<?php

namespace App\Services\Events;

use App\Models\QrCode;
use App\Models\QrEventRegistration;
use App\Services\Billing\PlatformEmailClient;
use App\Services\Billing\PlatformSmsClient;
use App\Services\Billing\SmsService;
use App\Services\Messaging\MessagingCredentialsService;
use Illuminate\Support\Collection;

class EventCommsService
{
    public const MODE_PROGRAMME = 'programme';
    public const MODE_JOIN = 'join';
    public const MODE_BOTH = 'both';

    private const SMS_SEGMENT_CHARS = 160;
    private const SMS_PRICE_GHS = 0.03;
    private const EMAIL_PRICE_GHS = 0.0135;

    public function __construct(
        private readonly EventEmailService $email,
        private readonly SmsService $sms,
        private readonly MessagingCredentialsService $credentials,
        private readonly EventProgrammeService $programmes,
        private readonly PlatformEmailClient $platformEmail,
        private readonly PlatformSmsClient $platformSms,
    ) {}

    /** @return array{recipients: int, emails: int, sms: int, estimated_ghs: float, affordable: bool, integrations_error: ?string} */
    public function preview(QrCode $event, string $mode): array
    {
        $regs = $this->confirmedRegistrations($event);
        $emails = $regs->filter(fn ($r) => (bool) $r->attendee_email)->count();
        $phones = $regs->filter(fn ($r) => (bool) $r->attendee_phone)->count();
        $smsSegments = $phones * $this->estimateSmsSegments($event, $mode);
        $estimated = round(($emails * self::EMAIL_PRICE_GHS) + ($smsSegments * self::SMS_PRICE_GHS), 2);
        $ownerRef = (string) $event->user->public_id;
        $integrationsError = $this->integrationsError($event, $mode, $emails, $phones);

        return [
            'recipients' => $regs->count(),
            'emails' => $emails,
            'sms' => $phones,
            'estimated_ghs' => $estimated,
            'affordable' => $integrationsError === null,
            'integrations_error' => $integrationsError,
        ];
    }

    /**
     * @return array{emailed: int, texted: int, skipped: int}
     */
    public function send(QrCode $event, string $mode): array
    {
        $preview = $this->preview($event, $mode);
        abort_if($preview['integrations_error'] !== null, 422, $preview['integrations_error']);

        $programme = $this->programmeFor($event);
        $eventName = $event->content()['name'] ?? $event->label;
        $programmeUrl = $programme?->publicUrl();
        $joinUrl = $this->primaryJoinUrl($event);
        $ownerRef = (string) $event->user->public_id;
        $organizerEmail = $event->user->email;
        $organizerName = $event->user->name;

        $emailed = 0;
        $texted = 0;
        $skipped = 0;

        foreach ($this->confirmedRegistrations($event) as $reg) {
            $sent = false;

            if ($reg->attendee_email && in_array($mode, [self::MODE_PROGRAMME, self::MODE_BOTH], true) && $programmeUrl) {
                if ($mode === self::MODE_BOTH) {
                    $sent = $this->email->sendJoinAndProgramme($ownerRef, $reg->attendee_email, $eventName, $joinUrl, $programmeUrl, $reg->attendee_name, $organizerEmail, $organizerName);
                } else {
                    $sent = $this->email->sendProgrammeShare($ownerRef, $reg->attendee_email, $eventName, $programmeUrl, $reg->attendee_name, $organizerEmail, $organizerName);
                }
                if ($sent) {
                    $emailed++;
                }
            } elseif ($reg->attendee_email && $mode === self::MODE_JOIN && $joinUrl !== '') {
                $sent = $this->email->sendJoinLink($ownerRef, $reg->attendee_email, $eventName, $joinUrl, $reg->attendee_name, $organizerEmail, $organizerName);
                if ($sent) {
                    $emailed++;
                }
            }

            if ($reg->attendee_phone) {
                $message = $this->smsBody($reg, $eventName, $mode, $programmeUrl, $joinUrl);
                if ($message !== '' && $this->sms->send($ownerRef, $reg->attendee_phone, $message)) {
                    $texted++;
                    $sent = true;
                }
            }

            if (! $sent) {
                $skipped++;
            }
        }

        return compact('emailed', 'texted', 'skipped');
    }

    /** @return Collection<int, QrEventRegistration> */
    private function confirmedRegistrations(QrCode $event): Collection
    {
        return $event->eventRegistrations()
            ->where('status', QrEventRegistration::STATUS_CONFIRMED)
            ->get();
    }

    private function programmeFor(QrCode $event): ?QrCode
    {
        $programmeId = (int) ($event->content()['programme_qr_id'] ?? 0);
        if ($programmeId <= 0) {
            return null;
        }

        return QrCode::where('id', $programmeId)
            ->where('user_id', $event->user_id)
            ->where('type', QrCode::TYPE_ITINERARY)
            ->first();
    }

    public function primaryJoinUrl(QrCode $event): string
    {
        foreach ((array) ($event->content()['virtual_sessions'] ?? []) as $session) {
            if (! is_array($session)) {
                continue;
            }
            $url = trim((string) ($session['join_url'] ?? ''));
            if ($url !== '') {
                return $url;
            }
        }

        return '';
    }

    private function smsBody(QrEventRegistration $reg, string $eventName, string $mode, ?string $programmeUrl, string $joinUrl): string
    {
        $first = explode(' ', $reg->attendee_name ?? 'there')[0];

        return match ($mode) {
            self::MODE_PROGRAMME => $programmeUrl
                ? sprintf('Hi %s, the programme for %s: %s', $first, $eventName, $programmeUrl)
                : '',
            self::MODE_JOIN => $joinUrl !== ''
                ? sprintf('Hi %s, join %s here: %s', $first, $eventName, $joinUrl)
                : '',
            self::MODE_BOTH => ($programmeUrl && $joinUrl !== '')
                ? sprintf('Hi %s, %s — programme: %s | join: %s', $first, $eventName, $programmeUrl, $joinUrl)
                : ($joinUrl !== '' ? sprintf('Hi %s, join %s: %s', $first, $eventName, $joinUrl) : ''),
            default => '',
        };
    }

    private function estimateSmsSegments(QrCode $event, string $mode): int
    {
        $sample = $this->smsBody(
            new QrEventRegistration(['attendee_name' => 'Guest']),
            $event->content()['name'] ?? $event->label,
            $mode,
            $this->programmeFor($event)?->publicUrl(),
            $this->primaryJoinUrl($event),
        );

        return max(1, (int) ceil(strlen($sample) / self::SMS_SEGMENT_CHARS));
    }

    private function integrationsError(QrCode $event, string $mode, int $emails, int $phones): ?string
    {
        $ownerRef = (string) $event->user->public_id;
        $credential = $this->credentials->forOwner($ownerRef);
        $programmeUrl = $this->programmeFor($event)?->publicUrl();
        $joinUrl = $this->primaryJoinUrl($event);

        $needsEmail = $emails > 0 && (
            (in_array($mode, [self::MODE_PROGRAMME, self::MODE_BOTH], true) && $programmeUrl)
            || ($mode === self::MODE_JOIN && $joinUrl !== '')
        );

        $needsSms = $phones > 0 && $this->smsBody(
            new QrEventRegistration(['attendee_name' => 'Guest']),
            $event->content()['name'] ?? $event->label,
            $mode,
            $programmeUrl,
            $joinUrl,
        ) !== '';

        $emailReady = $this->platformEmail->isConfigured() || $credential->hasValidBird();
        $smsReady = $this->platformSms->isConfigured() || $credential->hasValidSms();

        if ($needsEmail && ! $emailReady) {
            return 'Email is not available yet. Bind a mailbox under Account → Messaging once platform keys are configured, or connect Bird under Advanced keys.';
        }

        if ($needsSms && ! $smsReady) {
            return 'SMS is not available yet. Ensure platform SMS is configured on this Events instance, or connect a product SMS key under Advanced keys.';
        }

        return null;
    }
}