Initial

2023-11-27 06:56:03 +02:00
commit 343564fcc0
236 changed files with 101156 additions and 0 deletions
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+namespace TaxCalculator.Api.Services
+{
+    using DAL;
+
+    public class TaxCalculatorService : ITaxCalculatorService
+    {
+        private readonly ITaxBandRepository _taxBandRepository;
+
+        public TaxCalculatorService(ITaxBandRepository taxBandRepository)
+        {
+            _taxBandRepository = taxBandRepository ?? throw new ArgumentNullException(nameof(taxBandRepository));
+        }
+
+        public async Task<decimal> CalculateTax(int annualSalary)
+        {
+            if (annualSalary < 0)
+            {
+                throw new ArgumentException("Gross annual salary must be non-negative.");
+            }
+
+            decimal taxPaid = 0;
+
+            foreach (var band in await _taxBandRepository.GetTaxBands())
+            {
+                if (annualSalary <= band.LowerLimit)
+                    continue;
+
+                decimal taxableAmountInBand = band.UpperLimit.HasValue
+                    ? Math.Min(annualSalary, band.UpperLimit.Value) - band.LowerLimit
+                    : annualSalary - band.LowerLimit;
+
+                decimal taxInBand = taxableAmountInBand * (band.TaxRate / 100m);
+                taxPaid += taxInBand;
+
+                if (!band.UpperLimit.HasValue || annualSalary <= band.UpperLimit.Value)
+                    break;
+            }
+
+            return taxPaid;
+        }
+    }
+}