<?php

namespace Tests\Unit;

use App\Models\Model;
use App\Models\ModelFormula;
use App\Models\ModelParameter;
use App\Services\ModelFormulaService;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Tests\TestCase;

class ModelFormulaServiceTest extends TestCase
{
    use RefreshDatabase;

    private ModelFormulaService $service;
    private Model $model;

    protected function setUp(): void
    {
        parent::setUp();
        $this->service = new ModelFormulaService();
        $this->service->setTenantId(1)->setApiUserId(1);

        $this->model = Model::factory()->screen()->create();
    }

    /** @test */
    public function it_can_get_all_formulas_for_model()
    {
        // Arrange
        ModelFormula::factory()
            ->count(3)
            ->create(['model_id' => $this->model->id]);

        // Act
        $result = $this->service->getFormulasByModel($this->model->id);

        // Assert
        $this->assertCount(3, $result);
        $this->assertEquals($this->model->id, $result->first()->model_id);
    }

    /** @test */
    public function it_filters_inactive_formulas()
    {
        // Arrange
        ModelFormula::factory()
            ->create(['model_id' => $this->model->id, 'is_active' => true]);
        ModelFormula::factory()
            ->create(['model_id' => $this->model->id, 'is_active' => false]);

        // Act
        $result = $this->service->getFormulasByModel($this->model->id);

        // Assert
        $this->assertCount(1, $result);
        $this->assertTrue($result->first()->is_active);
    }

    /** @test */
    public function it_orders_formulas_by_sort_order()
    {
        // Arrange
        ModelFormula::factory()
            ->create(['model_id' => $this->model->id, 'sort_order' => 3, 'name' => 'third']);
        ModelFormula::factory()
            ->create(['model_id' => $this->model->id, 'sort_order' => 1, 'name' => 'first']);
        ModelFormula::factory()
            ->create(['model_id' => $this->model->id, 'sort_order' => 2, 'name' => 'second']);

        // Act
        $result = $this->service->getFormulasByModel($this->model->id);

        // Assert
        $this->assertEquals('first', $result->get(0)->name);
        $this->assertEquals('second', $result->get(1)->name);
        $this->assertEquals('third', $result->get(2)->name);
    }

    /** @test */
    public function it_can_create_formula()
    {
        // Arrange
        $data = [
            'name' => 'test_formula',
            'expression' => 'W0 * H0',
            'description' => 'Test calculation',
            'return_type' => 'NUMBER',
            'sort_order' => 1,
        ];

        // Act
        $result = $this->service->createFormula($this->model->id, $data);

        // Assert
        $this->assertInstanceOf(ModelFormula::class, $result);
        $this->assertEquals('test_formula', $result->name);
        $this->assertEquals('W0 * H0', $result->expression);
        $this->assertEquals($this->model->id, $result->model_id);
        $this->assertEquals(1, $result->tenant_id);
        $this->assertEquals(1, $result->created_by);
    }

    /** @test */
    public function it_can_update_formula()
    {
        // Arrange
        $formula = ModelFormula::factory()
            ->create(['model_id' => $this->model->id, 'name' => 'old_name']);

        $updateData = [
            'name' => 'new_name',
            'expression' => 'W0 + H0',
            'description' => 'Updated description',
        ];

        // Act
        $result = $this->service->updateFormula($formula->id, $updateData);

        // Assert
        $this->assertEquals('new_name', $result->name);
        $this->assertEquals('W0 + H0', $result->expression);
        $this->assertEquals('Updated description', $result->description);
        $this->assertEquals(1, $result->updated_by);
    }

    /** @test */
    public function it_can_delete_formula()
    {
        // Arrange
        $formula = ModelFormula::factory()
            ->create(['model_id' => $this->model->id]);

        // Act
        $result = $this->service->deleteFormula($formula->id);

        // Assert
        $this->assertTrue($result);
        $this->assertSoftDeleted('model_formulas', ['id' => $formula->id]);
    }

    /** @test */
    public function it_evaluates_simple_arithmetic_expressions()
    {
        // Arrange
        $formula = ModelFormula::factory()
            ->create([
                'model_id' => $this->model->id,
                'expression' => 'W0 * H0',
                'return_type' => 'NUMBER',
            ]);

        $parameters = ['W0' => 1000, 'H0' => 800];

        // Act
        $result = $this->service->evaluateFormula($formula, $parameters);

        // Assert
        $this->assertEquals(800000, $result);
    }

    /** @test */
    public function it_evaluates_complex_expressions_with_functions()
    {
        // Arrange
        $formula = ModelFormula::factory()
            ->create([
                'model_id' => $this->model->id,
                'expression' => 'CEIL(W0 / 600)',
                'return_type' => 'NUMBER',
            ]);

        $parameters = ['W0' => 1400];

        // Act
        $result = $this->service->evaluateFormula($formula, $parameters);

        // Assert
        $this->assertEquals(3, $result); // ceil(1400/600) = ceil(2.33) = 3
    }

    /** @test */
    public function it_evaluates_conditional_expressions()
    {
        // Arrange
        $formula = ModelFormula::factory()
            ->create([
                'model_id' => $this->model->id,
                'expression' => 'IF(area <= 3, "SMALL", IF(area <= 6, "MEDIUM", "LARGE"))',
                'return_type' => 'STRING',
            ]);

        // Test cases
        $testCases = [
            ['area' => 2, 'expected' => 'SMALL'],
            ['area' => 5, 'expected' => 'MEDIUM'],
            ['area' => 8, 'expected' => 'LARGE'],
        ];

        foreach ($testCases as $testCase) {
            // Act
            $result = $this->service->evaluateFormula($formula, $testCase);

            // Assert
            $this->assertEquals($testCase['expected'], $result);
        }
    }

    /** @test */
    public function it_handles_formula_dependencies()
    {
        // Arrange - Create formulas with dependencies
        $w1Formula = ModelFormula::factory()
            ->create([
                'model_id' => $this->model->id,
                'name' => 'W1',
                'expression' => 'W0 + 120',
                'sort_order' => 1,
            ]);

        $h1Formula = ModelFormula::factory()
            ->create([
                'model_id' => $this->model->id,
                'name' => 'H1',
                'expression' => 'H0 + 100',
                'sort_order' => 2,
            ]);

        $areaFormula = ModelFormula::factory()
            ->create([
                'model_id' => $this->model->id,
                'name' => 'area',
                'expression' => 'W1 * H1 / 1000000',
                'sort_order' => 3,
            ]);

        $parameters = ['W0' => 1000, 'H0' => 800];

        // Act
        $results = $this->service->evaluateAllFormulas($this->model->id, $parameters);

        // Assert
        $this->assertEquals(1120, $results['W1']); // 1000 + 120
        $this->assertEquals(900, $results['H1']);  // 800 + 100
        $this->assertEquals(1.008, $results['area']); // 1120 * 900 / 1000000
    }

    /** @test */
    public function it_validates_formula_syntax()
    {
        // Test valid expressions
        $validExpressions = [
            'W0 + H0',
            'W0 * H0 / 1000',
            'CEIL(W0 / 600)',
            'IF(area > 5, "LARGE", "SMALL")',
            'SIN(angle * PI / 180)',
        ];

        foreach ($validExpressions as $expression) {
            $isValid = $this->service->validateExpressionSyntax($expression);
            $this->assertTrue($isValid, "Expression should be valid: {$expression}");
        }

        // Test invalid expressions
        $invalidExpressions = [
            'W0 + + H0',        // Double operator
            'W0 * )',           // Unmatched parenthesis
            'UNKNOWN_FUNC(W0)', // Unknown function
            '',                 // Empty expression
            'W0 AND',           // Incomplete expression
        ];

        foreach ($invalidExpressions as $expression) {
            $isValid = $this->service->validateExpressionSyntax($expression);
            $this->assertFalse($isValid, "Expression should be invalid: {$expression}");
        }
    }

    /** @test */
    public function it_detects_circular_dependencies()
    {
        // Arrange - Create circular dependency
        ModelFormula::factory()
            ->create([
                'model_id' => $this->model->id,
                'name' => 'A',
                'expression' => 'B + 10',
            ]);

        ModelFormula::factory()
            ->create([
                'model_id' => $this->model->id,
                'name' => 'B',
                'expression' => 'C * 2',
            ]);

        ModelFormula::factory()
            ->create([
                'model_id' => $this->model->id,
                'name' => 'C',
                'expression' => 'A / 3', // Circular dependency
            ]);

        // Act & Assert
        $this->expectException(\InvalidArgumentException::class);
        $this->expectExceptionMessage('Circular dependency detected');

        $this->service->evaluateAllFormulas($this->model->id, []);
    }

    /** @test */
    public function it_respects_tenant_isolation()
    {
        // Arrange
        $otherTenantModel = Model::factory()->create(['tenant_id' => 2]);
        ModelFormula::factory()
            ->create(['model_id' => $otherTenantModel->id, 'tenant_id' => 2]);

        // Act
        $result = $this->service->getFormulasByModel($otherTenantModel->id);

        // Assert
        $this->assertCount(0, $result);
    }

    /** @test */
    public function it_handles_missing_parameters_gracefully()
    {
        // Arrange
        $formula = ModelFormula::factory()
            ->create([
                'model_id' => $this->model->id,
                'expression' => 'W0 * H0',
            ]);

        $incompleteParameters = ['W0' => 1000]; // Missing H0

        // Act & Assert
        $this->expectException(\InvalidArgumentException::class);
        $this->expectExceptionMessage('Missing parameter: H0');

        $this->service->evaluateFormula($formula, $incompleteParameters);
    }

    /** @test */
    public function it_can_bulk_update_formulas()
    {
        // Arrange
        $formulas = ModelFormula::factory()
            ->count(3)
            ->create(['model_id' => $this->model->id]);

        $updateData = [
            [
                'id' => $formulas[0]->id,
                'name' => 'updated_formula_1',
                'expression' => 'W0 + 100',
            ],
            [
                'id' => $formulas[1]->id,
                'name' => 'updated_formula_2',
                'expression' => 'H0 + 50',
            ],
            [
                'id' => $formulas[2]->id,
                'is_active' => false,
            ],
        ];

        // Act
        $result = $this->service->bulkUpdateFormulas($this->model->id, $updateData);

        // Assert
        $this->assertTrue($result);

        $updated = ModelFormula::whereIn('id', $formulas->pluck('id'))->get();
        $this->assertEquals('updated_formula_1', $updated->where('id', $formulas[0]->id)->first()->name);
        $this->assertEquals('W0 + 100', $updated->where('id', $formulas[0]->id)->first()->expression);
        $this->assertFalse($updated->where('id', $formulas[2]->id)->first()->is_active);
    }
}