using LCU.API.Internal.Operations.IncentiveApi.Extensions;
using LCU.Library.Internal.IncentiveApiModels.Entities;
using LCU.Library.Internal.IncentiveApiModels.Enums;
using LCU.API.Internal.Operations.IncentiveApi.Models;
using LCU.API.Internal.Operations.IncentiveApi.Models.GoalDispersal;
using LCU.API.Internal.Operations.IncentiveApiLib.Services;

namespace LCU.API.Internal.Operations.IncentiveApi.Services.DispersalStrategy;

public class DispersalStrategyService : IDispersalStrategyService
{
    private readonly IUserService _userService;
    public DispersalStrategyService(IUserService userService)
    {
        _userService = userService;
    }

    public GoalDispersalReceipt ExtrapolateFromExistingGoals(ExtrapolationGoalDispersalData data)
    {
        var receipt = new GoalDispersalReceipt(data.DepartmentId, GoalDispersalStrategy.ExtrapolateFromExistingGoals);
        foreach (var (employeeId, modelEmployeeProductGoals) in data.ModelPersonnelGoals.Goals)
        {
            var employee = data.DispersalMonthPersonnel.FirstOrDefault(x => x.EmployeeId.Equals(employeeId));
            if (employee == null)
            {
                var missingEmployee =
                    data.ModelPersonnelGoals.Personnel.FirstOrDefault(x => x.EmployeeId == employeeId);
                receipt.AddNewDispersalError(GoalDispersalError.UserNoLongerInDepartment, employeeId,
                    $"This employee is not assigned to dept: {data.DepartmentId} for the selected dispersal month", missingEmployee?.FullName);
                continue;
            }
            foreach (var (goalProduct, dispersalMonthGoalValue) in data.DispersalMonthDepartmentGoals.ProductGoals)
            {
                ExtrapolateAndCreateEmployeeGoalChangesForProduct(employee,goalProduct, data, receipt);
            }
        }

        BuildDispersalReceipt(data.DispersalMonthPersonnel, receipt);
        CheckForAndLogDuplicates(receipt.GoalChanges, "Extrapolate");

        return receipt;
    }

    private void ExtrapolateAndCreateEmployeeGoalChangesForProduct(AppUser employee, Product product,
        ExtrapolationGoalDispersalData data,
        GoalDispersalReceipt receipt)
    {
        var dispersalMonthGoalValue = data.DispersalMonthDepartmentGoals.ProductGoals[product];
        var dispersalEmployeePerProductGoal = data.DispersalMonthPersonnelGoals.Goals[employee.EmployeeId];
        var modelEmployeePerProductGoal = data.ModelPersonnelGoals.Goals[employee.EmployeeId];

        try
        {
            double modelPersonnelValue = modelEmployeePerProductGoal.ProductGoals[product];
            double dispersalPersonnelValue = dispersalEmployeePerProductGoal.ProductGoals[product];
            double modelDeptGoalValue = data.ModelDepartmentGoals.ProductGoals[product];
            int newValue;

            if (modelDeptGoalValue == 0)
            {
                newValue = 0;
            }
            else
            {
                newValue =  (int) Math.Ceiling(modelPersonnelValue / modelDeptGoalValue * dispersalMonthGoalValue);
            }

            if (newValue == (int) dispersalPersonnelValue)
            {
                return;
            }

            receipt.GoalChanges.Add(new GoalChange()
            {
                AppUserId = employee.Id,
                DepartmentId = data.DepartmentId,
                EndDate = data.DispersalMonthStartDate.EndOfMonth(),
                PersonId = employee.EmployeeId,
                Product = product,
                StartDate = data.DispersalMonthStartDate,
                Value = newValue
            });
        }
        catch (Exception ex)
        {
            Log.Error(ex,
                $"Failed to create goal change for employee {employee.EmployeeId} on product: {product} in department {data.DepartmentId}");
            receipt.AddNewDispersalError(GoalDispersalError.ErrorsDuringDisperse, employee.EmployeeId,
                $"Failed to create goal change for product: {product}. See Logs.");
        }
    }

    private List<GoalDispersalReceiptItem> BuildDispersalReceipt(List<AppUser> dispersalMonthPersonnel, GoalDispersalReceipt receipt)
    {
        dispersalMonthPersonnel.ForEach(user =>
        {
            if (receipt.GoalChanges.Any(x => x.PersonId == user.EmployeeId && x.Value > 0))
            {
                if (!user.UserHasPermission(Permission.HaveSalesGoals))
                {
                    receipt.AddNewDispersalError(GoalDispersalError.DispersedToUserWithoutPermission,
                        user.EmployeeId, "User received goals, but does not have HasSalesGoal permission. May require manual update.", user.FullName);
                }
            }

            if(!receipt.GoalChanges.Any(x => x.PersonId == user.EmployeeId && x.Value > 0))
            {
                if (user.UserHasPermission(Permission.HaveSalesGoals))
                {
                    receipt.AddNewDispersalError(GoalDispersalError.NewUserRequiresManualEntry, user.EmployeeId,
                        "User did not receive goals, but has HasSalesGoal permission. May require manual update.", user.FullName);
                }
            }
        });

        return receipt.GoalDispersalErrors.ToList();
    }

    public GoalDispersalReceipt DefaultWeightedDispersal(DefaultWeightedGoalDispersalData data)
    {
        var receipt = new GoalDispersalReceipt(data.DepartmentId, GoalDispersalStrategy.DefaultDisperseWithWeights);
        var allRolesInDept = data.DispersalMonthPersonnel.Select(x => x.Departments.First(d => d.DepartmentId == data.DepartmentId).Role).ToList();

        foreach (var employee in data.DispersalMonthPersonnel)
        {
            foreach (var (goalProduct, goalValue) in data.DispersalMonthDepartmentGoals.ProductGoals)
            {
                try
                {
                    var userDept = employee.Departments.First(x => x.DepartmentId == data.DepartmentId);
                    receipt.GoalChanges.Add(new GoalChange()
                    {
                        AppUserId = employee.Id,
                        DepartmentId = data.DepartmentId,
                        EndDate = data.DispersalMonthStartDate.EndOfMonth(),
                        PersonId = employee.EmployeeId,
                        Product = goalProduct,
                        StartDate = data.DispersalMonthStartDate,
                        Value = CalculateDefaultWeightedValue(userDept.Role, goalValue, allRolesInDept)
                    });
                }
                catch (Exception ex)
                {
                    Log.Error(ex,
                        $"Failed to create goal change for employee {employee.EmployeeId} on product: {goalProduct} in department {data.DepartmentId}");
                    receipt.AddNewDispersalError(GoalDispersalError.ErrorsDuringDisperse, employee.EmployeeId,
                        $"Failed to create goal change for product: {goalProduct}. See logs.");
                }
            }
        }

        CheckForAndLogDuplicates(receipt.GoalChanges, "DefaultWeight");

        return receipt;
    }

    public int CalculateDefaultWeightedValue(Role role, int goalValue, List<Role> allRolesInDept)
    {
        if (role == Role.PFO)
        {
            return (int) Math.Ceiling(goalValue * 0.6 / allRolesInDept.Count(x => x.Equals(Role.PFO)));
        }

        if (role == Role.BM)
        {
            return (int) Math.Ceiling(goalValue * 0.25 / allRolesInDept.Count(x => x.Equals(Role.BM)));
        }

        if (role == Role.ABM)
        {
            return (int) Math.Ceiling(goalValue * 0.15 / allRolesInDept.Count(x => x.Equals(Role.ABM)));
        }

        return 0;
    }

    public GoalDispersalReceipt ExtrapolateSingleDepartmentProduct(DepartmentGoalExtrapolationRequest request, PersonnelGoals departmentPersonnelGoals)
    {
        var receipt = new GoalDispersalReceipt(request.DepartmentId, GoalDispersalStrategy.ExtrapolateSingleDepartmentProduct);

        foreach (var (employeeId, personnelPerProductGoals) in departmentPersonnelGoals.Goals)
        {
            try
            {
                var existingEmployeeGoal = personnelPerProductGoals.ProductGoals[request.Product];
                int newValue;
                if (request.OriginalDepartmentGoal == 0)
                {
                    newValue = existingEmployeeGoal;
                }
                else
                {
                    newValue = (int)Math.Ceiling((decimal)request.NewDepartmentGoal / request.OriginalDepartmentGoal *
                                                 existingEmployeeGoal);
                }

                if (newValue == existingEmployeeGoal)
                {
                    continue;
                }

                var appUser = _userService.GetActiveUserByEmployeeIdAsync(employeeId).GetAwaiter().GetResult();
                receipt.GoalChanges.Add(new GoalChange()
                {
                    AppUserId = appUser.Id,
                    PersonId = employeeId,
                    DepartmentId = request.DepartmentId,
                    Value = newValue,
                    Product = request.Product,
                    StartDate = request.DepartmentGoalStartDate.StartOfMonth(),
                    EndDate = request.DepartmentGoalEndDate.EndOfMonth()
                });
            }
            catch (Exception ex)
            {
                Log.Error(ex,
                    $"Failed to create goal change for employee {employeeId} on product: {request.Product} in department {request.DepartmentId}");
                receipt.AddNewDispersalError(GoalDispersalError.ErrorsDuringDisperse, employeeId,
                    $"Failed to create goal change for product: {request.Product}. See logs.");
            }
        }

        return receipt;

    }

    public GoalDispersalReceipt
        CustomWeightedDispersal(CustomWeightedDispersalRequest request, List<AppUser> personnel, int departmentGoal)
    {
        var receipt = new GoalDispersalReceipt(request.DepartmentId, GoalDispersalStrategy.CustomWeightedDispersal);
        var dispersalDate = new DateTime(request.year, request.month, 01);
        var allRolesInDept = personnel
            .Select(x => x.Departments.FirstOrDefault(d => d.DepartmentId == request.DepartmentId))
            .Where(x => x != null)
            .Select(x => x.Role)
            .ToList();

        foreach (var user in personnel)
        {
            var userDept = user.Departments.FirstOrDefault(x => x.DepartmentId == request.DepartmentId);
            if(userDept == null){continue;}
            if (request.DispersalWeightByRole.TryGetValue(userDept.Role.Name, out var percentage))
            {
                var newValue = (int)Math.Ceiling(departmentGoal * percentage /
                                                 allRolesInDept.Count(x =>
                                                     x.Name.ToLowerInvariant() == userDept.Role.Name.ToLowerInvariant()));
                receipt.GoalChanges.Add(new GoalChange()
                {
                    AppUserId = user.Id,
                    PersonId = user.EmployeeId,
                    DepartmentId = request.DepartmentId,
                    Value = newValue,
                    Product = request.DispersalProduct,
                    StartDate = dispersalDate.StartOfMonth(),
                    EndDate = dispersalDate.EndOfMonth()
                });
            }
        }

        CheckForAndLogDuplicates(receipt.GoalChanges, "CustomWeight");
        
        return receipt;
    }


    private void CheckForAndLogDuplicates(List<GoalChange> goalChanges, string strategy)
    {
        if (goalChanges == null)
        {
            return;
        }

        var duplicateGoals = goalChanges.GroupBy(g => new {
            g.StartDate,
            g.EndDate,
            g.Product,
            g.Value,
            g.PersonId })
            .Where(g => g.Skip(1).Any());

        if (duplicateGoals.Any())
        {
            Log.Information($"Duplicate goals in department {goalChanges.Select(g => g.DepartmentId).FirstOrDefault()} during {strategy} strategy.");
        }
    }
}