package cn.iocoder.yudao.module.wxcp.controller.admin.notice;

import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.util.StrUtil;
import cn.iocoder.yudao.module.system.controller.admin.storage.vo.SystemStorageBlobRespVO;
import cn.iocoder.yudao.module.wxcp.dal.dataobject.notice.WxCpNoticeDO;
import cn.iocoder.yudao.module.wxcp.enums.notice.WxCpNoticeStatusEnum;
import cn.iocoder.yudao.module.wxcp.enums.notice.WxCpNoticeTypeEnum;
import cn.iocoder.yudao.module.wxcp.service.notice.WxCpNoticeService;
import io.swagger.v3.oas.annotations.Operation;
import io.swagger.v3.oas.annotations.Parameter;
import io.swagger.v3.oas.annotations.tags.Tag;
import jakarta.annotation.Resource;
import jakarta.annotation.security.PermitAll;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.MediaType;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import java.net.URI;
import java.util.List;
import java.util.Objects;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * 企业微信通知 - 成员预览页（免登录）
 *
 * 说明：放在 controller.admin 包下从而带上 /admin-api 前缀。
 * 前端 Vite 开发代理只转发 /admin-api，若放到 /app-api，
 * 成员在企业微信里打开链接会打到前端静态服务返回 404。
 *
 * @author 超级管理员
 */
@Tag(name = "用户 App - 企业微信通知预览")
@RestController
@RequestMapping("/wxcp/notice")
@Validated
@Slf4j
public class WxCpNoticePublicController {

    /** 行内代码 */
    private static final Pattern MD_CODE = Pattern.compile("`([^`]+)`");
    /** 加粗 */
    private static final Pattern MD_STRONG = Pattern.compile("\\*\\*(.+?)\\*\\*");
    /** 链接 [文案](地址) */
    private static final Pattern MD_LINK = Pattern.compile("\\[([^\\]]+)]\\(([^)]+)\\)");

    @Resource
    private WxCpNoticeService noticeService;

    @GetMapping(value = "/preview-page", produces = MediaType.TEXT_HTML_VALUE)
    @PermitAll
    @Operation(summary = "通知预览页（HTML）", description = "图片/附件通知推送给成员后，成员打开此页查看图片与附件")
    @Parameter(name = "id", description = "通知编号", required = true)
    public String previewPage(@RequestParam("id") Long id) {
        WxCpNoticeDO notice = noticeService.getNotice(id);
        if (notice == null) {
            return renderMessagePage("通知不存在", "通知可能已被删除，请联系通知发起人确认。");
        }
        if (!WxCpNoticeStatusEnum.PUBLISHED.getStatus().equals(notice.getStatus())) {
            return renderMessagePage("通知未开放", "该通知尚未发布或已撤回，请联系通知发起人确认。");
        }
        return renderPreviewPage(notice);
    }

    private String renderPreviewPage(WxCpNoticeDO notice) {
        List<SystemStorageBlobRespVO> images = noticeService.getNoticeImageAttachments(notice.getId());
        List<SystemStorageBlobRespVO> files = noticeService.getNoticeFileAttachments(notice.getId());
        List<SystemStorageBlobRespVO> videos = noticeService.getNoticeVideoAttachments(notice.getId());

        StringBuilder sb = new StringBuilder(2048);
        sb.append("<!DOCTYPE html><html lang=\"zh-CN\"><head><meta charset=\"UTF-8\">")
                .append("<meta name=\"viewport\" content=\"width=device-width,initial-scale=1,maximum-scale=1\">")
                .append("<title>").append(esc(notice.getTitle())).append("</title>")
                .append("<style>")
                .append("*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}")
                .append("body{margin:0;padding:16px;font-family:-apple-system,BlinkMacSystemFont,'PingFang SC','Microsoft YaHei',sans-serif;")
                .append("background:#f5f6f8;color:#1f2329;font-size:15px;line-height:1.6}")
                .append(".card{background:#fff;border-radius:12px;padding:18px;margin-bottom:12px;box-shadow:0 1px 4px rgba(0,0,0,.06)}")
                .append("h1{font-size:19px;margin:0 0 14px;font-weight:600;word-break:break-all}")
                .append(".desc{white-space:pre-wrap;word-break:break-word;color:#3f444d}")
                .append(".detail-img{display:block;margin:12px 0 0}")
                .append(".detail-img img{display:block;width:100%;height:auto;border-radius:8px;background:#f2f3f5}")
                .append(".file-title{font-weight:600;margin-bottom:8px}")
                .append(".file-list div{padding:8px 0;border-bottom:1px solid #f0f1f3;word-break:break-all}")
                .append(".file-list div:last-child{border-bottom:0}")
                .append(".file-list a{color:#3370ff;text-decoration:none}")
                .append(".file-size{color:#8f959e;font-size:12px;margin-left:6px}")
                .append(".video-wrap video{display:block;width:100%;border-radius:8px;background:#000}")
                .append(".markdown h1,.markdown h2,.markdown h3{margin:14px 0 8px;font-weight:600;line-height:1.4}")
                .append(".markdown h1{font-size:19px}.markdown h2{font-size:17px}.markdown h3{font-size:16px}")
                .append(".markdown p{margin:8px 0}")
                .append(".markdown ul,.markdown ol{margin:8px 0;padding-left:20px}")
                .append(".markdown li{margin:4px 0}")
                .append(".markdown blockquote{margin:10px 0;padding:8px 12px;border-left:3px solid #dee0e3;")
                .append("background:#f7f8fa;color:#646a73;border-radius:4px}")
                .append(".markdown code{padding:1px 5px;border-radius:4px;background:#f2f3f5;font-size:13px}")
                .append(".markdown a{color:#3370ff;text-decoration:none}")
                .append(".btn{display:block;margin-top:16px;padding:12px;border-radius:8px;background:#3370ff;color:#fff;")
                .append("font-size:15px;font-weight:500;text-align:center;text-decoration:none}")
                .append(".tip{margin-top:12px;font-size:12px;color:#8f959e;text-align:center}")
                .append("</style></head><body>");

        sb.append("<div class=\"card\"><h1>").append(esc(notice.getTitle())).append("</h1>");
        if (StrUtil.isNotBlank(notice.getContent())) {
            if (Objects.equals(notice.getNoticeType(), WxCpNoticeTypeEnum.MARKDOWN.getType())) {
                // Markdown 通知在预览页按富文本展示，渲染前已对用户内容做 HTML 转义
                sb.append("<div class=\"desc markdown\">").append(renderMarkdown(notice.getContent())).append("</div>");
            } else {
                sb.append("<div class=\"desc\">").append(esc(notice.getContent())).append("</div>");
            }
        }
        if (StrUtil.isNotBlank(notice.getLinkUrl())) {
            String link = StrUtil.blankToDefault(notice.getLinkBtnText(), "查看详情");
            sb.append("<a class=\"btn\" href=\"").append(esc(notice.getLinkUrl()))
                    .append("\" target=\"_blank\" rel=\"noopener\">").append(esc(link)).append("</a>");
        }
        sb.append("</div>");

        // 图片：按原图比例完整展示，点一下用浏览器打开原图，方便放大查看
        if (CollUtil.isNotEmpty(images)) {
            sb.append("<div class=\"card\">");
            for (SystemStorageBlobRespVO image : images) {
                String raw = StrUtil.blankToDefault(image.getPreviewURL(), image.getUrl());
                if (StrUtil.isBlank(raw)) {
                    continue;
                }
                String url = toSameOriginUrl(raw);
                sb.append("<a class=\"detail-img\" href=\"").append(esc(url))
                        .append("\" target=\"_blank\" rel=\"noopener\">")
                        .append("<img src=\"").append(esc(url)).append("\" alt=\"通知图片\">")
                        .append("</a>");
            }
            sb.append("</div>");
        }

        // 视频：成员点开即可播放
        if (CollUtil.isNotEmpty(videos)) {
            sb.append("<div class=\"card\">");
            for (SystemStorageBlobRespVO video : videos) {
                String raw = StrUtil.blankToDefault(video.getPreviewURL(), video.getUrl());
                if (StrUtil.isBlank(raw)) {
                    continue;
                }
                String url = toSameOriginUrl(raw);
                sb.append("<div class=\"video-wrap\"><video controls preload=\"metadata\" src=\"")
                        .append(esc(url)).append("\"></video></div>");
            }
            sb.append("</div>");
        }

        // 附件：成员点开即可预览/下载
        if (CollUtil.isNotEmpty(files)) {
            sb.append("<div class=\"card\"><div class=\"file-title\">附件</div><div class=\"file-list\">");
            for (SystemStorageBlobRespVO file : files) {
                String raw = StrUtil.blankToDefault(file.getDownloadURL(),
                        StrUtil.blankToDefault(file.getUrl(), file.getPreviewURL()));
                if (StrUtil.isBlank(raw)) {
                    continue;
                }
                String url = toSameOriginUrl(raw);
                String name = StrUtil.blankToDefault(file.getOriginalFilename(),
                        StrUtil.blankToDefault(file.getName(), "附件"));
                sb.append("<div><a href=\"").append(esc(url)).append("\" target=\"_blank\" rel=\"noopener\">")
                        .append(esc(name)).append("</a>");
                if (file.getByteSize() != null) {
                    sb.append("<span class=\"file-size\">").append(formatSize(file.getByteSize())).append("</span>");
                }
                sb.append("</div>");
            }
            sb.append("</div></div>");
        }

        sb.append("<div class=\"tip\">来自企业微信通知，请在企业微信内查看</div></body></html>");
        return sb.toString();
    }

    private String formatSize(Long bytes) {
        if (bytes == null || bytes <= 0) {
            return "";
        }
        if (bytes < 1024) {
            return bytes + " B";
        }
        if (bytes < 1024 * 1024) {
            return String.format("%.1f KB", bytes / 1024.0);
        }
        return String.format("%.1f MB", bytes / (1024.0 * 1024.0));
    }

    /**
     * 把附件地址转成同源相对地址
     *
     * 附件里存的是带签名的绝对地址，域名取自 yudao.storage.domain（通常是内网地址）。
     * 成员手机通过公网域名打开本页时直连内网地址会加载不出图片，
     * 这里剥掉协议与域名只留 /admin-api/... 路径，交给同源代理转发。
     */
    private String toSameOriginUrl(String url) {
        String trimmed = url.trim();
        if (!StrUtil.startWithAnyIgnoreCase(trimmed, "http://", "https://")) {
            return trimmed;
        }
        try {
            URI uri = URI.create(trimmed);
            String path = uri.getRawPath();
            if (StrUtil.isBlank(path)) {
                return trimmed;
            }
            String query = uri.getRawQuery();
            return StrUtil.isBlank(query) ? path : path + "?" + query;
        } catch (IllegalArgumentException e) {
            // 地址不合规就原样透出，不能因为一张图片让整页打不开
            log.warn("通知附件地址解析失败，按原样输出：{}", trimmed);
            return trimmed;
        }
    }

    private String renderMessagePage(String title, String desc) {
        return "<!DOCTYPE html><html lang=\"zh-CN\"><head><meta charset=\"UTF-8\">"
                + "<meta name=\"viewport\" content=\"width=device-width,initial-scale=1\">"
                + "<title>" + esc(title) + "</title><style>"
                + "body{margin:0;padding:60px 24px;font-family:-apple-system,'PingFang SC','Microsoft YaHei',sans-serif;"
                + "background:#f5f6f8;color:#1f2329;text-align:center}"
                + "h1{font-size:18px;font-weight:600;margin:0 0 12px}"
                + "p{color:#646a73;font-size:14px;line-height:1.7;margin:0}"
                + "</style></head><body><h1>" + esc(title) + "</h1><p>" + esc(desc) + "</p></body></html>";
    }

    /**
     * 轻量 Markdown 渲染：只支持企业微信通知常用的标题、加粗、列表、引用、代码、链接、分隔线
     *
     * 安全前提：所有用户内容先用 {@link #esc(String)} 转义，之后才拼接标签，
     * 因此不会执行原始 HTML；链接只允许 http/https/站内路径。
     */
    private String renderMarkdown(String markdown) {
        String normalized = markdown.replace("\r\n", "\n").replace("\r", "\n");
        String[] lines = normalized.split("\n", -1);
        StringBuilder html = new StringBuilder(1024);
        boolean inList = false;
        for (String rawLine : lines) {
            String line = rawLine.trim();
            if (line.isEmpty()) {
                if (inList) {
                    html.append("</ul>");
                    inList = false;
                }
                continue;
            }
            if (line.startsWith("- ") || line.startsWith("* ")) {
                if (!inList) {
                    html.append("<ul>");
                    inList = true;
                }
                html.append("<li>").append(renderInline(line.substring(2))).append("</li>");
                continue;
            }
            if (inList) {
                html.append("</ul>");
                inList = false;
            }
            if (line.startsWith("### ")) {
                html.append("<h3>").append(renderInline(line.substring(4))).append("</h3>");
            } else if (line.startsWith("## ")) {
                html.append("<h2>").append(renderInline(line.substring(3))).append("</h2>");
            } else if (line.startsWith("# ")) {
                html.append("<h1>").append(renderInline(line.substring(2))).append("</h1>");
            } else if (line.startsWith("> ")) {
                html.append("<blockquote>").append(renderInline(line.substring(2))).append("</blockquote>");
            } else if ("---".equals(line) || "***".equals(line)) {
                html.append("<hr>");
            } else {
                html.append("<p>").append(renderInline(line)).append("</p>");
            }
        }
        if (inList) {
            html.append("</ul>");
        }
        return html.toString();
    }

    /**
     * 渲染行内 Markdown；输入已转义，输出只包含受控标签
     */
    private String renderInline(String text) {
        String result = esc(text);
        result = MD_CODE.matcher(result).replaceAll("<code>$1</code>");
        result = MD_STRONG.matcher(result).replaceAll("<strong>$1</strong>");
        Matcher matcher = MD_LINK.matcher(result);
        StringBuilder sb = new StringBuilder();
        while (matcher.find()) {
            String label = matcher.group(1);
            String url = matcher.group(2).trim();
            String replacement = isSafeUrl(url)
                    ? "<a href=\"" + url + "\" target=\"_blank\" rel=\"noopener\">" + label + "</a>"
                    : label;
            matcher.appendReplacement(sb, Matcher.quoteReplacement(replacement));
        }
        matcher.appendTail(sb);
        return sb.toString();
    }

    /**
     * 只允许 http/https 与站内路径，避免 javascript: 等危险协议
     */
    private boolean isSafeUrl(String url) {
        String lower = url.trim().toLowerCase();
        return lower.startsWith("http://") || lower.startsWith("https://") || lower.startsWith("/");
    }

    /**
     * HTML 转义，避免通知标题/内容里的特殊字符破坏页面或造成 XSS
     */
    private String esc(String raw) {
        if (raw == null) {
            return "";
        }
        return raw.replace("&", "&amp;")
                .replace("<", "&lt;")
                .replace(">", "&gt;")
                .replace("\"", "&quot;")
                .replace("'", "&#39;");
    }

}