<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;

class WhatsAppCloudService
{
    public function isEnabled()
    {
        return (bool) config('whatsapp.whatsapp_cloud_enabled')
            && ! empty(config('whatsapp.token'))
            && ! empty(config('whatsapp.phone_number_id'));
    }

    /**
     * Normalize Malaysian phone numbers to digits with country code (e.g. 60123456789).
     */
    public function normalizePhone($phone)
    {
        if ($phone === null || $phone === '') {
            return null;
        }

        $digits = preg_replace('/\D+/', '', (string) $phone);
        if ($digits === '') {
            return null;
        }

        if (strpos($digits, '60') === 0) {
            return $digits;
        }

        if (strpos($digits, '0') === 0) {
            return '6'.$digits;
        }

        return '60'.ltrim($digits, '0');
    }

    /**
     * In non-production, always send to ADMIN_PHONE_NUMBER.
     */
    public function resolveRecipient($phone)
    {
        if (config('app.env') !== 'production') {
            return $this->normalizePhone(config('app.admin_phone_number'));
        }

        return $this->normalizePhone($phone);
    }

    /**
     * Send an approved WhatsApp Cloud API template message.
     *
     * @param  string  $to  E.164-ish digits without +
     * @param  string  $templateName
     * @param  array<int, string>  $bodyParams  Ordered body variables {{1}}, {{2}}, ...
     * @return array{ok:bool,status:int,body:mixed}
     */
    public function sendTemplate($to, $templateName, array $bodyParams = [], $languageCode = null)
    {
        if (! $this->isEnabled()) {
            Log::warning('WhatsApp Cloud API skipped: not enabled or missing credentials.');

            return ['ok' => false, 'status' => 0, 'body' => 'disabled'];
        }

        $to = $this->normalizePhone($to);
        if (! $to) {
            return ['ok' => false, 'status' => 0, 'body' => 'invalid_phone'];
        }

        $languageCode = $languageCode ?: config('whatsapp.template_lang', 'en_US');
        $version = config('whatsapp.api_version', 'v25.0');
        $phoneNumberId = config('whatsapp.phone_number_id');
        $url = "https://graph.facebook.com/{$version}/{$phoneNumberId}/messages";

        $template = [
            'name' => $templateName,
            'language' => ['code' => $languageCode],
        ];

        if (! empty($bodyParams)) {
            $template['components'] = [[
                'type' => 'body',
                'parameters' => array_map(function ($value) {
                    return [
                        'type' => 'text',
                        'text' => (string) $value,
                    ];
                }, array_values($bodyParams)),
            ]];
        }

        $payload = [
            'messaging_product' => 'whatsapp',
            'to' => $to,
            'type' => 'template',
            'template' => $template,
        ];

        $response = Http::withToken(config('whatsapp.token'))
            ->acceptJson()
            ->asJson()
            ->post($url, $payload);

        $result = [
            'ok' => $response->successful(),
            'status' => $response->status(),
            'body' => $response->json() ?? $response->body(),
        ];

        if (! $result['ok']) {
            Log::error('WhatsApp Cloud API template send failed', [
                'to' => $to,
                'template' => $templateName,
                'status' => $result['status'],
                'body' => $result['body'],
            ]);
        } else {
            Log::info('WhatsApp Cloud API template sent', [
                'to' => $to,
                'template' => $templateName,
                'message_id' => data_get($result['body'], 'messages.0.id'),
            ]);
        }

        return $result;
    }
}