import { NextResponse } from "next/server";
import { z } from "zod";

import { auth } from "@/app/(auth)/auth";
import { createAgentWorkflowPreviewImageBuffer } from "@/lib/agents/workflow-preview-images";
import { upsertMediaAsset } from "@/lib/db/queries";
import { isSiteAdminType } from "@/lib/middleware/admin";
import { uploadFile } from "@/lib/storage/service";
import { createLogger } from "@/lib/observability/logger";

const logger = createLogger("upload-api");
/**
 * 使用Sharp智能优化图片（保持原格式）
 * 策略：避免双重压缩，只在需要时优化
 * - 如果文件已经很小（<3MB），跳过优化（客户端已处理）
 * - 如果文件较大，使用MozJPEG/PNG优化算法进一步优化
 */
async function optimizeImage(buffer: Buffer, mimeType: string): Promise<Buffer> {
  try {
    const fileSizeMB = buffer.length / 1024 / 1024;
    const OPTIMIZE_THRESHOLD_MB = 3; // 3MB阈值：小于此值不优化（避免双重压缩）
    
    // ✅ 智能判断：如果文件已经很小，跳过优化（避免双重压缩）
    if (fileSizeMB < OPTIMIZE_THRESHOLD_MB) {
      logger.debug(`[Upload] 文件已较小(${fileSizeMB.toFixed(2)}MB < ${OPTIMIZE_THRESHOLD_MB}MB)，跳过优化，避免双重压缩`);
      return buffer;
    }
    
    const sharp = await import("sharp");
    const image = sharp.default(buffer);
    
    if (mimeType === 'image/jpeg' || mimeType === 'image/jpg') {
      // ✅ 使用MozJPEG编码器，高质量压缩
      // 注意：这里使用MozJPEG重新编码，使用更好的算法，而不是降低质量
      const optimized = await image
        .jpeg({
          quality: 92,              // 高质量（92%质量，画质优秀）
          mozjpeg: true,           // 使用MozJPEG编码器（比标准JPEG压缩率高15-25%，但质量更好）
          progressive: true,       // 渐进式JPEG，加载体验更好
          optimizeScans: true,    // 优化扫描
          trellisQuantisation: true, // 网格量化，更好的压缩
          overshootDeringing: true,  // 过冲去振铃，减少伪影
          optimizeCoding: true,   // 优化编码
        })
        .toBuffer();
      
      // 只有优化后文件明显更小才使用（避免不必要的处理）
      const reductionPercent = ((1 - optimized.length / buffer.length) * 100);
      if (reductionPercent > 5) {  // 只有减少超过5%才使用
        logger.debug(`[Upload] JPEG优化: ${buffer.length} → ${optimized.length} bytes (减少${reductionPercent.toFixed(1)}%)`);
        return optimized;
      } else {
        logger.debug(`[Upload] JPEG优化效果不明显(${reductionPercent.toFixed(1)}%)，使用原图`);
        return buffer;
      }
    } else if (mimeType === 'image/png') {
      // ✅ PNG优化压缩（无损优化）
      const metadata = await image.metadata();
      const optimized = await image
        .png({
          compressionLevel: 6,      // 压缩级别（0-9，6是平衡点）
          adaptiveFiltering: true,   // 自适应过滤，减少文件大小
          palette: !metadata.hasAlpha, // 无透明通道时使用调色板模式
          quality: 100,              // PNG质量（100=无损）
          effort: 6,                 // 压缩努力程度（0-10，6是平衡点）
        })
        .toBuffer();
      
      // 只有优化后文件明显更小才使用
      const reductionPercent = ((1 - optimized.length / buffer.length) * 100);
      if (reductionPercent > 5) {  // 只有减少超过5%才使用
        logger.debug(`[Upload] PNG优化: ${buffer.length} → ${optimized.length} bytes (减少${reductionPercent.toFixed(1)}%)`);
        return optimized;
      } else {
        logger.debug(`[Upload] PNG优化效果不明显(${reductionPercent.toFixed(1)}%)，使用原图`);
        return buffer;
      }
    }
    
    // 其他格式返回原图
    return buffer;
  } catch (error) {
    logger.error("[Upload] 图片优化失败，使用原图:", error);
    // 优化失败时返回原图，不影响上传流程
    return buffer;
  }
}

function toArrayBuffer(buffer: Buffer): ArrayBuffer {
  const view = new Uint8Array(buffer.buffer, buffer.byteOffset, buffer.byteLength);
  return view.slice().buffer;
}

// Use Blob instead of File since File is not available in Node.js environment
const FileSchema = z.object({
  file: z
    .instanceof(Blob)
    .refine((file) => file.size <= 50 * 1024 * 1024, {
      message: "File size should be less than 50MB",
    })
    // Update the file type based on the kind of files you want to accept
    .refine(
      (file) =>
        ["image/jpeg", "image/png", "image/webp", "image/svg+xml"].includes(
          file.type
        ),
      {
        message: "File type should be JPEG, PNG, WebP or SVG",
      }
    ),
});

export async function POST(request: Request) {
  logger.debug("[Upload API] Received upload request");
  
  const session = await auth();

  if (!session) {
    logger.debug("[Upload API] Unauthorized - no session");
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  if (request.body === null) {
    logger.debug("[Upload API] Request body is empty");
    return new Response("Request body is empty", { status: 400 });
  }

  try {
    const formData = await request.formData();
    const file = formData.get("file") as Blob;

    logger.debug("[Upload API] FormData received, file exists:", !!file);

    if (!file) {
      logger.debug("[Upload API] No file in FormData");
      return NextResponse.json({ error: "No file uploaded" }, { status: 400 });
    }

    const uploadPurpose = String(formData.get("purpose") || "");
    const isSvgUpload = file.type === "image/svg+xml";
    if (
      isSvgUpload &&
      (uploadPurpose !== "admin-svg-icon" || !isSiteAdminType(session.user.type))
    ) {
      return NextResponse.json(
        { error: "SVG uploads are only allowed for administrator icon settings" },
        { status: 403 }
      );
    }

    logger.debug("[Upload API] File info:", {
      type: file.type,
      size: file.size,
      sizeInMB: (file.size / 1024 / 1024).toFixed(2) + "MB"
    });

    const validatedFile = FileSchema.safeParse({ file });

    if (!validatedFile.success) {
      const errorMessage = validatedFile.error.errors
        .map((error) => error.message)
        .join(", ");

      logger.debug("[Upload API] Validation failed:", errorMessage);
      return NextResponse.json({ error: errorMessage }, { status: 400 });
    }

    // Get filename from formData since Blob doesn't have name property
    const filename = (formData.get("file") as File).name;
    logger.debug("[Upload API] Filename:", filename);
    
    const fileBuffer = await file.arrayBuffer();
    logger.debug("[Upload API] File buffer size:", fileBuffer.byteLength);

    try {
      if (uploadPurpose === "agent-workflow-preview" && file.type !== "image/svg+xml") {
        const preview = await createAgentWorkflowPreviewImageBuffer(Buffer.from(fileBuffer));
        const previewResult = await uploadFile(
          `${filename.replace(/\.[^.]+$/, "") || "agent-workflow-preview"}.webp`,
          toArrayBuffer(preview.buffer)
        );

        let assetId: string | null = null;
        try {
          const asset = await upsertMediaAsset({
            userId: session.user.id,
            mediaType: "image",
            sourceType: "agent_workflow_preview_upload",
            status: "ready",
            originalUrl: previewResult.url,
            previewUrl: previewResult.url,
            thumbnailUrl: previewResult.url,
            mimeType: "image/webp",
            width: preview.width,
            height: preview.height,
            displayName: filename,
            sourceTable: "agent_workflow_preview_upload",
            metadata: {
              pathname: previewResult.pathname,
              originalSize: fileBuffer.byteLength,
              previewSize: preview.buffer.length,
              purpose: uploadPurpose,
            },
          });
          assetId = asset?.id ?? null;
        } catch (assetError) {
          logger.warn("[Upload API] Failed to register workflow preview asset:", assetError);
        }

        return NextResponse.json({
          ...previewResult,
          url: previewResult.url,
          previewUrl: previewResult.url,
          thumbnailUrl: previewResult.url,
          originalUrl: previewResult.url,
          previewImageSourceUrl: previewResult.url,
          assetId,
          width: preview.width,
          height: preview.height,
          optimizedFor: uploadPurpose,
        });
      }

      // ✅ 使用Sharp优化图片（保持原格式）
      let optimizedBuffer: Buffer = Buffer.from(fileBuffer);
      
      // ✅ 优化原图（保持JPG/PNG格式）
      // WebP格式不优化（用于预览图，保持原样）
      const shouldOptimizeImage =
        uploadPurpose !== "canvas-upload" &&
        (file.type === 'image/jpeg' || file.type === 'image/jpg' || file.type === 'image/png');

      if (shouldOptimizeImage) {
        optimizedBuffer = await optimizeImage(optimizedBuffer, file.type);
      } else if (file.type === 'image/webp' || file.type === 'image/svg+xml') {
        // WebP/SVG 不优化；SVG 是矢量文件，交给前端按状态反色渲染。
        logger.debug(`[Upload] ${file.type}格式，跳过优化，直接上传`);
      } else if (uploadPurpose === "canvas-upload") {
        logger.debug("[Upload] Canvas upload, skip server-side image optimization for faster paste/drop");
      }
      
      // 将Buffer转换为ArrayBuffer用于上传
      const optimizedArrayBuffer = optimizedBuffer.buffer.slice(
        optimizedBuffer.byteOffset,
        optimizedBuffer.byteOffset + optimizedBuffer.byteLength
      ) as ArrayBuffer;
      
      // 使用统一的存储服务（支持数据库配置的 S3、环境变量 S3 或 Vercel Blob）
      // 使用优化后的buffer上传
      const data = await uploadFile(filename, optimizedArrayBuffer);

      let assetId: string | null = null;
      try {
        const asset = await upsertMediaAsset({
          userId: session.user.id,
          mediaType: "image",
          sourceType: "upload",
          status: "ready",
          originalUrl: data.url,
          previewUrl: data.url,
          thumbnailUrl: data.url,
          mimeType: data.contentType || file.type || null,
          displayName: filename,
          sourceTable: "upload",
          metadata: {
            pathname: data.pathname,
            size: optimizedBuffer.length,
          },
        });
        assetId = asset?.id ?? null;
      } catch (assetError) {
        logger.warn("[Upload API] Failed to register uploaded image as media asset:", assetError);
      }

      logger.debug("[Upload API] Upload successful:", data.url);
      return NextResponse.json({
        ...data,
        assetId,
      });
    } catch (_error) {
      logger.error("[Upload API] Upload failed:", _error);
      return NextResponse.json({ 
        error: "Upload failed", 
        details: _error instanceof Error ? _error.message : String(_error)
      }, { status: 500 });
    }
  } catch (_error) {
    logger.error("[Upload API] Request processing failed:", _error);
    return NextResponse.json(
      { 
        error: "Failed to process request",
        details: _error instanceof Error ? _error.message : String(_error)
      },
      { status: 500 }
    );
  }
}