fuel-alert/tests/Unit/Services/Forecasting/Phase6Test.php

<?php

use App\Services\Forecasting\AccuracyHistory;
use App\Services\Forecasting\DutyChangeDetector;
use App\Services\Forecasting\OutcomeResolver;
use Carbon\Carbon;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Support\Facades\DB;

uses(RefreshDatabase::class);

function seedFlatPrices(int $weeks, int $duty = 5295): void
{
    $start = Carbon::parse('2024-01-01');
    for ($i = 0; $i < $weeks; $i++) {
        DB::table('weekly_pump_prices')->insert([
            'date' => $start->copy()->addWeeks($i)->toDateString(),
            'ulsp_pence' => 14000,
            'ulsd_pence' => 15000,
            'ulsp_duty_pence' => $duty,
            'ulsd_duty_pence' => $duty,
            'ulsp_vat_pct' => 20,
            'ulsd_vat_pct' => 20,
        ]);
    }
}

it('DutyChangeDetector returns false when duty is constant across the window', function () {
    seedFlatPrices(20);

    $detector = new DutyChangeDetector;

    expect($detector->isAdjacent(Carbon::parse('2024-03-04')))->toBeFalse();
});

it('DutyChangeDetector returns true when duty changes within ±4 weeks', function () {
    // 8 weeks at 57.95p, then 8 weeks at 52.95p
    $start = Carbon::parse('2024-01-01');
    for ($i = 0; $i < 8; $i++) {
        DB::table('weekly_pump_prices')->insert([
            'date' => $start->copy()->addWeeks($i)->toDateString(),
            'ulsp_pence' => 14000,
            'ulsd_pence' => 15000,
            'ulsp_duty_pence' => 5795,
            'ulsd_duty_pence' => 5795,
            'ulsp_vat_pct' => 20,
            'ulsd_vat_pct' => 20,
        ]);
    }
    for ($i = 8; $i < 16; $i++) {
        DB::table('weekly_pump_prices')->insert([
            'date' => $start->copy()->addWeeks($i)->toDateString(),
            'ulsp_pence' => 14000,
            'ulsd_pence' => 15000,
            'ulsp_duty_pence' => 5295,
            'ulsd_duty_pence' => 5295,
            'ulsp_vat_pct' => 20,
            'ulsd_vat_pct' => 20,
        ]);
    }

    $detector = new DutyChangeDetector;

    // Target Mon at week 7 — change happens at week 8 → within ±4 weeks
    expect($detector->isAdjacent(Carbon::parse('2024-02-19')))->toBeTrue();
});

it('AccuracyHistory returns null when fewer than 4 outcomes', function () {
    $history = new AccuracyHistory;

    DB::table('forecast_outcomes')->insert([
        'forecast_for' => Carbon::now()->subWeeks(2)->toDateString(),
        'model_version' => 'm1',
        'predicted_class' => 'rising',
        'actual_class' => 'rising',
        'correct' => true,
        'abs_error_pence' => 50,
        'resolved_at' => now(),
    ]);

    expect($history->trailingHitRate('m1'))->toBeNull();
});

it('AccuracyHistory computes hit rate over the last 13 weeks', function () {
    $history = new AccuracyHistory;

    // 4 correct, 1 wrong → 80%
    foreach ([true, true, true, true, false] as $i => $correct) {
        DB::table('forecast_outcomes')->insert([
            'forecast_for' => Carbon::now()->subWeeks($i + 1)->toDateString(),
            'model_version' => 'm1',
            'predicted_class' => 'rising',
            'actual_class' => $correct ? 'rising' : 'falling',
            'correct' => $correct,
            'abs_error_pence' => 50,
            'resolved_at' => now(),
        ]);
    }

    expect($history->trailingHitRate('m1'))->toBe(0.8);
});

it('AccuracyHistory excludes outcomes outside the 13-week window', function () {
    $history = new AccuracyHistory;

    // 4 inside window (correct), 4 outside (wrong) → 100% inside
    foreach (range(1, 4) as $i) {
        DB::table('forecast_outcomes')->insert([
            'forecast_for' => Carbon::now()->subWeeks($i)->toDateString(),
            'model_version' => 'm1',
            'predicted_class' => 'rising',
            'actual_class' => 'rising',
            'correct' => true,
            'abs_error_pence' => 0,
            'resolved_at' => now(),
        ]);
    }
    foreach (range(20, 23) as $i) {
        DB::table('forecast_outcomes')->insert([
            'forecast_for' => Carbon::now()->subWeeks($i)->toDateString(),
            'model_version' => 'm1',
            'predicted_class' => 'rising',
            'actual_class' => 'falling',
            'correct' => false,
            'abs_error_pence' => 100,
            'resolved_at' => now(),
        ]);
    }

    expect($history->trailingHitRate('m1'))->toBe(1.0);
});

it('OutcomeResolver pairs forecasts with actual deltas idempotently', function () {
    seedFlatPrices(20);

    // Insert a forecast for week index 5 (2024-02-05)
    DB::table('weekly_forecasts')->insert([
        'forecast_for' => '2024-02-05',
        'model_version' => 'ridge-test',
        'direction' => 'rising',
        'magnitude_pence' => 80,
        'ridge_confidence' => 60,
        'flagged_duty_change' => false,
        'reasoning' => 'test',
        'generated_at' => now(),
        'created_at' => now(),
        'updated_at' => now(),
    ]);

    // Override now() so the resolver sees the forecast as past.
    Carbon::setTestNow('2024-02-12');

    $resolver = new OutcomeResolver;
    $first = $resolver->resolvePending();
    $second = $resolver->resolvePending();

    expect($first)->toBe(1)
        ->and($second)->toBe(0); // idempotent on re-run

    $row = DB::table('forecast_outcomes')->where('forecast_for', '2024-02-05')->first();
    expect($row->predicted_class)->toBe('rising')
        ->and($row->actual_class)->toBe('flat') // flat data → actual delta = 0
        ->and((bool) $row->correct)->toBeFalse();

    Carbon::setTestNow();
});