using System.Text.Json;
using ZB.MOM.WW.ScadaBridge.CLI.Commands;
using ZB.MOM.WW.ScadaBridge.Commons.Entities.Audit;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.Management;

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

/// <summary>
/// Tests for the compact <c>audit-config query</c> table projection (deferred-work
/// register row 57). The command passed no <c>tableProjector</c>, so the generic
/// renderer saw an <see cref="AuditLogQueryResult"/> OBJECT, took its Property/Value
/// branch, and printed the entire <c>entries</c> array as raw JSON inside one cell.
/// The projection unwraps the envelope to a row array, drops the per-entry
/// <c>afterStateJson</c> snapshot, and keeps <c>totalCount</c> visible as a trailing note.
/// </summary>
public class AuditConfigTableProjectionTests
{
    /// <summary>
    /// The real server shape, serialised from the REAL <see cref="AuditLogQueryResult"/>
    /// / <see cref="AuditLogEntry"/> types rather than hand-written JSON, so renaming one
    /// of their properties fails this test instead of silently blanking a column.
    /// </summary>
    private static string RealPayload(int totalCount) =>
        JsonSerializer.Serialize(
            new AuditLogQueryResult(
                new[]
                {
                    new AuditLogEntry("multi-role", "Created", "Template", "7", "PumpTemplate")
                    {
                        Id = 412,
                        AfterStateJson = "{\"id\":7,\"name\":\"PumpTemplate\",\"attributes\":[]}",
                        Timestamp = new DateTimeOffset(2026, 8, 15, 12, 0, 0, TimeSpan.Zero),
                    },
                    new AuditLogEntry("designer", "Deleted", "ExternalSystem", "3", "MES")
                    {
                        Id = 413,
                        AfterStateJson = null,
                        Timestamp = new DateTimeOffset(2026, 8, 15, 12, 5, 0, TimeSpan.Zero),
                    },
                },
                totalCount),
            new JsonSerializerOptions { PropertyNamingPolicy = JsonNamingPolicy.CamelCase });

    /// <summary>Verifies that projecting entries unwraps the envelope into rows.</summary>
    [Fact]
    public void ProjectEntries_UnwrapsTheEnvelopeIntoRows()
    {
        var compact = AuditConfigTableProjection.ProjectEntries(RealPayload(totalCount: 2));

        using var doc = JsonDocument.Parse(compact);
        var root = doc.RootElement;

        // An ARRAY is the whole point — the object envelope is what made the renderer
        // print one Property/Value row with the entries blob in a single cell.
        Assert.Equal(JsonValueKind.Array, root.ValueKind);
        Assert.Equal(2, root.GetArrayLength());

        var first = root[0];
        Assert.Equal(412, first.GetProperty("id").GetInt32());
        Assert.Equal("multi-role", first.GetProperty("user").GetString());
        Assert.Equal("Created", first.GetProperty("action").GetString());
        Assert.Equal("Template", first.GetProperty("entityType").GetString());
        Assert.Equal("PumpTemplate", first.GetProperty("entityName").GetString());
        Assert.Equal("7", first.GetProperty("entityId").GetString());
        Assert.Contains("2026-08-15", first.GetProperty("timestamp").GetString());

        var second = root[1];
        Assert.Equal("Deleted", second.GetProperty("action").GetString());
        Assert.Equal("MES", second.GetProperty("entityName").GetString());
    }

    /// <summary>Verifies that projecting entries drops the after-state JSON.</summary>
    [Fact]
    public void ProjectEntries_DropsAfterStateJson()
    {
        var compact = AuditConfigTableProjection.ProjectEntries(RealPayload(totalCount: 2));

        using var doc = JsonDocument.Parse(compact);
        // The fat field must NOT survive — one entity snapshot per row fills the terminal,
        // which is the audit analogue of template's child arrays.
        Assert.False(doc.RootElement[0].TryGetProperty("afterStateJson", out _));
        Assert.DoesNotContain("afterStateJson", compact, StringComparison.OrdinalIgnoreCase);
    }

    /// <summary>Verifies that a truncated page appends a note with the total count.</summary>
    [Fact]
    public void ProjectEntries_TruncatedPage_AppendsTotalCountNote()
    {
        var compact = AuditConfigTableProjection.ProjectEntries(RealPayload(totalCount: 137));

        using var doc = JsonDocument.Parse(compact);
        var root = doc.RootElement;

        // Two entries plus the note row.
        Assert.Equal(3, root.GetArrayLength());
        var note = root[2].GetProperty("note").GetString();
        Assert.Contains("2 of 137", note);
        // The note must not masquerade as an entry.
        Assert.False(root[2].TryGetProperty("id", out _));
    }

    /// <summary>Verifies that a result set returned in full emits no note column.</summary>
    [Fact]
    public void ProjectEntries_WholeResultSet_EmitsNoNoteColumn()
    {
        // When the page IS the result set the count adds nothing the operator cannot
        // already see, so the column must not appear and widen every small query.
        var compact = AuditConfigTableProjection.ProjectEntries(RealPayload(totalCount: 2));

        using var doc = JsonDocument.Parse(compact);
        Assert.Equal(2, doc.RootElement.GetArrayLength());
        Assert.DoesNotContain("note", compact, StringComparison.Ordinal);
    }

    /// <summary>Verifies that an empty result stays an empty array.</summary>
    [Fact]
    public void ProjectEntries_EmptyResult_StaysAnEmptyArray()
    {
        var json = JsonSerializer.Serialize(
            new AuditLogQueryResult(Array.Empty<AuditLogEntry>(), 0),
            new JsonSerializerOptions { PropertyNamingPolicy = JsonNamingPolicy.CamelCase });

        var compact = AuditConfigTableProjection.ProjectEntries(json);

        using var doc = JsonDocument.Parse(compact);
        // The renderer prints "(no results)" for an empty array; an empty OBJECT would
        // have printed an empty Property/Value table instead.
        Assert.Equal(JsonValueKind.Array, doc.RootElement.ValueKind);
        Assert.Equal(0, doc.RootElement.GetArrayLength());
    }

    /// <summary>Verifies that a bare array is still projected.</summary>
    [Fact]
    public void ProjectEntries_BareArray_IsStillProjected()
    {
        // Tolerated so the projection does not regress if the payload is ever unwrapped
        // upstream, or when the deprecated `audit-log` alias hits an older server.
        const string bare = """
        [ { "id": 1, "user": "u", "action": "Updated", "entityType": "Site",
            "entityName": "SiteA", "entityId": "2", "timestamp": "2026-08-15T12:00:00+00:00",
            "afterStateJson": "{\"big\":true}" } ]
        """;

        var compact = AuditConfigTableProjection.ProjectEntries(bare);

        using var doc = JsonDocument.Parse(compact);
        Assert.Equal(1, doc.RootElement.GetArrayLength());
        Assert.Equal("SiteA", doc.RootElement[0].GetProperty("entityName").GetString());
        Assert.False(doc.RootElement[0].TryGetProperty("afterStateJson", out _));
    }

    /// <summary>Verifies that an unrecognised JSON object is returned verbatim.</summary>
    [Fact]
    public void ProjectEntries_UnrecognisedObject_ReturnedVerbatim()
    {
        // e.g. an error envelope — leave it to the renderer's own fallbacks rather than
        // projecting it into an empty table that hides the message.
        const string other = """{ "error": "boom" }""";
        Assert.Equal(other, AuditConfigTableProjection.ProjectEntries(other));
    }

    /// <summary>Verifies that non-JSON input is returned verbatim.</summary>
    [Fact]
    public void ProjectEntries_NonJson_ReturnedVerbatim()
    {
        const string notJson = "<html>proxy error</html>";
        Assert.Equal(notJson, AuditConfigTableProjection.ProjectEntries(notJson));
    }

    /// <summary>Verifies that the projection is substantially smaller than the raw payload.</summary>
    [Fact]
    public void ProjectEntries_IsSubstantiallySmallerThanTheRawPayload()
    {
        // The reported symptom was the whole entries array in one cell. A page of rows
        // carrying real afterStateJson snapshots must collapse hard.
        var entries = Enumerable.Range(0, 50).Select(i =>
            new AuditLogEntry("designer", "Updated", "Template", i.ToString(), $"Template{i}")
            {
                Id = i,
                AfterStateJson = new string('x', 2000),
                Timestamp = DateTimeOffset.UnixEpoch.AddMinutes(i),
            }).ToArray();
        var json = JsonSerializer.Serialize(new AuditLogQueryResult(entries, entries.Length),
            new JsonSerializerOptions { PropertyNamingPolicy = JsonNamingPolicy.CamelCase });

        var compact = AuditConfigTableProjection.ProjectEntries(json);

        Assert.True(compact.Length * 4 < json.Length,
            $"Expected compact ({compact.Length}) to be far smaller than raw ({json.Length}).");
    }
}