using Fitness_core_BE.Interfaces;
using Fitness_core_BE.Models;
using Microsoft.EntityFrameworkCore;

namespace Fitness_core_BE.Repos
{
    public class CustomerPlanRepository : ICustomerPlanRepository
    {
        // Client is central-bucket -- CustomerPlan.Client can't be a same-context Include once
        // central/tenant are physically separate (see TenantDbContext.OnModelCreating). Loaded
        // separately here and attached in memory, same convention as StaffRepository.User.
        private readonly TenantDbContext _context;
        private readonly CentralDbContext _central;

        public CustomerPlanRepository(TenantDbContext context, CentralDbContext central)
        {
            _context = context;
            _central = central;
        }

        private async Task AttachClientsAsync(IEnumerable<CustomerPlan> plans)
        {
            var clientIds = plans.Select(p => p.FKClientId).Distinct().ToList();
            if (clientIds.Count == 0) return;

            var clients = await _central.Client
                .AsNoTracking()
                .Where(c => clientIds.Contains(c.ClientId))
                .ToDictionaryAsync(c => c.ClientId);

            foreach (var plan in plans)
            {
                if (clients.TryGetValue(plan.FKClientId, out var client))
                    plan.Client = client;
            }
        }

        public async Task<List<CustomerPlan>> GetAllCustomerPlans(bool includeInactive = false, Guid? clientId = null)
        {
            var query = _context.CustomerPlans.AsQueryable();

            if (clientId.HasValue)
            {
                query = query.Where(cp => cp.FKClientId == clientId.Value);
            }

            if (!includeInactive)
            {
                query = query.Where(cp => cp.IsActive);
            }

            var plans = await query
                .OrderBy(cp => cp.PlanName)
                .ToListAsync();

            await AttachClientsAsync(plans);
            return plans;
        }

        public async Task<CustomerPlan?> GetCustomerPlanById(Guid customerPlanId)
        {
            var plan = await _context.CustomerPlans
                .FirstOrDefaultAsync(cp => cp.CustomerPlanId == customerPlanId);
            if (plan != null)
                await AttachClientsAsync(new[] { plan });
            return plan;
        }

        public async Task<CustomerPlan> CreateCustomerPlan(CustomerPlan customerPlan)
        {
            customerPlan.CustomerPlanId = Guid.NewGuid();
            customerPlan.CreatedAt = DateTime.UtcNow;
            customerPlan.IsActive = true;

            _context.CustomerPlans.Add(customerPlan);

            return customerPlan;
        }

        public async Task<CustomerPlan> UpdateCustomerPlan(CustomerPlan customerPlan)
        {
            var existingPlan = await _context.CustomerPlans.FindAsync(customerPlan.CustomerPlanId);

            if (existingPlan == null)
            {
                throw new Exception("Customer Plan not found");
            }

            // The service merges provided keys onto the loaded entity and validates
            // the combined configuration, so this is a direct full assignment.
            existingPlan.PlanName = customerPlan.PlanName;
            existingPlan.PlanDescription = customerPlan.PlanDescription;
            existingPlan.PlanPrice = customerPlan.PlanPrice;
            existingPlan.DurationInDays = customerPlan.DurationInDays;
            existingPlan.PlanScope = customerPlan.PlanScope;
            existingPlan.MemberLimit = customerPlan.MemberLimit;
            existingPlan.DurationMode = customerPlan.DurationMode;
            existingPlan.ValidFrom = customerPlan.ValidFrom;
            existingPlan.ValidTo = customerPlan.ValidTo;
            existingPlan.AllowSplitPayments = customerPlan.AllowSplitPayments;
            existingPlan.InstallmentCount = customerPlan.InstallmentCount;
            existingPlan.SessionsPerCycle = customerPlan.SessionsPerCycle;
            existingPlan.SessionRolloverPolicy = customerPlan.SessionRolloverPolicy;
            existingPlan.RolloverGraceDays = customerPlan.RolloverGraceDays;
            existingPlan.BillingTiming = customerPlan.BillingTiming;
            existingPlan.IsActive = customerPlan.IsActive;

            return existingPlan;
        }

        public async Task<CustomerPlan?> SetCustomerPlanActive(Guid customerPlanId, Guid clientId, bool isActive)
        {
            var plan = await _context.CustomerPlans
                .FirstOrDefaultAsync(cp => cp.CustomerPlanId == customerPlanId && cp.FKClientId == clientId);

            if (plan == null)
                return null;

            plan.IsActive = isActive;

            await AttachClientsAsync(new[] { plan });
            return plan;
        }

        public async Task<bool> DeleteCustomerPlan(Guid customerPlanId, bool softDelete = true)
        {
            var customerPlan = await _context.CustomerPlans.FindAsync(customerPlanId);
            
            if (customerPlan == null)
            {
                return false;
            }

            if (softDelete)
            {
                // Soft delete: just mark as inactive
                customerPlan.IsActive = false;
            }
            else
            {
                // Hard delete: remove from database
                _context.CustomerPlans.Remove(customerPlan);
            }

            return true;
        }
    }
}