package com.mini.capi.utils;

import org.springframework.util.StringUtils;

import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMultipart;
import javax.mail.internet.MimeUtility;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class MailParseUtils {

    /**
     * 解析邮件发件人（名称+地址）
     */
    public static String parseFrom(Message message) throws MessagingException {
        Address[] froms = message.getFrom();
        if (froms == null || froms.length == 0) {
            return "";
        }
        InternetAddress from = (InternetAddress) froms[0];
        String fromName = from.getPersonal(); // 发件人名称（可能为null）
        String fromAddr = from.getAddress();  // 发件人地址
        return StringUtils.hasText(fromName) ? fromName + "<" + fromAddr + ">" : fromAddr;
    }

    /**
     * 解析邮件收件人（多个用逗号分隔）
     */
    public static String parseTo(Message message) throws MessagingException {
        return parseRecipients(message, Message.RecipientType.TO);
    }

    /**
     * 解析邮件抄送人（多个用逗号分隔）
     */
    public static String parseCc(Message message) throws MessagingException {
        return parseRecipients(message, Message.RecipientType.CC);
    }

    /**
     * 通用解析收件人/抄送人
     */
    private static String parseRecipients(Message message, Message.RecipientType type) throws MessagingException {
        Address[] recipients = message.getRecipients(type);
        if (recipients == null || recipients.length == 0) {
            return "";
        }
        List<String> addrList = new ArrayList<>();
        for (Address addr : recipients) {
            InternetAddress internetAddr = (InternetAddress) addr;
            String name = internetAddr.getPersonal();
            String address = internetAddr.getAddress();
            addrList.add(StringUtils.hasText(name) ? name + "<" + address + ">" : address);
        }
        return String.join(",", addrList);
    }

    /**
     * 解析邮件内容（支持文本/HTML）
     */
    public static String parseContent(Part part) throws MessagingException, IOException {
        if (part.isMimeType("text/plain") || part.isMimeType("text/html")) {
            // 文本/HTML直接读取
            return (String) part.getContent();
        }
        // 多部分内容（含附件），递归解析文本部分
        if (part.isMimeType("multipart/*")) {
            MimeMultipart multipart = (MimeMultipart) part.getContent();
            for (int i = 0; i < multipart.getCount(); i++) {
                BodyPart bodyPart = multipart.getBodyPart(i);
                String content = parseContent(bodyPart);
                if (StringUtils.hasText(content)) {
                    return content;
                }
            }
        }
        return "";
    }

    /**
     * 提取邮件附件（返回附件流+原始文件名）
     */
    public static List<AttachmentInfo> extractAttachments(Part part) throws MessagingException, IOException {
        List<AttachmentInfo> attachments = new ArrayList<>();
        // 多部分内容才可能有附件
        if (part.isMimeType("multipart/*")) {
            MimeMultipart multipart = (MimeMultipart) part.getContent();
            for (int i = 0; i < multipart.getCount(); i++) {
                BodyPart bodyPart = multipart.getBodyPart(i);
                // 判断是否为附件（Disposition为ATTACHMENT或INLINE）
                String disposition = bodyPart.getDisposition();
                if (disposition != null && (disposition.equals(Part.ATTACHMENT) || disposition.equals(Part.INLINE))) {
                    // 获取原始文件名（处理中文乱码）
                    String originalFileName = MimeUtility.decodeText(bodyPart.getFileName());
                    // 获取附件输入流
                    InputStream inputStream = bodyPart.getInputStream();
                    attachments.add(new AttachmentInfo(originalFileName, inputStream));
                } else {
                    // 递归处理嵌套的多部分内容
                    attachments.addAll(extractAttachments(bodyPart));
                }
            }
        }
        return attachments;
    }

    /**
     * 附件信息封装（原始文件名+输入流）
     */
    public static class AttachmentInfo {
        private String originalFileName;
        private InputStream inputStream;

        public AttachmentInfo(String originalFileName, InputStream inputStream) {
            this.originalFileName = originalFileName;
            this.inputStream = inputStream;
        }

        // Getter
        public String getOriginalFileName() {
            return originalFileName;
        }

        public InputStream getInputStream() {
            return inputStream;
        }
    }
}