import { Router, Request, Response } from "express";
import { StorageFactory } from "../services/StorageFactory";
import { asyncHandler } from "../middleware/errorHandler";

export const imagesRouter = Router();

/**
 * GET /api/images/:orgId/:projectId/:category/:filename
 * Serves images via presigned URLs (redirect approach)
 */
imagesRouter.get(
  "/images/:orgId/:projectId/:category/:filename",
  asyncHandler(async (req: Request, res: Response) => {
    const { orgId, projectId, category, filename } = req.params;

    // Validate category
    if (!["uploads", "generated", "references"].includes(category)) {
      return res.status(400).json({
        success: false,
        message: "Invalid category",
      });
    }

    const storageService = await StorageFactory.getInstance();

    try {
      // Check if file exists first (fast check)
      const exists = await storageService.fileExists(
        orgId,
        projectId,
        category as "uploads" | "generated" | "references",
        filename,
      );

      if (!exists) {
        return res.status(404).json({
          success: false,
          message: "File not found",
        });
      }

      // Determine content type from filename
      const ext = filename.toLowerCase().split(".").pop();
      const contentType =
        {
          png: "image/png",
          jpg: "image/jpeg",
          jpeg: "image/jpeg",
          gif: "image/gif",
          webp: "image/webp",
          svg: "image/svg+xml",
        }[ext || ""] || "application/octet-stream";

      // Set headers for optimal caching and performance
      res.setHeader("Content-Type", contentType);
      res.setHeader("Cache-Control", "public, max-age=86400, immutable"); // 24 hours + immutable
      res.setHeader("ETag", `"${orgId}-${projectId}-${filename}"`); // Simple ETag

      // Handle conditional requests (304 Not Modified)
      const ifNoneMatch = req.headers["if-none-match"];
      if (ifNoneMatch === `"${orgId}-${projectId}-${filename}"`) {
        return res.status(304).end(); // Not Modified
      }

      // Stream the file directly through our API (memory efficient)
      const fileStream = await storageService.streamFile(
        orgId,
        projectId,
        category as "uploads" | "generated" | "references",
        filename,
      );

      // Handle stream errors
      fileStream.on("error", (streamError) => {
        console.error("Stream error:", streamError);
        if (!res.headersSent) {
          res.status(500).json({
            success: false,
            message: "Error streaming file",
          });
        }
      });

      // Stream the file without loading into memory
      fileStream.pipe(res);
    } catch (error) {
      console.error("Failed to stream file:", error);
      return res.status(404).json({
        success: false,
        message: "File not found",
      });
    }
  }),
);

/**
 * GET /api/images/url/:orgId/:projectId/:category/:filename
 * Returns a presigned URL instead of redirecting
 */
imagesRouter.get(
  "/images/url/:orgId/:projectId/:category/:filename",
  asyncHandler(async (req: Request, res: Response) => {
    const { orgId, projectId, category, filename } = req.params;
    const { expiry = "3600" } = req.query; // Default 1 hour

    if (!["uploads", "generated", "references"].includes(category)) {
      return res.status(400).json({
        success: false,
        message: "Invalid category",
      });
    }

    const storageService = await StorageFactory.getInstance();

    try {
      const presignedUrl = await storageService.getPresignedDownloadUrl(
        orgId,
        projectId,
        category as "uploads" | "generated" | "references",
        filename,
        parseInt(expiry as string, 10),
      );

      return res.json({
        success: true,
        url: presignedUrl,
        expiresIn: parseInt(expiry as string, 10),
      });
    } catch (error) {
      console.error("Failed to generate presigned URL:", error);
      return res.status(404).json({
        success: false,
        message: "File not found or access denied",
      });
    }
  }),
);