using System.Text.Json;
using AcDream.Headless.Configuration;

namespace AcDream.Headless.Tests;

/// <summary>
/// Campaign OP slice OP7 (2026-08-11), D8: schema tests for the optional
/// per-session <c>characterOptions</c> block —
/// docs/plans/2026-08-10-options-panel-campaign.md §4 OP7. Exercises
/// <see cref="HeadlessConfigurationLoader.Load"/> directly (rather than
/// through <c>HeadlessEntryPoint</c>'s CLI wrapper) so assertions can pin the
/// exact exception type/message for the semantic "unknown name" rejection,
/// matching the loader's own established split: type-shape violations
/// (missing required field, wrong JSON value kind) fail during
/// deserialization itself with a raw <see cref="JsonException"/>; semantic
/// violations of an already-well-typed value fail with
/// <see cref="HeadlessConfigurationException"/> (see
/// <see cref="HeadlessConfigurationLoader"/>'s own doc comment on
/// <c>ValidateCharacterOptions</c>).
/// </summary>
public sealed class HeadlessConfigurationLoaderTests
{
    [Fact]
    public void ValidCharacterOptionsBlockParsesExactDeclaredNames()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            ConfigurationWith(Session(
                "bot",
                "BOT_PASSWORD",
                """
                "characterOptions":{
                    "IgnoreAllegianceRequests":true,
                    "ListenToTradeChat":false,
                    "AutoTarget":true
                }
                """)));

        HeadlessConfiguration configuration =
            HeadlessConfigurationLoader.Load(file.Path);

        Dictionary<string, bool>? declared =
            Assert.Single(configuration.Sessions)!.CharacterOptions;
        Assert.NotNull(declared);
        Assert.Equal(3, declared!.Count);
        Assert.True(declared["IgnoreAllegianceRequests"]);
        Assert.False(declared["ListenToTradeChat"]);
        Assert.True(declared["AutoTarget"]);
    }

    [Fact]
    public void UnknownOptionNameFailsLoadNamingTheOffendingKey()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            ConfigurationWith(Session(
                "bot",
                "BOT_PASSWORD",
                "\"characterOptions\":{\"NotARealOption\":true}")));

        HeadlessConfigurationException exception = Assert.Throws<
            HeadlessConfigurationException>(
                () => HeadlessConfigurationLoader.Load(file.Path));

        Assert.Contains(
            "NotARealOption",
            exception.Message,
            StringComparison.Ordinal);
    }

    [Fact]
    public void PresentationOnlyTierThreeOptionNameFailsLoad()
    {
        // ShowHelm is a REAL CharacterOptionId member (0x2F) but is
        // deliberately outside the tier-1+2 bot-declarable subset (research
        // doc §5.2 tier 3) — excluded by construction, not merely absent
        // from an allow-list that forgot it.
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            ConfigurationWith(Session(
                "bot",
                "BOT_PASSWORD",
                "\"characterOptions\":{\"ShowHelm\":true}")));

        HeadlessConfigurationException exception = Assert.Throws<
            HeadlessConfigurationException>(
                () => HeadlessConfigurationLoader.Load(file.Path));

        Assert.Contains(
            "ShowHelm",
            exception.Message,
            StringComparison.Ordinal);
    }

    [Fact]
    public void NonBoolValueFailsLoad()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            ConfigurationWith(Session(
                "bot",
                "BOT_PASSWORD",
                "\"characterOptions\":{\"IgnoreAllegianceRequests\":\"yes\"}")));

        Assert.ThrowsAny<Exception>(
            () => HeadlessConfigurationLoader.Load(file.Path));
    }

    [Fact]
    public void AbsentCharacterOptionsBlockIsANoOp()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            ConfigurationWith(Session("bot", "BOT_PASSWORD")));

        HeadlessConfiguration configuration =
            HeadlessConfigurationLoader.Load(file.Path);

        Assert.Null(Assert.Single(configuration.Sessions)!.CharacterOptions);
    }

    [Fact]
    public void EmptyCharacterOptionsBlockIsANoOp()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            ConfigurationWith(Session(
                "bot",
                "BOT_PASSWORD",
                "\"characterOptions\":{}")));

        HeadlessConfiguration configuration =
            HeadlessConfigurationLoader.Load(file.Path);

        Dictionary<string, bool>? declared =
            Assert.Single(configuration.Sessions)!.CharacterOptions;
        Assert.NotNull(declared);
        Assert.Empty(declared!);
    }

    private static string ConfigurationWith(params string[] sessions) =>
        $$"""{"version":1,"sessions":[{{string.Join(",", sessions)}}]}""";

    private static string Session(
        string id,
        string credentialReference,
        string? extraTopLevelField = null)
    {
        string suffix = extraTopLevelField is null
            ? string.Empty
            : $",{extraTopLevelField}";
        return $"{{\"id\":\"{id}\",\"endpoint\":{{\"host\":\"127.0.0.1\",\"port\":9000}},"
            + "\"account\":\"account\",\"character\":{\"index\":0},"
            + "\"policy\":{\"id\":\"idle\"},\"credential\":"
            + $"{{\"provider\":\"environment\",\"reference\":\"{credentialReference}\"}}"
            + suffix
            + "}";
    }

    private sealed class TemporaryConfiguration : IDisposable
    {
        private TemporaryConfiguration(string path)
        {
            Path = path;
        }

        internal string Path { get; }

        internal static TemporaryConfiguration Create(string json)
        {
            string path = System.IO.Path.Combine(
                System.IO.Path.GetTempPath(),
                $"acdream-headless-op7-{Guid.NewGuid():N}.json");
            File.WriteAllText(path, json);
            return new TemporaryConfiguration(path);
        }

        public void Dispose()
        {
            File.Delete(Path);
        }
    }
}