LibreTube/app/src/main/java/com/github/libretube/util/TextUtils.kt

package com.github.libretube.util

import android.net.Uri
import java.net.URL
import java.time.format.DateTimeFormatter
import java.time.format.FormatStyle
import java.util.*
import kotlinx.datetime.LocalDate
import kotlinx.datetime.toJavaLocalDate

object TextUtils {
    /**
     * Separator used for descriptions
     */
    const val SEPARATOR = " • "

    /**
     * Regex to check for e-mails
     */
    const val EMAIL_REGEX = "^[A-Za-z](.*)([@]{1})(.{1,})(\\.)(.{1,})"

    /**
     * Reserved characters by unix which can not be used for file name.
     */
    const val RESERVED_CHARS = "?:\"*|/\\<>\u0000"

    /**
     * Check whether an Url is valid
     * @param url The url to test
     * @return Whether the URL is valid
     */
    fun validateUrl(url: String): Boolean {
        runCatching {
            URL(url).toURI()
            return true
        }
        return false
    }

    /**
     * Localize the date from a time string
     * @param date The date to parse
     * @param locale The locale to use, otherwise uses system default
     * return Localized date string
     */
    fun localizeDate(date: LocalDate, locale: Locale): String {
        val formatter = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(locale)
        return date.toJavaLocalDate().format(formatter)
    }

    /**
     * Get time in seconds from a youtube video link
     */
    fun getTimeInSeconds(uri: Uri): Long? {
        var time = uri.getQueryParameter("t") ?: return -1L

        var timeInSeconds: Long? = null

        // Find all spans containing hours, minutes or seconds
        listOf(Pair("h", 60 * 60), Pair("m", 60), Pair("s", 1)).forEach { (separator, timeFactor) ->
            if (time.contains(separator)) {
                time.substringBefore(separator).toLongOrNull()?.let {
                    timeInSeconds = (timeInSeconds ?: 0L) + it * timeFactor
                    time = time.substringAfter(separator)
                }
            }
        }

        // Time may not contain h, m or s. In that case, it is just a number of seconds
        if (timeInSeconds == null) {
            time.toLongOrNull()?.let {
                timeInSeconds = it
            }
        }

        return timeInSeconds
    }

    /**
     * Get video id if the link is a valid youtube video link
     */
    fun getVideoIdFromUri(link: String): String? {
        val uri = Uri.parse(link)

        if (link.contains("youtube.com")) {
            // the link may be in an unsupported format, so we should try/catch it
            return try {
                uri.getQueryParameter("v")
            } catch (e: Exception) {
                null
            }
        } else if (link.contains("youtu.be")) {
            return uri.lastPathSegment
        }

        return null
    }
}