<?php

namespace app\common;

use think\Db;
use think\Cache;
use think\Queue;
use PHPMailer\PHPMailer\PHPMailer;

class PromotionService
{
    private $logFile;

    public function __construct()
    {
        $this->logFile = ROOT_PATH . 'runtime' . DS . 'promotion_task.log';
    }

    /**
     * Process the next email in a promotion task (called by queue job)
     */
    public function processNextEmail($taskId)
    {
        $task = Db::name('promotion_task')->where('task_id', $taskId)->find();
        if (!$task) {
            return ['done' => true, 'reason' => 'task_not_found'];
        }
        if ($task['state'] != 1) {
            return ['done' => true, 'reason' => 'task_not_running', 'state' => $task['state']];
        }

        $currentHour = intval(date('G'));
        if ($currentHour < $task['send_start_hour'] || $currentHour >= $task['send_end_hour']) {
            $this->enqueueNextEmail($taskId, 300);
            return ['done' => false, 'reason' => 'outside_send_window', 'retry_in' => 300];
        }

        if ($task['sent_count'] > 0 && $task['max_bounce_rate'] > 0) {
            $bounceRate = ($task['bounce_count'] / $task['sent_count']) * 100;
            if ($bounceRate >= $task['max_bounce_rate']) {
                Db::name('promotion_task')->where('task_id', $taskId)->update([
                    'state' => 2,
                    'utime' => time(),
                ]);
                $this->log("Task {$taskId} auto-paused: bounce rate {$bounceRate}% >= {$task['max_bounce_rate']}%");
                return ['done' => true, 'reason' => 'auto_paused_bounce_rate', 'bounce_rate' => $bounceRate];
            }
        }

        $logEntry = Db::name('promotion_email_log')
            ->where('task_id', $taskId)
            ->where('state', 0)
            ->order('log_id asc')
            ->find();

        if (!$logEntry) {
            Db::name('promotion_task')->where('task_id', $taskId)->update([
                'state' => 3,
                'utime' => time(),
            ]);
            return ['done' => true, 'reason' => 'all_emails_processed'];
        }

        $expert = Db::name('expert')->where('expert_id', $logEntry['expert_id'])->find();
        if (!$expert || $expert['state'] == 4 || $expert['state'] == 5) {
            Db::name('promotion_email_log')->where('log_id', $logEntry['log_id'])->update([
                'state'     => 2,
                'error_msg' => 'Expert invalid or deleted (state=' . (isset($expert['state']) ? $expert['state'] : 'null') . ')',
                'send_time' => time(),
            ]);
            Db::name('promotion_task')->where('task_id', $taskId)->setInc('fail_count');
            Db::name('promotion_task')->where('task_id', $taskId)->update(['utime' => time()]);
            $this->enqueueNextEmail($taskId, 2);
            return ['done' => false, 'skipped' => $logEntry['email_to'], 'reason' => 'expert_invalid'];
        }

        $account = $this->pickSmtpAccountForTask($task);
        if (!$account) {
            $this->enqueueNextEmail($taskId, 600);
            return ['done' => false, 'reason' => 'no_smtp_quota', 'retry_in' => 600];
        }

        $journal     = Db::name('journal')->where('journal_id', $task['journal_id'])->find();
        $expertVars  = $this->buildExpertVars($expert);
        $journalVars = $this->buildJournalVars($journal);
        $vars        = array_merge($journalVars, $expertVars);

        $rendered = $this->renderFromTemplate(
            $task['template_id'],
            $task['journal_id'],
            json_encode($vars, JSON_UNESCAPED_UNICODE),
            $task['style_id']
        );

        if ($rendered['code'] !== 0) {
            Db::name('promotion_email_log')->where('log_id', $logEntry['log_id'])->update([
                'state'     => 2,
                'error_msg' => 'Template render failed: ' . $rendered['msg'],
                'send_time' => time(),
            ]);
            Db::name('promotion_task')->where('task_id', $taskId)->setInc('fail_count');
            Db::name('promotion_task')->where('task_id', $taskId)->update(['utime' => time()]);
            $this->enqueueNextEmail($taskId, 2);
            return ['done' => false, 'failed' => $logEntry['email_to'], 'reason' => 'template_error'];
        }

        $subject = $rendered['data']['subject'];
        $body    = $rendered['data']['body'];

        $result = $this->doSendEmail($account, $logEntry['email_to'], $subject, $body);

        $now = time();
        if ($result['status'] === 1) {
            Db::name('promotion_email_log')->where('log_id', $logEntry['log_id'])->update([
                'j_email_id' => $account['j_email_id'],
                'subject'    => mb_substr($subject, 0, 512),
                'state'      => 1,
                'send_time'  => $now,
            ]);
            Db::name('journal_email')->where('j_email_id', $account['j_email_id'])->setInc('today_sent');
            Db::name('expert')->where('expert_id', $expert['expert_id'])->update(['ltime' => $now]);
            Db::name('promotion_task')->where('task_id', $taskId)->setInc('sent_count');
        } else {
            Db::name('promotion_email_log')->where('log_id', $logEntry['log_id'])->update([
                'j_email_id' => $account['j_email_id'],
                'subject'    => mb_substr($subject, 0, 512),
                'state'      => 2,
                'error_msg'  => mb_substr($result['data'], 0, 512),
                'send_time'  => $now,
            ]);
            Db::name('promotion_task')->where('task_id', $taskId)->setInc('fail_count');
        }

        Db::name('promotion_task')->where('task_id', $taskId)->update(['utime' => $now]);

        $delay = rand(max(5, $task['min_interval']), max($task['min_interval'], $task['max_interval']));
        $this->enqueueNextEmail($taskId, $delay);

        return [
            'done'    => false,
            'sent'    => $result['status'] === 1,
            'email'   => $logEntry['email_to'],
            'next_in' => $delay,
        ];
    }

    // ==================== Queue ====================

    public function enqueueNextEmail($taskId, $delay = 0)
    {
        $jobClass = 'app\api\job\PromotionSend@fire';
        $data     = ['task_id' => $taskId];

        if ($delay > 0) {
            Queue::later($delay, $jobClass, $data, 'promotion');
        } else {
            Queue::push($jobClass, $data, 'promotion');
        }
    }

    // ==================== SMTP ====================

    public function pickSmtpAccountForTask($task)
    {
        $journalId = $task['journal_id'];
        $smtpIds   = $task['smtp_ids'] ? array_map('intval', explode(',', $task['smtp_ids'])) : [];

        $query = Db::name('journal_email')
            ->where('journal_id', $journalId)
            ->where('state', 0);

        if (!empty($smtpIds)) {
            $query->where('j_email_id', 'in', $smtpIds);
        }

        $accounts = $query->select();
        if (empty($accounts)) {
            return null;
        }

        $best = null;
        $bestRemaining = -1;

        foreach ($accounts as $acc) {
            $this->resetDailyCountIfNeeded($acc);
            $remaining = $acc['daily_limit'] - $acc['today_sent'];
            if ($remaining > 0 && $remaining > $bestRemaining) {
                $best = $acc;
                $bestRemaining = $remaining;
            }
        }

        return $best;
    }

    public function resetDailyCountIfNeeded(&$account)
    {
        $todayDate = date('Y-m-d');
        $cacheKey  = 'smtp_reset_' . $account['j_email_id'];
        $lastReset = Cache::get($cacheKey);

        if ($lastReset !== $todayDate) {
            Db::name('journal_email')
                ->where('j_email_id', $account['j_email_id'])
                ->update(['today_sent' => 0]);
            $account['today_sent'] = 0;
            Cache::set($cacheKey, $todayDate, 86400);
        }
    }

    public function doSendEmail($account, $toEmail, $subject, $htmlContent)
    {
        try {
            $mail = new PHPMailer(true);
            $mail->isSMTP();
            $mail->SMTPDebug  = 0;
            $mail->CharSet    = 'UTF-8';
            $mail->Host       = $account['smtp_host'];
            $mail->Port       = intval($account['smtp_port']);
            $mail->SMTPAuth   = true;
            $mail->Username   = $account['smtp_user'];
            $mail->Password   = $account['smtp_password'];

            if ($account['smtp_encryption'] === 'ssl') {
                $mail->SMTPSecure = 'ssl';
            } elseif ($account['smtp_encryption'] === 'tls') {
                $mail->SMTPSecure = 'tls';
            } else {
                $mail->SMTPSecure = false;
                $mail->SMTPAutoTLS = false;
            }

            $fromName = !empty($account['smtp_from_name']) ? $account['smtp_from_name'] : $account['smtp_user'];
            $mail->setFrom($account['smtp_user'], $fromName);
            $mail->addReplyTo($account['smtp_user'], $fromName);
            $mail->addAddress($toEmail);

            $mail->isHTML(true);
            $mail->Subject = $subject;
            $mail->Body    = $htmlContent;
            $mail->AltBody = strip_tags($htmlContent);

            $mail->send();

            return ['status' => 1, 'data' => 'success'];
        } catch (\Exception $e) {
            return ['status' => 0, 'data' => $e->getMessage()];
        }
    }

    // ==================== Template Rendering ====================

    public function renderFromTemplate($templateId, $journalId, $varsJson, $styleId = 0)
    {
        $tpl = Db::name('mail_template')->where('template_id', $templateId)->where('journal_id', $journalId)->where('state', 0)->find();
        if (!$tpl) {
            return ['code' => 1, 'msg' => 'Template not found'];
        }

        $vars = [];
        if ($varsJson) {
            $decoded = json_decode($varsJson, true);
            if (is_array($decoded)) $vars = $decoded;
        }

        $subject   = $this->renderVars($tpl['subject'], $vars);
        $body      = $this->renderVars($tpl['body_html'], $vars);
        $finalBody = $body;

        if ($styleId) {
            $style = Db::name('mail_style')->where('style_id', $styleId)->where('state', 0)->find();
            if ($style) {
                $header = $style['header_html'] ?? '';
                $footer = $style['footer_html'] ?? '';
                $finalBody = $header . $body . $footer;
            }
        }

        return ['code' => 0, 'msg' => 'success', 'data' => ['subject' => $subject, 'body' => $finalBody]];
    }

    public function buildExpertVars($expert)
    {
        return [
            'name'        => $expert['name'] ?? '',
            'email'       => $expert['email'] ?? '',
            'affiliation' => $expert['affiliation'] ?? '',
            'field'       => $expert['field'] ?? '',
        ];
    }

    public function buildJournalVars($journal)
    {
        if (!$journal) return [];
        return [
            'journal_title' => $journal['title'] ?? '',
            'journal_abbr'  => $journal['jabbr'] ?? '',
            'journal_url'   => $journal['website'] ?? '',
        ];
    }

    public function renderVars($tpl, $vars)
    {
        if (!is_string($tpl) || $tpl === '') return '';
        if (!is_array($vars) || empty($vars)) return $tpl;

        $replace = [];
        foreach ($vars as $k => $v) {
            $key = trim((string)$k);
            if ($key === '') continue;
            $replace['{{' . $key . '}}'] = (string)$v;
            $replace['{' . $key . '}'] = (string)$v;
        }
        return str_replace(array_keys($replace), array_values($replace), $tpl);
    }

    // ==================== Logging ====================

    public function log($msg)
    {
        $line = date('Y-m-d H:i:s') . ' ' . $msg . PHP_EOL;
        @file_put_contents($this->logFile, $line, FILE_APPEND);
    }
}