using Age.Engine.Diagnostics;
using Age.Engine.Model;
using Age.Engine.Sys4;
using Age.Engine.Vm;
using Xunit;

public class RootReloadTests
{
    private static Operand I(long value) => new(0, value);
    private static Operand G(long address) => new(3, address);

    [Fact]
    public void ExitScriptDiscardsEveryCallerAndReloadsRawScriptZero()
    {
        var table = OpcodeTableJson.Load(Paths.OpcodesJson);
        var system4 = ScriptAssembler.Assemble(table, "SYSTEM4", new List<(int, Operand[])>
        {
            (0x1b6, new[] { G(0x220) }),
            (0x19a, new[] { G(0x221) }),
            (0x55, new[] { G(0x202), I(0x99) }),
            (0x2, Array.Empty<Operand>()),
        }, Array.Empty<string>());
        var deepest = ScriptAssembler.Assemble(table, "DEEPEST", new List<(int, Operand[])>
        {
            (0x55, new[] { G(0x203), I(3) }),
            (0x9, Array.Empty<Operand>()),
            (0x55, new[] { G(0x204), I(4) }),
        }, Array.Empty<string>());
        var child = ScriptAssembler.Assemble(table, "CHILD", new List<(int, Operand[])>
        {
            (0x3, new[] { I(2) }),
            (0x55, new[] { G(0x205), I(5) }),
            (0x2, Array.Empty<Operand>()),
        }, Array.Empty<string>());
        var initial = ScriptAssembler.Assemble(table, "INITIAL", new List<(int, Operand[])>
        {
            (0x1b7, new[] { I(1) }),
            (0x88, new[] { I(1) }),
            (0x55, new[] { G(0x200), I(1) }),
            (0x3, new[] { I(1) }),
            (0x55, new[] { G(0x201), I(2) }),
            (0x2, Array.Empty<Operand>()),
        }, Array.Empty<string>());
        var provider = new MapProvider(new Dictionary<long, Script>
        {
            [0] = system4,
            [1] = child,
            [2] = deepest,
        });
        var host = new RecordingHost();
        var trace = new RecordingTraceSink();
        var vm = new VirtualMachine(initial, table, host, provider: provider, sink: trace);
        vm.Globals[0x2ff] = 0x1234;
        vm.ExternalGlobals[7] = 0x5678;
        vm.Gfx.SetSurface(5, 0x33, 0);
        vm.Gfx.BindDraw(0x100, 5, 0, 0, 1, 1, 0, 0);
        vm.TextHistory.DefineLayout(1, 10, 10, 0, 0);
        vm.TextHistory.AppendText(1, 0, "preserved", AdvTextStyle.Default);
        vm.TextHistory.SetRecordingEnabled(false);

        vm.Run();

        Assert.Equal("exit", vm.HaltReason);
        Assert.Equal(1, vm.Globals[0x200]);
        Assert.Equal(3, vm.Globals[0x203]);
        Assert.Equal(0x99, vm.Globals[0x202]);
        Assert.False(vm.Globals.ContainsKey(0x201));
        Assert.False(vm.Globals.ContainsKey(0x204));
        Assert.False(vm.Globals.ContainsKey(0x205));
        Assert.Equal(0x1234, vm.Globals[0x2ff]);
        Assert.Equal(0x5678, vm.ExternalGlobals[7]);
        Assert.Equal(0, vm.Globals[0x220]);
        Assert.Equal(0, vm.Globals[0x221]);
        Assert.Empty(vm.Gfx.SnapshotVisibleObjects());
        Assert.Single(vm.TextHistory.Records, r => r.Text == "preserved");
        Assert.False(vm.TextHistory.RecordingSuppressed);
        Assert.Equal(1, host.SceneContextResets);
        Assert.False(host.MessageSkip);

        var rootEnter = Assert.Single(trace.Events,
            e => e.Kind == TraceEventKind.FrameEnter && e.Name == "SYSTEM4");
        Assert.Equal(FrameCause.RootReload, rootEnter.Cause);
        Assert.Equal(3, trace.Events.Count(e =>
            e.Kind == TraceEventKind.FrameExit && e.Text == "RootReload"));
    }

    [Fact]
    public void HimegariRawScriptZeroIsSystem4()
    {
        var table = OpcodeTableJson.Load(Paths.OpcodesJson);
        var scripts = Sys4ScriptProvider.Load(table);

        Assert.Equal("SYSTEM4.BIN", scripts.GetById(0)?.Name);
    }

    [Fact]
    public void ExitScriptResetsSceneBeforeAnUnresolvedRootLoadFails()
    {
        var table = OpcodeTableJson.Load(Paths.OpcodesJson);
        var script = ScriptAssembler.Assemble(table, "NO_ROOT", new List<(int, Operand[])>
        {
            (0x9, Array.Empty<Operand>()),
        }, Array.Empty<string>());
        var host = new RecordingHost();
        var vm = new VirtualMachine(script, table, host);
        vm.Gfx.SetSurface(5, 0x33, 0);
        vm.Gfx.BindDraw(0x100, 5, 0, 0, 1, 1, 0, 0);

        vm.Run();

        Assert.Equal("root-reload-unresolved:0x0", vm.HaltReason);
        Assert.Equal(1, host.SceneContextResets);
        Assert.Empty(vm.Gfx.SnapshotVisibleObjects());
    }
}