<?php

namespace Tests\Feature\Calculator;

use CodeIgniter\Test\CIUnitTestCase;
use App\Services\CalculatorService;

class CalculatorTest extends CIUnitTestCase
{
  protected CalculatorService $calculator;

  public function setUp(): void {
    parent::setUp();
    $this->calculator = new CalculatorService();
  }

  /**
   * Test basic arithmetic operations
   */
  public function testBasicArithmetic() {
    // Addition and multiplication precedence
    $result = $this->calculator->calculate('1+2*3');
    $this->assertEquals(7.0, $result);

    // Parentheses
    $result = $this->calculator->calculate('(1+2)*3');
    $this->assertEquals(9.0, $result);

    // Division
    $result = $this->calculator->calculate('10/2');
    $this->assertEquals(5.0, $result);

    // Power
    $result = $this->calculator->calculate('2^3');
    $this->assertEquals(8.0, $result);
  }

  /**
   * Test formula with simple variables
   */
  public function testFormulaWithVariables() {
    $formula = '{result} * {factor}';
    $variables = ['result' => 50, 'factor' => 2];
    
    $result = $this->calculator->calculate($formula, $variables);
    $this->assertEquals(100.0, $result);
  }

  /**
   * Test formula with gender variable (numeric values)
   */
  public function testFormulaWithGenderNumeric() {
    // Gender: 0=Unknown, 1=Female, 2=Male
    $formula = '50 + {gender} * 10';
    
    // Male (2)
    $result = $this->calculator->calculate($formula, ['gender' => 2]);
    $this->assertEquals(70.0, $result);
    
    // Female (1)
    $result = $this->calculator->calculate($formula, ['gender' => 1]);
    $this->assertEquals(60.0, $result);
    
    // Unknown (0)
    $result = $this->calculator->calculate($formula, ['gender' => 0]);
    $this->assertEquals(50.0, $result);
  }

  /**
   * Test formula with gender variable (string values)
   */
  public function testFormulaWithGenderString() {
    $formula = '50 + {gender} * 10';
    
    // String values
    $result = $this->calculator->calculate($formula, ['gender' => 'male']);
    $this->assertEquals(70.0, $result);
    
    $result = $this->calculator->calculate($formula, ['gender' => 'female']);
    $this->assertEquals(60.0, $result);
    
    $result = $this->calculator->calculate($formula, ['gender' => 'unknown']);
    $this->assertEquals(50.0, $result);
  }

  /**
   * Test mathematical functions
   */
  public function testMathFunctions() {
    // Square root
    $result = $this->calculator->calculate('sqrt(16)');
    $this->assertEquals(4.0, $result);

    // Sine
    $result = $this->calculator->calculate('sin(pi/2)');
    $this->assertEqualsWithDelta(1.0, $result, 0.0001);

    // Cosine
    $result = $this->calculator->calculate('cos(0)');
    $this->assertEquals(1.0, $result);

    // Logarithm
    $result = $this->calculator->calculate('log(100)');
    $this->assertEqualsWithDelta(4.60517, $result, 0.0001);

    // Natural log (ln)
    $result = $this->calculator->calculate('ln(2.71828)');
    $this->assertEqualsWithDelta(1.0, $result, 0.0001);

    // Exponential
    $result = $this->calculator->calculate('exp(1)');
    $this->assertEqualsWithDelta(2.71828, $result, 0.0001);
  }

  /**
   * Test formula validation
   */
  public function testFormulaValidation() {
    // Valid formula
    $validation = $this->calculator->validate('{result} * 2 + 5');
    $this->assertTrue($validation['valid']);
    $this->assertNull($validation['error']);

    // Invalid formula
    $validation = $this->calculator->validate('{result} * * 2');
    $this->assertFalse($validation['valid']);
    $this->assertNotNull($validation['error']);
  }

  /**
   * Test variable extraction
   */
  public function testExtractVariables() {
    $formula = '{result} * {factor} + {gender} - {age}';
    $variables = $this->calculator->extractVariables($formula);
    
    $this->assertEquals(['result', 'factor', 'gender', 'age'], $variables);
  }

  /**
   * Test missing variable error
   */
  public function testMissingVariableError() {
    $this->expectException(\Exception::class);
    $this->expectExceptionMessage("Missing variable value for: missing_var");
    
    $this->calculator->calculate('{result} + {missing_var}', ['result' => 10]);
  }

  /**
   * Test invalid formula syntax error
   */
  public function testInvalidFormulaError() {
    $this->expectException(\Exception::class);
    $this->expectExceptionMessage("Invalid formula");
    
    $this->calculator->calculate('1 + * 2');
  }

  /**
   * Test complex formula with multiple variables
   */
  public function testComplexFormula() {
    // Complex formula: (result * factor / 100) + (gender * 5) - (age * 0.1)
    $formula = '({result} * {factor} / 100) + ({gender} * 5) - ({age} * 0.1)';
    $variables = [
      'result' => 200,
      'factor' => 10,
      'gender' => 2,  // Male
      'age' => 30
    ];
    
    // Expected: (200 * 10 / 100) + (2 * 5) - (30 * 0.1) = 20 + 10 - 3 = 27
    $result = $this->calculator->calculate($formula, $variables);
    $this->assertEquals(27.0, $result);
  }

  /**
   * Test calculation from TestDefCal definition
   */
  public function testCalculateFromDefinition() {
    $calcDef = [
      'FormulaCode' => '{result} * {factor} + 10',
      'Factor' => 2,
    ];
    
    $testValues = [
      'result' => 50,
    ];
    
    // Expected: 50 * 2 + 10 = 110
    $result = $this->calculator->calculateFromDefinition($calcDef, $testValues);
    $this->assertEquals(110.0, $result);
  }

  /**
   * Test calculation with all optional variables
   */
  public function testCalculateWithAllVariables() {
    $calcDef = [
      'FormulaCode' => '{result} + {factor} + {gender} + {age} + {ref_low} + {ref_high}',
      'Factor' => 5,
    ];
    
    $testValues = [
      'result' => 10,
      'gender' => 1,
      'age' => 25,
      'ref_low' => 5,
      'ref_high' => 15,
    ];
    
    // Expected: 10 + 5 + 1 + 25 + 5 + 15 = 61
    $result = $this->calculator->calculateFromDefinition($calcDef, $testValues);
    $this->assertEquals(61.0, $result);
  }

  /**
   * Test empty formula error
   */
  public function testEmptyFormulaError() {
    $this->expectException(\Exception::class);
    $this->expectExceptionMessage("No formula defined");
    
    $calcDef = [
      'FormulaCode' => '',
      'Factor' => 1,
    ];
    
    $this->calculator->calculateFromDefinition($calcDef, ['result' => 10]);
  }

  /**
   * Test implicit multiplication
   */
  public function testImplicitMultiplication() {
    // math-parser supports implicit multiplication (2x means 2*x)
    $result = $this->calculator->calculate('2*3');
    $this->assertEquals(6.0, $result);
  }

  /**
   * Test decimal calculations
   */
  public function testDecimalCalculations() {
    $formula = '{result} / 3';
    $result = $this->calculator->calculate($formula, ['result' => 10]);
    $this->assertEqualsWithDelta(3.33333, $result, 0.0001);
  }
}