using System;
using UnitTestSharp;

namespace Vellum.Generator.UnitTests
{
    public class CodeWriterTests : TestFixture
    {
        public class NewLineTests : TestFixture
        {
            public void WritesABlankLineEvenWhenIndented()
            {
                var code = new CodeWriter();
                code.Indent();

                code.NewLine();

                CheckEqual("\r\n", code.ToString());
            }
        }

        public class AddLineTests : TestFixture
        {
            public void WritesTheContentWithACarriageReturnLineFeed()
            {
                var code = new CodeWriter();

                code.AddLine("int x;");

                CheckEqual("int x;\r\n", code.ToString());
            }

            public void EmptyContent_WritesABlankLineEvenWhenIndented()
            {
                var code = new CodeWriter();
                code.Indent();

                code.AddLine("");

                CheckEqual("\r\n", code.ToString());
            }

            public void Indented_PrefixesFourSpacesPerLevel()
            {
                var code = new CodeWriter();
                code.Indent();
                code.Indent();

                code.AddLine("int x;");

                CheckEqual("        int x;\r\n", code.ToString());
            }
        }

        public class IndentTests : TestFixture
        {
            public void AffectsOnlyTheLinesAfterIt()
            {
                var code = new CodeWriter();
                code.AddLine("before");

                code.Indent();
                code.AddLine("after");

                CheckEqual("before\r\n    after\r\n", code.ToString());
            }
        }

        public class DedentTests : TestFixture
        {
            public void UndoesOneIndent()
            {
                var code = new CodeWriter();
                code.Indent();
                code.Indent();

                code.Dedent();
                code.AddLine("x");

                CheckEqual("    x\r\n", code.ToString());
            }

            public void WithoutAnIndent_Throws()
            {
                var code = new CodeWriter();

                CheckThrow(typeof(InvalidOperationException));
                code.Dedent();
            }
        }

        public class OpenNewBlockTests : TestFixture
        {
            public void WithoutAHeader_WritesABraceAndIndents()
            {
                var code = new CodeWriter();

                code.OpenNewBlock();
                code.AddLine("x");

                CheckEqual("{\r\n    x\r\n", code.ToString());
            }

            public void WithAHeader_WritesItAboveTheBrace()
            {
                var code = new CodeWriter();

                code.OpenNewBlock("class A");
                code.AddLine("x");

                CheckEqual("class A\r\n{\r\n    x\r\n", code.ToString());
            }

            public void Nested_IndentsEachLevel()
            {
                var code = new CodeWriter();

                code.OpenNewBlock("class A");
                code.OpenNewBlock("void B()");
                code.AddLine("x");

                CheckEqual("class A\r\n{\r\n    void B()\r\n    {\r\n        x\r\n", code.ToString());
            }
        }

        public class CloseBlockTests : TestFixture
        {
            public void DedentsThenWritesTheClosingBrace()
            {
                var code = new CodeWriter();
                code.OpenNewBlock("class A");

                code.CloseBlock();
                code.AddLine("after");

                CheckEqual("class A\r\n{\r\n}\r\nafter\r\n", code.ToString());
            }

            public void Nested_ClosesInnermostFirst()
            {
                var code = new CodeWriter();
                code.OpenNewBlock("class A");
                code.OpenNewBlock("void B()");

                code.CloseBlock();
                code.CloseBlock();

                CheckEqual("class A\r\n{\r\n    void B()\r\n    {\r\n    }\r\n}\r\n", code.ToString());
            }

            public void WithoutAnOpenBlock_Throws()
            {
                var code = new CodeWriter();

                CheckThrow(typeof(InvalidOperationException));
                code.CloseBlock();
            }
        }

        public class ToStringTests : TestFixture
        {
            public void NothingWritten_IsEmpty()
            {
                CheckEqual("", new CodeWriter().ToString());
            }
        }
    }
}