using Shouldly;
using Xunit;

namespace ZB.MOM.WW.OtOpcUa.Driver.S7.Tests;

/// <summary>
///     Unit tests for <see cref="S7Driver"/>'s <c>IReadable</c>/<c>IWritable</c> surface
///     that don't require a live PLC — covers error paths (not-initialized, unknown tag,
///     read-only write rejection, unsupported data types). Wire-level round-trip tests
///     against a live S7 or a mock-server land in a follow-up PR since S7.Net doesn't ship
///     an in-process fake and an adequate mock is non-trivial.
/// </summary>
[Trait("Category", "Unit")]
public sealed class S7DriverReadWriteTests
{
    /// <summary>Verifies that initialization rejects invalid tag addresses and fails fast.</summary>
    [Fact]
    public async Task Initialize_rejects_invalid_tag_address_and_fails_fast()
    {
        // A bad address is refused PER TAG at every gate (mapper/editor, deploy gate, driver init):
        // it reads BadNodeIdUnknown while its neighbours keep working. It used to throw at init and
        // fault every tag on the PLC, with the actor retrying the same init every 10 s forever.
        await S7TagSkipAssert.RefusedPerTagAsync(
            new S7TagDefinition("BadTag", "NOT-AN-S7-ADDRESS", S7DataType.Int16), "does not parse");
    }

    /// <summary>Verifies that ReadAsync without initialize throws InvalidOperationException.</summary>
    [Fact]
    public async Task ReadAsync_without_initialize_throws_InvalidOperationException()
    {
        using var drv = new S7Driver(new S7DriverOptions { Host = "192.0.2.1" }, "s7-uninit");
        await Should.ThrowAsync<InvalidOperationException>(async () =>
            await drv.ReadAsync(["Any"], TestContext.Current.CancellationToken));
    }

    /// <summary>Verifies that WriteAsync without initialize throws InvalidOperationException.</summary>
    [Fact]
    public async Task WriteAsync_without_initialize_throws_InvalidOperationException()
    {
        using var drv = new S7Driver(new S7DriverOptions { Host = "192.0.2.1" }, "s7-uninit");
        await Should.ThrowAsync<InvalidOperationException>(async () =>
            await drv.WriteAsync(
                [new(FullReference: "Any", Value: (short)0)],
                TestContext.Current.CancellationToken));
    }
}