using System.Text.Json;
using Koogle.Domain.Enums;

namespace Koogle.Application.Games.DeathBox;

/// <summary>
/// Game logic service for DeathBox (Totenkisten) game.
/// Players collect marks and are eliminated when their coffin is full.
/// Last player standing wins.
/// </summary>
public class DeathBoxGameLogicService : IGameLogicService
{
    private static readonly Random Random = new();

    /// <inheritdoc />
    public object CreateInitialModel(Guid[] playerIds, object? setupOptions)
    {
        var options = ParseSetupOptions(setupOptions);

        var playerOrder = options.RandomizePlayerOrder
            ? playerIds.OrderBy(_ => Random.Next()).ToArray()
            : playerIds.ToArray();

        var playerStates = playerIds.ToDictionary(
            id => id,
            _ => new DeathBoxPlayerState());

        return new DeathBoxGameModel
        {
            CoffinSize = options.CoffinSize,
            PlayerStates = playerStates,
            PlayerOrder = playerOrder,
            CurrentPlayerIndex = 0,
            PreviousPlayerId = null,
            EliminatedPlayers = [],
            WinnerId = null,
            IsGameOver = false,
            LastThrow = null
        };
    }

    /// <inheritdoc />
    public (object UpdatedModel, ThrowResult Result) ProcessThrow(object gameModel, AfterThrowState afterThrow)
    {
        var model = CastModel(gameModel);
        var playerId = afterThrow.CurrentPlayerId;
        var pinsKnocked = afterThrow.PinsKnocked;

        if (model.IsGameOver)
        {
            return (model, new ThrowResult
            {
                PointsScored = 0,
                ShouldRotatePlayer = false,
                IsGameOver = true,
                WinnerId = model.WinnerId
            });
        }

        var playerStates = new Dictionary<Guid, DeathBoxPlayerState>(model.PlayerStates);
        var eliminatedPlayers = new List<Guid>(model.EliminatedPlayers);
        var triggers = new List<TriggerEvent>();
        var assignX = false;

        // Get current player state
        var currentState = playerStates[playerId];
        currentState.ThrowCount++;
        currentState.TotalPins += pinsKnocked;

        // Track last throw info
        var lastThrow = new DeathBoxLastThrow
        {
            PlayerId = playerId,
            PinsKnocked = pinsKnocked,
            WasGutter = afterThrow.IsGutter,
            WasCleared = afterThrow.IsCleared
        };

        // Determine if this is a new round (all 9 pins were standing before throw)
        bool isNewRound = IsNewRound(afterThrow);
        lastThrow = lastThrow with { IsNewRound = isNewRound };

        // 1. NEW ROUND processing (when 9 pins were standing)
        if (isNewRound)
        {
            // Always collect X on new round
            //currentState.XCount++;
            //lastThrow = lastThrow with { EarnedX = true };

            // Penalty for <3 pins on new round
            if (pinsKnocked < 3)
            {
                currentState.Marks++;
                lastThrow = lastThrow with { WasPenalty = true };
            }

            // Check X conversion (3 X's -> 1 mark)
            if (currentState.XCount >= 3)
            {
                currentState.XCount = 0;
                currentState.Marks++;
                lastThrow = lastThrow with { ConvertedXsToMark = true };
            }
        }

        // 2. GUTTER / NO WOOD processing (0 pins knocked)
        if (pinsKnocked == 0)
        {
            // Only add mark if not already penalized from new round rule
            // (new round with 0 pins = already got mark from <3 rule)
            if (!isNewRound)
            {
                currentState.Marks++;
            }

            if (afterThrow.IsGutter)
            {
                lastThrow = lastThrow with { WasGutter = true };
                triggers.Add(new TriggerEvent
                {
                    TriggerType = ExpenseTriggerType.Gutter.ToString(),
                    PersonId = playerId,
                    Multiplier = 1
                });
            }
            else
            {
                lastThrow = lastThrow with { WasNoWood = true };
                triggers.Add(new TriggerEvent
                {
                    TriggerType = ExpenseTriggerType.NoWood.ToString(),
                    PersonId = playerId,
                    Multiplier = 1
                });
            }
        }

        // 3. CLEARED processing (all remaining pins hit)
        //Guid? previousPlayerPenalizedId = null;
        bool previousPlayerEliminated = false;

        if (afterThrow.IsCleared /*&& !isNewRound*/)
        {
            // Current player gets egg
            currentState.EggCount++;
            lastThrow = lastThrow with { EarnedEgg = true };

            // Check egg conversion (3 eggs -> -1 mark if possible)
            if (currentState.EggCount >= 3)
            {
                currentState.EggCount = 0;
                if (currentState.Marks > 0)
                {
                    currentState.Marks--;
                    lastThrow = lastThrow with { ConvertedEggsToRemoveMark = true };
                }
                // Eggs expire if no marks to remove
            }

            // in case eggs have been earned, next player will get another X
            assignX = true;

            // Previous player gets mark (if exists and not eliminated)
            if (model.PreviousPlayerId.HasValue &&
                playerStates.TryGetValue(model.PreviousPlayerId.Value, out var prevState) &&
                !prevState.IsEliminated)
            {
                prevState.Marks++;
                lastThrow = lastThrow with
                {
                    PreviousPlayerGotMark = true,
                    PreviousPlayerPenalizedId = model.PreviousPlayerId.Value
                };
                //previousPlayerPenalizedId = model.PreviousPlayerId.Value;

                // Check if previous player is eliminated
                if (prevState.Marks >= model.CoffinSize)
                {
                    prevState.IsEliminated = true;
                    eliminatedPlayers.Add(model.PreviousPlayerId.Value);
                    previousPlayerEliminated = true;

                    // Calculate penalty (remaining players after this elimination)
                    int remainingPlayers = CountActivePlayers(playerStates);
                    if (remainingPlayers > 0)
                    {
                        triggers.Add(new TriggerEvent
                        {
                            TriggerType = ExpenseTriggerType.ExpensePoint.ToString(),
                            PersonId = model.PreviousPlayerId.Value,
                            Multiplier = remainingPlayers
                        });
                    }
                }
            }
        }

        lastThrow = lastThrow with { PreviousPlayerEliminated = previousPlayerEliminated };

        // 4. Check ELIMINATION for current player
        bool currentPlayerEliminated = false;
        if (currentState.Marks >= model.CoffinSize && !currentState.IsEliminated)
        {
            currentState.IsEliminated = true;
            eliminatedPlayers.Add(playerId);
            currentPlayerEliminated = true;
            lastThrow = lastThrow with { PlayerEliminated = true };

            // Calculate penalty (remaining players after this elimination)
            int remainingPlayers = CountActivePlayers(playerStates);
            if (remainingPlayers > 0)
            {
                triggers.Add(new TriggerEvent
                {
                    TriggerType = ExpenseTriggerType.ExpensePoint.ToString(),
                    PersonId = playerId,
                    Multiplier = remainingPlayers
                });
            }
        }

        // Update player states
        playerStates[playerId] = currentState;

        // 5. Check GAME END
        bool isGameOver = false;
        Guid? winnerId = null;
        int activePlayersCount = CountActivePlayers(playerStates);

        if (activePlayersCount <= 1)
        {
            isGameOver = true;
            winnerId = playerStates
                .Where(kvp => !kvp.Value.IsEliminated)
                .Select(kvp => kvp.Key)
                .FirstOrDefault();
        }

        // 6. Determine next player (skip eliminated players)
        // Find current player's index in PlayerOrder based on actual playerId from throw
        int currentIndex = Array.IndexOf(model.PlayerOrder, playerId);
        if (currentIndex < 0) currentIndex = model.CurrentPlayerIndex;

        int nextPlayerIndex = GetNextActivePlayerIndex(model.PlayerOrder, currentIndex, playerStates);
        var nextPlayerId = model.PlayerOrder[nextPlayerIndex];
        if (assignX)
        {
            var nextState = playerStates[nextPlayerId];
            nextState.XCount ++;
            lastThrow = lastThrow with { EarnedX = true };

            lastThrow = lastThrow with
            {
                EarnedX = true,
                NextPlayerPenalizedId = nextPlayerId
            };

            // Check X conversion (3 X's -> 1 mark)
            if (nextState.XCount >= 3)
            {
                lastThrow = lastThrow with
                {
                    NextPlayerGotMark = true,
                    NextPlayerPenalizedId = nextPlayerId
                };
                

                nextState.XCount = 0;
                nextState.Marks++;
                lastThrow = lastThrow with { ConvertedXsToMark = true };
            }

            playerStates[nextPlayerId] = nextState;
        }

        // Update model
        model = model with
        {
            PlayerStates = playerStates,
            EliminatedPlayers = eliminatedPlayers,
            CurrentPlayerIndex = nextPlayerIndex,
            PreviousPlayerId = playerId,
            IsGameOver = isGameOver,
            WinnerId = winnerId,
            LastThrow = lastThrow
        };

        var result = new ThrowResult
        {
            PointsScored = pinsKnocked,
            ShouldRotatePlayer = true,
            IsGameOver = isGameOver,
            WinnerId = winnerId,
            Triggers = triggers,
            Overrides = isGameOver ? null : new GameLogicOverrides
            {
                NextPlayerId = model.PlayerOrder[nextPlayerIndex]
            }
        };

        return (model, result);
    }

    /// <inheritdoc />
    public (bool IsGameOver, Guid? WinnerId) CheckGameEnd(object gameModel)
    {
        var model = CastModel(gameModel);
        return (model.IsGameOver, model.WinnerId);
    }

    /// <inheritdoc />
    public IReadOnlyDictionary<Guid, PlayerStatsSummary> GetPlayerStats(object gameModel)
    {
        var model = CastModel(gameModel);

        return model.PlayerStates.ToDictionary(
            kvp => kvp.Key,
            kvp => new PlayerStatsSummary
            {
                ThrowCount = kvp.Value.ThrowCount,
                PinCount = kvp.Value.TotalPins,
                CircleCount = 0,
                StrikeCount = 0,
                CurrentPoints = kvp.Value.Marks,
                CustomStats = new Dictionary<string, object>
                {
                    ["Marks"] = kvp.Value.Marks,
                    ["CoffinSize"] = model.CoffinSize,
                    ["XCount"] = kvp.Value.XCount,
                    ["EggCount"] = kvp.Value.EggCount,
                    ["IsEliminated"] = kvp.Value.IsEliminated,
                    ["IsWinner"] = model.WinnerId == kvp.Key,
                    ["EliminationOrder"] = model.EliminatedPlayers.IndexOf(kvp.Key) + 1
                }
            });
    }

    /// <inheritdoc />
    public IReadOnlyList<GameActionDescriptor> GetAvailableActions(object gameModel, Guid currentPlayerId)
    {
        // DeathBox has no custom actions
        return [];
    }

    /// <inheritdoc />
    public GameActionResult ExecuteAction(
        object gameModel,
        string actionId,
        Guid currentPlayerId,
        IReadOnlyDictionary<string, object>? parameters = null)
    {
        return GameActionResult.Failure($"Unknown action: {actionId}");
    }

    /// <inheritdoc />
    public GameSetupValidationResult ValidateSetup(object? setupOptions)
    {
        if (setupOptions is null)
        {
            return GameSetupValidationResult.Valid();
        }

        var options = ParseSetupOptions(setupOptions);
        var errors = new List<string>();

        if (options.CoffinSize < 6 || options.CoffinSize > 12)
        {
            errors.Add("Sarggröße muss zwischen 6 und 12 liegen.");
        }

        return errors.Count > 0
            ? GameSetupValidationResult.Invalid(errors.ToArray())
            : GameSetupValidationResult.Valid();
    }

    #region Helper Methods

    private static bool IsNewRound(AfterThrowState afterThrow)
    {
        // New round = 9 pins were standing before this throw
        // If it's a strike, all 9 were knocked down from 9 standing
        if (afterThrow.IsStrike) return true;

        // Otherwise check if standing pins before throw = 9
        // We can infer this from: if all pins are now accounted for (knocked + still standing = 9)
        // and pins knocked equals the change
        var snapshot = afterThrow.ThrowPanel;
        var standingBefore = snapshot.StandingPinCount() + afterThrow.PinsKnocked;
        return standingBefore == 9;
    }

    private static int CountActivePlayers(Dictionary<Guid, DeathBoxPlayerState> playerStates)
    {
        return playerStates.Values.Count(s => !s.IsEliminated);
    }

    private static int GetNextActivePlayerIndex(
        Guid[] playerOrder,
        int currentIndex,
        Dictionary<Guid, DeathBoxPlayerState> playerStates)
    {
        int playerCount = playerOrder.Length;
        int nextIndex = (currentIndex + 1) % playerCount;

        // Find next non-eliminated player
        for (int i = 0; i < playerCount; i++)
        {
            var playerId = playerOrder[nextIndex];
            if (playerStates.TryGetValue(playerId, out var state) && !state.IsEliminated)
            {
                return nextIndex;
            }
            nextIndex = (nextIndex + 1) % playerCount;
        }

        // All eliminated (shouldn't happen if game end is checked first)
        return currentIndex;
    }

    private static DeathBoxGameSetup ParseSetupOptions(object? setupOptions)
    {
        if (setupOptions is null)
        {
            return new DeathBoxGameSetup();
        }

        if (setupOptions is DeathBoxGameSetup typedSetup)
        {
            return typedSetup;
        }

        if (setupOptions is JsonElement jsonElement)
        {
            try
            {
                return JsonSerializer.Deserialize<DeathBoxGameSetup>(
                    jsonElement.GetRawText(),
                    GameModelFactory.JsonSerializerOptions) ?? new DeathBoxGameSetup();
            }
            catch
            {
                return new DeathBoxGameSetup();
            }
        }

        return new DeathBoxGameSetup();
    }

    private static DeathBoxGameModel CastModel(object gameModel)
    {
        if (gameModel is DeathBoxGameModel model)
        {
            return model;
        }

        if (gameModel is JsonElement jsonElement)
        {
            return JsonSerializer.Deserialize<DeathBoxGameModel>(
                jsonElement.GetRawText(),
                GameModelFactory.JsonSerializerOptions)!;
        }

        throw new InvalidOperationException($"Expected DeathBoxGameModel but got {gameModel.GetType().Name}");
    }

    #endregion
}