using Microsoft.VisualStudio.TestTools.UnitTesting;

using System.Collections.Generic;

namespace YesNt.Interpreter.Tests;

[TestClass]
public class CodeFlowTests
{
    [TestMethod]
    public void FunctionTest()
    {
        List<string> lines =
        [
            "call yes",
            "func yes:",
            "global result = 1",
            "return",
            "${result}"
        ];
        YesNtAssert.IsLastLineEqual(lines, "1");
    }

    [TestMethod]
    public void LabelsTest()
    {
        List<string> lines =
        [
            "var result = 1",
            "goto yes",
            "var result = 0",
            "label yes:",
            "${result}"
        ];
        YesNtAssert.IsLastLineEqual(lines, "1");
    }

    [TestMethod]
    public void IfBlockTrueTest()
    {
        List<string> lines =
        [
            "var result = low",
            "if 6 > 5:",
            "var result = high",
            "end_if",
            "${result}"
        ];

        YesNtAssert.IsLastLineEqual(lines, "high");
    }

    [TestMethod]
    public void IfElseFalseBranchTest()
    {
        List<string> lines =
        [
            "var result = low",
            "if 6 < 5:",
            "var result = high",
            "else:",
            "var result = medium",
            "end_if",
            "${result}"
        ];

        YesNtAssert.IsLastLineEqual(lines, "medium");
    }

    [TestMethod]
    public void NestedIfElseTest()
    {
        List<string> lines =
        [
            "var result = 0",
            "if 1 == 1:",
            "if 2 == 3:",
            "var result = 1",
            "else:",
            "var result = 2",
            "end_if",
            "end_if",
            "${result}"
        ];

        YesNtAssert.IsLastLineEqual(lines, "2");
    }

    [TestMethod]
    public void WhileLoopTest()
    {
        List<string> lines =
        [
            "var i = 3",
            "while ${i} > 0:",
            "var i = ${i} - 1 calc",
            "end_while",
            "${i}"
        ];

        YesNtAssert.IsLastLineEqual(lines, "0");
    }

    [TestMethod]
    public void WhileSkipBodyWhenFalseTest()
    {
        List<string> lines =
        [
            "var i = 0",
            "while ${i} > 0:",
            "var i = 99",
            "end_while",
            "${i}"
        ];

        YesNtAssert.IsLastLineEqual(lines, "0");
    }

    [TestMethod]
    public void NestedWhileLoopTest()
    {
        List<string> lines =
        [
            "var outer = 2",
            "var count = 0",
            "while ${outer} > 0:",
            "var inner = 2",
            "while ${inner} > 0:",
            "var count = ${count} + 1 calc",
            "var inner = ${inner} - 1 calc",
            "end_while",
            "var outer = ${outer} - 1 calc",
            "end_while",
            "${count}"
        ];

        YesNtAssert.IsLastLineEqual(lines, "4");
    }

    [TestMethod]
    public void IfElseTrueSkipsElseBranchTest()
    {
        List<string> lines =
        [
            "var result = 0",
            "if 2 > 1:",
            "var result = 1",
            "else:",
            "var result = 2",
            "end_if",
            "${result}"
        ];

        YesNtAssert.IsLastLineEqual(lines, "1");
    }

    [TestMethod]
    public void IfWithoutElseFalseSkipsBodyTest()
    {
        List<string> lines =
        [
            "var result = 5",
            "if 1 == 2:",
            "var result = 1",
            "end_if",
            "${result}"
        ];

        YesNtAssert.IsLastLineEqual(lines, "5");
    }

    [TestMethod]
    public void IfGotoTrueTest()
    {
        List<string> lines =
        [
            "var result = 0",
            "if 1 == 1 goto done",
            "var result = 2",
            "label done:",
            "var result = ${result} + 1 calc",
            "${result}"
        ];

        YesNtAssert.IsLastLineEqual(lines, "1");
    }

    [TestMethod]
    public void IfCallTrueTest()
    {
        List<string> lines =
        [
            "func set_result:",
            "global result = ok",
            "return",
            "if 1 == 1 call set_result",
            "${result}"
        ];

        YesNtAssert.IsLastLineEqual(lines, "ok");
    }

    [TestMethod]
    public void LabelWithoutColonFailsTest()
    {
        List<string> lines =
        [
            "label loop"
        ];

        YesNtAssert.ContainsTerminationMessage(lines, "Invalid statement");
    }

    [TestMethod]
    public void FunctionWithoutColonFailsTest()
    {
        List<string> lines =
        [
            "func missing"
        ];

        YesNtAssert.ContainsTerminationMessage(lines, "Invalid statement");
    }

    [TestMethod]
    public void MissingEndIfFailsTest()
    {
        List<string> lines =
        [
            "if 1 == 2:",
            "var result = 1"
        ];

        YesNtAssert.ContainsTerminationMessage(lines, "No matching end_if found");
    }

    [TestMethod]
    public void ElseWithoutIfFailsTest()
    {
        List<string> lines =
        [
            "else:"
        ];

        YesNtAssert.ContainsTerminationMessage(lines, "No matching end_if found");
    }

    [TestMethod]
    public void MissingEndWhileFailsTest()
    {
        List<string> lines =
        [
            "var i = 0",
            "while ${i} > 1:",
            "var i = ${i} + 1 calc"
        ];

        YesNtAssert.ContainsTerminationMessage(lines, "No matching end_while found");
    }

    [TestMethod]
    public void EndWhileWithoutWhileFailsTest()
    {
        List<string> lines =
        [
            "end_while"
        ];

        YesNtAssert.ContainsTerminationMessage(lines, "No matching while found");
    }
}