using RPGCore.Core.Objects;
using RPGCore.ObjectModules.EventObjectModule;
using RPGCore.Stats.ObjectModules.StatsObjectModule.Events;
using RPGCoreCommon.DynamicValues;
using UnityEngine;

namespace RPGCore.Stats.ObjectModules.StatsObjectModule
{
    /// <summary>
    /// <b>You should never instantiate this by yourself!</b>
    /// Instantiated automatically by <see cref="StatsModule"/> for every available <see cref="StatDefinitionSO"/>.
    /// </summary>
    public sealed class StatValue
    {
        public readonly StatDefinitionSO definition;
        private readonly BaseObject _parent;
        public readonly DynamicValueSourceContext sourceContext = new();
        
        /// <summary>
        /// Base value defined in <see cref="StatsModule"/> attached to <see cref="BaseObject"/>.
        /// Formula result will be added to this base value.
        /// Default base value is ZERO.
        /// </summary>
        public int baseValue { get; private set; }
        
        /// <summary>
        /// This value is calculated by <see cref="DynamicValue"/> in <see cref="StatDefinitionSO"/> and can have two meanings:<br/>
        /// 1. If <see cref="StatType.Value"/> - just simple value stat<br/>
        /// 2. If <see cref="StatType.Resource"/> - this is maximum value for that resource
        /// </summary>
        public int value { get; private set; }
        
        /// <summary>
        /// Usable only when <see cref="StatDefinitionSO"/>.<see cref="StatType"/> is <see cref="StatType.Resource"/>.<br/>
        /// This value represent current resource of this stat. Always between <see cref="baseValue"/> and <see cref="value"/>
        /// </summary>
        public int resource { get; private set; }

        internal StatValue(StatDefinitionSO definition, int baseValue, BaseObject parent)
        {
            this.definition = definition;
            _parent = parent;
            this.baseValue = baseValue;
        }

        /// <summary>
        /// Refreshes <see cref="value"/>, by calculating formula again.
        /// </summary>
        internal void Refresh()
        {
            var previous = value;
            value = baseValue + definition.dynamicValue.GetValue(sourceContext);
            _parent.events.Invoke(new StatValueChangeEvent
            {
                after = value,
                before = previous,
                statDefinition = definition,
                target = _parent
            });
        }

        /// <summary>
        /// Sets new <see cref="baseValue"/> and then do <see cref="Refresh"/> to recalculate whole <see cref="value"/>
        /// </summary>
        /// <param name="amount">New base value</param>
        public void SetBase(int amount)
        {
            baseValue = amount;
            Refresh();
        }

        /// <summary>
        /// Changes (or simpler - uses) <see cref="resource"/> of this stat value by given amount.
        /// It just calls <see cref="SetResource(int)"/> with: <see cref="resource"/> + <see cref="amount"/>
        /// </summary>
        /// <param name="amount">Amount that will be added or subtracted from <see cref="resource"/></param>
        public void ChangeResource(int amount)
        {
            SetResource(resource + amount);
        }

        /// <summary>
        /// Sets <see cref="resource"/> to given amount. Amount will be clamped between ZERO and <see cref="value"/>.
        /// </summary>
        /// <param name="amount">New amount</param>
        public void SetResource(int amount)
        {
            var old = resource;
            resource = Mathf.Clamp(amount, 0, value);
            _parent.events.Invoke(new StatResourceChangeEvent
            {
                delta = resource - old,
                after = resource,
                before = old,
                statDefinition = definition,
                target = _parent
            });
        }

        /// <summary>
        /// Sets <see cref="resource"/> to given percentage. Percentage will be clamped between ZERO and ONE.
        /// </summary>
        /// <param name="percentage">New percentage</param>
        public void SetResource(float percentage)
        {
            SetResource(Mathf.CeilToInt(Mathf.Clamp01(percentage) * value));
        }
    }
}