using Shouldly;
using Xunit;

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

/// <summary>
///     Gitea #551 item 2: <see cref="S7TagDefinitionFactory.Inspect"/> is <b>accept-gate-first</b> — it asks
///     <see cref="S7TagDefinitionFactory.FromTagConfig"/> for the verdict and only explains a refusal. See
///     <c>ModbusInspectAcceptGateTests</c>'s remarks for why both directions (never stricter, never silent)
///     are pinned.
///     <para>
///         S7 carries the fleet's one unique rule: the reader REQUIRES the <c>dataType</c> key to be
///         present. A blob with only an <c>address</c> therefore deploys green and reads
///         <c>BadNodeIdUnknown</c> forever — and neither this gate nor the AdminUI model said a word about
///         it until #551.
///     </para>
/// </summary>
public sealed class S7InspectAcceptGateTests
{
    private const string RawPath = "cell/s7/dev1/T1";

    /// <summary>Blobs the mapper ACCEPTS — the gate must say nothing about any of them.</summary>
    public static TheoryData<string> Accepted() =>
    [
        """{"address":"DB1.DBW0","dataType":"Int16"}""",
        """{"address":"M0.0","dataType":"Bool"}""",
        """{"address":"DB1.DBB0","dataType":"String","stringLength":254}""",
        // stringLength is irrelevant to a non-String tag, so an out-of-range remnant is ACCEPTED.
        """{"address":"DB1.DBW0","dataType":"Int16","stringLength":9999}""",
        // A non-string dataType token satisfies the PRESENCE rule and then reads as absent ⇒ Int16.
        """{"address":"DB1.DBW0","dataType":7}""",
    ];

    /// <summary>Blobs the mapper REJECTS — the gate must produce at least one warning for each.</summary>
    public static TheoryData<string> Rejected() =>
    [
        """{"dataType":"Int16"}""",                                        // no address
        """{"address":"","dataType":"Int16"}""",                           // blank address
        """{"address":123,"dataType":"Int16"}""",                          // address not a string
        """{"address":"DB1.DBW0"}""",                                      // no dataType key at all (#551)
        """{"address":"DB1.DBW0","dataType":"Intt16"}""",                  // typo'd dataType
        """{"address":"DB1.DBB0","dataType":"String","stringLength":255}""", // over the 254 S7 limit
        """{"address":"DB1.DBB0","dataType":"String","stringLength":-1}""",  // negative length
    ];

    [Theory]
    [MemberData(nameof(Accepted))]
    public void A_config_the_mapper_accepts_draws_no_warning(string tagConfig)
    {
        S7TagDefinitionFactory.FromTagConfig(tagConfig, RawPath, out _).ShouldBeTrue("fixture must be accepted");
        S7TagDefinitionFactory.Inspect(tagConfig).ShouldBeEmpty();
    }

    [Theory]
    [MemberData(nameof(Rejected))]
    public void A_config_the_mapper_rejects_is_never_passed_over_in_silence(string tagConfig)
    {
        S7TagDefinitionFactory.FromTagConfig(tagConfig, RawPath, out _).ShouldBeFalse("fixture must be rejected");
        S7TagDefinitionFactory.Inspect(tagConfig).ShouldNotBeEmpty();
    }

    /// <summary>The headline case: present-and-typo'd was reported; ABSENT was not (Gitea #551 item 2).</summary>
    [Fact]
    public void An_absent_dataType_is_named()
        => S7TagDefinitionFactory.Inspect("""{"address":"DB1.DBW0"}""")
            .ShouldContain(w => w.Contains("no 'dataType'"));

    [Fact]
    public void An_absent_address_is_named()
        => S7TagDefinitionFactory.Inspect("""{"dataType":"Int16"}""")
            .ShouldContain(w => w.Contains("'address'"));

    [Fact]
    public void An_out_of_range_string_length_is_named()
        => S7TagDefinitionFactory.Inspect("""{"address":"DB1.DBB0","dataType":"String","stringLength":255}""")
            .ShouldContain(w => w.Contains("stringLength"));

    // ---- DeclaresDataType is the shared authority the AdminUI model asks (one rule, two doors) ----

    [Theory]
    [InlineData("""{"dataType":"Int16"}""", true)]
    [InlineData("""{"dataType":7}""", true)]          // presence is judged on the KEY, not the value
    [InlineData("""{"dataType":null}""", true)]
    [InlineData("""{"address":"DB1.DBW0"}""", false)]
    public void DeclaresDataType_judges_the_key_not_the_value(string tagConfig, bool expected)
    {
        using var doc = System.Text.Json.JsonDocument.Parse(tagConfig);
        S7TagDefinitionFactory.DeclaresDataType(doc.RootElement).ShouldBe(expected);
    }

    [Fact]
    public void A_blank_reference_draws_nothing()
        => S7TagDefinitionFactory.Inspect("   ").ShouldBeEmpty();

    [Fact]
    public void Unparseable_json_names_the_json()
        => S7TagDefinitionFactory.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;
        S7TagDefinitionFactory.FromTagConfig(padded, RawPath, out _)
            .ShouldBeTrue("the mapper's JsonDocument.Parse skips leading whitespace");
        S7TagDefinitionFactory.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;
        S7TagDefinitionFactory.FromTagConfig(padded, RawPath, out _)
            .ShouldBeFalse("the mapper's verdict is unchanged by padding");
        S7TagDefinitionFactory.Inspect(padded).ShouldBe(S7TagDefinitionFactory.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)
    {
        S7TagDefinitionFactory.FromTagConfig(reference, RawPath, out _).ShouldBeFalse();
        S7TagDefinitionFactory.Inspect(reference).ShouldBeEmpty();
    }
}