using Shouldly;
using Xunit;

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

/// <summary>
///     Gitea #551 items 2/3: <see cref="ModbusTagDefinitionFactory.Inspect"/> is <b>accept-gate-first</b> —
///     it asks <see cref="ModbusTagDefinitionFactory.FromTagConfig"/> for the verdict and only explains a
///     refusal.
///     <para>
///         Two properties, and they pull in opposite directions, which is why both are pinned here. The
///         gate must never be <b>stricter</b> than the mapper (a warning can be promoted to a blocking
///         deploy error by <c>TagConfigValidationMode.Error</c>, so a warning on a blob the driver serves
///         would refuse a working config); and it must never be <b>silent</b> on a blob the mapper refuses
///         (that tag deploys green and then reads <c>BadNodeIdUnknown</c> forever). The previous hand-list
///         of enum checks satisfied the first and failed the second for every cause not on the list —
///         an absent <c>region</c>, a bad <c>address</c>, <c>stringByteOrder</c>, and the two
///         type-dependent guards.
///     </para>
/// </summary>
public sealed class ModbusInspectAcceptGateTests
{
    private const string RawPath = "cell/modbus/dev1/T1";
    private const string Clean = """{"region":"HoldingRegisters","address":1,"dataType":"Int16"}""";

    /// <summary>Every blob below is one the mapper ACCEPTS, so the gate must say nothing about it.</summary>
    public static TheoryData<string> Accepted() =>
    [
        Clean,
        """{"region":"Coils","address":0,"dataType":"Bool"}""",
        """{"region":"HoldingRegisters","address":65535,"dataType":"String","stringLength":10,"stringByteOrder":"LowByteFirst"}""",
        """{"region":"HoldingRegisters","address":1,"dataType":"BitInRegister","bitIndex":15}""",
        // The byte/ushort NARROWING is part of the mapper's rule: bitIndex 256 truncates to bit 0 and is
        // ACCEPTED. A gate that described the un-narrowed value would refuse a tag the driver serves.
        """{"region":"HoldingRegisters","address":1,"dataType":"BitInRegister","bitIndex":256}""",
        // A non-string enum token reads as ABSENT, not invalid — the mapper accepts it as the default.
        """{"region":"HoldingRegisters","address":1,"dataType":3}""",
    ];

    /// <summary>Every blob below is one the mapper REJECTS, so the gate must produce at least one warning.</summary>
    public static TheoryData<string> Rejected() =>
    [
        """{"address":1,"dataType":"Int16"}""",                                                   // no region
        """{"region":"HoldingRegisters","dataType":"Int16"}""",                                    // no address
        """{"region":"HoldingRegisters","address":-1,"dataType":"Int16"}""",                       // address < 0
        """{"region":"HoldingRegisters","address":65536,"dataType":"Int16"}""",                    // address > ushort
        """{"region":"HoldingRegisters","address":"1","dataType":"Int16"}""",                      // address not a number
        """{"region":"HoldingRegisterz","address":1,"dataType":"Int16"}""",                        // typo'd region
        """{"region":"HoldingRegisters","address":1,"dataType":"Intt16"}""",                       // typo'd dataType
        """{"region":"HoldingRegisters","address":1,"dataType":"Int16","byteOrder":"Bigg"}""",     // typo'd byteOrder
        """{"region":"HoldingRegisters","address":1,"dataType":"Int16","stringByteOrder":"Nope"}""", // typo'd stringByteOrder
        """{"region":"HoldingRegisters","address":1,"dataType":"String"}""",                       // String with no length
        """{"region":"HoldingRegisters","address":1,"dataType":"BitInRegister","bitIndex":16}""",  // bit out of range
    ];

    [Theory]
    [MemberData(nameof(Accepted))]
    public void A_config_the_mapper_accepts_draws_no_warning(string tagConfig)
    {
        ModbusTagDefinitionFactory.FromTagConfig(tagConfig, RawPath, out _).ShouldBeTrue("fixture must be accepted");
        ModbusTagDefinitionFactory.Inspect(tagConfig).ShouldBeEmpty();
    }

    [Theory]
    [MemberData(nameof(Rejected))]
    public void A_config_the_mapper_rejects_is_never_passed_over_in_silence(string tagConfig)
    {
        ModbusTagDefinitionFactory.FromTagConfig(tagConfig, RawPath, out _).ShouldBeFalse("fixture must be rejected");
        ModbusTagDefinitionFactory.Inspect(tagConfig).ShouldNotBeEmpty();
    }

    // ---- The specific causes the issue named, each with a message that points at the right key ----

    [Fact]
    public void An_absent_region_is_named()
        => ModbusTagDefinitionFactory.Inspect("""{"address":1,"dataType":"Int16"}""")
            .ShouldContain(w => w.Contains("'region'"));

    [Fact]
    public void An_out_of_range_address_is_named()
        => ModbusTagDefinitionFactory.Inspect("""{"region":"Coils","address":70000,"dataType":"Int16"}""")
            .ShouldContain(w => w.Contains("'address'"));

    /// <summary>Gitea #551 item 3: read strictly by the mapper since R2-11, checked by nothing until now.</summary>
    [Fact]
    public void A_typo_in_stringByteOrder_is_named()
        => ModbusTagDefinitionFactory.Inspect(
                """{"region":"HoldingRegisters","address":1,"dataType":"Int16","stringByteOrder":"HighByteFrist"}""")
            .ShouldContain(w => w.Contains("stringByteOrder") && w.Contains("HighByteFrist"));

    [Fact]
    public void A_String_tag_with_no_stringLength_is_named()
        => ModbusTagDefinitionFactory.Inspect("""{"region":"HoldingRegisters","address":1,"dataType":"String"}""")
            .ShouldContain(w => w.Contains("stringLength"));

    [Fact]
    public void A_BitInRegister_tag_with_a_bit_over_15_is_named()
        => ModbusTagDefinitionFactory.Inspect(
                """{"region":"HoldingRegisters","address":1,"dataType":"BitInRegister","bitIndex":16}""")
            .ShouldContain(w => w.Contains("bitIndex"));

    // ---- Framing rules preserved from the pre-#551 shape ----

    [Fact]
    public void A_blank_reference_draws_nothing()
        => ModbusTagDefinitionFactory.Inspect("   ").ShouldBeEmpty();

    /// <summary>
    ///     The pre-existing framing convention, deliberately left alone by #551 and shared by all eleven
    ///     inspectors: a reference that does not START with <c>{</c> is not an equipment-tag TagConfig at
    ///     all, so it draws nothing — even though the mapper would refuse it. Widening this is a separate
    ///     decision about what a TagConfig IS, not about how a refusal is explained.
    /// </summary>
    /// <param name="reference">The non-object reference.</param>
    [Theory]
    [InlineData("just a string")]
    [InlineData("[1,2,3]")]
    [InlineData("42")]
    public void A_non_object_reference_draws_nothing_because_it_is_not_a_TagConfig(string reference)
    {
        ModbusTagDefinitionFactory.FromTagConfig(reference, RawPath, out _).ShouldBeFalse();
        ModbusTagDefinitionFactory.Inspect(reference).ShouldBeEmpty();
    }

    [Fact]
    public void Unparseable_json_names_the_json()
        => ModbusTagDefinitionFactory.Inspect("{oops").ShouldContain(w => w.Contains("not valid JSON"));

    // ---- Gitea #556 item 1: leading whitespace no longer defeats the framing pre-filter ----

    /// <summary>
    ///     Padding a blob with leading whitespace. A driver is handed whatever authoring persisted, and
    ///     <c>FromTagConfig</c> passes it straight to <c>JsonDocument.Parse</c>, which skips leading
    ///     whitespace — so the MAPPER's verdict is identical padded or not, and the gate's must be too.
    /// </summary>
    private const string Pad = " \t\r\n ";

    /// <summary>
    ///     Never stricter, under padding: a padded blob the mapper still accepts draws nothing. (This
    ///     direction already held before #556 — the pre-filter returned empty for everything padded — and
    ///     is kept so a future "just trim everywhere" change cannot start warning about a served tag.)
    /// </summary>
    /// <param name="tagConfig">An accepted fixture, padded below.</param>
    [Theory]
    [MemberData(nameof(Accepted))]
    public void Leading_whitespace_leaves_an_accepted_config_silent(string tagConfig)
    {
        var padded = Pad + tagConfig;
        ModbusTagDefinitionFactory.FromTagConfig(padded, RawPath, out _)
            .ShouldBeTrue("the mapper's JsonDocument.Parse skips leading whitespace");
        ModbusTagDefinitionFactory.Inspect(padded).ShouldBeEmpty();
    }

    /// <summary>
    ///     Never silent, under padding — the #556 item 1 defect itself. The pre-filter tested
    ///     <c>reference[0] != '{'</c>, so EVERY padded blob returned empty and a padded config the driver
    ///     refuses deployed clean. Asserting equality with the untrimmed inspection (rather than merely
    ///     "not empty") also pins that padding changes no message.
    /// </summary>
    /// <param name="tagConfig">A rejected fixture, padded below.</param>
    [Theory]
    [MemberData(nameof(Rejected))]
    public void Leading_whitespace_draws_exactly_the_warnings_the_untrimmed_blob_draws(string tagConfig)
    {
        var padded = Pad + tagConfig;
        ModbusTagDefinitionFactory.FromTagConfig(padded, RawPath, out _)
            .ShouldBeFalse("the mapper's verdict is unchanged by padding");
        ModbusTagDefinitionFactory.Inspect(padded).ShouldBe(ModbusTagDefinitionFactory.Inspect(tagConfig));
    }

    /// <summary>
    ///     The other half of the same fix, and the one it would be easy to lose: trimming widens the gate
    ///     ONLY for JSON objects. A reference that is still not object-framed after the trim is not an
    ///     equipment-tag TagConfig at all — the pre-existing convention shared by all eleven inspectors —
    ///     so it keeps drawing nothing even though the mapper refuses it.
    /// </summary>
    /// <param name="reference">A padded, non-object reference.</param>
    [Theory]
    [InlineData("   just a string")]
    [InlineData("  [1,2,3]")]
    [InlineData(" \t\r\n 42")]
    [InlineData("  \"a\"")]
    [InlineData("  ")]
    public void A_non_object_reference_still_draws_nothing_after_trimming(string reference)
    {
        ModbusTagDefinitionFactory.FromTagConfig(reference, RawPath, out _).ShouldBeFalse();
        ModbusTagDefinitionFactory.Inspect(reference).ShouldBeEmpty();
    }
}