package com.yunhai.flowcenter.controller.open;

import com.yunhai.flowcenter.entity.FlwInstance;
import com.yunhai.flowcenter.model.FlowModels;
import com.yunhai.flowcenter.repository.FlwDefRepository;
import com.yunhai.flowcenter.repository.FlwInstanceRepository;
import com.yunhai.flowcenter.service.DiagramImageService;
import com.yunhai.flowcenter.service.DiagramTokenService;
import com.yunhai.flowcenter.service.FlowDiagramService;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
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;

/**
 * 免签图片流端点（/open/flow/**，用户拍板 2026-09-16，"CAS 验证码式"嵌入）。
 * <p>
 * 故意不落 /api/**（CAS 会话）也不落 /oapi/**（app-sign）：&lt;img src&gt; 两者都带不了鉴权头；
 * 免签资格由 10 分钟短时 token 承担（DiagramTokenService，token 由 app-sign 的
 * GET /oapi/flow/diagram/url 签发）。token 分发点之外，本端点不接受任何业务参数直接定位——
 * 免签面收窄到"只认 token"，定位与可见性全在签发侧（OapiFlowService.diagramUrl）完成。
 */
@Slf4j
@RestController
@RequestMapping("/open/flow")
@RequiredArgsConstructor
public class OpenDiagramImageController {

    private final DiagramTokenService tokenService;
    private final DiagramImageService imageService;
    private final FlwInstanceRepository instanceRepository;
    private final FlwDefRepository defRepository;
    private final FlowDiagramService diagramService;

    @GetMapping("/diagram/img")
    public ResponseEntity<byte[]> diagramImg(@RequestParam("token") String token) {
        DiagramTokenService.TokenEntry entry = tokenService.resolve(token);
        if (entry == null) {
            return ResponseEntity.status(HttpStatus.NOT_FOUND)
                    .contentType(MediaType.TEXT_PLAIN)
                    .body("流程图已过期，请刷新页面重新获取".getBytes());
        }
        // 办件口径：节点带运行时状态（token 已收 schId，出图前再二次比对防漂移）
        if (entry.getInstanceId() != null) {
            FlwInstance instance = instanceRepository.findById(entry.getInstanceId()).orElse(null);
            if (instance == null || !entry.getSchId().equals(instance.getSchId())) {
                return ResponseEntity.status(HttpStatus.NOT_FOUND)
                        .contentType(MediaType.TEXT_PLAIN)
                        .body("办件不存在".getBytes());
            }
            return png(diagramService.byInstance(instance, entry.getMode()));
        }
        // 定义口径（flowGuid 预览）
        return defRepository.findById(entry.getDefId())
                .map(def -> entry.getSchId().equals(def.getSchId())
                        ? png(diagramService.build(def, null, entry.getMode()))
                        : notFound("流程不存在"))
                .orElseGet(() -> notFound("流程不存在"));
    }

    private ResponseEntity<byte[]> png(FlowModels.DiagramVo vo) {
        return ResponseEntity.ok()
                .contentType(MediaType.IMAGE_PNG)
                .cacheControl(org.springframework.http.CacheControl.noStore())
                .body(imageService.renderPng(vo));
    }

    private ResponseEntity<byte[]> notFound(String msg) {
        return ResponseEntity.status(HttpStatus.NOT_FOUND)
                .contentType(MediaType.TEXT_PLAIN)
                .body(msg.getBytes());
    }
}