<?php

namespace app\common\utils\email;

use support\Db;

class Emails
{

    private $mailbox = '{imap.feishu.cn:993/imap/ssl}INBOX';
    private $username = 'info@borderlesscar.com';
    private $password = 'ErkhUA629aocm7Bc';
    private $limit = 5;
    private $per_page = 20;
    private $batch_size = 10;


    public function __construct($options = [])
    {
        if ($options) {
            $this->mailbox = $options['mailbox'];
            $this->username = $options['username'];
            $this->password = $options['password'];
            $this->limit = $options['limit'];
            $this->per_page = $options['per_page'];
            $this->batch_size = $options['batch_size'];
        }
    }

    /**
     * 将任意字符串清洗为有效 UTF-8，移除或替换无效字节
     */
    protected function sanitizeUtf8(string $text): string
    {
        return iconv('UTF-8', 'UTF-8//IGNORE', $text);
    }

    /**
     * 记录错误到日志
     */
    protected function logError(string $msg): void
    {
        $line = '[' . date('Y-m-d H:i:s') . '] ' . $msg . "\n";
        file_put_contents(
            runtime_path('logs/email_errors.log'),
            $line,
            FILE_APPEND | LOCK_EX
        );
    }

    /**
     * 按编码解码并保留 "\r\n"
     */
    protected function getMailBody($inbox, int $id, bool $isUid = false): string
    {
        $flags     = $isUid ? FT_UID : 0;
        $structure = imap_fetchstructure($inbox, $id, $flags);

        if (!empty($structure->parts)) {
            // HTML 部分
            foreach ($structure->parts as $i => $part) {
                if (isset($part->subtype) && strtolower($part->subtype) === 'html') {
                    $data = imap_fetchbody($inbox, $id, (string)($i+1), $flags);
                    return $this->decodeBody($data, $part->encoding);
                }
            }
            // 文本部分
            foreach ($structure->parts as $i => $part) {
                if (isset($part->subtype) && strtolower($part->subtype) === 'plain') {
                    $data = imap_fetchbody($inbox, $id, (string)($i+1), $flags);
                    return $this->decodeBody($data, $part->encoding);
                }
            }
            // 原始 body
            return imap_body($inbox, $id, $flags);
        }

        return imap_body($inbox, $id, $flags);
    }

    /**
     * 按编码解码
     */
    protected function decodeBody(string $body, int $encoding): string
    {
        switch ($encoding) {
            case 3: return imap_base64($body);
            case 4: return imap_qprint($body);
            default: return $body;
        }
    }

    /**
     * 解析 HTML，找不到 <h2>Preview</h2> 则返回 null，
     * 否则提取所有 <span>Key:</span> Value 为小写蛇形 key=>value 数组
     */
    protected function parseHtml(string $html): ?array
    {
        $doc = new \DOMDocument();
        libxml_use_internal_errors(true);
        $doc->loadHTML('<?xml encoding="utf-8"?>' . $html);
        libxml_clear_errors();

        $xpath = new \DOMXPath($doc);

        // 类型检查
        if ($xpath->query("//h2[text()='Preview']")->length === 0) {
            return null;
        }

        $nodes = $xpath->query("//div[span]");
        $data  = [];

        /** @var \DOMElement $node */
        foreach ($nodes as $node) {
            $span = $xpath->query("span", $node)->item(0);
            if (! $span) {
                continue;
            }

            // 原始键名
            $key = trim(str_replace(':', '', $span->textContent));
            // 转成小写蛇形
            $col = strtolower(str_replace(' ', '_', $key));

            // 获取值
            $a = $xpath->query(".//a", $node)->item(0);
            if ($a && $a->hasAttribute('href')) {
                $value = trim($a->getAttribute('href'));
            } else {
                $clone = $node->cloneNode(true);
                $spanClone = $xpath->query(".//span", $clone)->item(0);
                if ($spanClone) {
                    $spanClone->parentNode->removeChild($spanClone);
                }
                $value = trim($clone->textContent);
            }

            $data[$col] = $value;
        }

        return $data;
    }
    
    /**
     * 拉取邮件uid
     */
    public function uids()
    {
        try {
            $retryTimes = 3;
            $retryDelay = 10;
            $inbox = false;
            $attempt = 0;

            $maxUid = Db::table('email_uids')->max('uid');

            while ($attempt < $retryTimes) {
                $attempt++;
                flg("尝试第 {$attempt} 次连接 IMAP...", false);

                $inbox = @imap_open($this->mailbox, $this->username, $this->password);

                if ($inbox) {
                    break;
                }

                $error = imap_last_error();
                flg("<comment>第 {$attempt} 次失败：{$error}</comment>");
                
                // 若出现 too many login failures 立即暂停一段时间
                if (stripos($error, 'Too many login failures') !== false) {
                    flg("<error>检测到登录失败次数过多，暂停 60 秒避免封禁</error>");
                    sleep(60);
                } else {
                    sleep($retryDelay);
                }
            }

            if (!$inbox) {
                flg("<error>最终仍然连接失败：" . imap_last_error() . "</error>");
                return false;
            }

            // 拉取 UID 并入库
            flg("开始拉取 UID 并入库 …", false);
            $uids = imap_search($inbox, 'ALL', SE_UID) ?: [];

            $uids = array_filter($uids, function($uid) use ($maxUid) {
                return $uid > $maxUid;
            });

            sort($uids);
            $now = time();
            $count = 0;

            foreach ($uids as $uid) {
                try {
                    Db::table('email_uids')->insert([
                        'uid'        => $uid,
                        'fetched_at' => $now,
                        'email'      => $this->username
                    ]);
                    $count++;
                    flg("UID：".$uid." 已写入数据库", false);
                } catch (\Throwable $e) {
                    flg("<comment>{$e->getMessage()}</comment>");
                }
            }

            imap_close($inbox);
            flg("✔ 获取到新询盘邮件 {$count} 条 ...", false);
            return true;
        } catch (\Throwable $th) {
            flg(dpr($th));
            return false;
        }
    }
    
    /**
     * 获取邮件详情
     */
    public function details()
    {
        try {
            $inbox = @imap_open($this->mailbox, $this->username, $this->password);
            if (!$inbox) {
                flg("<error>IMAP 连接失败：". imap_last_error() ."</error>");
                return false;
            }

            // 依次拉取详情并写入 emails 表
            flg("依次拉取详情并写入 emails 表 …", false);
            while (true) {
                $pending = Db::table('email_uids')
                    ->where('status', 0)
                    ->orderBy('uid', 'desc')
                    ->limit(2)
                    ->get();

                if (count($pending) === 0) {
                    flg("邮件UID的详情，已拉取完毕。", false);
                    break;
                }

                flg("处理下一批 " . count($pending) . " 条 …", false);

                foreach ($pending as $row) {
                    $uid = $row->uid;

                    // 包裹整行处理在 try/catch 中，任何异常都不会中断循环
                    try {
                        flg("---- 开始处理 UID={$uid} ----", false);

                        // 1. fetch overview
                        $ov = @imap_fetch_overview($inbox, $uid, FT_UID)[0] ?? null;
                        if (!$ov) {
                            $err = imap_last_error() ?: '未知错误';
                            flg("UID={$uid} overview 失败：{$err}");
                            continue;
                        }
                        $subject = mb_convert_encoding($ov->subject ?? '', 'UTF-8', 'GBK,UTF-8');
                        $from    = $ov->from    ?? '';
                        $date    = $ov->date    ?? '';

                        flg("UID={$uid} overview 成功，subject={$subject}", false);

                        // 2. fetch body
                        $body = $this->getMailBody($inbox, $uid, true);
                        flg("UID={$uid} body 长度：" . strlen($body), false);

                        // 3. sanitize & insert
                        $body     = $this->sanitizeUtf8($body);
                        $now      = time();

                        try {
                            Db::table('emails')->insert([
                                'uid'        => $uid,
                                'subject'    => $subject,
                                'from'       => $from,
                                'date'       => $date,
                                'body'       => $body,
                                'created_at' => $now,
                                'updated_at' => $now,
                            ]);
                            flg("UID={$uid} 写入 emails 成功", false);
                        } catch (\Throwable $e) {
                            flg("UID={$uid} 写入失败：{$e->getMessage()}");
                            continue;
                        }

                        // 4. 标记已处理
                        try {
                            Db::table('email_uids')
                                ->where('uid', $uid)
                                ->update([
                                    'status'       => 1,
                                    'processed_at' => $now,
                                ]);
                            flg("UID={$uid} 标记为已处理", false);
                        } catch (\Throwable $e) {
                            flg("UID={$uid} 标记状态失败：{$e->getMessage()}", false);
                            // 即使更新 status 失败，也继续下一条
                        }
                    } catch (\Throwable $e) {
                        // 捕获任何非预期错误
                        flg("UID={$uid} 处理异常：{$e->getMessage()}");
                        continue;
                    }
                }

                // 批次结束后稍作休眠，防止服务器过载
                sleep(1);
            }

            imap_close($inbox);
            flg("✔ 新邮件详情拉取完成 ...", false);
            return true;
        } catch (\Throwable $th) {
            flg(dpr($th));
            return false;
        }
    }

    /**
     * 邮件清洗处理
     */
    public function process()
    {
        try { 
            $page = 0;

            // 明确定义 parsed_contacts 表里要插入的所有列（顺序无所谓，但要全部包含）
            $fields = [
                'email_id',
                'date',
                'email',
                'name',
                'tel',
                'company',
                'country',
                'form_url',
                'message',
                'ip',
                'iplocation',
                'ilang',
                'mailto',
                'navigator_language',
                'navigator_platform',
                'screen_width',
                'screen_height',
                'ucountry',
            ];

            $maxEmailId = Db::table('email_parsed_result')->max('email_id');

            while (true) {
                $rows = Db::table('emails')
                    ->where('status', 0)
                    ->where('id', '>', $maxEmailId)
                    ->orderBy('id', 'asc')
                    ->limit($this->batch_size)
                    ->offset($page * $this->batch_size)
                    ->get();

                if ($rows->isEmpty()) {
                    break;
                }

                $toInsert = [];
                foreach ($rows as $row) {
                    $parsed = $this->parseHtml($row->body);
                    if ($parsed === null) {
                        flg("  ↳ [{$row->id}] skip: not a contact-form HTML", false);
                        continue;
                    }

                    // 严格按 $fields 顺序填充每条记录，缺失的字段补 null
                    $record = [];
                    foreach ($fields as $col) {
                        if ($col === 'email_id') {
                            $record[$col] = $row->id;
                        } else {
                            $record[$col] = $parsed[$col] ?? null;
                        }
                    }

                    $toInsert[] = $record;
                }

                if (!empty($toInsert)) {
                    Db::table('email_parsed_result')->insert($toInsert);

                    $emailId = array_column($toInsert, 'email_id');
                    Db::table('emails')->whereIn('id', $emailId)->update(['status' => 1]);

                    flg("Inserted batch #" . ($page + 1) . ", count: " . count($toInsert), false);
                }

                $page++;
            }

            flg("✔ 邮件清洗完毕，等待分配 ...", false);
            return true;
        } catch (\Throwable $th) {
            flg(dpr($th));
            return false;
        }
    }
}