amethyst/app/src/main/java/com/vitorpamplona/amethyst/ui/components/RichTextViewer.kt

package com.vitorpamplona.amethyst.ui.components

import android.util.Patterns
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.padding
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.livedata.observeAsState
import androidx.compose.ui.ExperimentalComposeUiApi
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import com.google.accompanist.flowlayout.FlowRow
import com.vitorpamplona.amethyst.model.LocalCache
import com.vitorpamplona.amethyst.model.Note
import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
import java.net.MalformedURLException
import java.net.URISyntaxException
import java.net.URL
import java.util.regex.Pattern

val imageExtension = Pattern.compile("(.*/)*.+\\.(png|jpg|gif|bmp|jpeg|webp)$")
val videoExtension = Pattern.compile("(.*/)*.+\\.(mp4|avi|wmv|mpg|amv|webm)$")
val noProtocolUrlValidator = Pattern.compile("^[-a-zA-Z0-9@:%._\\+~#=]{1,256}\\.[a-zA-Z0-9()]{1,6}\\b(?:[-a-zA-Z0-9()@:%_\\+.~#?&//=]*)$")
val tagIndex = Pattern.compile("\\#\\[([0-9]*)\\]")

val mentionsPattern: Pattern = Pattern.compile("@([A-Za-z0-9_-]+)")
val hashTagsPattern: Pattern = Pattern.compile("#([A-Za-z0-9_-]+)")
val urlPattern: Pattern = Patterns.WEB_URL

fun isValidURL(url: String?): Boolean {
  return try {
    URL(url).toURI()
    true
  } catch (e: MalformedURLException) {
    false
  } catch (e: URISyntaxException) {
    false
  }
}

@OptIn(ExperimentalComposeUiApi::class)
@Composable
fun RichTextViewer(content: String, tags: List<List<String>>?, note: Note, accountViewModel: AccountViewModel) {
  Column(modifier = Modifier.padding(top = 5.dp)) {
    // FlowRow doesn't work well with paragraphs. So we need to split them
    content.split('\n').forEach { paragraph ->

      FlowRow() {
        paragraph.split(' ').forEach { word: String ->
          // Explicit URL
          val lnInvoice = LnInvoiceUtil.findInvoice(word)
          if (lnInvoice != null) {
            InvoicePreview(lnInvoice)
          } else if (isValidURL(word)) {
            val removedParamsFromUrl = word.split("?")[0].toLowerCase()
            if (imageExtension.matcher(removedParamsFromUrl).matches()) {
              ExtendedImageView(word)
            } else if (videoExtension.matcher(removedParamsFromUrl).matches()) {
              VideoView(word)
            } else {
              UrlPreview(word, word)
            }
          } else if (noProtocolUrlValidator.matcher(word).matches()) {
            UrlPreview("https://$word", word)
          } else if (tagIndex.matcher(word).matches() && tags != null) {
            TagLink(word, tags)
          } else {
            Text(text = "$word ")
          }
        }
      }

    }
  }
}

@Composable
fun TagLink(word: String, tags: List<List<String>>) {
  val matcher = tagIndex.matcher(word)

  val index = try {
    matcher.find()
    matcher.group(1).toInt()
  } catch (e: Exception) {
    println("Couldn't link tag ${word}")
    null
  }

  if (index == null) {
    return Text(text = "$word ")
  }

  if (index > 0 && index < tags.size) {
    if (tags[index][0] == "p") {
      val user = LocalCache.users[tags[index][1]]
      if (user != null) {
        val innerUserState by user.live.observeAsState()
        Text(
          "${innerUserState?.user?.toBestDisplayName()}"
        )
      }
    } else if (tags[index][0] == "e") {
      val note = LocalCache.notes[tags[index][1]]
      if (note != null) {
        val innerNoteState by note.live.observeAsState()
        Text(
          "${innerNoteState?.note?.idDisplayHex}"
        )
      }
    } else
      Text(text = "$word ")
  }
}