<?php

namespace App\Services\Billing;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use App\Models\User;

/**
 * Client for the platform Billing HTTP API — the one UserWallet lives on the
 * platform; Bird only consumes it. Amounts are integer minor units; the user is
 * identified by public_id. Authenticates with the per-consumer config('billing.service') key.
 * Contract validated in the monolith (smtp-extraction-runbook §4-A).
 */
class BillingClient
{
    private function base(): string
    {
        return rtrim((string) config('billing.api_url'), '/');
    }

    private function token(): string
    {
        return (string) (config('billing.api_key') ?? '');
    }

    private function get(string $path, array $query): array
    {
        $res = Http::withToken($this->token())->acceptJson()->timeout(10)->get($this->base().$path, $query);
        $res->throw();

        return (array) $res->json();
    }

    public function balanceMinor(string $publicId): int
    {
        return (int) ($this->get('/balance', ['user' => $publicId])['balance_minor'] ?? 0);
    }

    public function canAfford(string $publicId, int $amountMinor): bool
    {
        return (bool) ($this->get('/can-afford', ['user' => $publicId, 'amount_minor' => $amountMinor])['affordable'] ?? false);
    }

    public function serviceLedger(string $publicId, string $service): array
    {
        return $this->get('/service-ledger', ['user' => $publicId, 'service' => $service]);
    }

    /**
     * Debit the wallet. Returns true on success, false on insufficient balance
     * (HTTP 402). Idempotent by $reference.
     */
    public function debit(string $publicId, int $amountMinor, string $service, string $source, string $reference, ?int $serviceId = null, ?string $description = null): bool
    {
        $res = Http::withToken($this->token())->acceptJson()->timeout(10)->post($this->base().'/debit', array_filter([
            'user' => $publicId,
            'amount_minor' => $amountMinor,
            'service' => $service,
            'source' => $source,
            'reference' => $reference,
            'service_id' => $serviceId,
            'description' => $description,
        ], static fn ($v) => $v !== null));

        if ($res->status() === 402) {
            return false;
        }
        $res->throw();

        return true;
    }

    public function credit(string $publicId, int $amountMinor, string $service, string $source, string $reference, ?int $serviceId = null, ?string $description = null): array
    {
        $res = Http::withToken($this->token())->acceptJson()->timeout(10)->post($this->base().'/credit', array_filter([
            'user' => $publicId,
            'amount_minor' => $amountMinor,
            'service' => $service,
            'source' => $source,
            'reference' => $reference,
            'service_id' => $serviceId,
            'description' => $description,
        ], static fn ($v) => $v !== null));
        $res->throw();

        return (array) $res->json();
    }

    public function configured(): bool
    {
        return $this->base() !== '' && $this->token() !== '';
    }

    /**
     * @return array{ok: bool, insufficient: bool, balance_minor: ?int, error: ?string}
     */
    public function charge(User $user, int $amountMinor, string $reference, string $description): array
    {
        if (! $this->configured()) {
            return ['ok' => false, 'insufficient' => false, 'balance_minor' => null, 'error' => 'Billing is not configured.'];
        }

        try {
            $res = Http::withToken($this->token())
                ->acceptJson()->timeout(20)
                ->post($this->base().'/debit', [
                    'user' => $user->public_id,
                    'amount_minor' => $amountMinor,
                    'service' => (string) config('billing.service', 'events'),
                    'source' => 'subscription',
                    'reference' => $reference,
                    'description' => $description,
                ]);
        } catch (\Throwable $e) {
            Log::warning('Events BillingClient: charge failed', ['user' => $user->public_id, 'error' => $e->getMessage()]);

            return ['ok' => false, 'insufficient' => false, 'balance_minor' => null, 'error' => 'Could not reach the billing service.'];
        }

        if ($res->status() === 402) {
            return ['ok' => false, 'insufficient' => true, 'balance_minor' => (int) $res->json('balance_minor', 0), 'error' => 'Insufficient wallet balance.'];
        }

        if ($res->failed()) {
            return ['ok' => false, 'insufficient' => false, 'balance_minor' => null, 'error' => 'Billing error ('.$res->status().').'];
        }

        return ['ok' => true, 'insufficient' => false, 'balance_minor' => null, 'error' => null];
    }

    /**
     * @param  array<string, mixed>  $metadata
     * @return array{checkout_url: string, reference: string}
     */
    public function initiatePlanCheckout(
        User $user,
        string $plan,
        int $months,
        int $amountMinor,
        string $returnUrl,
        array $metadata = [],
    ): array {
        $res = Http::withToken($this->token())
            ->acceptJson()->timeout(15)
            ->post($this->base().'/plan-checkout', [
                'user' => $user->public_id,
                'app' => (string) config('billing.service', 'events'),
                'plan' => $plan,
                'months' => $months,
                'amount_minor' => $amountMinor,
                'return_url' => $returnUrl,
                'metadata' => $metadata,
            ]);
        $res->throw();

        return [
            'checkout_url' => (string) $res->json('checkout_url'),
            'reference' => (string) $res->json('reference'),
        ];
    }

    /** @return array<string, mixed> */
    public function verifyPlanCheckout(string $reference): array
    {
        $res = Http::withToken($this->token())
            ->acceptJson()->timeout(15)
            ->post($this->base().'/plan-checkout/verify', [
                'reference' => $reference,
            ]);

        if ($res->status() === 422) {
            return ['paid' => false, 'error' => $res->json('error')];
        }
        $res->throw();

        return $res->json();
    }
}