namespace RuleEngine.Dsl;

using YamlDotNet.Serialization;
using YamlDotNet.Serialization.NamingConventions;

public class CapabilityRegistry
{
    private readonly HashSet<string> _capabilities = new();

    public void Register(string id) => _capabilities.Add(id);

    public bool Has(string id) => _capabilities.Contains(id);

    public void Check(IEnumerable<string> required)
    {
        var missing = required.Where(r => !_capabilities.Contains(r)).ToList();
        if (missing.Count > 0)
        {
            string list = string.Join("\n  ", missing.Select(m =>
                $"❌ {m} — 引擎尚未实现"));
            throw new InvalidOperationException(
                $"DSL 需要的以下算法能力引擎尚未实现:\n  {list}\n\n" +
                $"请添加对应实现后注册 Capability。\n" +
                $"当前引擎能力: {string.Join(", ", _capabilities)}");
        }
    }
}

// === DSL POCO types ===
public class MahjongDslRoot
{
    public GameInfo Game { get; set; } = new();
    public List<string> Requires { get; set; } = new();
    public DeckConfig Deck { get; set; } = new();
    public DealConfig Deal { get; set; } = new();
    public WildcardConfig? WildcardRules { get; set; }
    public WinConditionConfig? WinCondition { get; set; }
    public WinRuleConfig? WinRule { get; set; }
    public List<PreHookConfig> PreHooks { get; set; } = new();
    public List<FanTypeConfig> FanTypes { get; set; } = new();
    public string FanStacking { get; set; } = "add";
    public int MaxFan { get; set; } = int.MaxValue;
    public List<PhaseDslConfig> Phases { get; set; } = new();
    public ScoringDslConfig Scoring { get; set; } = new();
    public int WinMinFan { get; set; } = 0;
    public FlowerDslConfig? FlowerRules { get; set; }
}

public class GameInfo { public string Name { get; set; } = ""; public string Type { get; set; } = ""; }
public class DeckConfig
{
    public string Generator { get; set; } = "mahjong";
    public int Total { get; set; }
    public bool IncludeHonors { get; set; }
    public bool IncludeFlowers { get; set; }
    public int WildcardCount { get; set; }
    public string? WildcardTile { get; set; }
}
public class DealConfig { public int CardsPerPlayer { get; set; } = 13; public int DealerExtra { get; set; } = 1; }
public class WildcardConfig
{
    public string Type { get; set; } = "";
    public string Behavior { get; set; } = "";
    public int WildcardEncoding { get; set; } = 50;
    public List<string>? Tiles { get; set; }
    public WildcardScoringConfig? Scoring { get; set; }
    public string FanCalculationPolicy { get; set; } = "optimal";
}
public class WildcardScoringConfig { public int PerWildcardInWin { get; set; } }
public class WinConditionConfig { public bool PairMustBe258 { get; set; } }
public class WinRuleConfig { public bool JiHuSelfDrawOnly { get; set; } }
public class PreHookConfig { public string Name { get; set; } = ""; public string Description { get; set; } = ""; }
public class FanTypeConfig
{
    public string Name { get; set; } = "";
    public int BaseFan { get; set; }
    public int Level { get; set; }
    public List<string>? Excludes { get; set; }
    public List<string>? Conflicts { get; set; }
    public string? Condition { get; set; }
}
public class PhaseDslConfig
{
    public string Name { get; set; } = "";
    public string Type { get; set; } = "";
    public string? Action { get; set; }
    public string? Next { get; set; }
    public SubPhasesConfig? SubPhases { get; set; }
    public List<EndConditionDsl>? EndConditions { get; set; }
    public bool ParallelElimination { get; set; }
    public string? OnEliminate { get; set; }
}
public class SubPhasesConfig
{
    public DrawSubPhase? Draw { get; set; }
    public SelfActionSubPhase? SelfAction { get; set; }
    public OthersReactionSubPhase? OthersReaction { get; set; }
}
public class DrawSubPhase { public string Type { get; set; } = "auto"; public string Action { get; set; } = "draw_card"; }
public class SelfActionSubPhase { public List<ActionOptionDsl> Options { get; set; } = new(); }
public class OthersReactionSubPhase
{
    public List<ActionOptionDsl> Options { get; set; } = new();
    public string PriorityPolicy { get; set; } = "highest_wins";
    public string? OnWin { get; set; }
}
public class ActionOptionDsl { public string Action { get; set; } = ""; public int Priority { get; set; } public string? Condition { get; set; } }
public class EndConditionDsl { public string Type { get; set; } = ""; public string Action { get; set; } = ""; }
public class ScoringDslConfig { public string Mode { get; set; } = "fan_table"; public int MaxCap { get; set; } = int.MaxValue; }
public class FlowerDslConfig { public string OnDraw { get; set; } = ""; }

public class DslLoader
{
    private readonly CapabilityRegistry _caps;
    private readonly IDeserializer _deserializer;

    public DslLoader(CapabilityRegistry caps)
    {
        _caps = caps;
        _deserializer = new DeserializerBuilder()
            .WithNamingConvention(UnderscoredNamingConvention.Instance)
            .IgnoreUnmatchedProperties()
            .Build();
    }

    public MahjongDslRoot Load(string path)
    {
        if (!File.Exists(path))
            throw new FileNotFoundException($"DSL file not found: {path}");

        var yaml = File.ReadAllText(path);
        return LoadString(yaml, path);
    }

    public MahjongDslRoot LoadString(string yaml, string source = "inline")
    {
        var dsl = _deserializer.Deserialize<MahjongDslRoot>(yaml)
            ?? throw new InvalidOperationException($"Failed to parse DSL: {source}");

        // Check capabilities
        _caps.Check(dsl.Requires);

        return dsl;
    }
}