fuel-price/tests/Unit/Services/OilPriceServiceTest.php

<?php

use App\Enums\PredictionSource;
use App\Enums\TrendDirection;
use App\Models\BrentPrice;
use App\Models\PricePrediction;
use App\Services\ApiLogger;
use App\Services\LlmPrediction\OilPredictionProvider;
use App\Services\OilPriceService;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Support\Facades\Http;

uses(RefreshDatabase::class);

beforeEach(function (): void {
    Http::preventStrayRequests();
    $this->provider = Mockery::mock(OilPredictionProvider::class);
    $this->service = new OilPriceService(new ApiLogger, $this->provider);
});

// --- fetchBrentPrices ---

it('fetches and stores brent prices from FRED', function (): void {
    Http::fake([
        '*/fred/series/observations*' => Http::response([
            'observations' => [
                ['date' => '2026-03-31', 'value' => '74.50'],
                ['date' => '2026-04-01', 'value' => '75.10'],
                ['date' => '2026-04-02', 'value' => '73.80'],
            ],
        ]),
    ]);

    $this->service->fetchBrentPrices();

    expect(BrentPrice::count())->toBe(3)
        ->and(BrentPrice::find('2026-04-02')->price_usd)->toBe('73.80');
});

it('filters out FRED missing value markers', function (): void {
    Http::fake([
        '*/fred/series/observations*' => Http::response([
            'observations' => [
                ['date' => '2026-04-01', 'value' => '75.10'],
                ['date' => '2026-04-02', 'value' => '.'],
                ['date' => '2026-04-03', 'value' => '74.20'],
            ],
        ]),
    ]);

    $this->service->fetchBrentPrices();

    expect(BrentPrice::count())->toBe(2)
        ->and(BrentPrice::find('2026-04-02'))->toBeNull();
});

it('upserts existing brent price rows on refetch', function (): void {
    Http::fake([
        '*/fred/series/observations*' => Http::sequence()
            ->push(['observations' => [['date' => '2026-04-01', 'value' => '74.00']]])
            ->push(['observations' => [['date' => '2026-04-01', 'value' => '75.50']]]),
    ]);

    $this->service->fetchBrentPrices();
    $this->service->fetchBrentPrices();

    expect(BrentPrice::count())->toBe(1)
        ->and(BrentPrice::find('2026-04-01')->price_usd)->toBe('75.50');
});

// --- generateEwmaPrediction ---

it('detects a rising trend when 3-day EWMA exceeds 7-day EWMA by threshold', function (): void {
    $prices = collect(range(1, 14))->map(fn (int $i) => new BrentPrice([
        'date' => now()->subDays(14 - $i)->toDateString(),
        'price_usd' => 70.0 + ($i * 2.0),
    ]));

    $prediction = $this->service->generateEwmaPrediction($prices);

    expect($prediction->direction)->toBe(TrendDirection::Rising)
        ->and($prediction->source)->toBe(PredictionSource::Ewma)
        ->and($prediction->confidence)->toBeGreaterThan(0)
        ->and($prediction->confidence)->toBeLessThanOrEqual(65);
});

it('detects a falling trend when 3-day EWMA falls below 7-day EWMA by threshold', function (): void {
    $prices = collect(range(1, 14))->map(fn (int $i) => new BrentPrice([
        'date' => now()->subDays(14 - $i)->toDateString(),
        'price_usd' => 85.0 - ($i * 2.0),
    ]));

    $prediction = $this->service->generateEwmaPrediction($prices);

    expect($prediction->direction)->toBe(TrendDirection::Falling)
        ->and($prediction->source)->toBe(PredictionSource::Ewma);
});

it('returns flat when price movement is within threshold', function (): void {
    $prices = collect(range(1, 14))->map(fn (int $i) => new BrentPrice([
        'date' => now()->subDays(14 - $i)->toDateString(),
        'price_usd' => 75.0 + (($i % 2 === 0) ? 0.1 : -0.1),
    ]));

    $prediction = $this->service->generateEwmaPrediction($prices);

    expect($prediction->direction)->toBe(TrendDirection::Flat)
        ->and($prediction->confidence)->toBe(50);
});

it('returns null when fewer than 14 prices are available for EWMA', function (): void {
    $prices = collect(range(1, 10))->map(fn (int $i) => new BrentPrice([
        'date' => now()->subDays(10 - $i)->toDateString(),
        'price_usd' => 75.0,
    ]));

    expect($this->service->generateEwmaPrediction($prices))->toBeNull();
});

// --- generatePrediction (orchestrator) ---

it('stores both EWMA and LLM predictions when provider succeeds', function (): void {
    BrentPrice::insert(
        collect(range(1, 20))->map(fn (int $i) => [
            'date' => now()->subDays(20 - $i)->toDateString(),
            'price_usd' => 75.0 + $i,
        ])->all()
    );

    $this->provider->shouldReceive('predict')->once()->andReturn(new PricePrediction([
        'predicted_for' => now()->toDateString(),
        'source' => PredictionSource::LlmWithContext,
        'direction' => TrendDirection::Rising,
        'confidence' => 70,
        'reasoning' => 'Trend is up.',
        'generated_at' => now(),
    ]));

    $prediction = $this->service->generatePrediction();

    expect($prediction->source)->toBe(PredictionSource::LlmWithContext)
        ->and(PricePrediction::count())->toBe(2);
});

it('returns LLM prediction when provider succeeds', function (): void {
    BrentPrice::insert(
        collect(range(1, 20))->map(fn (int $i) => [
            'date' => now()->subDays(20 - $i)->toDateString(),
            'price_usd' => 75.0 + $i,
        ])->all()
    );

    $llmPrediction = new PricePrediction([
        'predicted_for' => now()->toDateString(),
        'source' => PredictionSource::Llm,
        'direction' => TrendDirection::Rising,
        'confidence' => 65,
        'reasoning' => 'Rising trend.',
        'generated_at' => now(),
    ]);

    $this->provider->shouldReceive('predict')->once()->andReturn($llmPrediction);

    $prediction = $this->service->generatePrediction();

    expect($prediction->source)->toBe(PredictionSource::Llm);
});

it('falls back to EWMA when provider returns null', function (): void {
    BrentPrice::insert(
        collect(range(1, 20))->map(fn (int $i) => [
            'date' => now()->subDays(20 - $i)->toDateString(),
            'price_usd' => 75.0 + ($i * 0.8),
        ])->all()
    );

    $this->provider->shouldReceive('predict')->once()->andReturn(null);

    $prediction = $this->service->generatePrediction();

    expect($prediction->source)->toBe(PredictionSource::Ewma)
        ->and(PricePrediction::count())->toBe(1);
});

it('returns null when there is insufficient price data', function (): void {
    BrentPrice::insert([
        ['date' => now()->subDays(2)->toDateString(), 'price_usd' => 75.0],
        ['date' => now()->subDay()->toDateString(), 'price_usd' => 76.0],
    ]);

    $this->provider->shouldNotReceive('predict');

    expect($this->service->generatePrediction())->toBeNull()
        ->and(PricePrediction::count())->toBe(0);
});