// Copyright (c) StellaOps. All rights reserved.
// Licensed under AGPL-3.0-or-later. See LICENSE in the project root.

using System.Collections.Immutable;
using FluentAssertions;
using Microsoft.Extensions.Logging.Abstractions;
using StellaOps.BinaryIndex.Disassembly;
using Xunit;

namespace StellaOps.BinaryIndex.Semantic.Tests;

[Trait("Category", "Unit")]
public class IrLiftingServiceTests
{
    private readonly IrLiftingService _sut;

    public IrLiftingServiceTests()
    {
        _sut = new IrLiftingService(NullLogger<IrLiftingService>.Instance);
    }

    [Theory]
    [InlineData(CpuArchitecture.X86)]
    [InlineData(CpuArchitecture.X86_64)]
    [InlineData(CpuArchitecture.ARM32)]
    [InlineData(CpuArchitecture.ARM64)]
    public void SupportsArchitecture_ShouldReturnTrue_ForSupportedArchitectures(CpuArchitecture arch)
    {
        // Act
        var result = _sut.SupportsArchitecture(arch);

        // Assert
        result.Should().BeTrue();
    }

    [Theory]
    [InlineData(CpuArchitecture.MIPS32)]
    [InlineData(CpuArchitecture.RISCV64)]
    [InlineData(CpuArchitecture.Unknown)]
    public void SupportsArchitecture_ShouldReturnFalse_ForUnsupportedArchitectures(CpuArchitecture arch)
    {
        // Act
        var result = _sut.SupportsArchitecture(arch);

        // Assert
        result.Should().BeFalse();
    }

    [Fact]
    public async Task LiftToIrAsync_ShouldLiftSimpleInstructions()
    {
        // Arrange
        var instructions = new List<DisassembledInstruction>
        {
            CreateInstruction(0x1000, "MOV", InstructionKind.Move, "RAX", "RBX"),
            CreateInstruction(0x1004, "ADD", InstructionKind.Arithmetic, "RAX", "RCX"),
            CreateInstruction(0x1008, "RET", InstructionKind.Return)
        };

        // Act
        var result = await _sut.LiftToIrAsync(
            instructions,
            "test_func",
            0x1000,
            CpuArchitecture.X86_64);

        // Assert
        result.Should().NotBeNull();
        result.Name.Should().Be("test_func");
        result.Address.Should().Be(0x1000);
        result.Statements.Should().HaveCount(3);
        result.BasicBlocks.Should().NotBeEmpty();
    }

    [Fact]
    public async Task LiftToIrAsync_ShouldCreateBasicBlocksOnBranches()
    {
        // Arrange
        var instructions = new List<DisassembledInstruction>
        {
            CreateInstruction(0x1000, "MOV", InstructionKind.Move, "RAX", "0"),
            CreateInstruction(0x1004, "CMP", InstructionKind.Compare, "RAX", "10"),
            CreateInstruction(0x1008, "JE", InstructionKind.ConditionalBranch, "0x1020"),
            CreateInstruction(0x100C, "ADD", InstructionKind.Arithmetic, "RAX", "1"),
            CreateInstruction(0x1010, "RET", InstructionKind.Return)
        };

        // Act
        var result = await _sut.LiftToIrAsync(
            instructions,
            "branch_func",
            0x1000,
            CpuArchitecture.X86_64);

        // Assert
        result.BasicBlocks.Should().HaveCountGreaterThan(1);
        result.Cfg.Edges.Should().NotBeEmpty();
    }

    [Fact]
    public async Task LiftToIrAsync_ShouldThrow_ForUnsupportedArchitecture()
    {
        // Arrange
        var instructions = new List<DisassembledInstruction>
        {
            CreateInstruction(0x1000, "NOP", InstructionKind.Nop)
        };

        // Act
        var act = () => _sut.LiftToIrAsync(
            instructions,
            "test",
            0x1000,
            CpuArchitecture.MIPS32);

        // Assert
        await act.Should().ThrowAsync<NotSupportedException>();
    }

    [Fact]
    public async Task TransformToSsaAsync_ShouldVersionVariables()
    {
        // Arrange
        var instructions = new List<DisassembledInstruction>
        {
            CreateInstruction(0x1000, "MOV", InstructionKind.Move, "RAX", "0"),
            CreateInstruction(0x1004, "ADD", InstructionKind.Arithmetic, "RAX", "1"),
            CreateInstruction(0x1008, "ADD", InstructionKind.Arithmetic, "RAX", "2"),
            CreateInstruction(0x100C, "RET", InstructionKind.Return)
        };

        var lifted = await _sut.LiftToIrAsync(
            instructions,
            "ssa_test",
            0x1000,
            CpuArchitecture.X86_64);

        // Act
        var ssa = await _sut.TransformToSsaAsync(lifted);

        // Assert
        ssa.Should().NotBeNull();
        ssa.Name.Should().Be("ssa_test");
        ssa.Statements.Should().HaveCount(4);

        // RAX should have multiple versions
        var raxVersions = ssa.Statements
            .Where(s => s.Destination?.BaseName == "RAX")
            .Select(s => s.Destination!.Version)
            .Distinct()
            .ToList();

        raxVersions.Should().HaveCountGreaterThan(1);
    }

    [Fact]
    public async Task TransformToSsaAsync_ShouldBuildDefUseChains()
    {
        // Arrange
        var instructions = new List<DisassembledInstruction>
        {
            CreateInstruction(0x1000, "MOV", InstructionKind.Move, "RAX", "0"),
            CreateInstruction(0x1004, "ADD", InstructionKind.Arithmetic, "RBX", "RAX"),
            CreateInstruction(0x1008, "RET", InstructionKind.Return)
        };

        var lifted = await _sut.LiftToIrAsync(
            instructions,
            "defuse_test",
            0x1000,
            CpuArchitecture.X86_64);

        // Act
        var ssa = await _sut.TransformToSsaAsync(lifted);

        // Assert
        ssa.DefUse.Should().NotBeNull();
        ssa.DefUse.Definitions.Should().NotBeEmpty();
    }

    private static DisassembledInstruction CreateInstruction(
        ulong address,
        string mnemonic,
        InstructionKind kind,
        params string[] operands)
    {
        var ops = operands.Select((o, i) =>
        {
            if (long.TryParse(o, out var val))
            {
                return new Operand(OperandType.Immediate, o, val);
            }
            if (o.StartsWith("0x", StringComparison.OrdinalIgnoreCase))
            {
                return new Operand(OperandType.Address, o);
            }
            return new Operand(OperandType.Register, o, Register: o);
        }).ToImmutableArray();

        return new DisassembledInstruction(
            address,
            [0x90], // NOP placeholder
            mnemonic,
            string.Join(", ", operands),
            kind,
            ops);
    }
}