#nullable enable
using Managing.Application.Abstractions;
using Managing.Application.Abstractions.Grains;
using Managing.Application.Abstractions.Services;
using Managing.Application.Bots.Models;
using Managing.Application.Orleans;
using Managing.Common;
using Managing.Core;
using Managing.Core.Exceptions;
using Managing.Domain.Bots;
using Managing.Domain.Statistics;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Orleans.Concurrency;
using static Managing.Common.Enums;

namespace Managing.Application.Bots.Grains;

/// <summary>
/// Orleans grain for Agent operations.
/// Uses custom trading placement with load balancing and built-in fallback.
/// </summary>
[TradingPlacement] // Use custom trading placement with load balancing
public class AgentGrain : Grain, IAgentGrain
{
    private readonly IPersistentState<AgentGrainState> _state;
    private readonly ILogger<AgentGrain> _logger;
    private readonly IBotService _botService;
    private readonly IAgentService _agentService;
    private readonly IExchangeService _exchangeService;
    private readonly IUserService _userService;
    private readonly IAccountService _accountService;
    private readonly ITradingService _tradingService;
    private readonly IServiceScopeFactory _scopeFactory;

    public AgentGrain(
        [PersistentState("agent-state", "agent-store")]
        IPersistentState<AgentGrainState> state,
        ILogger<AgentGrain> logger,
        IBotService botService,
        IAgentService agentService,
        IExchangeService exchangeService,
        IUserService userService,
        IAccountService accountService,
        ITradingService tradingService,
        IServiceScopeFactory scopeFactory)
    {
        _state = state;
        _logger = logger;
        _botService = botService;
        _agentService = agentService;
        _exchangeService = exchangeService;
        _userService = userService;
        _accountService = accountService;
        _tradingService = tradingService;
        _scopeFactory = scopeFactory;
    }

    public override async Task OnActivateAsync(CancellationToken cancellationToken)
    {
        _logger.LogInformation("AgentGrain activated for user {UserId}", this.GetPrimaryKeyLong());
        await base.OnActivateAsync(cancellationToken);
    }

    public async Task InitializeAsync(int userId, string agentName)
    {
        _state.State.AgentName = agentName;
        await _state.WriteStateAsync();

        // Create an empty AgentSummary for the new agent
        var emptySummary = new AgentSummary
        {
            UserId = userId,
            AgentName = agentName,
            TotalPnL = 0,
            TotalROI = 0,
            Wins = 0,
            Losses = 0,
            Runtime = null,
            CreatedAt = DateTime.UtcNow,
            UpdatedAt = DateTime.UtcNow,
            ActiveStrategiesCount = 0,
            TotalVolume = 0,
            TotalBalance = 0
        };

        await _agentService.SaveOrUpdateAgentSummary(emptySummary);
        _logger.LogInformation("Agent {UserId} initialized with name {AgentName} and empty summary", userId, agentName);

         // Notify platform summary about new agent activation
        await ServiceScopeHelpers.WithScopedService<IGrainFactory>(_scopeFactory, async grainFactory =>
        {
            var platformGrain = grainFactory.GetGrain<IPlatformSummaryGrain>("platform-summary");
            await platformGrain.IncrementAgentCountAsync();
            _logger.LogDebug("Notified platform summary about new agent activation for user {UserId}", userId);
        });
    }

    public async Task UpdateAgentNameAsync(string agentName)
    {
        _state.State.AgentName = agentName;
        await _state.WriteStateAsync();
        
        // Use the efficient method to update only the agent name in the summary
        await _agentService.UpdateAgentSummaryNameAsync((int)this.GetPrimaryKeyLong(), agentName);
        _logger.LogInformation("Agent {UserId} updated with name {AgentName}", this.GetPrimaryKeyLong(), agentName);
    }

    public async Task OnPositionOpenedAsync(PositionOpenEvent evt)
    {
        try
        {
            _logger.LogInformation("Position opened event received for user {UserId}, position: {PositionId}",
                this.GetPrimaryKeyLong(), evt.PositionIdentifier);

            await UpdateSummary();
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error processing position opened event for user {UserId}",
                this.GetPrimaryKeyLong());
        }
    }

    public async Task OnPositionClosedAsync(PositionClosedEvent evt)
    {
        try
        {
            _logger.LogInformation("Position closed event received for user {UserId}, position: {PositionId}, PnL: {PnL}",
                this.GetPrimaryKeyLong(), evt.PositionIdentifier, evt.RealizedPnL);

            await UpdateSummary();
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error processing position closed event for user {UserId}",
                this.GetPrimaryKeyLong());
        }
    }

    public async Task OnPositionUpdatedAsync(PositionUpdatedEvent evt)
    {
        try
        {
            _logger.LogInformation("Position updated event received for user {UserId}, position: {PositionId}",
                this.GetPrimaryKeyLong(), evt.PositionIdentifier);

            await UpdateSummary();
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error processing position updated event for user {UserId}",
                this.GetPrimaryKeyLong());
        }
    }

    /// <summary>
    /// Updates the agent summary by recalculating from position data (used for initialization or manual refresh)
    /// </summary>
    [OneWay]
    private async Task UpdateSummary()
    {
        try
        {
            // Get all positions for this agent's bots as initiator
            var positions = await _tradingService.GetPositionByUserIdAsync((int)this.GetPrimaryKeyLong());

            // Calculate aggregated statistics from position data
            var totalPnL = positions.Sum(p => p.ProfitAndLoss?.Realized ?? 0);
            var totalVolume = positions.Sum(p => p.Open.Price * p.Open.Quantity * p.Open.Leverage);
            var collateral = positions.Sum(p => p.Open.Price * p.Open.Quantity);
            var totalFees = positions.Sum(p => p.CalculateTotalFees());
            
            // Store total fees in grain state for caching
            _state.State.TotalFees = totalFees;

            // Calculate wins/losses from position PnL
            var totalWins = positions.Count(p => (p.ProfitAndLoss?.Realized ?? 0) > 0);
            var totalLosses = positions.Count(p => (p.ProfitAndLoss?.Realized ?? 0) <= 0);

            // Calculate ROI based on PnL minus fees
            var netPnL = totalPnL - totalFees;
            var totalROI = collateral switch
            {
                > 0 => (netPnL / collateral) * 100,
                >= 0 => 0,
                _ => 0
            };

            // Calculate total balance (USDC + open positions value)
            decimal totalBalance = 0;
            try
            {
                var userId = (int)this.GetPrimaryKeyLong();
                var user = await _userService.GetUserByIdAsync(userId);

                if (user != null)
                {
                    var userAccounts = await _accountService.GetAccountsByUserAsync(user, hideSecrets: true, true);

                    foreach (var account in userAccounts)
                    {
                        // Get USDC balance
                        var usdcBalances = await GetOrRefreshBalanceDataAsync(account.Name);
                        var usdcBalance = usdcBalances?.UsdcValue ?? 0;
                        totalBalance += usdcBalance;
                    }

                    foreach (var position in positions.Where(p => !p.IsFinished()))
                    {
                        totalBalance += position.Open.Price * position.Open.Quantity;
                        totalBalance += position.ProfitAndLoss?.Realized ?? 0;
                    }
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error calculating total balance for agent {UserId}", this.GetPrimaryKeyLong());
                totalBalance = 0; // Set to 0 if calculation fails
            }

             var bots = await ServiceScopeHelpers.WithScopedService<IBotService, IEnumerable<Bot>> (_scopeFactory, async (botService) => {
                return await botService.GetBotsByUser((int)this.GetPrimaryKeyLong());
            });

             // Calculate Runtime based on the earliest position date
            DateTime? runtime = null;
            if (positions.Any())
            {
                runtime = bots.Min(p => p.StartupTime);
            }

            var activeStrategiesCount = bots.Count(b => b.Status == BotStatus.Running);

            var summary = new AgentSummary
            {
                UserId = (int)this.GetPrimaryKeyLong(),
                AgentName = _state.State.AgentName,
                TotalPnL = totalPnL, // Use net PnL without fees
                Wins = totalWins,
                Losses = totalLosses,
                TotalROI = totalROI,
                Runtime = runtime,
                ActiveStrategiesCount = activeStrategiesCount,
                TotalVolume = totalVolume,
                TotalBalance = totalBalance,
                TotalFees = totalFees,
            };

            // Save summary to database
            await _agentService.SaveOrUpdateAgentSummary(summary);
            
            _logger.LogDebug("Updated agent summary from position data for user {UserId}: NetPnL={NetPnL}, TotalPnL={TotalPnL}, Fees={Fees}, Volume={Volume}, Wins={Wins}, Losses={Losses}",
                this.GetPrimaryKeyLong(), netPnL, totalPnL, totalFees, totalVolume, totalWins, totalLosses);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error calculating agent summary for user {UserId}", this.GetPrimaryKeyLong());
        }
    }

    public async Task RegisterBotAsync(Guid botId)
    {
        if (_state.State.BotIds.Add(botId))
        {
            await _state.WriteStateAsync();
            _logger.LogInformation("Bot {BotId} registered to Agent {UserId}", botId, this.GetPrimaryKeyLong());
            await UpdateSummary();
        }
    }

    public async Task UnregisterBotAsync(Guid botId)
    {
        if (_state.State.BotIds.Remove(botId))
        {
            await _state.WriteStateAsync();
            _logger.LogInformation("Bot {BotId} unregistered from Agent {UserId}", botId, this.GetPrimaryKeyLong());
            await UpdateSummary();
        }
    }

    public async Task<BalanceCheckResult> CheckAndEnsureEthBalanceAsync(Guid requestingBotId, string accountName)
    {
        // Check if a swap is already in progress
        if (_state.State.IsSwapInProgress)
        {
            _logger.LogInformation("Swap already in progress for agent {UserId}, bot {RequestingBotId} will wait",
                this.GetPrimaryKeyLong(), requestingBotId);
            return new BalanceCheckResult
            {
                IsSuccessful = false,
                FailureReason = BalanceCheckFailureReason.SwapInProgress,
                Message = "Swap operation already in progress",
                ShouldStopBot = false
            };
        }

        // Check cooldown period (5 minutes between swaps)
        if (_state.State.LastSwapTime.HasValue &&
            DateTime.UtcNow - _state.State.LastSwapTime.Value < TimeSpan.FromMinutes(5))
        {
            _logger.LogInformation(
                "Swap cooldown period active for agent {UserId}, bot {RequestingBotId} will wait",
                this.GetPrimaryKeyLong(), requestingBotId);
            return new BalanceCheckResult
            {
                IsSuccessful = false,
                FailureReason = BalanceCheckFailureReason.SwapCooldownActive,
                Message = "Swap cooldown period active",
                ShouldStopBot = false
            };
        }

        // Get or refresh cached balance data
        var balanceData = await GetOrRefreshBalanceDataAsync(accountName);
        if (balanceData == null)
        {
            _logger.LogError("Failed to get balance data for account {AccountName}, user {UserId}",
                accountName, this.GetPrimaryKeyLong());
            return new BalanceCheckResult
            {
                IsSuccessful = false,
                FailureReason = BalanceCheckFailureReason.BalanceFetchError,
                Message = "Failed to fetch balance data",
                ShouldStopBot = false
            };
        }

        _logger.LogInformation(
            "Agent {UserId} balance check - ETH: {EthValue:F2} USD, USDC: {UsdcValue:F2} USD (cached: {IsCached})",
            this.GetPrimaryKeyLong(), balanceData.EthValueInUsd, balanceData.UsdcValue,
            _state.State.CachedBalanceData?.IsValid == true);

        // Check USDC minimum balance first (this will stop the bot if insufficient)
        if (balanceData.UsdcValue < Constants.GMX.Config.MinimumPositionAmount)
        {
            _logger.LogWarning(
                "USDC balance is below minimum required amount - ETH: {EthValue:F2} USD, USDC: {UsdcValue:F2} USD (minimum: {Minimum})",
                balanceData.EthValueInUsd, balanceData.UsdcValue, Constants.GMX.Config.MinimumPositionAmount);
            return new BalanceCheckResult
            {
                IsSuccessful = false,
                FailureReason = BalanceCheckFailureReason.InsufficientUsdcBelowMinimum,
                Message =
                    $"USDC balance below minimum required amount ({Constants.GMX.Config.MinimumPositionAmount} USD)",
                ShouldStopBot = true
            };
        }

        // If ETH balance is sufficient, return success
        if (balanceData.EthValueInUsd >= Constants.GMX.Config.MinimumTradeEthBalanceUsd)
        {
            return new BalanceCheckResult
            {
                IsSuccessful = true,
                FailureReason = BalanceCheckFailureReason.None,
                Message = "Balance check successful - Enough ETH balance for trading",
                ShouldStopBot = false
            };
        }

        if (balanceData.EthValueInUsd < Constants.GMX.Config.MinimumSwapEthBalanceUsd)
        {
            return new BalanceCheckResult
            {
                IsSuccessful = false,
                FailureReason = BalanceCheckFailureReason.InsufficientEthBelowMinimum,
                Message = "ETH balance below minimum required amount",
                ShouldStopBot = true
            };
        }

        // Check if we have enough USDC for swap (need at least 5 USD for swap)
        if (balanceData.UsdcValue <
            (Constants.GMX.Config.MinimumPositionAmount + (decimal)Constants.GMX.Config.AutoSwapAmount))
        {
            _logger.LogWarning(
                "Insufficient USDC balance for swap - ETH: {EthValue:F2} USD, USDC: {UsdcValue:F2} USD (need {AutoSwapAmount} USD for swap)",
                balanceData.EthValueInUsd, balanceData.UsdcValue, Constants.GMX.Config.AutoSwapAmount);
            return new BalanceCheckResult
            {
                IsSuccessful = false,
                FailureReason = BalanceCheckFailureReason.InsufficientUsdcForSwap,
                Message = $"Insufficient USDC balance for swap (need {Constants.GMX.Config.AutoSwapAmount} USD)",
                ShouldStopBot = true
            };
        }

        // Mark swap as in progress
        _state.State.IsSwapInProgress = true;
        await _state.WriteStateAsync();

        try
        {
            _logger.LogInformation("Initiating USDC to ETH swap for agent {UserId} - swapping 5 USDC",
                this.GetPrimaryKeyLong());

            // Get user for the swap
            var userId = (int)this.GetPrimaryKeyLong();
            var user = await _userService.GetUserByIdAsync(userId);

            // Perform the swap
            var swapInfo = await _accountService.SwapGmxTokensAsync(user, accountName,
                Ticker.USDC, Ticker.ETH, Constants.GMX.Config.AutoSwapAmount);

            if (swapInfo.Success)
            {
                _logger.LogInformation(
                    "Successfully swapped 5 USDC to ETH for agent {UserId}, transaction hash: {Hash}",
                    userId, swapInfo.Hash);

                // Update last swap time and invalidate cache
                _state.State.LastSwapTime = DateTime.UtcNow;
                _state.State.CachedBalanceData = null; // Invalidate cache after successful swap
                return new BalanceCheckResult
                {
                    IsSuccessful = true,
                    FailureReason = BalanceCheckFailureReason.None,
                    Message = "Swap completed successfully",
                    ShouldStopBot = false
                };
            }
            else
            {
                _logger.LogError("Failed to swap USDC to ETH for agent {UserId}: {Error}",
                    userId, swapInfo.Error ?? swapInfo.Message);
                return new BalanceCheckResult
                {
                    IsSuccessful = false,
                    FailureReason = BalanceCheckFailureReason.SwapExecutionError,
                    Message = swapInfo.Error ?? swapInfo.Message ?? "Swap execution failed",
                    ShouldStopBot = true
                };
            }
        }
        catch (InvalidOperationException ex) when (ex.InnerException is InsufficientFundsException insufficientFundsEx)
        {
            // Handle allowance exception (insufficient ETH for gas fees)
            _logger.LogError(insufficientFundsEx,
                "Insufficient funds during autoswap for agent {UserId}: {ErrorMessage}",
                this.GetPrimaryKeyLong(), insufficientFundsEx.Message);

            return new BalanceCheckResult
            {
                IsSuccessful = false,
                FailureReason = BalanceCheckFailureReason.SwapExecutionError,
                Message = insufficientFundsEx.UserMessage ??
                          "Insufficient ETH for gas fees during autoswap. Bot cannot continue trading.",
                ShouldStopBot = true
            };
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error during autoswap for agent {UserId}, bot {RequestingBotId}",
                this.GetPrimaryKeyLong(), requestingBotId);

            return new BalanceCheckResult
            {
                IsSuccessful = false,
                FailureReason = BalanceCheckFailureReason.SwapExecutionError,
                Message = ex.Message,
                ShouldStopBot = true
            };
        }
        finally
        {
            // Always clear the swap in progress flag
            _state.State.IsSwapInProgress = false;
            await _state.WriteStateAsync();
        }
    }

    /// <summary>
    /// Gets cached balance data or fetches fresh data if cache is invalid/expired
    /// </summary>
    private async Task<CachedBalanceData?> GetOrRefreshBalanceDataAsync(string accountName)
    {
        try
        {
            // Check if we have valid cached data for the same account
            if (_state.State.CachedBalanceData?.IsValid == true &&
                _state.State.CachedBalanceData.AccountName == accountName)
            {
                _logger.LogDebug("Using cached balance data for account {AccountName}", accountName);
                return _state.State.CachedBalanceData;
            }

            // Fetch fresh balance data
            _logger.LogInformation("Fetching fresh balance data for account {AccountName}", accountName);

            var userId = (int)this.GetPrimaryKeyLong();
            var user = await _userService.GetUserByIdAsync(userId);
            if (user == null)
            {
                _logger.LogError("User {UserId} not found for balance check", userId);
                return null;
            }

            var userAccounts = await _accountService.GetAccountsByUserAsync(user, hideSecrets: true, true);
            var account = userAccounts.FirstOrDefault(a => a.Name == accountName);
            if (account == null)
            {
                _logger.LogError("Account {AccountName} not found for user {UserId}", accountName, userId);
                return null;
            }

            // Get current balances
            var balances = await _exchangeService.GetBalances(account);
            var ethBalance = balances.FirstOrDefault(b => b.TokenName?.ToUpper() == "ETH");
            var usdcBalance = balances.FirstOrDefault(b => b.TokenName?.ToUpper() == "USDC");

            var ethValueInUsd = ethBalance?.Amount * ethBalance?.Price ?? 0;
            var usdcValue = usdcBalance?.Value ?? 0;

            // Cache the balance data
            var balanceData = new CachedBalanceData
            {
                LastFetched = DateTime.UtcNow,
                AccountName = accountName,
                EthValueInUsd = ethValueInUsd,
                UsdcValue = usdcValue
            };

            _state.State.CachedBalanceData = balanceData;
            await _state.WriteStateAsync();

            return balanceData;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error fetching balance data for account {AccountName}, user {UserId}",
                accountName, this.GetPrimaryKeyLong());
            return null;
        }
    }
}