using Upsilon.BaseTypes;
using Upsilon.BaseTypes.Number;
using Upsilon.Evaluator;
using Xunit;

namespace UpsilonTests
{
    public class FunctionTests
    {
        [Fact]
        public void BasicFunctionTest()
        {
            const string input = @"
function testFunc ()
    a = 100
end
a = 50
testFunc()
";
            var script = new Script(input);
            Assert.Empty(script.Diagnostics.Messages);
            script.Evaluate();
            Assert.Empty(script.Diagnostics.Messages);
            Assert.True(script.Scope.TryGet("testFunc", out var func));
            Assert.IsType<LuaFunction>(func);
            Assert.True(script.Scope.TryGet("a", out var a));
            Assert.Equal(100, (long)(NumberLong)a);
        }

        [Fact]
        public void ParameterTest()
        {
            const string input = @"
function testFunc (var1)
    a = var1
end
a = 50
testFunc(100)
";
            var script = new Script(input);
            Assert.Empty(script.Diagnostics.Messages);
            script.Evaluate();
            Assert.Empty(script.Diagnostics.Messages);
            Assert.True(script.Scope.TryGet("testFunc", out var func));
            Assert.IsType<LuaFunction>(func);
            Assert.True(script.Scope.TryGet("a", out var a));
            Assert.Equal(100, (long)(NumberLong)a);
        }

        [Fact]
        public void ParameterBindTest()
        {
            const string input = @"
function testFunc (var1)
    var1 == true
end
testFunc(100)
";
            var script = new Script(input);
            Assert.Empty(script.Diagnostics.Messages);
            script.Evaluate();
            Assert.Single(script.Diagnostics.Messages);
            Assert.True(script.Scope.TryGet("testFunc", out var func));
            Assert.IsType<LuaFunction>(func);
        }

        [Fact]
        public void BindUnusedFunctions()
        {
            const string input = @"
function testFunc (var1)
    var1 == true
end
";
            var script = new Script(input);
            Assert.Empty(script.Diagnostics.Messages);
            script.Evaluate();
            Assert.Empty(script.Diagnostics.Messages);
            Assert.True(script.Scope.TryGet("testFunc", out var func));
            var castType = Assert.IsType<LuaFunction>(func);
            Assert.NotNull(castType.Block);
        }

        [Fact]
        public void ReturnFromFunction()
        {
            const string input = @"
function testFunc ()
    return 5
end
a = testFunc()
";
            var script = new Script(input);
            Assert.Empty(script.Diagnostics.Messages);
            script.Evaluate();
            Assert.Empty(script.Diagnostics.Messages);
            Assert.True(script.Scope.TryGet("a", out var result));
            Assert.Equal(5, (long)(NumberLong)result);
        }

        [Fact]
        public void ReturnFromFunctionOnce()
        {
            const string input = @"
function testFunc ()
    return 5
    return 10
end
a = testFunc()
";
            var script = new Script(input);
            Assert.Empty(script.Diagnostics.Messages);
            script.Evaluate();
            Assert.Empty(script.Diagnostics.Messages);
            Assert.True(script.Scope.TryGet("a", out var result));
            Assert.Equal(5, (long)(NumberLong)result);
        }

        [Fact]
        public void ReturnFromFunctionNested()
        {
            const string input = @"
function testFunc ()
    if true then
        return 5
    end
    return 10
end
a = testFunc()
";
            var script = new Script(input);
            Assert.Empty(script.Diagnostics.Messages);
            script.Evaluate();
            Assert.Empty(script.Diagnostics.Messages);
            Assert.True(script.Scope.TryGet("a", out var result));
            Assert.Equal(5, (long)(NumberLong)result);
        }

        [Fact]
        public void ReturnFromScriptAsFunction()
        {
            const string input = @"
a = 100
return 60
a = 87
";
            var script = new Script(input);
            Assert.Empty(script.Diagnostics.Messages);
            var result = script.Evaluate<NumberLong>();
            Assert.Empty(script.Diagnostics.Messages);
            Assert.Equal(60, (long)(NumberLong)result);
        }

        [Fact]
        public void ReturnFromCSharpCall()
        {
            const string input = @"
function testFunc ()
    return 100
end
";
            var script = new Script(input);
            Assert.Empty(script.Diagnostics.Messages);
            var result = script.EvaluateFunction<NumberLong>("testFunc");
            Assert.Empty(script.Diagnostics.Messages);
            Assert.Equal(100, (long)result);
        }

    }
}