import { client } from "$lib/server/nextcloud";
import { error } from "@sveltejs/kit";
import type { RequestHandler } from "./$types";
import mime from "mime-types";
import { env } from "$env/dynamic/private";

export const GET: RequestHandler = async ({ params, url }) => {
    const { path } = params;
    const width = url.searchParams.get("w");
    const height = url.searchParams.get("h");
    
    if (!path) {
        throw error(400, "Path is required");
    }

    try {
        let buffer: ArrayBuffer;
        let contentType: string;

        if (width || height) {
            // Use Nextcloud Preview API
            const baseUrl = env.NEXTCLOUD_URL?.endsWith("/") ? env.NEXTCLOUD_URL : `${env.NEXTCLOUD_URL}/`;
            
            let fullPath = path;
            if (env.NEXTCLOUD_BASE_DIR) {
                const baseDir = env.NEXTCLOUD_BASE_DIR.replace(/^\/+|\/+$/g, "");
                fullPath = baseDir ? `${baseDir}/${path}` : path;
            }

            const previewUrl = new URL(`${baseUrl}index.php/core/preview`);
            // Ensure leading slash for the file parameter
            const fileParam = fullPath.startsWith('/') ? fullPath : `/${fullPath}`;
            previewUrl.searchParams.set("file", fileParam);
            if (width) previewUrl.searchParams.set("x", width);
            if (height) previewUrl.searchParams.set("y", height);
            previewUrl.searchParams.set("forceIcon", "0");

            const auth = Buffer.from(`${env.NEXTCLOUD_USER}:${env.NEXTCLOUD_PASSWORD}`).toString("base64");
            
            console.log(`Fetching preview: ${previewUrl.toString()} for file: ${fullPath}`);

            try {
                const response = await fetch(previewUrl.toString(), {
                    headers: {
                        "Authorization": `Basic ${auth}`
                    }
                });

                if (response.ok) {
                    buffer = await response.arrayBuffer();
                    contentType = response.headers.get("Content-Type") || "image/png";
                    
                    return new Response(buffer, {
                        headers: {
                            "Content-Type": contentType,
                            "Cache-Control": "public, max-age=86400",
                            "Vary": "Accept-Encoding"
                        }
                    });
                } else {
                    console.warn(`Nextcloud preview failed (${response.status} ${response.statusText}) for ${fullPath}. Falling back to original.`);
                }
            } catch (fetchError) {
                console.error(`Fetch error during preview request for ${fullPath}:`, fetchError);
            }
        }

        // Fetch original via WebDAV (Fallback or no resize requested)
        console.log(`Fetching original file via WebDAV: /${path}`);
        const data = await client.getFileContents("/" + path);
        buffer = data as ArrayBuffer;
        contentType = mime.lookup(path) || "application/octet-stream";
        
        return new Response(buffer, {
            headers: {
                "Content-Type": contentType,
                "Cache-Control": "public, max-age=86400",
                "Vary": "Accept-Encoding"
            }
        });
    } catch (e) {
        console.error(`Error fetching asset from Nextcloud: ${path}`, e);
        throw error(404, "Asset not found");
    }
};