// <returns>Value from the field, if possible</returns>
        public double? GetDoubleFieldValue(string? fieldName)
        {
            // Invalid field cannot be processed
            if (fieldName == null || !_internal.ContainsKey(fieldName))
                return default;

            // Try to parse directly
            double? doubleValue = _internal.ReadDouble(fieldName);
            if (doubleValue != null)
                return doubleValue;

            // Try to parse from the string
            string? stringValue = _internal.ReadString(fieldName);
            return NumberHelper.ConvertToDouble(stringValue);
        }

        /// <summary>
        /// Get the value from a field based on the type provided
        /// </summary>
        /// <param name="fieldName">Field to retrieve</param>
        /// <returns>Value from the field, if possible</returns>
        public long? GetInt64FieldValue(string? fieldName)
        {
            // Invalid field cannot be processed
            if (fieldName == null || !_internal.ContainsKey(fieldName))
                return default;

            // Try to parse directly
            long? longValue = _internal.ReadLong(fieldName);
            if (longValue != null)
                return longValue;

            // Try to parse from the string
            string? stringValue = _internal.ReadString(fieldName);
            return NumberHelper.ConvertToInt64(stringValue);
        }

        /// <summary>
        /// Get the value from a field based on the type provided
        /// </summary>
        /// <param name="fieldName">Field to retrieve</param>
        /// <returns>Value from the field, if possible</returns>
        public string? GetStringFieldValue(string? fieldName)
        {
            // Invalid field cannot be processed
            if (fieldName == null || !_internal.ContainsKey(fieldName))
                return default;

            // Get the value based on the type
            return _internal.ReadString(fieldName);
        }

        /// <summary>
        /// Get the value from a field based on the type provided
        /// </summary>
        /// <param name="fieldName">Field to retrieve</param>
        /// <returns>Value from the field, if possible</returns>
        public string[]? GetStringArrayFieldValue(string? fieldName)
        {
            // Invalid field cannot be processed
            if (fieldName == null || !_internal.ContainsKey(fieldName))
                return default;

            // Get the value based on the type
            return _internal.ReadStringArray(fieldName);
        }

        /// <summary>
        /// Set the value from a field based on the type provided
        /// </summary>
        /// <typeparam name="U">Type of the value to set in the internal model</typeparam>
        /// <param name="fieldName">Field to set</param>
        /// <param name="value">Value to set</param>
        /// <returns>True if the value was set, false otherwise</returns>
        public bool SetFieldValue<U>(string? fieldName, U? value)
        {
            // Invalid field cannot be processed
            if (fieldName == null)
                return false;

            // Set the value based on the type
            _internal[fieldName] = value;
            return true;
        }

        #endregion

        #region Comparision Methods

        /// <inheritdoc/>
        public abstract bool Equals(ModelBackedItem<T>? other);

        #endregion

        #region Manipulation

        /// <summary>
        /// Remove a field from the backing item
        /// </summary>
        public bool RemoveField(string? fieldName)
        {
            // If the item or field name are missing, we can't do anything
            if (_internal == null || string.IsNullOrEmpty(fieldName))
                return false;

            // If the key doesn't exist, then it's already removed
            if (!_internal.ContainsKey(fieldName!))
                return true;

            // Remove the key
            _internal.Remove(fieldName!);
            return true;
        }

        /// <summary>
        /// Replace a field from another ModelBackedItem
        /// </summary>
        public bool ReplaceField(ModelBackedItem<T>? from, string? fieldName)
        {
            // If the items or field name are missing, we can't do anything
            if (from?._internal == null || _internal == null || string.IsNullOrEmpty(fieldName))
                return false;

            // If the types of the items are not the same, we can't do anything
            if (from._internal.GetType() != _internal.GetType())
                return false;

            // If the key doesn't exist in the source, we can't do anything
            if (!from._internal.ContainsKey(fieldName!))
                return false;

            // Set the key
            _internal[fieldName!] = from._internal[fieldName!];
            return true;
        }

        /// <summary>
        /// Set a field from the backing item
        /// </summary>
        public bool SetField(string? fieldName, object value)
        {
            // If the item or field name are missing, we can't do anything
            if (_internal == null || string.IsNullOrEmpty(fieldName))
                return false;

            // Retrieve the list of valid fields for the item
            var constants = TypeHelper.GetConstants(_internal.GetType());
            if (constants == null)
                return false;

            // Get the value that matches the field name provided
            string? realField = Array.Find(constants, c => string.Equals(c, fieldName, StringComparison.OrdinalIgnoreCase));
            if (realField == null)
                return false;

            // Set the field with the new value
            _internal[realField] = value;
            return true;
        }

        #endregion
    }
}