package com.yunhai.cms.theme;

import java.util.List;
import java.util.function.Predicate;

/**
 * 主题包规范校验（W1 重构点，方案 §5.5：校验语义收敛于本类，Registry 与 PackageService 共用，
 * 杜绝两套校验漂移）。原 ThemeRegistry.validate 的规则原文平移：
 * specVersion=1、name 规范、name=目录名、必备模板（home/list/detail/single）、
 * fragments/head.html、param 规范、screenshot 存在。
 * existsFn 判定资源存在：classpath 包用 ClassPathResource、外部包用 Files.exists（§5.4 步骤 1）。
 */
public final class ThemePackageValidator {

    private ThemePackageValidator() {
    }

    /** 校验不通过抛 IllegalArgumentException（bad package 语义，Registry 剔除 + log.warn） */
    public static void validate(ThemeInfo info, String dirName, Predicate<String> existsFn) {
        if (info == null) {
            throw new IllegalArgumentException("清单为空");
        }
        if (info.getSpecVersion() == null || info.getSpecVersion() != 1) {
            throw new IllegalArgumentException("specVersion 必须为 1");
        }
        if (!ThemeRegistry.isValidName(info.getName())) {
            throw new IllegalArgumentException("name 缺失或不符合命名规范：" + info.getName());
        }
        if (!info.getName().equals(dirName)) {
            throw new IllegalArgumentException("name 与目录名不一致：" + dirName + " != " + info.getName());
        }
        for (String template : ThemeRegistry.requiredTemplates()) {
            if (!existsFn.test(template)) {
                throw new IllegalArgumentException("缺必备模板 " + template);
            }
        }
        // fragments/ 目录存在性以 head.html 片段代替（jar 内目录项不可靠）
        if (!existsFn.test("fragments/head.html")) {
            throw new IllegalArgumentException("缺 fragments/head.html 公共片段");
        }
        validateParams(info);
        String shot = info.screenshotPath();
        if (!existsFn.test(shot)) {
            throw new IllegalArgumentException("声明的 screenshot 不存在：" + shot);
        }
    }

    /** param 规范（key/类型/重复/cssVar 仅 color/select 必带 options）；不合法抛 IllegalArgumentException */
    public static void validateParams(ThemeInfo info) {
        List<ThemeParam> params = info.getParams();
        List<String> seen = new java.util.ArrayList<>();
        for (ThemeParam p : params) {
            if (p.getKey() == null || !ThemeParam.KEY_PATTERN.matcher(p.getKey()).matches()) {
                throw new IllegalArgumentException("param key 非法：" + p.getKey());
            }
            if (seen.contains(p.getKey())) {
                throw new IllegalArgumentException("param key 重复：" + p.getKey());
            }
            seen.add(p.getKey());
            String type = p.getType();
            boolean knownType = ThemeParam.TYPE_COLOR.equals(type) || ThemeParam.TYPE_IMAGE.equals(type)
                    || ThemeParam.TYPE_SELECT.equals(type) || ThemeParam.TYPE_TEXT.equals(type);
            if (!knownType) {
                throw new IllegalArgumentException("param " + p.getKey() + " 类型非法：" + type);
            }
            if (p.getCssVar() != null && !p.getCssVar().isEmpty() && !ThemeParam.TYPE_COLOR.equals(type)) {
                throw new IllegalArgumentException("cssVar 仅允许 color 类型参数：" + p.getKey());
            }
            if (ThemeParam.TYPE_SELECT.equals(type)
                    && (p.getOptions() == null || p.getOptions().isEmpty())) {
                throw new IllegalArgumentException("select 参数缺 options：" + p.getKey());
            }
        }
    }
}