using System.Text;

namespace CompilerDesignIFlr1
{
    internal class LR1Table
    {
        internal List<Row> Rows = [];

        internal LR1Table(LR1Creator creator)
        {
            for (int i = 0; i < creator.Closures.Count; i++)
            {
                LR1Closure closure = creator.Closures[i];
                Dictionary<string, int> @goto = [];
                Dictionary<string, string> action = [];
                foreach (var (by, nextIndex) in closure.Next)
                {
                    if (creator.TokenUnit.ContainsKey(by))
                        action.Add(by, "s" + nextIndex);
                    else
                        @goto.Add(by, nextIndex);
                }
                foreach (var unit in closure.GetReduceUnits())
                {
                    foreach (string prospect in unit.Prospect)
                    {
                        if (action.ContainsKey(prospect))
                            throw new Exception("Reduce,Reduce/Reduce,Shift error occurred.");
                        action.Add(prospect, "r" + unit.Id);
                    }
                }
                Rows.Add(new Row(i, @goto, action));
            }
            PrintRow();
            return;
        }

        private void PrintRow()
        {
            foreach (Row row in Rows)
            {
                Console.WriteLine(row);
            }
        }
    }

    internal class Row
    {
        internal int Id;
        internal Dictionary<string, int> GOTO;
        internal Dictionary<string, string> ACTION;

        internal Row(int id, Dictionary<string, int> @goto, Dictionary<string, string> action)
        {
            Id = id;
            GOTO = @goto;
            ACTION = action;
        }

        public override string ToString()
        {
            StringBuilder sb = new StringBuilder();
            sb.Append(Id + "   \n");
            sb.Append("ACTION: \n");
            foreach (var (key, value) in ACTION)
                sb.Append(key).Append(": ").Append(value).Append(", ");
            if(GOTO.Count != 0)
                sb.Append("\nGOTO: \n");
            foreach (var (key, value) in GOTO)
                sb.Append(key).Append(": ").Append(value).Append(", ");
            sb.Append('\n');
            return sb.ToString();
        }

        public (string, int) Next(string name)
        {
            if (name == "StatementList" && Id == 0)
                return ("ACC", 0);
            if (GOTO.TryGetValue(name, out var result))
                return ("GOTO", result);
            if (ACTION.TryGetValue(name, out var value))
                if (value.StartsWith("s"))
                    return ("GOTO", int.Parse(value.Substring(1)));
                else if (value.StartsWith("r"))
                    return ("Reduce", int.Parse(value.Substring(1)));
                else
                    throw new Exception($"Value can't be recognized. {value}");
            throw new InvalidOperationException($"Code error in state {Id}: {name} not found");
        }
    }
}