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 NumericKeyFailsLoadInsteadOfAliasingIntoAnAllowedId()
    {
        // SF-1 (OP7 review fix, 2026-08-11): Enum.TryParse on a non-[Flags]
        // enum accepts a decimal numeric string — "15" parsed to 0x0F
        // (FellowshipShareXP), which IS allow-listed, so the old
        // parsed-value check let a key that is not an enum-member spelling
        // at all silently pass. Validation must reject the STRING.
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            ConfigurationWith(Session(
                "bot",
                "BOT_PASSWORD",
                "\"characterOptions\":{\"15\":true}")));

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

        Assert.Contains("15", exception.Message, StringComparison.Ordinal);
    }

    [Fact]
    public void CommaCombinedKeyFailsLoadInsteadOfOrCombiningIntoAnAllowedId()
    {
        // SF-1 companion case: Enum.TryParse OR-combines a comma-separated
        // member list — "ToggleRun,AutoTarget" (0x0A | 0x0D) parsed to
        // 0x0F (FellowshipShareXP), again allow-listed, so a config that
        // reads as two movement options would have silently set fellowship
        // XP sharing instead.
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            ConfigurationWith(Session(
                "bot",
                "BOT_PASSWORD",
                "\"characterOptions\":{\"ToggleRun,AutoTarget\":true}")));

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

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

    [Fact]
    public void BothFellowshipExclusionOptionsTrueFailsLoadNamingBothKeys()
    {
        // SF-2 (OP7 review fix, 2026-08-11): retail's own OnChanged mutual
        // exclusion means IgnoreFellowshipRequests and
        // FellowshipAutoAcceptRequests can never both be true at once —
        // turning one on always clears the other. A config declaring both
        // true would have the seeder oscillate (re-send) on every connect
        // forever with neither value ever actually honoured. Reject it at
        // load instead.
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            ConfigurationWith(Session(
                "bot",
                "BOT_PASSWORD",
                "\"characterOptions\":{\"IgnoreFellowshipRequests\":true,"
                + "\"FellowshipAutoAcceptRequests\":true}")));

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

        Assert.Contains(
            "IgnoreFellowshipRequests",
            exception.Message,
            StringComparison.Ordinal);
        Assert.Contains(
            "FellowshipAutoAcceptRequests",
            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!);
    }

    // ── Campaign LA slice LA2: probe-mode `mode` field shape validation ──

    [Fact]
    public void ProbeSessionOmittingCharacterAndPolicyLoads()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            """
            {
              "version": 1,
              "sessions": [
                {
                  "id": "probe-session",
                  "endpoint": { "host": "127.0.0.1", "port": 9000 },
                  "account": "account",
                  "mode": "probe",
                  "credential": { "provider": "environment", "reference": "PROBE_PASSWORD" }
                }
              ]
            }
            """);

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

        HeadlessSessionDescriptor session = Assert.Single(configuration.Sessions)!;
        Assert.Null(session.Character);
        Assert.Null(session.Policy);
    }

    /// <summary>
    /// The pinned v1 contract has one named mode value: <c>"probe"</c>.
    /// In particular, the enum's underlying numeric zero must not become an
    /// accidental second spelling through an enum converter configured to
    /// allow integers.
    /// </summary>
    [Theory]
    [InlineData("\"play\"")]
    [InlineData("0")]
    public void SessionModeRejectsEveryValueOtherThanTheNamedProbeMode(
        string modeJson)
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            $$"""
            {
              "version": 1,
              "sessions": [
                {
                  "id": "unsupported-mode",
                  "endpoint": { "host": "127.0.0.1", "port": 9000 },
                  "account": "account",
                  "mode": {{modeJson}},
                  "credential": { "provider": "environment", "reference": "PROBE_PASSWORD" }
                }
              ]
            }
            """);

        Assert.Throws<JsonException>(
            () => HeadlessConfigurationLoader.Load(file.Path));
    }

    /// <summary>
    /// Campaign LA LA2 review fix: the pinned contract is presence-aware.
    /// Normal play omits mode and supplies character/policy; probe supplies
    /// mode and omits character/policy. JSON null is not another spelling of
    /// omission for any of those conditional fields.
    /// </summary>
    [Theory]
    [InlineData(false, "mode")]
    [InlineData(false, "character")]
    [InlineData(false, "policy")]
    [InlineData(true, "character")]
    [InlineData(true, "policy")]
    public void ConditionalSessionFieldsRejectExplicitJsonNull(
        bool probe,
        string nullField)
    {
        string mode = probe
            ? "\"mode\":\"probe\","
            : nullField == "mode"
                ? "\"mode\":null,"
                : string.Empty;
        string character = nullField == "character"
            ? "\"character\":null,"
            : probe
                ? string.Empty
                : "\"character\":{\"index\":0},";
        string policy = nullField == "policy"
            ? "\"policy\":null,"
            : probe
                ? string.Empty
                : "\"policy\":{\"id\":\"idle\"},";
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            $$"""
            {
              "version": 1,
              "sessions": [
                {
                  "id": "explicit-null",
                  "endpoint": { "host": "127.0.0.1", "port": 9000 },
                  "account": "account",
                  {{mode}}
                  {{character}}
                  {{policy}}
                  "credential": { "provider": "environment", "reference": "PASSWORD" }
                }
              ]
            }
            """);

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

        Assert.Contains(
            $"'{nullField}'",
            exception.Message,
            StringComparison.Ordinal);
        Assert.Contains(
            "cannot be null",
            exception.Message,
            StringComparison.Ordinal);
    }

    [Fact]
    public void PresenceAwareValidationKeepsUnmappedMemberRejection()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            ConfigurationWith(Session(
                "bot",
                "PASSWORD",
                "\"notAContractField\":true")));

        Assert.Throws<JsonException>(
            () => HeadlessConfigurationLoader.Load(file.Path));
    }

    [Fact]
    public void PresenceAwareValidationKeepsTypedValueRejection()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            """
            {
              "version": 1,
              "sessions": [
                {
                  "id": "wrong-type",
                  "endpoint": { "host": "127.0.0.1", "port": 9000 },
                  "account": "account",
                  "mode": { "value": "probe" },
                  "credential": { "provider": "environment", "reference": "PASSWORD" }
                }
              ]
            }
            """);

        Assert.Throws<JsonException>(
            () => HeadlessConfigurationLoader.Load(file.Path));
    }

    [Fact]
    public void ProbeSessionDeclaringCharacterFailsLoadNamingTheField()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            """
            {
              "version": 1,
              "sessions": [
                {
                  "id": "probe-with-character",
                  "endpoint": { "host": "127.0.0.1", "port": 9000 },
                  "account": "account",
                  "mode": "probe",
                  "character": { "index": 0 },
                  "credential": { "provider": "environment", "reference": "PROBE_PASSWORD" }
                }
              ]
            }
            """);

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

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

    [Fact]
    public void ProbeSessionDeclaringPolicyFailsLoadNamingTheField()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            """
            {
              "version": 1,
              "sessions": [
                {
                  "id": "probe-with-policy",
                  "endpoint": { "host": "127.0.0.1", "port": 9000 },
                  "account": "account",
                  "mode": "probe",
                  "policy": { "id": "idle" },
                  "credential": { "provider": "environment", "reference": "PROBE_PASSWORD" }
                }
              ]
            }
            """);

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

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

    /// <summary>
    /// A play session (mode absent) missing `character` must still fail —
    /// the LA2 change moved this requiredness from `[JsonRequired]` (a raw
    /// <see cref="System.Text.Json.JsonException"/> at deserialize time) to
    /// <see cref="HeadlessConfigurationLoader.ValidateSession"/>'s semantic
    /// check (a <see cref="HeadlessConfigurationException"/> naming the
    /// missing field). Exit-code parity (both map to
    /// <c>HeadlessExitCode.ConfigurationError</c>) is proven at
    /// <c>HeadlessEntryPointTests</c>; this test pins the loader-level
    /// exception type/message.
    /// </summary>
    [Fact]
    public void PlaySessionMissingCharacterStillFailsLoad()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            """
            {
              "version": 1,
              "sessions": [
                {
                  "id": "play-missing-character",
                  "endpoint": { "host": "127.0.0.1", "port": 9000 },
                  "account": "account",
                  "policy": { "id": "idle" },
                  "credential": { "provider": "environment", "reference": "PLAY_PASSWORD" }
                }
              ]
            }
            """);

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

        Assert.Contains(
            "requires a character selector",
            exception.Message,
            StringComparison.Ordinal);
    }

    /// <summary>Same parity claim as
    /// <see cref="PlaySessionMissingCharacterStillFailsLoad"/> for the
    /// `policy` field.</summary>
    [Fact]
    public void PlaySessionMissingPolicyStillFailsLoad()
    {
        using TemporaryConfiguration file = TemporaryConfiguration.Create(
            """
            {
              "version": 1,
              "sessions": [
                {
                  "id": "play-missing-policy",
                  "endpoint": { "host": "127.0.0.1", "port": 9000 },
                  "account": "account",
                  "character": { "index": 0 },
                  "credential": { "provider": "environment", "reference": "PLAY_PASSWORD" }
                }
              ]
            }
            """);

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

        Assert.Contains(
            "requires a non-empty policy id",
            exception.Message,
            StringComparison.Ordinal);
    }

    [Fact]
    public void PlaySessionKeepsTodaysStrictCharacterSelectorAndPolicyValidation()
    {
        // Unrelated to `mode` — proves the LA2 refactor of ValidateSession
        // did not loosen the existing selector-shape/policy-id checks for
        // ordinary play sessions (mode absent).
        using TemporaryConfiguration badSelector = TemporaryConfiguration.Create(
            """
            {
              "version": 1,
              "sessions": [
                {
                  "id": "bad-selector",
                  "endpoint": { "host": "127.0.0.1", "port": 9000 },
                  "account": "account",
                  "character": { "index": 0, "name": "Two" },
                  "policy": { "id": "idle" },
                  "credential": { "provider": "environment", "reference": "A" }
                }
              ]
            }
            """);
        using TemporaryConfiguration blankPolicy = TemporaryConfiguration.Create(
            """
            {
              "version": 1,
              "sessions": [
                {
                  "id": "blank-policy",
                  "endpoint": { "host": "127.0.0.1", "port": 9000 },
                  "account": "account",
                  "character": { "index": 0 },
                  "policy": { "id": "" },
                  "credential": { "provider": "environment", "reference": "B" }
                }
              ]
            }
            """);

        Assert.Throws<HeadlessConfigurationException>(
            () => HeadlessConfigurationLoader.Load(badSelector.Path));
        Assert.Throws<HeadlessConfigurationException>(
            () => HeadlessConfigurationLoader.Load(blankPolicy.Path));
    }

    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);
        }
    }
}