using System.Text.Json;
using ZB.MOM.WW.ScadaBridge.CLI.Commands;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Templates;

namespace ZB.MOM.WW.ScadaBridge.CLI.Tests;

/// <summary>
/// Tests for the compact <c>template list</c>/<c>get</c> table projection (followup #6):
/// the full per-template attribute/alarm/script dumps are collapsed to counts so table
/// output is usable in a terminal, while the array/object shape is preserved.
///
/// <para>
/// Two server shapes must both project correctly: <c>template get</c> still returns a
/// full <c>Template</c> entity with child ARRAYS, while <c>template list</c> returns
/// database-projected <see cref="TemplateSummary"/> rows carrying pre-computed COUNT
/// scalars and no arrays at all. Reading only the arrays made every listed template
/// render as zeros.
/// </para>
/// </summary>
public class TemplateTableProjectionTests
{
    private const string ListJson = """
    [
      {
        "id": 3,
        "name": "MESReceiver",
        "description": "base",
        "parentTemplateId": null,
        "isDerived": false,
        "attributes": [ {"id":1},{"id":2},{"id":3} ],
        "alarms": [ {"id":10} ],
        "scripts": [ {"id":20},{"id":21} ],
        "compositions": [],
        "nativeAlarmSources": []
      },
      {
        "id": 5,
        "name": "LeftMESReceiver",
        "description": null,
        "parentTemplateId": 3,
        "isDerived": false,
        "attributes": [ {"id":1} ],
        "alarms": [],
        "scripts": [],
        "compositions": [ {"id":99} ],
        "nativeAlarmSources": [ {"id":7} ]
      }
    ]
    """;

    [Fact]
    public void ProjectSummary_Array_DropsMemberArraysAndKeepsCounts()
    {
        var compact = TemplateTableProjection.ProjectSummary(ListJson);

        using var doc = JsonDocument.Parse(compact);
        var root = doc.RootElement;
        Assert.Equal(JsonValueKind.Array, root.ValueKind);
        Assert.Equal(2, root.GetArrayLength());

        var first = root[0];
        Assert.Equal(3, first.GetProperty("id").GetInt32());
        Assert.Equal("MESReceiver", first.GetProperty("name").GetString());
        Assert.Equal("base", first.GetProperty("description").GetString());
        Assert.Equal(JsonValueKind.Null, first.GetProperty("parentTemplateId").ValueKind);
        Assert.Equal(3, first.GetProperty("#attrs").GetInt32());
        Assert.Equal(1, first.GetProperty("#alarms").GetInt32());
        Assert.Equal(2, first.GetProperty("#scripts").GetInt32());
        Assert.Equal(0, first.GetProperty("#comps").GetInt32());
        Assert.Equal(0, first.GetProperty("#nativeAlarms").GetInt32());

        // The full member arrays must NOT survive — that is the whole point of the projection.
        Assert.False(first.TryGetProperty("attributes", out _));
        Assert.False(first.TryGetProperty("scripts", out _));

        var second = root[1];
        Assert.Equal(5, second.GetProperty("id").GetInt32());
        Assert.Equal(3, second.GetProperty("parentTemplateId").GetInt32());
        Assert.Equal(1, second.GetProperty("#comps").GetInt32());
        Assert.Equal(1, second.GetProperty("#nativeAlarms").GetInt32());
        // A null description stays null (it is not invented).
        Assert.Equal(JsonValueKind.Null, second.GetProperty("description").ValueKind);
    }

    [Fact]
    public void ProjectSummary_SingleObject_ProducesCompactObject()
    {
        const string getJson = """
        { "id": 7, "name": "ReactorSide", "description": "d", "parentTemplateId": null,
          "isDerived": false, "attributes": [ {"id":1},{"id":2} ], "alarms": [], "scripts": [],
          "compositions": [], "nativeAlarmSources": [] }
        """;

        var compact = TemplateTableProjection.ProjectSummary(getJson);

        using var doc = JsonDocument.Parse(compact);
        var root = doc.RootElement;
        Assert.Equal(JsonValueKind.Object, root.ValueKind);
        Assert.Equal(7, root.GetProperty("id").GetInt32());
        Assert.Equal(2, root.GetProperty("#attrs").GetInt32());
        Assert.False(root.TryGetProperty("attributes", out _));
    }

    /// <summary>
    /// The <c>template list</c> shape. Serialised from the REAL
    /// <see cref="TemplateSummary"/> record rather than hand-written JSON, so a
    /// rename of one of its count properties fails this test instead of silently
    /// putting zeros back on every row.
    /// </summary>
    [Fact]
    public void ProjectSummary_SummaryRows_ReadsCountScalars()
    {
        var rows = new[]
        {
            new TemplateSummary(
                Id: 3, Name: "MESReceiver", Description: "base", ParentTemplateId: null,
                FolderId: null, IsDerived: false, OwnerCompositionId: null,
                AttributeCount: 3, AlarmCount: 1, ScriptCount: 2,
                CompositionCount: 0, NativeAlarmSourceCount: 0),
            new TemplateSummary(
                Id: 5, Name: "LeftMESReceiver", Description: null, ParentTemplateId: 3,
                FolderId: 2, IsDerived: false, OwnerCompositionId: null,
                AttributeCount: 1, AlarmCount: 0, ScriptCount: 0,
                CompositionCount: 1, NativeAlarmSourceCount: 1),
        };
        var json = JsonSerializer.Serialize(rows,
            new JsonSerializerOptions { PropertyNamingPolicy = JsonNamingPolicy.CamelCase });

        var compact = TemplateTableProjection.ProjectSummary(json);

        using var doc = JsonDocument.Parse(compact);
        var root = doc.RootElement;
        Assert.Equal(2, root.GetArrayLength());

        var first = root[0];
        Assert.Equal(3, first.GetProperty("id").GetInt32());
        Assert.Equal("MESReceiver", first.GetProperty("name").GetString());
        Assert.Equal(3, first.GetProperty("#attrs").GetInt32());
        Assert.Equal(1, first.GetProperty("#alarms").GetInt32());
        Assert.Equal(2, first.GetProperty("#scripts").GetInt32());
        Assert.Equal(0, first.GetProperty("#comps").GetInt32());
        Assert.Equal(0, first.GetProperty("#nativeAlarms").GetInt32());

        var second = root[1];
        Assert.Equal(5, second.GetProperty("id").GetInt32());
        Assert.Equal(3, second.GetProperty("parentTemplateId").GetInt32());
        Assert.Equal(1, second.GetProperty("#attrs").GetInt32());
        Assert.Equal(1, second.GetProperty("#comps").GetInt32());
        Assert.Equal(1, second.GetProperty("#nativeAlarms").GetInt32());
    }

    /// <summary>
    /// A count scalar wins over a child array when (hypothetically) both are
    /// present, so a payload that gains summary fields never regresses to array
    /// counting.
    /// </summary>
    [Fact]
    public void ProjectSummary_PrefersCountScalarOverArray()
    {
        const string bothJson = """
        { "id": 1, "name": "T", "attributeCount": 42, "attributes": [ {"id":1} ] }
        """;

        var compact = TemplateTableProjection.ProjectSummary(bothJson);

        using var doc = JsonDocument.Parse(compact);
        Assert.Equal(42, doc.RootElement.GetProperty("#attrs").GetInt32());
    }

    [Fact]
    public void ProjectSummary_NonJson_ReturnedVerbatim()
    {
        const string notJson = "<html>proxy error</html>";
        Assert.Equal(notJson, TemplateTableProjection.ProjectSummary(notJson));
    }

    [Fact]
    public void ProjectSummary_IsSubstantiallySmallerThanFullDump()
    {
        // Sanity check that the projection actually shrinks output (the reported symptom
        // was ~171 KB table dumps). A template with a fat attribute array should collapse.
        var fatAttributes = string.Join(",",
            Enumerable.Range(0, 200).Select(i =>
                $"{{\"id\":{i},\"name\":\"Attr{i}\",\"dataType\":\"String\",\"value\":\"some long-ish default value {i}\"}}"));
        var fullJson = $$"""
        [ { "id": 1, "name": "T", "description": "d", "parentTemplateId": null, "isDerived": false,
            "attributes": [ {{fatAttributes}} ], "alarms": [], "scripts": [], "compositions": [], "nativeAlarmSources": [] } ]
        """;

        var compact = TemplateTableProjection.ProjectSummary(fullJson);

        Assert.True(compact.Length * 4 < fullJson.Length,
            $"Expected compact ({compact.Length}) to be far smaller than full ({fullJson.Length}).");
        using var doc = JsonDocument.Parse(compact);
        Assert.Equal(200, doc.RootElement[0].GetProperty("#attrs").GetInt32());
    }
}
