using System.Linq.Expressions;
using System.Reflection;
using PkmnLib.Dynamic.AI.Explicit;
using PkmnLib.Plugin.Gen7.Scripts.Moves;
using PkmnLib.Plugin.Gen7.Scripts.Pokemon;
using PkmnLib.Static.Moves;

namespace PkmnLib.Plugin.Gen7.AI;

public static class ExplicitAIFunctions
{
    public static void RegisterAIFunctions(ExplicitAIHandlers handlers)
    {
        var baseType = typeof(Script);
        foreach (var type in typeof(ExplicitAIFunctions).Assembly.GetTypes().Where(t => baseType.IsAssignableFrom(t)))
        {
            var attribute = type.GetCustomAttribute<ScriptAttribute>();
            if (attribute == null)
                continue;

            if (attribute.Category == ScriptCategory.Move)
            {
                var failureMethod = type.GetMethods(BindingFlags.Public | BindingFlags.Static).FirstOrDefault(m =>
                    m.GetCustomAttribute<AIMoveFailureFunctionAttribute>() != null);
                if (failureMethod != null)
                {
                    if (failureMethod.ReturnType != typeof(bool) || failureMethod.GetParameters().Length != 1 ||
                        failureMethod.GetParameters()[0].ParameterType != typeof(MoveOption))
                    {
                        throw new InvalidOperationException(
                            $"Method {failureMethod.Name} in {type.Name} must return bool and take a single MoveOption parameter.");
                    }
                    var optionParam = Expression.Parameter(typeof(MoveOption), "option");
                    var functionExpression = Expression.Lambda<AIBoolHandler>(
                        Expression.Call(null, failureMethod, optionParam), optionParam).Compile();
                    handlers.MoveFailureCheck.Add(attribute.Name, functionExpression);
                }

                var scoreMethod = type.GetMethods(BindingFlags.Public | BindingFlags.Static).FirstOrDefault(m =>
                    m.GetCustomAttribute<AIMoveScoreFunctionAttribute>() != null);
                if (scoreMethod != null)
                {
                    if (scoreMethod.ReturnType != typeof(void) || scoreMethod.GetParameters().Length != 2 ||
                        scoreMethod.GetParameters()[0].ParameterType != typeof(MoveOption) ||
                        scoreMethod.GetParameters()[1].ParameterType != typeof(int).MakeByRefType())
                    {
                        throw new InvalidOperationException(
                            $"Method {scoreMethod.Name} in {type.Name} must return void and take a MoveOption and an int by reference parameter.");
                    }
                    var optionParam = Expression.Parameter(typeof(MoveOption), "option");
                    var scoreParam = Expression.Parameter(typeof(int).MakeByRefType(), "score");
                    var functionExpression = Expression.Lambda<AIScoreMoveHandler>(
                        Expression.Call(null, scoreMethod, optionParam, scoreParam), optionParam, scoreParam).Compile();
                    handlers.MoveEffectScore.Add(attribute.Name, functionExpression);
                }
            }
        }

        handlers.GeneralMoveAgainstTargetScore.Add("predicated_damage", PredictedDamageScore);
    }

    private static void PredictedDamageScore(MoveOption option, ref int score)
    {
        var target = option.Target;
        if (target == null)
            return;
        if (option.Move.Move.Category == MoveCategory.Status)
            return;
        var damage = option.EstimatedDamage;
        if (target.Volatile.TryGet<SubstituteEffect>(out var substitute))
        {
            var health = substitute.Health;
            score += (int)Math.Min(15.0f * damage / health, 20);
            return;
        }

        score += (int)Math.Min(15.0f * damage / target.CurrentHealth, 30);

        if (damage > target.CurrentHealth * 1.1f)
        {
            score += 10;
            if ((option.Move.Move.HasFlag("multi_hit") && target.CurrentHealth == target.MaxHealth &&
                 target.ActiveAbility?.Name == "sturdy") || target.HasHeldItem("focus_sash"))
            {
                score += 8;
            }
        }
    }
}