import { NextResponse } from "next/server";
import { readFile } from "fs/promises";
import { existsSync } from "fs";
import { unlink } from "fs/promises";
import path from "path";
import db from "@/lib/db";

export async function GET(request, { params }) {
	const { fileId } = await params;

	try {
		// Get file info from database
		const file = db.prepare(`
			SELECT * FROM file_attachments WHERE file_id = ?
		`).get(parseInt(fileId));

		if (!file) {
			return NextResponse.json(
				{ error: "File not found" },
				{ status: 404 }
			);
		}

		// Construct the full file path
		const fullPath = path.join(process.cwd(), "public", file.file_path);

		// Check if file exists
		if (!existsSync(fullPath)) {
			return NextResponse.json(
				{ error: "File not found on disk" },
				{ status: 404 }
			);
		}

		// Read the file
		const fileBuffer = await readFile(fullPath);

		// Return the file with appropriate headers
		return new NextResponse(fileBuffer, {
			headers: {
				"Content-Type": file.mime_type || "application/octet-stream",
				"Content-Disposition": `attachment; filename="${encodeURIComponent(file.original_filename)}"`,
				"Content-Length": fileBuffer.length.toString(),
			},
		});

	} catch (error) {
		console.error("Error downloading file:", error);
		return NextResponse.json(
			{ error: "Failed to download file" },
			{ status: 500 }
		);
	}
}

export async function PUT(request, { params }) {
	const { fileId } = await params;
	try {
		const body = await request.json();
		const { description, original_filename } = body;

		// Validate input
		if (description !== undefined && typeof description !== 'string') {
			return NextResponse.json(
				{ error: "Description must be a string" },
				{ status: 400 }
			);
		}

		if (original_filename !== undefined && typeof original_filename !== 'string') {
			return NextResponse.json(
				{ error: "Original filename must be a string" },
				{ status: 400 }
			);
		}

		// Check if file exists
		const existingFile = db.prepare(`
			SELECT * FROM file_attachments WHERE file_id = ?
		`).get(parseInt(fileId));

		if (!existingFile) {
			return NextResponse.json(
				{ error: "File not found" },
				{ status: 404 }
			);
		}

		// Build update query
		const updates = [];
		const values = [];

		if (description !== undefined) {
			updates.push('description = ?');
			values.push(description);
		}

		if (original_filename !== undefined) {
			updates.push('original_filename = ?');
			values.push(original_filename);
		}

		if (updates.length === 0) {
			return NextResponse.json(
				{ error: "No valid fields to update" },
				{ status: 400 }
			);
		}

		values.push(parseInt(fileId));

		const result = db.prepare(`
			UPDATE file_attachments 
			SET ${updates.join(', ')}
			WHERE file_id = ?
		`).run(...values);

		if (result.changes === 0) {
			return NextResponse.json(
				{ error: "File not found" },
				{ status: 404 }
			);
		}

		// Get updated file
		const updatedFile = db.prepare(`
			SELECT * FROM file_attachments WHERE file_id = ?
		`).get(parseInt(fileId));

		return NextResponse.json(updatedFile);

	} catch (error) {
		console.error("Error updating file:", error);
		return NextResponse.json(
			{ error: "Failed to update file" },
			{ status: 500 }
		);
	}
}

export async function DELETE(request, { params }) {
	const { fileId } = await params;
	try {
		// Get file info from database
		const file = db.prepare(`
			SELECT * FROM file_attachments WHERE file_id = ?
		`).get(parseInt(fileId));

		if (!file) {
			return NextResponse.json(
				{ error: "File not found" },
				{ status: 404 }
			);
		}

		// Delete physical file
		try {
			const fullPath = path.join(process.cwd(), "public", file.file_path);
			await unlink(fullPath);
		} catch (fileError) {
			console.warn("Could not delete physical file:", fileError.message);
			// Continue with database deletion even if file doesn't exist
		}

		// Delete from database
		const result = db.prepare(`
			DELETE FROM file_attachments WHERE file_id = ?
		`).run(parseInt(fileId));

		if (result.changes === 0) {
			return NextResponse.json(
				{ error: "File not found" },
				{ status: 404 }
			);
		}

		return NextResponse.json({ success: true });

	} catch (error) {
		console.error("Error deleting file:", error);
		return NextResponse.json(
			{ error: "Failed to delete file" },
			{ status: 500 }
		);
	}
}