using System;
using System.Linq;
using System.Reflection;
using Mono.Cecil;
using Mono.Cecil.Cil;

namespace StardewModdingAPI.AssemblyRewriters.Framework
{
    /// <summary>Base class for a method finder.</summary>
    public abstract class BaseMethodFinder : IInstructionFinder
    {
        /*********
        ** Public methods
        *********/
        /// <summary>Get whether a CIL instruction matches.</summary>
        /// <param name="instruction">The IL instruction.</param>
        /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
        public bool IsMatch(Instruction instruction, bool platformChanged)
        {
            if (instruction.OpCode != OpCodes.Call && instruction.OpCode != OpCodes.Callvirt)
                return false; // not a method reference
            return this.IsMatch(instruction, (MethodReference)instruction.Operand, platformChanged);
        }


        /*********
        ** Protected methods
        *********/
        /// <summary>Get whether a method reference should be rewritten.</summary>
        /// <param name="instruction">The IL instruction.</param>
        /// <param name="methodRef">The method reference.</param>
        /// <param name="platformChanged">Whether the mod was compiled on a different platform.</param>
        protected abstract bool IsMatch(Instruction instruction, MethodReference methodRef, bool platformChanged);

        /// <summary>Get whether a method definition matches the signature expected by a method reference.</summary>
        /// <param name="definition">The method definition.</param>
        /// <param name="reference">The method reference.</param>
        protected bool HasMatchingSignature(MethodInfo definition, MethodReference reference)
        {
            // same name
            if (definition.Name != reference.Name)
                return false;

            // same arguments
            ParameterInfo[] definitionParameters = definition.GetParameters();
            ParameterDefinition[] referenceParameters = reference.Parameters.ToArray();
            if (referenceParameters.Length != definitionParameters.Length)
                return false;
            for (int i = 0; i < referenceParameters.Length; i++)
            {
                if (!RewriteHelper.IsMatchingType(definitionParameters[i].ParameterType, referenceParameters[i].ParameterType))
                    return false;
            }
            return true;
        }

        /// <summary>Get whether a type has a method whose signature matches the one expected by a method reference.</summary>
        /// <param name="type">The type to check.</param>
        /// <param name="reference">The method reference.</param>
        protected bool HasMatchingSignature(Type type, MethodReference reference)
        {
            return type
                .GetMethods(BindingFlags.Instance | BindingFlags.DeclaredOnly | BindingFlags.Public)
                .Any(method => this.HasMatchingSignature(method, reference));
        }
    }
}