// Copyright (c) .NET Foundation and contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System;
using System.Collections.Generic;
using System.Linq;
using Mono.Cecil;
using Mono.Cecil.Cil;

namespace TLens.Analyzers
{
    sealed class LargeStringsAnalyzer : Analyzer
    {
        readonly List<(int, MethodDefinition)> ldstrs = new List<(int, MethodDefinition)>();

        protected override void ProcessMethod(MethodDefinition method)
        {
            var reported = new List<string>();
            foreach (var instr in method.Body.Instructions)
            {
                switch (instr.OpCode.Code)
                {
                    case Code.Ldstr:
                        string str = (string)instr.Operand;
                        if (reported.Contains(str))
                            break;

                        if (str.Length > 1)
                            ldstrs.Add((str.Length, method));

                        reported.Add(str);
                        break;
                }
            }
        }

        public override void PrintResults(int maxCount)
        {
            var entries = ldstrs.OrderByDescending(l => l.Item1).Take(maxCount);
            if (!entries.Any())
                return;

            PrintHeader("Methods with large string loads");

            foreach (var entry in entries)
            {
                Console.WriteLine($"Method '{entry.Item2.ToDisplay()}' loads '{entry.Item1}' characters long string");
            }
        }
    }
}