import { NextRequest, NextResponse } from "next/server";
import { auth } from "@/app/(auth)/auth";
import { generateText } from "ai";
import { getEnabledAiModelsWithProvider } from "@/lib/db/queries";
import { getLanguageModelById } from "@/lib/ai/dynamic-provider";

export async function POST(request: NextRequest) {
  console.log("[Auto-title] API called");
  
  try {
    const session = await auth();
    if (!session?.user?.id) {
      console.log("[Auto-title] Unauthorized");
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }

    const { imageUrl } = await request.json();
    console.log("[Auto-title] Image URL:", imageUrl);

    if (!imageUrl) {
      return NextResponse.json({ error: "Image URL is required" }, { status: 400 });
    }

    // 从数据库获取支持视觉的模型（优先使用 supportsVision）
    const modelsData = await getEnabledAiModelsWithProvider();
    console.log("[Auto-title] Available models count:", modelsData.length);
    console.log("[Auto-title] All model IDs:", modelsData.map(m => m.model.modelId));
    
    let visionModelData = modelsData.find(m => m.model.supportsVision);
    if (!visionModelData) {
      // 兼容旧配置：根据模型名称兜底匹配
      visionModelData = modelsData.find(m => {
        const id = m.model.modelId?.toLowerCase() || '';
        const name = m.model.displayName?.toLowerCase() || '';
        return id.includes('qwen-vl') || 
               id.includes('qwen3-vl') ||
               id.includes('qwen2.5-vl') ||
               id.includes('vision') ||
               name.includes('vl') ||
               name.includes('视觉');
      });
    }
    
    console.log("[Auto-title] Found vision model:", visionModelData?.model.modelId, visionModelData?.model.displayName);

    if (!visionModelData) {
      console.log("[Auto-title] No vision model found, using default title");
      return NextResponse.json({ title: "未命名画布" });
    }

    const visionModel = visionModelData.model;
    const model = await getLanguageModelById(visionModel.id);
    if (!model) {
      console.log("[Auto-title] Failed to load vision model");
      return NextResponse.json({ title: "未命名画布" });
    }

    // 构造 Prompt
    const prompt = "请用2-4个字概括这张图片的主体内容，作为文件标题。直接返回标题，不要包含任何标点符号或其他文字。";

    const { text } = await generateText({
      model,
      messages: [
        {
          role: 'user',
          content: [
            { type: 'text', text: prompt },
            { type: 'image', image: imageUrl },
          ],
        },
      ],
      temperature: 0.2,
      maxTokens: 50,
    });

    let title = (text || "").trim();
    title = title.replace(/[\s\p{P}\p{S}]+/gu, "");
    if (title.length > 4) title = title.slice(0, 4);
    if (title.length < 2) title = "新画布";
    console.log("[Auto-title] Generated title:", title);
    return NextResponse.json({ title });

  } catch (error) {
    console.error("[Auto-title] Error:", error);
    // 失败时返回默认标题，不报错中断流程
    return NextResponse.json({ title: "新画布" });
  }
}