using System;
using System.IO;
using System.Linq;
using Junction.Domain.Models;
using Junction.Protocols.MTConnect.Parsing;
using Xunit;

namespace Junction.Tests.Unit
{
    public sealed class MtconnectParserTests
    {
        private static readonly Guid MachineId = Guid.Parse("11111111-2222-3333-4444-555555555555");

        private static string LoadFixture(string name)
        {
            var path = Path.Combine(AppContext.BaseDirectory, "Fixtures", "mtconnect", name);
            return File.ReadAllText(path);
        }

        // ---- PROBE ----

        [Fact]
        public void Probe_ParsesDataItemDescriptors()
        {
            var result = MtconnectProbeParser.Parse(LoadFixture("probe.xml"));

            Assert.True(result.IsSuccess);
            var items = result.Value;
            Assert.True(items.Count > 0);

            // Spot-check a known DataItem from the fixture.
            var pos = items.SingleOrDefault(d => d.Id == "x1_pos");
            Assert.NotNull(pos);
            Assert.Equal("POSITION", pos!.Type);
            Assert.Equal("SAMPLE", pos.Category);
            Assert.Equal("ACTUAL", pos.SubType);
            Assert.Equal("MILLIMETER", pos.Units);
            Assert.Equal("dev1", pos.DeviceId);
            Assert.Equal("junction-vmc-01", pos.DeviceUuid);

            // Availability descriptor present.
            Assert.Contains(items, d => d.Id == "dev1_avail" && d.Type == "AVAILABILITY");
        }

        [Fact]
        public void Probe_MalformedRoot_Fails()
        {
            var result = MtconnectProbeParser.Parse("<NotAProbe/>");

            Assert.False(result.IsSuccess);
            Assert.False(result.WasCancelled);
            Assert.NotEmpty(result.Errors);
        }

        // ---- CURRENT ----

        [Fact]
        public void Current_ParsesSnapshot_WithKnownObservations()
        {
            var result = MtconnectCurrentParser.Parse(LoadFixture("current.xml"), MachineId);

            Assert.True(result.IsSuccess);
            var snapshot = result.Value;

            Assert.Equal(MachineId, snapshot.MachineId);
            Assert.False(snapshot.IsEmpty);

            // Known position value.
            var xPos = snapshot.TryGetItem("x1_pos");
            Assert.NotNull(xPos);
            Assert.Equal("125.4300", xPos!.Value);
            Assert.Equal("Position", xPos.Name);
            Assert.Equal("Samples", xPos.Category);

            // EXECUTION = ACTIVE.
            var exec = snapshot.TryGetItem("path1_exec");
            Assert.NotNull(exec);
            Assert.Equal("ACTIVE", exec!.Value);

            // Condition state carried as value.
            var tempCond = snapshot.TryGetItem("c1_temp_cond");
            Assert.NotNull(tempCond);
            Assert.Equal("Condition", tempCond!.Category);
            Assert.Equal("Normal", tempCond.Value);

            // AVAILABILITY -> Connected.
            Assert.Equal(ConnectionState.Connected, snapshot.ConnectionState);

            // CapturedAt = latest observed timestamp (10240 seq @ .240Z).
            Assert.Equal(
                DateTimeOffset.Parse("2026-07-21T09:15:30.240Z"),
                snapshot.CapturedAt);
        }

        [Fact]
        public void Current_Unavailable_YieldsDisconnected()
        {
            var result = MtconnectCurrentParser.Parse(LoadFixture("current_unavailable.xml"), MachineId);

            Assert.True(result.IsSuccess);
            Assert.Equal(ConnectionState.Disconnected, result.Value.ConnectionState);
        }

        [Fact]
        public void Current_Malformed_FailsWithoutThrowing()
        {
            // current_malformed.xml is truncated (unclosed elements) -> XmlException internally.
            var result = MtconnectCurrentParser.Parse(LoadFixture("current_malformed.xml"), MachineId);

            Assert.False(result.IsSuccess);
            Assert.False(result.WasCancelled);
            Assert.NotEmpty(result.Errors);
        }

        // ---- VERSION-AGNOSTIC PROOF ----

        [Fact]
        public void Current_IsNamespaceVersionAgnostic()
        {
            var v17 = LoadFixture("current.xml");
            var v20 = v17.Replace(":1.7", ":2.0");
            Assert.Contains(":2.0", v20);
            Assert.DoesNotContain(":1.7", v20);

            var r17 = MtconnectCurrentParser.Parse(v17, MachineId);
            var r20 = MtconnectCurrentParser.Parse(v20, MachineId);

            Assert.True(r17.IsSuccess);
            Assert.True(r20.IsSuccess);

            var s17 = r17.Value;
            var s20 = r20.Value;

            Assert.Equal(s17.Items.Count, s20.Items.Count);
            Assert.Equal(s17.ConnectionState, s20.ConnectionState);
            Assert.Equal(s17.CapturedAt, s20.CapturedAt);

            // Item-by-item identical (id, value, category, timestamp).
            foreach (var a in s17.Items)
            {
                var b = s20.TryGetItem(a.Id);
                Assert.NotNull(b);
                Assert.Equal(a.Value, b!.Value);
                Assert.Equal(a.Category, b.Category);
                Assert.Equal(a.Name, b.Name);
                Assert.Equal(a.Timestamp, b.Timestamp);
            }
        }

        [Fact]
        public void Probe_IsNamespaceVersionAgnostic()
        {
            var v17 = LoadFixture("probe.xml");
            var v20 = v17.Replace(":1.7", ":2.0");

            var r17 = MtconnectProbeParser.Parse(v17);
            var r20 = MtconnectProbeParser.Parse(v20);

            Assert.True(r17.IsSuccess);
            Assert.True(r20.IsSuccess);
            Assert.Equal(r17.Value.Count, r20.Value.Count);
        }
    }
}