<?php
declare(strict_types=1);

/**
 * Sinch Engage (formerly MessageMedia) Messages API adapter (server-only).
 *
 * Verified against the Sinch Engage OpenAPI spec (github.com/messagemedia/sinchengage-developer):
 *   POST {SINCH_API_BASE}/v1/messages
 *   Authorization: Basic base64(api_key:api_secret)
 *   Account: <sub-account id>          (optional; lets a parent key send as a campus sub-account)
 *   { "messages": [ { "content", "destination_number", "source_number", "format": "SMS",
 *                     "delivery_report": true, "metadata": {...}, "message_expiry_timestamp" } ] }
 *
 * Regional hosts: https://us.app.api.sinch.com (US), https://eu.app.api.sinch.com, https://au.app.api.sinch.com
 *
 * Config: SINCH_API_BASE, SINCH_API_KEY, SINCH_API_SECRET, SINCH_DEFAULT_SOURCE_NUMBER,
 *         SINCH_USE_CAMPUS_SUBACCOUNTS (default true), SINCH_INTERNAL_NOTIFY_NUMBER (optional)
 *
 * Idempotency: a lead is only sent once. The DB row is marked "sending" before the
 * request and updated with the provider message_id after; retries skip rows that are
 * not in a retryable state.
 */
final class Sinch
{
    public const TEMPLATE_DEFAULT = "Hi {{first_name}} — we're excited that you're considering Waters Church {{campus_name}}. Your visit details: {{service_or_date}}. Have a question? Reply to this message. Reply STOP to opt out.";

    /**
     * @param array<string,mixed> $lead
     * @param array<string,mixed> $campus
     * @return array{status:string, detail:?string, message_id:?string, transient:bool}
     */
    public static function sendVisitConfirmation(array $lead, array $campus): array
    {
        if (!(int)$lead['sms_consent']) {
            return ['status' => 'skipped', 'detail' => 'no sms consent', 'message_id' => null, 'transient' => false];
        }
        $to = $lead['phone_e164'] ?? null;
        if (!$to || !Phone::isE164($to)) {
            return ['status' => 'failed', 'detail' => 'no valid phone', 'message_id' => null, 'transient' => false];
        }
        $content = self::buildConfirmation($lead, $campus);
        $from = self::sourceNumberFor($campus);
        $account = self::accountFor($campus);

        if (Config::isMock()) {
            Log::info('[mock] Sinch send', ['account' => $account, 'source' => $from, 'chars' => mb_strlen($content)]);
            return ['status' => 'mock', 'detail' => 'mock mode; would send from ' . ($from ?? 'default') . ($account ? " as $account" : ''), 'message_id' => 'mock-' . substr($lead['submission_id'], 0, 8), 'transient' => false];
        }

        $message = [
            'content' => $content,
            'destination_number' => $to,
            'format' => 'SMS',
            'delivery_report' => true,
            'metadata' => ['submission_id' => $lead['submission_id'], 'campus' => $campus['id'], 'source' => 'visit.waterschurch.org'],
            'message_expiry_timestamp' => gmdate('Y-m-d\TH:i:s\Z', time() + 6 * 3600),
        ];
        if ($from) {
            $message['source_number'] = $from;
        }
        $r = self::post('/v1/messages', ['messages' => [$message]], $account);
        if ($r['status'] === 202 || $r['status'] === 200) {
            $msg = $r['json']['messages'][0] ?? [];
            $id = is_array($msg) ? ($msg['message_id'] ?? null) : null;
            $status = is_array($msg) ? ($msg['status'] ?? 'queued') : 'queued';
            // Only claim success when the provider actually accepted the message.
            if (!$id) {
                return ['status' => 'failed', 'detail' => 'provider response missing message_id', 'message_id' => null, 'transient' => true];
            }
            return ['status' => 'sent', 'detail' => "provider status: $status", 'message_id' => $id, 'transient' => false];
        }
        $detail = is_array($r['json']) ? json_encode($r['json']) : ($r['error'] ?? "HTTP {$r['status']}");
        Log::warn('Sinch send failed', ['status' => $r['status'], 'detail' => substr((string)$detail, 0, 300)]);
        return ['status' => 'failed', 'detail' => substr((string)$detail, 0, 500), 'message_id' => null, 'transient' => Http::isTransient($r['status'], $r['error'])];
    }

    /**
     * Optional internal heads-up to campus staff. Enabled only when
     * SINCH_INTERNAL_NOTIFY_NUMBER is set. Contains no visitor PII beyond first name.
     *
     * @param array<string,mixed> $lead
     * @param array<string,mixed> $campus
     */
    public static function sendInternalLeadNotification(array $lead, array $campus): ?array
    {
        $to = Config::get('SINCH_INTERNAL_NOTIFY_NUMBER');
        if (!$to) {
            return null;
        }
        $content = sprintf('New first-time visitor plan: %s → %s%s. View in the leads export.', $lead['first_name'], $campus['name'], $lead['visit_date'] ? ' on ' . $lead['visit_date'] : '');
        if (Config::isMock()) {
            Log::info('[mock] Sinch internal notify', ['to' => $to]);
            return ['status' => 'mock'];
        }
        $r = self::post('/v1/messages', ['messages' => [['content' => $content, 'destination_number' => $to, 'format' => 'SMS', 'source_number' => Config::get('SINCH_DEFAULT_SOURCE_NUMBER')]]], null);
        return ['status' => ($r['status'] === 202 || $r['status'] === 200) ? 'sent' : 'failed'];
    }

    public static function normalizePhoneNumber(string $raw): ?string
    {
        return Phone::normalizeNanp($raw);
    }

    /**
     * @param array<string,mixed> $lead
     * @param array<string,mixed> $campus
     */
    public static function buildConfirmation(array $lead, array $campus): string
    {
        $template = Config::get('SINCH_CONFIRMATION_TEMPLATE') ?: self::TEMPLATE_DEFAULT;
        $when = self::serviceOrDate($lead, $campus);
        $vars = [
            '{{first_name}}' => $lead['first_name'],
            '{{campus_name}}' => $campus['name'],
            '{{service_or_date}}' => $when,
            '{{address}}' => $campus['address']['line1'] . ', ' . $campus['address']['city'],
        ];
        $text = strtr($template, $vars);
        $text = preg_replace('/\s+/', ' ', trim($text)) ?? $text;
        // Keep to a sane length; carriers concatenate but cost rises. 320 chars = 2 segments (GSM) or ~4 (UCS-2).
        return mb_substr($text, 0, 320);
    }

    /**
     * @param array<string,mixed> $lead
     * @param array<string,mixed> $campus
     */
    public static function serviceOrDate(array $lead, array $campus): string
    {
        $parts = [];
        if (!empty($lead['visit_date'])) {
            $ts = strtotime($lead['visit_date']);
            $parts[] = $ts ? date('D, M j', $ts) : $lead['visit_date'];
        }
        if (!empty($lead['service_time'])) {
            $parts[] = $lead['service_time'];
        }
        if (!$parts) {
            $parts[] = Campuses::timesSummary($campus);
        }
        return implode(' · ', $parts);
    }

    /** @param array<string,mixed> $campus */
    public static function sourceNumberFor(array $campus): ?string
    {
        if (Config::bool('SINCH_USE_CAMPUS_NUMBERS', true) && !empty($campus['smsNumber'])) {
            return $campus['smsNumber'];
        }
        return Config::get('SINCH_DEFAULT_SOURCE_NUMBER');
    }

    /** @param array<string,mixed> $campus */
    public static function accountFor(array $campus): ?string
    {
        if (Config::bool('SINCH_USE_CAMPUS_SUBACCOUNTS', true) && !empty($campus['sinchAccountId'])) {
            return $campus['sinchAccountId'];
        }
        return Config::get('SINCH_ACCOUNT_ID');
    }

    /**
     * @param array<string,mixed> $payload
     * @return array{status:int, body:string, json:mixed, error:?string}
     */
    private static function post(string $path, array $payload, ?string $account): array
    {
        $base = rtrim(Config::get('SINCH_API_BASE', 'https://us.app.api.sinch.com') ?? '', '/');
        $key = Config::require('SINCH_API_KEY');
        $secret = Config::require('SINCH_API_SECRET');
        $headers = ['Authorization' => 'Basic ' . base64_encode("$key:$secret")];
        if ($account) {
            $headers['Account'] = $account;
        }
        return Http::json('POST', $base . $path, $payload, $headers, 10);
    }
}