<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;

/**
 * One Stripe Price a priced catalogue row has had, live or superseded.
 *
 * Two of them are live at any moment, not one: `reverse_charge` says whether a
 * row is the DOMESTIC GROSS Price, which is what the website quotes and what
 * everybody who is charged VAT pays, or the BARE NET one, which is the whole of
 * what a business in another member state with a verified VAT id owes. Which of
 * the two a checkout uses is TaxTreatment's decision — see
 * App\Services\Billing\PlanPrices.
 *
 * `plan_prices.stripe_price_id` points at the domestic one, because that is the
 * ordinary sale and it must have a single source; the net one is only ever read
 * from here. And because a Price id is unique in this table, joining it on
 * `subscriptions.stripe_price_id` is what says which of the two a running
 * contract is actually billed on.
 *
 * The rest is history, and it exists because a Stripe Price cannot be edited.
 * When the amount a row is charged at changes — a change to the VAT rate moves
 * the gross Price and leaves the net one alone — a new Price is minted, the old
 * row is archived, and the old Price stays in Stripe for as long as a contract is
 * still billing on it. See the migrations for why that history has to be
 * readable.
 */
class StripePlanPrice extends Model
{
    protected $guarded = [];

    protected function casts(): array
    {
        return [
            'charged_cents' => 'integer',
            'reverse_charge' => 'boolean',
            'archived_at' => 'datetime',
        ];
    }

    public function planPrice(): BelongsTo
    {
        return $this->belongsTo(PlanPrice::class);
    }

    /** Is this the Price the catalogue is selling on right now? */
    public function isLive(): bool
    {
        return $this->archived_at === null;
    }
}