package com.yunhai.cms.controller.api;

import com.yunhai.cms.service.impl.ThemeService;
import com.yunhai.cms.theme.ThemeRegistry;
import lombok.RequiredArgsConstructor;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.http.CacheControl;
import org.springframework.http.MediaType;
import org.springframework.http.MediaTypeFactory;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;
import java.time.Duration;
import java.util.List;

/**
 * 主题管理接口（方案 §5.2，路径对齐 /api/{domain} 约定）：
 * /api/theme/list 主题列表；/api/theme/{name}/asset/** 主题资产代理
 * （screenshot 与预览资产共用，防穿越同 PortalAssetController，name 先过 Registry 白名单）。
 * 走 /api/* CAS 鉴权（现状边界）。
 */
@RestController
@RequestMapping("/api/theme")
@RequiredArgsConstructor
public class ThemeController {

    private static final Duration ASSET_CACHE = Duration.ofHours(1);

    private final ThemeService themeService;
    private final ThemeRegistry themeRegistry;

    @GetMapping("/list")
    public List<com.yunhai.cms.model.vo.ThemeVo> list() {
        return themeService.list();
    }

    @GetMapping("/{name}/asset/**")
    public ResponseEntity<Resource> asset(@PathVariable("name") String name,
                                          HttpServletRequest request) {
        if (!themeRegistry.contains(name)) {
            return ResponseEntity.notFound().build();
        }
        String path = extractRelativePath(request, name);
        if (path == null || path.isEmpty() || path.contains("..")) {
            return ResponseEntity.badRequest().build();
        }
        Resource resource = new ClassPathResource("templates/themes/" + name + "/assets/" + path);
        if (!resource.exists()) {
            return ResponseEntity.notFound().build();
        }
        MediaType mediaType = MediaTypeFactory.getMediaType(path)
                .orElse(MediaType.APPLICATION_OCTET_STREAM);
        return ResponseEntity.ok()
                .contentType(mediaType)
                .cacheControl(CacheControl.maxAge(ASSET_CACHE).cachePublic())
                .body(resource);
    }

    /**
     * 从请求 URI 截取 /asset/ 之后的相对路径（同 PortalAssetController：
     * 直接解析 URL-decode 后的 URI，兼容两种路径匹配器语义）。
     */
    private String extractRelativePath(HttpServletRequest request, String name) {
        String uri = request.getRequestURI();
        String prefix = request.getContextPath() + "/api/theme/" + name + "/asset/";
        int index = uri.indexOf(prefix);
        if (index < 0) {
            return null;
        }
        String relative = uri.substring(index + prefix.length());
        try {
            relative = java.net.URLDecoder.decode(relative, "UTF-8");
        } catch (java.io.UnsupportedEncodingException e) {
            return null;
        }
        return relative.replace('\\', '/');
    }
}