/*
 * Copyright 2020-2022 Soren Stoutner <soren@stoutner.com>.
 *
 * This file is part of Privacy Browser Android <https://www.stoutner.com/privacy-browser-android>.
 *
 * Privacy Browser Android is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Privacy Browser Android is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Privacy Browser Android.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.stoutner.privacybrowser.helpers

import android.content.Context
import android.webkit.CookieManager

import com.stoutner.privacybrowser.R

import java.lang.Exception
import java.net.HttpURLConnection
import java.net.URL
import java.text.NumberFormat

object GetUrlSizeHelper {
    fun getUrl(context: Context, url: URL, userAgent: String, cookiesEnabled: Boolean): String {
        // Initialize the formatted file size string.
        var formattedFileSize = context.getString(R.string.unknown_size)

        // Because everything relating to requesting data from a webserver can throw errors, the entire section must catch exceptions.
        try {
            // Instantiate the proxy helper.
            val proxyHelper = ProxyHelper()

            // Get the current proxy.
            val proxy = proxyHelper.getCurrentProxy(context)

            // Open a connection to the URL.  No data is actually sent at this point.
            val httpUrlConnection = url.openConnection(proxy) as HttpURLConnection

            // Add the user agent to the header property.
            httpUrlConnection.setRequestProperty("User-Agent", userAgent)

            // Add the cookies if they are enabled.
            if (cookiesEnabled) {
                // Get the cookies for the current domain.
                val cookiesString = CookieManager.getInstance().getCookie(url.toString())

                // Only add the cookies if they are not null.
                if (cookiesString != null) {
                    // Add the cookies to the header property.
                    httpUrlConnection.setRequestProperty("Cookie", cookiesString)
                }
            }

            // The actual network request is in a `try` bracket so that `disconnect()` is run in the `finally` section even if an error is encountered in the main block.
            try {
                // Get the status code.  This initiates a network connection.
                val responseCode = httpUrlConnection.responseCode

                // Check the response code.
                if (responseCode >= 400) {  // The response code is an error message.
                    // Set the formatted file size to indicate a bad URL.
                    formattedFileSize = context.getString(R.string.invalid_url)
                } else {  // The response code is not an error message.
                    // Get the content length header.
                    val contentLengthString = httpUrlConnection.getHeaderField("Content-Length")

                    // Only process the content length string if it isn't null.
                    if (contentLengthString != null) {
                        // Convert the content length string to a long.
                        val fileSize = contentLengthString.toLong()

                        // Format the file size.
                        formattedFileSize = NumberFormat.getInstance().format(fileSize) + " " + context.getString(R.string.bytes)
                    }
                }
            } finally {
                // Disconnect the HTTP URL connection.
                httpUrlConnection.disconnect()
            }
        } catch (exception: Exception) {
            // Set the formatted file size to indicate a bad URL.
            formattedFileSize = context.getString(R.string.invalid_url)
        }

        // Return the formatted file size.
        return formattedFileSize
    }
}