import { NextRequest, NextResponse } from "next/server";
import { auth } from "@/app/(auth)/auth";
import { uploadFile } from "@/lib/storage/service";
import { db } from "@/lib/db";
import { generatedImage } from "@/lib/db/schema";

/**
 * 压缩图片生成缩略图（使用 sharp）
 */
async function createThumbnail(buffer: Buffer, mimeType: string): Promise<Buffer> {
  try {
    const sharp = await import("sharp");
    
    // 创建缩略图（宽度 500px，高度按比例，质量 80%）
    const thumbnailBuffer = await sharp.default(buffer)
      .resize(500, null, {
        fit: "inside",
        withoutEnlargement: true,
      })
      .png({ quality: 80 }) // PNG格式保持透明背景
      .toBuffer();
    
    console.log(`[Resize] Thumbnail created, size: ${thumbnailBuffer.length} bytes (original: ${buffer.length} bytes)`);
    return thumbnailBuffer;
  } catch (error) {
    console.error("[Resize] Failed to create thumbnail:", error);
    // 如果失败，返回原图
    return buffer;
  }
}

/**
 * 将 base64 图片上传到 S3，返回缩略图和原图的 URL
 */
async function uploadBase64ToS3(base64Data: string, mimeType: string = "image/png"): Promise<{ thumbnail: string; original: string }> {
  try {
    // 解析 base64 数据
    const buffer = Buffer.from(base64Data, "base64");
    
    // 生成文件名
    const ext = mimeType.split("/")[1] || "png";
    const timestamp = Date.now();
    const randomStr = Math.random().toString(36).slice(2, 8);
    const thumbnailFilename = `resize-thumb-${timestamp}-${randomStr}.${ext}`;
    const originalFilename = `resize-orig-${timestamp}-${randomStr}.${ext}`;
    
    console.log(`[Resize] Original size: ${buffer.length} bytes`);
    
    // 生成缩略图
    const thumbnailBuffer = await createThumbnail(buffer, mimeType);
    
    // 转换为 ArrayBuffer
    const thumbnailArrayBuffer = thumbnailBuffer.buffer.slice(
      thumbnailBuffer.byteOffset, 
      thumbnailBuffer.byteOffset + thumbnailBuffer.byteLength
    ) as ArrayBuffer;
    const originalArrayBuffer = buffer.buffer.slice(
      buffer.byteOffset, 
      buffer.byteOffset + buffer.byteLength
    ) as ArrayBuffer;
    
    // 并行上传缩略图和原图到 S3
    console.log(`[Resize] Uploading thumbnail and original to S3...`);
    const [thumbnailResult, originalResult] = await Promise.all([
      uploadFile(thumbnailFilename, thumbnailArrayBuffer),
      uploadFile(originalFilename, originalArrayBuffer),
    ]);
    
    console.log(`[Resize] Uploaded to S3:`);
    console.log(`  - Thumbnail: ${thumbnailResult.url}`);
    console.log(`  - Original: ${originalResult.url}`);
    
    return {
      thumbnail: thumbnailResult.url,
      original: originalResult.url,
    };
  } catch (error) {
    console.error("[Resize] Failed to upload to S3:", error);
    throw new Error(`图片上传到存储桶失败: ${error instanceof Error ? error.message : "未知错误"}。请检查系统设置中的存储配置。`);
  }
}

/**
 * 尺寸调整API路由
 * 接收前端处理后的Base64图片，上传到S3并保存到数据库
 */
export async function POST(request: NextRequest) {
  try {
    // 0. 获取用户会话
    const session = await auth();
    if (!session?.user?.id) {
      return NextResponse.json(
        { error: "未授权，请先登录" },
        { status: 401 }
      );
    }

    const userId = session.user.id;

    // 1. 获取请求体
    const contentType = request.headers.get("content-type") || "";
    
    let imageBase64: string;
    let prompt = "尺寸调整处理";
    let chatId: string | null = null;
    let messageId: string | null = null;
    let canvasWidth: number;
    let canvasHeight: number;
    let mimeType = "image/png";
    
    if (contentType.includes("application/json")) {
      const body = await request.json();
      imageBase64 = body.image_base64;
      prompt = body.prompt || "尺寸调整处理";
      chatId = body.chatId || null;
      messageId = body.messageId || null;
      canvasWidth = body.canvasWidth;
      canvasHeight = body.canvasHeight;
      mimeType = body.mimeType || "image/png";
      
      if (!imageBase64) {
        return NextResponse.json(
          { error: "缺少image_base64参数" },
          { status: 400 }
        );
      }
      
      if (!canvasWidth || !canvasHeight) {
        return NextResponse.json(
          { error: "缺少canvasWidth或canvasHeight参数" },
          { status: 400 }
        );
      }
    } else {
      return NextResponse.json(
        { error: "不支持的Content-Type，请使用application/json" },
        { status: 400 }
      );
    }

    console.log(`[Resize API] 图片Base64长度: ${imageBase64.length} 字符`);
    console.log(`[Resize API] 画布尺寸: ${canvasWidth}x${canvasHeight}`);

    // 2. 上传处理后的图片到S3存储桶
    let thumbnailUrl: string;
    let originalUrl: string;
    
    try {
      const uploadResult = await uploadBase64ToS3(imageBase64, mimeType);
      thumbnailUrl = uploadResult.thumbnail;
      originalUrl = uploadResult.original;
      console.log(`[Resize] ✅ Images uploaded to S3 successfully`);
    } catch (uploadError) {
      console.error("[Resize] ❌ Failed to upload to S3:", uploadError);
      return NextResponse.json(
        { 
          error: "图片上传到存储桶失败", 
          detail: uploadError instanceof Error ? uploadError.message : "未知错误" 
        },
        { status: 500 }
      );
    }

    // 3. 保存图片记录到数据库（相册和生图记录）
    try {
      const [savedImage] = await db.insert(generatedImage).values({
        userId,
        chatId: chatId || null,
        messageId: messageId || null,
        thumbnailUrl,
        originalUrl,
        imageSize: `${canvasWidth}x${canvasHeight}`, // 使用实际尺寸
        prompt: prompt || "尺寸调整处理",
        modelId: "resize-1.0", // 标记为尺寸调整处理
      }).returning();
      console.log(`[Resize] ✅ 图片已保存到相册和生图记录，ID: ${savedImage.id}`);
    } catch (dbError) {
      console.error("[Resize] ❌ 保存到数据库失败:", dbError);
      // 数据库保存失败时仍然返回成功，但记录错误（图片已上传到S3，用户可以访问）
    }

    // 4. 返回结果（包含S3 URL和Base64，前端可以选择使用）
    return NextResponse.json({
      success: true,
      image_base64: imageBase64, // 保留Base64用于前端立即显示
      thumbnail_url: thumbnailUrl, // S3缩略图URL
      original_url: originalUrl, // S3原图URL
      canvas_width: canvasWidth,
      canvas_height: canvasHeight,
    });
  } catch (error) {
    console.error("[Resize API] 处理错误:", error);
    return NextResponse.json(
      { error: "服务器内部错误", detail: error instanceof Error ? error.message : "未知错误" },
      { status: 500 }
    );
  }
}