using System.Text.Json;
using NullDepth.Models;

var root = FindRoot();
var webRoot = Path.Combine(root, "src", "NullDepth", "wwwroot");
var options = new JsonSerializerOptions(JsonSerializerDefaults.Web);
var data = JsonSerializer.Deserialize<GameData>(File.ReadAllText(Path.Combine(webRoot, "data", "game.json")), options)
           ?? throw new InvalidOperationException("game.json is empty.");
var sk = ReadLanguage("sk");
var en = ReadLanguage("en");
var checks = 0;

Check(data.Rooms.Count == 15, "The level must contain 15 rooms.");
Check(data.Rooms.Select(r => r.Id).Distinct().Count() == data.Rooms.Count, "Room IDs must be unique.");
Check(data.Rooms.Any(r => r.Id == data.StartRoomId), "Start room does not exist.");
Check(sk.Keys.Order().SequenceEqual(en.Keys.Order()), "SK and EN localization keys differ.");

var rooms = data.Rooms.ToDictionary(r => r.Id);
var items = data.Items.ToDictionary(i => i.Id);
var archive = data.Archive.ToDictionary(a => a.Id);
foreach (var item in data.InitialItems) Check(items.ContainsKey(item), $"Unknown initial item: {item}");

foreach (var room in data.Rooms)
{
    Key(room.NameKey); Key(room.DescriptionKey); Asset(room.Image);
    if (room.AlternateImage is not null) Asset(room.AlternateImage);
    foreach (var exit in room.Exits.Values)
    {
        Check(rooms.ContainsKey(exit.Target), $"Invalid exit target: {exit.Target}");
        if (exit.LockedMessageKey is not null) Key(exit.LockedMessageKey);
    }
    foreach (var interaction in room.Interactions)
    {
        Key(interaction.LabelKey); Key(interaction.ContentKey);
        foreach (var item in interaction.AddItems) Check(items.ContainsKey(item), $"Unknown item: {item}");
        if (interaction.ArchiveId is not null) Check(archive.ContainsKey(interaction.ArchiveId), $"Unknown archive entry: {interaction.ArchiveId}");
        foreach (var choice in interaction.Choices)
        {
            Key(choice.LabelKey);
            if (choice.ResultKey is not null) Key(choice.ResultKey);
            foreach (var item in choice.AddItems) Check(items.ContainsKey(item), $"Unknown item: {item}");
        }
    }
}
foreach (var item in data.Items) { Key(item.NameKey); Key(item.DescriptionKey); }
foreach (var entry in data.Archive) { Key(entry.TitleKey); Key(entry.ContentKey); }

TestEnding("release", "balanced");
TestEnding("shutdown", "balanced");
TestContainmentEnding();
TestDeathAndCheckpoint();
TestSaveRoundTrip();

Console.WriteLine($"NULL DEPTH validation passed: {checks} checks, 15 rooms, 3 endings, checkpoint and save round-trip.");
return;

Dictionary<string, string> ReadLanguage(string language) =>
    JsonSerializer.Deserialize<Dictionary<string, string>>(File.ReadAllText(Path.Combine(webRoot, "localization", $"{language}.json")), options)
    ?? throw new InvalidOperationException($"{language}.json is empty.");

void Key(string key) => Check(sk.ContainsKey(key) && en.ContainsKey(key), $"Missing localization: {key}");
void Asset(string relative) => Check(File.Exists(Path.Combine(webRoot, relative.Replace('/', Path.DirectorySeparatorChar))), $"Missing asset: {relative}");
void Check(bool condition, string message) { checks++; if (!condition) throw new InvalidOperationException(message); }

void TestEnding(string ending, string coolingChoice)
{
    var run = NewRun();
    AdvanceToLowerLevel(run);
    run.Move("east"); run.Move("south"); run.Choose("power_routing", coolingChoice); run.Move("north"); run.Move("east");
    run.Interact("cross_passage"); run.Move("east"); run.Move("east"); run.Choose("ai_dialogue", "openCore"); run.Move("east");
    run.Choose("final_diagnostic", ending);
    Check(run.Ending == ending, $"Ending '{ending}' is not reachable.");
}

void TestContainmentEnding()
{
    var run = NewRun();
    run.Interact("contractor_terminal"); run.Move("east"); run.Move("east"); run.Move("south"); run.Move("west");
    run.Interact("log_01"); run.Move("east"); run.Interact("auxiliary_grid"); run.Move("north"); run.Move("east");
    run.Interact("elevator_descent"); run.Interact("elevator_resume"); run.Move("south"); run.Interact("emergency_supply");
    run.Move("south"); run.Choose("manual_override", "takeOverride"); run.Move("north"); run.Move("east"); run.Interact("log_02");
    run.Move("south"); run.Choose("power_routing", "coolingOnly"); run.Move("north"); run.Move("east"); run.Interact("cross_passage");
    run.Move("east"); run.Interact("log_03"); run.Move("east"); run.Choose("ai_dialogue", "openCore"); run.Move("east");
    run.Choose("final_diagnostic", "containment");
    Check(run.Ending == "containment", "Containment ending is not reachable.");
    Check(run.Archive.Count == 3, "Recovered logs were not retained in the archive.");
    Check(run.Inventory.Contains("manual_override") && run.Inventory.Count >= 4, "Gameplay inventory is incomplete.");
}

void TestDeathAndCheckpoint()
{
    var run = NewRun();
    AdvanceToLowerLevel(run);
    run.Move("east"); run.Move("south"); run.Choose("power_routing", "balanced");
    var checkpointRoom = run.Room;
    run.Move("north"); run.Move("west"); run.Move("south");
    var death = run.Choose("manual_override", "forceLiveBus");
    Check(death.Death, "Fatal choice is not marked as death.");
    run.RestoreCheckpoint();
    Check(run.Room == checkpointRoom, "Checkpoint did not restore the expected room.");
}

void TestSaveRoundTrip()
{
    var state = new GameState { CurrentRoomId = data.StartRoomId, ContentVersion = data.Version, Inventory = [.. data.InitialItems], Archive = ["log_01"] };
    state.Flags.Add("entry_authorized"); state.VisitedRooms.Add(data.StartRoomId);
    var json = JsonSerializer.Serialize(state, options);
    var restored = JsonSerializer.Deserialize<GameState>(json, options)!;
    Check(restored.Version == 3 && restored.ContentVersion == data.Version, "Save version was not serialized.");
    Check(restored.Inventory.SequenceEqual(state.Inventory) && restored.Archive.SequenceEqual(state.Archive), "Save round-trip lost inventory or archive data.");
    try { JsonSerializer.Deserialize<GameState>("{broken", options); Check(false, "Corrupt save was accepted."); }
    catch (JsonException) { Check(true, "Corrupt save rejected."); }
}

Run NewRun() => new(data);
void AdvanceToLowerLevel(Run run)
{
    run.Interact("contractor_terminal"); run.Move("east"); run.Move("east"); run.Move("south"); run.Interact("auxiliary_grid");
    run.Move("north"); run.Move("east"); run.Interact("elevator_descent"); run.Interact("elevator_resume"); run.Move("south");
}

string FindRoot()
{
    var directory = new DirectoryInfo(AppContext.BaseDirectory);
    while (directory is not null && !File.Exists(Path.Combine(directory.FullName, "NullDepth.slnx"))) directory = directory.Parent;
    return directory?.FullName ?? throw new DirectoryNotFoundException("Repository root was not found.");
}

sealed class Run
{
    private readonly GameData _data;
    private Snapshot _checkpoint;
    public string Room { get; private set; }
    public HashSet<string> Flags { get; } = [];
    public List<string> Inventory { get; }
    public List<string> Archive { get; } = [];
    public string? Ending { get; private set; }

    public Run(GameData data)
    {
        _data = data; Room = data.StartRoomId; Inventory = [.. data.InitialItems]; _checkpoint = Capture();
    }

    public void Move(string direction)
    {
        var room = _data.Rooms.Single(r => r.Id == Room);
        if (!room.Exits.TryGetValue(direction, out var exit) || !exit.RequiresFlags.All(Flags.Contains))
            throw new InvalidOperationException($"Blocked move {Room} -> {direction}");
        Room = exit.Target;
    }

    public void Interact(string id)
    {
        var interaction = CurrentInteraction(id);
        Apply(interaction.SetFlags, interaction.ClearFlags, interaction.AddItems);
        if (interaction.ArchiveId is not null && !Archive.Contains(interaction.ArchiveId)) Archive.Add(interaction.ArchiveId);
        if (interaction.Checkpoint) _checkpoint = Capture();
    }

    public ChoiceDefinition Choose(string interactionId, string choiceToken)
    {
        var interaction = CurrentInteraction(interactionId);
        var choice = interaction.Choices.Single(c => c.LabelKey.EndsWith(choiceToken, StringComparison.OrdinalIgnoreCase) || c.Ending == choiceToken);
        if (!choice.RequiresFlags.All(Flags.Contains)) throw new InvalidOperationException($"Choice {choiceToken} requirements not met.");
        Apply(choice.SetFlags, choice.ClearFlags, choice.AddItems);
        Ending = choice.Ending;
        if (choice.Checkpoint) _checkpoint = Capture();
        return choice;
    }

    public void RestoreCheckpoint()
    {
        Room = _checkpoint.Room; Flags.Clear(); Flags.UnionWith(_checkpoint.Flags);
        Inventory.Clear(); Inventory.AddRange(_checkpoint.Inventory); Archive.Clear(); Archive.AddRange(_checkpoint.Archive); Ending = null;
    }

    private InteractionDefinition CurrentInteraction(string id)
    {
        var interaction = _data.Rooms.Single(r => r.Id == Room).Interactions.Single(i => i.Id == id);
        if (!interaction.RequiresFlags.All(Flags.Contains) || interaction.ForbiddenFlags.Any(Flags.Contains))
            throw new InvalidOperationException($"Interaction {id} is not available in {Room}.");
        return interaction;
    }

    private void Apply(IEnumerable<string> set, IEnumerable<string> clear, IEnumerable<string> items)
    {
        foreach (var flag in clear) Flags.Remove(flag); foreach (var flag in set) Flags.Add(flag);
        foreach (var item in items) if (!Inventory.Contains(item)) Inventory.Add(item);
    }
    private Snapshot Capture() => new(Room, [.. Flags], [.. Inventory], [.. Archive]);
    private sealed record Snapshot(string Room, HashSet<string> Flags, List<string> Inventory, List<string> Archive);
}