package com.keylesspalace.tusky.util
import android.text.Spannable
import android.text.Spanned
import android.text.style.CharacterStyle
import android.text.style.ForegroundColorSpan
import android.text.style.URLSpan
import java.util.regex.Pattern
import kotlin.math.max
/**
* @see
* Tag#HASHTAG_RE.
*/
private const val TAG_REGEX = "(?:^|[^/)A-Za-z0-9_])#([\\w_]*[\\p{Alpha}_][\\w_]*)"
/**
* @see
* Account#MENTION_RE
*/
private const val MENTION_REGEX = "(?:^|[^/[:word:]])@([a-z\\d_-]+(?:@[a-z0-9\\.\\-]+[a-z0-9]+)?)"
private const val HTTP_URL_REGEX = "(?:(^|\\b)http://[^\\s]+)"
private const val HTTPS_URL_REGEX = "(?:(^|\\b)https://[^\\s]+)"
/**
* Dump of android.util.Patterns.WEB_URL
*/
private val STRICT_WEB_URL_PATTERN = Pattern.compile("(((?:(?i:http|https|rtsp)://(?:(?:[a-zA-Z0-9\\\$\\-\\_\\.\\+\\!\\*\\'\\(\\)\\,\\;\\?\\&\\=]|(?:\\%[a-fA-F0-9]{2})){1,64}(?:\\:(?:[a-zA-Z0-9\\\$\\-\\_\\.\\+\\!\\*\\'\\(\\)\\,\\;\\?\\&\\=]|(?:\\%[a-fA-F0-9]{2})){1,25})?\\@)?)?(?:(([a-zA-Z0-9[ -\uD7FF豈-\uFDCFﷰ-\uFFEF\uD800\uDC00-\uD83F\uDFFD\uD840\uDC00-\uD87F\uDFFD\uD880\uDC00-\uD8BF\uDFFD\uD8C0\uDC00-\uD8FF\uDFFD\uD900\uDC00-\uD93F\uDFFD\uD940\uDC00-\uD97F\uDFFD\uD980\uDC00-\uD9BF\uDFFD\uD9C0\uDC00-\uD9FF\uDFFD\uDA00\uDC00-\uDA3F\uDFFD\uDA40\uDC00-\uDA7F\uDFFD\uDA80\uDC00-\uDABF\uDFFD\uDAC0\uDC00-\uDAFF\uDFFD\uDB00\uDC00-\uDB3F\uDFFD\uDB44\uDC00-\uDB7F\uDFFD&&[^ [ - ]\u2028\u2029 ]]](?:[a-zA-Z0-9[ -\uD7FF豈-\uFDCFﷰ-\uFFEF\uD800\uDC00-\uD83F\uDFFD\uD840\uDC00-\uD87F\uDFFD\uD880\uDC00-\uD8BF\uDFFD\uD8C0\uDC00-\uD8FF\uDFFD\uD900\uDC00-\uD93F\uDFFD\uD940\uDC00-\uD97F\uDFFD\uD980\uDC00-\uD9BF\uDFFD\uD9C0\uDC00-\uD9FF\uDFFD\uDA00\uDC00-\uDA3F\uDFFD\uDA40\uDC00-\uDA7F\uDFFD\uDA80\uDC00-\uDABF\uDFFD\uDAC0\uDC00-\uDAFF\uDFFD\uDB00\uDC00-\uDB3F\uDFFD\uDB44\uDC00-\uDB7F\uDFFD&&[^ [ - ]\u2028\u2029 ]]_\\-]{0,61}[a-zA-Z0-9[ -\uD7FF豈-\uFDCFﷰ-\uFFEF\uD800\uDC00-\uD83F\uDFFD\uD840\uDC00-\uD87F\uDFFD\uD880\uDC00-\uD8BF\uDFFD\uD8C0\uDC00-\uD8FF\uDFFD\uD900\uDC00-\uD93F\uDFFD\uD940\uDC00-\uD97F\uDFFD\uD980\uDC00-\uD9BF\uDFFD\uD9C0\uDC00-\uD9FF\uDFFD\uDA00\uDC00-\uDA3F\uDFFD\uDA40\uDC00-\uDA7F\uDFFD\uDA80\uDC00-\uDABF\uDFFD\uDAC0\uDC00-\uDAFF\uDFFD\uDB00\uDC00-\uDB3F\uDFFD\uDB44\uDC00-\uDB7F\uDFFD&&[^ [ - ]\u2028\u2029 ]]]){0,1}\\.)+(xn\\-\\-[\\w\\-]{0,58}\\w|[a-zA-Z[ -\uD7FF豈-\uFDCFﷰ-\uFFEF\uD800\uDC00-\uD83F\uDFFD\uD840\uDC00-\uD87F\uDFFD\uD880\uDC00-\uD8BF\uDFFD\uD8C0\uDC00-\uD8FF\uDFFD\uD900\uDC00-\uD93F\uDFFD\uD940\uDC00-\uD97F\uDFFD\uD980\uDC00-\uD9BF\uDFFD\uD9C0\uDC00-\uD9FF\uDFFD\uDA00\uDC00-\uDA3F\uDFFD\uDA40\uDC00-\uDA7F\uDFFD\uDA80\uDC00-\uDABF\uDFFD\uDAC0\uDC00-\uDAFF\uDFFD\uDB00\uDC00-\uDB3F\uDFFD\uDB44\uDC00-\uDB7F\uDFFD&&[^ [ - ]\u2028\u2029 ]]]{2,63})|((25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9])\\.(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9]|0)\\.(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9]|0)\\.(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[0-9]))))(?:\\:\\d{1,5})?)([/\\?](?:(?:[a-zA-Z0-9[ -\uD7FF豈-\uFDCFﷰ-\uFFEF\uD800\uDC00-\uD83F\uDFFD\uD840\uDC00-\uD87F\uDFFD\uD880\uDC00-\uD8BF\uDFFD\uD8C0\uDC00-\uD8FF\uDFFD\uD900\uDC00-\uD93F\uDFFD\uD940\uDC00-\uD97F\uDFFD\uD980\uDC00-\uD9BF\uDFFD\uD9C0\uDC00-\uD9FF\uDFFD\uDA00\uDC00-\uDA3F\uDFFD\uDA40\uDC00-\uDA7F\uDFFD\uDA80\uDC00-\uDABF\uDFFD\uDAC0\uDC00-\uDAFF\uDFFD\uDB00\uDC00-\uDB3F\uDFFD\uDB44\uDC00-\uDB7F\uDFFD&&[^ [ - ]\u2028\u2029 ]];/\\?:@&=#~\\-\\.\\+!\\*'\\(\\),_\\\$])|(?:%[a-fA-F0-9]{2}))*)?(?:\\b|\$|^))")
private val spanClasses = listOf(ForegroundColorSpan::class.java, URLSpan::class.java)
private val finders = mapOf(
FoundMatchType.HTTP_URL to PatternFinder(':', HTTP_URL_REGEX, 5, Character::isWhitespace),
FoundMatchType.HTTPS_URL to PatternFinder(':', HTTPS_URL_REGEX, 6, Character::isWhitespace),
FoundMatchType.TAG to PatternFinder('#', TAG_REGEX, 1, ::isValidForTagPrefix),
FoundMatchType.MENTION to PatternFinder('@', MENTION_REGEX, 1, Character::isWhitespace) // TODO: We also need a proper validator for mentions
)
private enum class FoundMatchType {
HTTP_URL,
HTTPS_URL,
TAG,
MENTION,
}
private class FindCharsResult {
lateinit var matchType: FoundMatchType
var start: Int = -1
var end: Int = -1
}
private class PatternFinder(val searchCharacter: Char, regex: String, val searchPrefixWidth: Int,
val prefixValidator: (Int) -> Boolean) {
val pattern: Pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE)
}
private fun clearSpans(text: Spannable, spanClass: Class) {
for(span in text.getSpans(0, text.length, spanClass)) {
text.removeSpan(span)
}
}
private fun findPattern(string: String, fromIndex: Int): FindCharsResult {
val result = FindCharsResult()
for (i in fromIndex..string.lastIndex) {
val c = string[i]
for (matchType in FoundMatchType.values()) {
val finder = finders[matchType]
if (finder!!.searchCharacter == c
&& ((i - fromIndex) < finder.searchPrefixWidth ||
finder.prefixValidator(string.codePointAt(i - finder.searchPrefixWidth)))) {
result.matchType = matchType
result.start = max(0, i - finder.searchPrefixWidth)
findEndOfPattern(string, result, finder.pattern)
if (result.start + finder.searchPrefixWidth <= i + 1 && // The found result is actually triggered by the correct search character
result.end >= result.start) { // ...and we actually found a valid result
return result
}
}
}
}
return result
}
private fun findEndOfPattern(string: String, result: FindCharsResult, pattern: Pattern) {
val matcher = pattern.matcher(string)
if (matcher.find(result.start)) {
// Once we have API level 26+, we can use named captures...
val end = matcher.end()
result.start = matcher.start()
when (result.matchType) {
FoundMatchType.TAG -> {
if (isValidForTagPrefix(string.codePointAt(result.start))) {
if (string[result.start] != '#' ||
(string[result.start] == '#' && string[result.start + 1] == '#')) {
++result.start
}
}
}
else -> {
if (Character.isWhitespace(string.codePointAt(result.start))) {
++result.start
}
}
}
when (result.matchType) {
FoundMatchType.HTTP_URL, FoundMatchType.HTTPS_URL -> {
// Preliminary url patterns are fast/permissive, now we'll do full validation
if (STRICT_WEB_URL_PATTERN.matcher(string.substring(result.start, end)).matches()) {
result.end = end
}
}
else -> result.end = end
}
}
}
private fun getSpan(matchType: FoundMatchType, string: String, colour: Int, start: Int, end: Int): CharacterStyle {
return when(matchType) {
FoundMatchType.HTTP_URL -> CustomURLSpan(string.substring(start, end))
FoundMatchType.HTTPS_URL -> CustomURLSpan(string.substring(start, end))
else -> ForegroundColorSpan(colour)
}
}
/** Takes text containing mentions and hashtags and urls and makes them the given colour. */
fun highlightSpans(text: Spannable, colour: Int) {
// Strip all existing colour spans.
for (spanClass in spanClasses) {
clearSpans(text, spanClass)
}
// Colour the mentions and hashtags.
val string = text.toString()
val length = text.length
var start = 0
var end = 0
while (end >= 0 && end < length && start >= 0) {
// Search for url first because it can contain the other characters
val found = findPattern(string, end)
start = found.start
end = found.end
if (start >= 0 && end > start) {
text.setSpan(getSpan(found.matchType, string, colour, start, end), start, end, Spanned.SPAN_INCLUSIVE_EXCLUSIVE)
start += finders[found.matchType]!!.searchPrefixWidth
}
}
}
private fun isWordCharacters(codePoint: Int): Boolean {
return (codePoint in 0x30..0x39) || // [0-9]
(codePoint in 0x41..0x5a) || // [A-Z]
(codePoint == 0x5f) || // _
(codePoint in 0x61..0x7a) // [a-z]
}
private fun isValidForTagPrefix(codePoint: Int): Boolean {
return !(isWordCharacters(codePoint) || // \w
(codePoint == 0x2f) || // /
(codePoint == 0x29)) // )
}