using System.Collections.Generic;
using System.Linq;

namespace HeuristicLab.Problems.ProgramSynthesis.Push.Stack {
  using System.Globalization;

  using HeuristicLab.Problems.ProgramSynthesis.Push.Constants;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Extensions;
  using HeuristicLab.Problems.ProgramSynthesis.Push.Interpreter;

  public static class InterpreterStackStringifier {

    public static IEnumerable<string> StringifyStack(this IPushInterpreter interpreter, StackTypes type) {
      switch (type) {
        case StackTypes.Boolean: return StringifyLiteralStack(interpreter.BooleanStack);
        case StackTypes.Integer: return StringifyLiteralStack(interpreter.IntegerStack);
        case StackTypes.Float: return StringifyFloatStack(interpreter.FloatStack, interpreter.Configuration.FloatStringFormat);
        case StackTypes.Char: return StringifyCharStack(interpreter.CharStack);
        case StackTypes.String: return StringifyLiteralStack(interpreter.StringStack, PushEnvironment.StringSymbolStr, PushEnvironment.StringSymbolStr);
        case StackTypes.Name: return StringifyLiteralStack(interpreter.NameStack);
        case StackTypes.Code: return StringifyLiteralStack(interpreter.CodeStack);
        case StackTypes.Exec: return StringifyLiteralStack(interpreter.ExecStack);
        case StackTypes.Print: return StringifyLiteralStack(interpreter.PrintStack, PushEnvironment.StringSymbolStr, PushEnvironment.StringSymbolStr, false);

        case StackTypes.BooleanVector: return StringifyVectorStack(interpreter.BooleanVectorStack);
        case StackTypes.IntegerVector: return StringifyVectorStack(interpreter.IntegerVectorStack);
        case StackTypes.FloatVector: return StringifyFloatVectorStack(interpreter.FloatVectorStack, interpreter.Configuration.FloatStringFormat);
        case StackTypes.StringVector: return StringifyVectorStack(interpreter.StringVectorStack, PushEnvironment.StringSymbolStr, PushEnvironment.StringSymbolStr);

        default: return Enumerable.Empty<string>();
      }
    }

    private static IEnumerable<string> StringifyCharStack(IPushStack<char> stack) {
      var result = stack.AsEnumerable();

      return result.Select(x => PushEnvironment.CharSymbol + x.Printify() + PushEnvironment.CharSymbol);
    }

    private static IEnumerable<string> StringifyFloatStack(IPushStack<double> stack, string format) {
      var result = stack.AsEnumerable();

      return result.Select(x => x.ToString(format, CultureInfo.InvariantCulture));
    }

    private static IEnumerable<string> StringifyLiteralStack(IPushStack stack, string prefix = "", string postfix = "", bool reverse = true) {
      var result = stack.AsStrings();

      if (reverse)
        result = result.Reverse();

      return result.Select(x => prefix + x.ToString() + postfix);
    }

    private static IEnumerable<string> StringifyFloatVectorStack(IPushStack<IReadOnlyList<double>> stack, string format) {
      var separator = PushEnvironment.VectorSeparatorSymbol.ToString();
      return stack
        .Reverse()
        .Select(x => PushEnvironment.VectorStartSymbol + string.Join(separator, x.Select(_ => _.ToString(format, CultureInfo.InvariantCulture))) + PushEnvironment.VectorEndSymbol);
    }

    private static IEnumerable<string> StringifyVectorStack<T>(IPushStack<IReadOnlyList<T>> stack, string prefix = "", string postfix = "") {
      var separator = PushEnvironment.VectorSeparatorSymbol.ToString();
      return stack
        .Reverse()
        .Select(x => PushEnvironment.VectorStartSymbol + string.Join(separator, x.Select(_ => prefix + _.ToString() + postfix)) + PushEnvironment.VectorEndSymbol);
    }
  }
}