<?php

namespace App\Http\Controllers\Api;

use Illuminate\Support\Facades\Log;
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;
use Symfony\Component\HttpFoundation\Response;

class EmailController extends BaseApiController
{
    public function send()
    {
        $data = $this->payloadData();
        if (empty($data)) {
            return $this->respondError('Invalid request data', Response::HTTP_BAD_REQUEST);
        }

        $rules = [
            'recipient'    => 'required|valid_email',
            'subject'      => 'required|min_length[3]',
            'html_message' => 'required',
        ];

        $errors = $this->validateRequest($data, $rules);
        if (!empty($errors)) {
            return $this->respondValidationError($errors);
        }

        $recipient     = $data['recipient'];
        $subject       = $data['subject'];
        $htmlMessage   = $data['html_message'];
        $profile       = $data['profile'] ?? null;
        $replyToEmail  = $data['reply_to_email'] ?? null;
        $replyToName   = $data['reply_to_name'] ?? null;
        $attachments   = $data['attachments'] ?? [];

        try {
            $sent = $this->sendEmail(
                $recipient,
                $subject,
                $htmlMessage,
                $profile,
                $replyToEmail,
                $replyToName,
                $attachments
            );

            if (!$sent) {
                return $this->respondError('Failed to send email', Response::HTTP_INTERNAL_SERVER_ERROR);
            }

            return $this->success([
                'recipient' => $recipient,
                'subject'   => $subject,
                'sent'      => true,
            ], 'Email sent successfully');
        } catch (\Throwable $e) {
            Log::error('Email send error: ' . $e->getMessage());
            return $this->respondError('Failed to send email', Response::HTTP_INTERNAL_SERVER_ERROR);
        }
    }

    /**
     * Send an email using a named profile (e.g., 'communication', 'payment', 'default').
     *
     * @param string      $recipient
     * @param string      $subject
     * @param string      $htmlMessage
     * @param string|null $profile         e.g. 'communication', 'payment'; if null uses MAIL_PROFILE_DEFAULT or 'default'
     * @param string|null $replyToEmail    optional override
     * @param string|null $replyToName     optional override
     * @param array       $attachments     [['path'=>..., 'name'=>...], ...]
     */
    public function sendEmail(
        string $recipient,
        string $subject,
        string $htmlMessage,
        ?string $profile = null,
        ?string $replyToEmail = null,
        ?string $replyToName  = null,
        array $attachments = []
    ): bool {
        $profile = $this->resolveProfile($profile);
        $cfg     = $this->getProfileConfig($profile);

        // Guard rails: refuse to proceed with missing essentials
        if (empty($cfg['host']) || empty($cfg['user']) || $cfg['pass'] === '') {
            Log::error("[mail:$profile] Missing SMTP config (host/user/pass). Check .env MAIL_{$this->envKeyFromProfile($profile)}_* or MAIL_DEFAULT_*.");
            return false;
        }

        // Optional env flags
        $debugEnabled = (bool) env('MAIL_DEBUG', false);
        $timeout      = (int)  env('MAIL_TIMEOUT', 15);   // seconds
        $keepAlive    = (bool) env('MAIL_KEEPALIVE', false);
        $verifyPeer   = env('MAIL_VERIFY_PEER', 'true');  // 'true'|'false' (string to allow .env)
        $verifyPeer   = filter_var($verifyPeer, FILTER_VALIDATE_BOOLEAN);

        // Preflight DNS + socket (helps distinguish firewall/DNS vs. auth)
        $targetHost = $cfg['host'];
        $targetPort = (int) $cfg['port'];

        $resolved = @gethostbyname($targetHost);
        if (!$resolved || $resolved === $targetHost) {
            // Not fatal (some environments block gethostbyname), but useful log
            Log::debug("[mail:$profile] DNS resolve note: host=$targetHost, resolved=$resolved");
        }

        $sockOk = @fsockopen($targetHost, $targetPort, $errno, $errstr, 5);
        if (!$sockOk) {
            Log::error("[mail:$profile] Socket preflight failed to {$targetHost}:{$targetPort} (errno=$errno, err=$errstr). Likely firewall/port/encryption mismatch or wrong host.");
        } else {
            fclose($sockOk);
        }

        $mail = new PHPMailer(true);

        try {
            // Capture PHPMailer's own debug if enabled
            if ($debugEnabled) {
                ob_start();
            }

            // PHPMailer core setup
            $mail->isSMTP();
            $mail->Host          = $cfg['host'];
            $mail->Port          = $cfg['port'];
            $mail->SMTPAuth      = true;
            $mail->Username      = $cfg['user'];
            $mail->Password      = $cfg['pass'];
            $mail->CharSet       = 'UTF-8';
            $mail->Timeout       = $timeout;      // socket timeout
            $mail->SMTPKeepAlive = $keepAlive;    // reuse connection for multiple sends
            $mail->SMTPAutoTLS   = true;          // allow auto TLS upgrade when possible

            // Encryption mapping: 'tls' => STARTTLS (587), 'ssl' => implicit TLS (465)
            if ($cfg['encryption'] === 'ssl') {
                $mail->SMTPSecure = PHPMailer::ENCRYPTION_SMTPS;
            } else {
                $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
            }

            // TLS verification options (can relax on demand via .env for on-prem/self-signed)
            $mail->SMTPOptions = [
                'ssl' => [
                    'verify_peer'       => $verifyPeer,
                    'verify_peer_name'  => $verifyPeer,
                    'allow_self_signed' => !$verifyPeer,
                ],
            ];

            // Optional verbose debugging (set MAIL_DEBUG=true in .env)
            $mail->SMTPDebug   = $debugEnabled ? 3 : 0;
            $mail->Debugoutput = 'error_log';

            // From / Return-Path
            $mail->setFrom($cfg['fromEmail'], $cfg['fromName']);
            if (!empty($cfg['returnPath'])) {
                $mail->Sender = $cfg['returnPath'];
            }

            // Configurable Reply-To: env overrides inputs/config; fallback to profile/defaults
            $mail->clearReplyTos();
            $rtEmail = env('MAIL_DEFAULT_REPLY_TO');
            $rtName  = env('MAIL_DEFAULT_REPLY_TO_NAME');

            if (!$rtEmail || !filter_var($rtEmail, FILTER_VALIDATE_EMAIL)) {
                $rtEmail = $replyToEmail ?: ($cfg['replyTo'] ?: $cfg['fromEmail']);
            }

            if (!$rtName) {
                $rtName = $replyToName ?: ($cfg['replyToName'] ?: $cfg['fromName']);
            }

            if ($rtEmail) {
                $mail->addReplyTo($rtEmail, $rtName);
            }

            // DKIM (optional)
            if (!empty($cfg['dkim']['domain']) && !empty($cfg['dkim']['private']) && !empty($cfg['dkim']['selector'])) {
                $mail->DKIM_domain   = $cfg['dkim']['domain'];
                $mail->DKIM_private  = $cfg['dkim']['private'];   // path to private key file
                $mail->DKIM_selector = $cfg['dkim']['selector'];
                $mail->DKIM_identity = $cfg['fromEmail'];
            }

            // Recipient(s)
            $mail->addAddress($recipient);

            // Attachments
            foreach ($attachments as $att) {
                if (!empty($att['path']) && is_file($att['path'])) {
                    $mail->addAttachment($att['path'], $att['name'] ?? '');
                }
            }

            // Content
            $mail->isHTML(true);
            $mail->Subject = $subject;
            $mail->Body    = $htmlMessage;

            // Send!
            $ok = $mail->send();
            $dbg = $debugEnabled ? (ob_get_clean() ?: '') : '';

            if ($ok) {
                Log::info("[mail:$profile] Sent to {$recipient}, subj='{$subject}' via {$cfg['host']}:{$cfg['port']}/{$cfg['encryption']}");
                return true;
            }

            Log::error("[mail:$profile] Failed: {$mail->ErrorInfo}. Debug: {$dbg}");
            return false;

        } catch (Exception $e) {
            $dbg = $debugEnabled ? (ob_get_clean() ?: '') : '';
            Log::error("[mail:$profile] Exception: {$e->getMessage()} | PHPMailer: {$mail->ErrorInfo} | Debug: {$dbg}");
            return false;
        }
    }

    /** Resolve null/alias profile names to a canonical env prefix. */
    private function resolveProfile(?string $profile): string
    {
        $p = strtolower(trim((string) $profile));

        if ($p === '' || $p === 'auto') {
            $p = strtolower((string) getenv('MAIL_PROFILE_DEFAULT')) ?: 'default';
        }

        return match ($p) {
            'comm', 'comms'       => 'communication',
            'sys', 'system'       => 'default',
            default               => $p, // e.g., 'payment', 'admissions', etc.
        };
    }

    /** Turn 'communication' into 'COMMUNICATION' for env lookups/logs. */
    private function envKeyFromProfile(string $profile): string
    {
        return strtoupper(preg_replace('/[^A-Z0-9]+/i', '_', $profile));
    }

    /**
     * Resolve SMTP & identity for any profile with layered fallbacks:
     * 1) MAIL_{PROFILE}_*
     * 2) MAIL_DEFAULT_*
     * 3) legacy SMTP_* (HOST/USER/PASS/PORT/ENCRYPTION)
     * 4) hard defaults
     */
    private function getProfileConfig(string $profile): array
    {
        $key = $this->envKeyFromProfile($profile);

        // Helper: first non-empty env from a list
        $envFirst = function (array $keys, $default = null) {
            foreach ($keys as $k) {
                $v = env($k);
                if (is_string($v)) $v = trim($v);
                if ($v !== null && $v !== '') return $v;
            }
            return $default;
        };

        // Core SMTP
        $host       = $envFirst(["MAIL_{$key}_HOST",       "MAIL_DEFAULT_HOST",       "SMTP_HOST"], '');
        $user       = $envFirst(["MAIL_{$key}_USER",       "MAIL_DEFAULT_USER",       "SMTP_USER"], '');
        $pass       = $envFirst(["MAIL_{$key}_PASS",       "MAIL_DEFAULT_PASS",       "SMTP_PASS"], '');
        $portRaw    = $envFirst(["MAIL_{$key}_PORT",       "MAIL_DEFAULT_PORT",       "SMTP_PORT"], 587);
        $encRaw     = $envFirst(["MAIL_{$key}_ENCRYPTION", "MAIL_DEFAULT_ENCRYPTION", "SMTP_ENCRYPTION"], 'tls');

        // Identity
        $fromEmail  = $envFirst(["MAIL_{$key}_FROM_EMAIL", "MAIL_DEFAULT_FROM_EMAIL"], $user ?: 'no-reply@alrahmaisgl.org');
        $fromName   = $envFirst(["MAIL_{$key}_FROM_NAME",  "MAIL_DEFAULT_FROM_NAME"],  'Al Rahma Sunday School');
        $replyTo    = $envFirst(["MAIL_{$key}_REPLY_TO",   "MAIL_DEFAULT_REPLY_TO"],   '');
        $replyToNm  = $envFirst(["MAIL_{$key}_REPLY_TO_NAME","MAIL_DEFAULT_REPLY_TO_NAME"], '');
        $returnPath = $envFirst(["MAIL_{$key}_RETURN_PATH","MAIL_DEFAULT_RETURN_PATH"], '');

        // DKIM (optional)
        $dkim = [
            'domain'   => $envFirst(["MAIL_{$key}_DKIM_DOMAIN",   "MAIL_DEFAULT_DKIM_DOMAIN"],   ''),
            'selector' => $envFirst(["MAIL_{$key}_DKIM_SELECTOR", "MAIL_DEFAULT_DKIM_SELECTOR"], ''),
            'private'  => $envFirst(["MAIL_{$key}_DKIM_PRIVATE",  "MAIL_DEFAULT_DKIM_PRIVATE"],  ''), // full path
        ];

        // Normalize types/values
        $port       = (int) $portRaw ?: 587;
        $encryption = strtolower((string) $encRaw);
        $encryption = in_array($encryption, ['tls','ssl'], true) ? $encryption : 'tls';

        // --- Autocorrect common mistakes (prevents silent handshake failures) ---
        if ($port === 587 && $encryption === 'ssl') {
            $encryption = 'tls';
        }
        if ($port === 465 && $encryption === 'tls') {
            $encryption = 'ssl';
        }

        return [
            'host'        => (string) $host,
            'user'        => (string) $user,
            'pass'        => (string) $pass,
            'port'        => $port,
            // map used above: 'tls' => STARTTLS, 'ssl' => SMTPS
            'encryption'  => $encryption,
            'fromEmail'   => (string) $fromEmail,
            'fromName'    => (string) $fromName,
            'replyTo'     => (string) $replyTo,
            'replyToName' => (string) $replyToNm,
            'returnPath'  => (string) $returnPath,
            'dkim'        => $dkim,
        ];
    }
}