using Shouldly;
using Xunit;

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

[Trait("Category", "Unit")]
public sealed class DirectLogicAddressTests
{
    [Theory]
    [InlineData("V0", (ushort)0x0000)]
    [InlineData("V1", (ushort)0x0001)]
    [InlineData("V7", (ushort)0x0007)]
    [InlineData("V10", (ushort)0x0008)]
    [InlineData("V2000", (ushort)0x0400)]  // canonical DL205/DL260 user-memory start
    [InlineData("V7777", (ushort)0x0FFF)]
    [InlineData("V10000", (ushort)0x1000)]
    [InlineData("V17777", (ushort)0x1FFF)]
    public void UserVMemoryToPdu_converts_octal_V_prefix(string v, ushort expected)
        => DirectLogicAddress.UserVMemoryToPdu(v).ShouldBe(expected);

    [Theory]
    [InlineData("0", (ushort)0)]
    [InlineData("2000", (ushort)0x0400)]
    [InlineData("v2000", (ushort)0x0400)]   // lowercase v
    [InlineData(" V2000 ", (ushort)0x0400)] // surrounding whitespace
    public void UserVMemoryToPdu_accepts_bare_or_prefixed_or_padded(string v, ushort expected)
        => DirectLogicAddress.UserVMemoryToPdu(v).ShouldBe(expected);

    [Theory]
    [InlineData("V8")]     // 8 is not a valid octal digit
    [InlineData("V19")]
    [InlineData("V2009")]
    public void UserVMemoryToPdu_rejects_non_octal_digits(string v)
    {
        Should.Throw<ArgumentException>(() => DirectLogicAddress.UserVMemoryToPdu(v))
            .Message.ShouldContain("octal");
    }

    [Theory]
    [InlineData(null)]
    [InlineData("")]
    [InlineData("   ")]
    [InlineData("V")]
    public void UserVMemoryToPdu_rejects_empty_input(string? v)
        => Should.Throw<ArgumentException>(() => DirectLogicAddress.UserVMemoryToPdu(v!));

    [Fact]
    public void UserVMemoryToPdu_overflow_rejected()
    {
        // 200000 octal = 0x10000 — one past ushort range.
        Should.Throw<OverflowException>(() => DirectLogicAddress.UserVMemoryToPdu("V200000"));
    }

    [Fact]
    public void SystemVMemoryBasePdu_is_0x2100_for_V40400()
    {
        // V40400 on DL260 / H2-ECOM100 absolute mode → PDU 0x2100 (decimal 8448), NOT 0x4100
        // which a naive octal-to-decimal of 40400 octal would give (= 16640).
        DirectLogicAddress.SystemVMemoryBasePdu.ShouldBe((ushort)0x2100);
        DirectLogicAddress.SystemVMemoryToPdu(0).ShouldBe((ushort)0x2100);
    }

    [Fact]
    public void SystemVMemoryToPdu_offsets_within_bank()
    {
        DirectLogicAddress.SystemVMemoryToPdu(1).ShouldBe((ushort)0x2101);
        DirectLogicAddress.SystemVMemoryToPdu(0x100).ShouldBe((ushort)0x2200);
    }

    [Fact]
    public void SystemVMemoryToPdu_rejects_overflow()
    {
        // ushort wrap: 0xFFFF - 0x2100 = 0xDEFF; anything above should throw.
        Should.NotThrow(() => DirectLogicAddress.SystemVMemoryToPdu(0xDEFF));
        Should.Throw<OverflowException>(() => DirectLogicAddress.SystemVMemoryToPdu(0xDF00));
    }
}