Add MessageParser helper class for parsing markdown and possibly others

app/src/main/java/chat/rocket/android/dagger/module/AppModule.kt

@@ -4,6 +4,7 @@ import android.app.Application
 import android.arch.persistence.room.Room
 import android.content.Context
 import android.content.SharedPreferences
+import android.graphics.Color
 import chat.rocket.android.BuildConfig
 import chat.rocket.android.app.RocketChatDatabase
 import chat.rocket.android.app.utils.CustomImageFormatConfigurator
@@ -11,16 +12,11 @@ import chat.rocket.android.authentication.infraestructure.MemoryTokenRepository
 import chat.rocket.android.authentication.infraestructure.SharedPreferencesMultiServerTokenRepository
 import chat.rocket.android.dagger.qualifier.ForFresco
 import chat.rocket.android.helper.FrescoAuthInterceptor
+import chat.rocket.android.helper.MessageParser
 import chat.rocket.android.infrastructure.LocalRepository
 import chat.rocket.android.infrastructure.SharedPrefsLocalRepository
-import chat.rocket.android.server.domain.ChatRoomsRepository
-import chat.rocket.android.server.domain.CurrentServerRepository
-import chat.rocket.android.server.domain.MultiServerTokenRepository
-import chat.rocket.android.server.domain.SettingsRepository
-import chat.rocket.android.server.infraestructure.MemoryChatRoomsRepository
-import chat.rocket.android.server.infraestructure.ServerDao
-import chat.rocket.android.server.infraestructure.SharedPreferencesSettingsRepository
-import chat.rocket.android.server.infraestructure.SharedPrefsCurrentServerRepository
+import chat.rocket.android.server.domain.*
+import chat.rocket.android.server.infraestructure.*
 import chat.rocket.android.util.AppJsonAdapterFactory
 import chat.rocket.android.util.TimberLogger
 import chat.rocket.common.util.PlatformLogger
@@ -38,7 +34,11 @@ import kotlinx.coroutines.experimental.Job
 import okhttp3.Interceptor
 import okhttp3.OkHttpClient
 import okhttp3.logging.HttpLoggingInterceptor
+import ru.noties.markwon.SpannableConfiguration
+import ru.noties.markwon.il.AsyncDrawableLoader
+import ru.noties.markwon.spans.SpannableTheme
 import timber.log.Timber
+import java.util.concurrent.Executors
 import javax.inject.Singleton
 
 @Module
@@ -196,4 +196,31 @@ class AppModule {
     fun provideMultiServerTokenRepository(repository: LocalRepository, moshi: Moshi): MultiServerTokenRepository {
         return SharedPreferencesMultiServerTokenRepository(repository, moshi)
     }
+
+    @Provides
+    @Singleton
+    fun provideMessageRepository(): MessagesRepository {
+        return MemoryMessagesRepository()
+    }
+
+    @Provides
+    @Singleton
+    fun provideConfiguration(context: Application, client: OkHttpClient): SpannableConfiguration {
+        return SpannableConfiguration.builder(context)
+                .asyncDrawableLoader(AsyncDrawableLoader.builder()
+                        .client(client)
+                        .executorService(Executors.newCachedThreadPool())
+                        .resources(context.resources)
+                        .build())
+                .theme(SpannableTheme.builder()
+                        .linkColor(Color.BLUE)
+                        .build())
+                .build()
+    }
+
+    @Provides
+    @Singleton
+    fun provideMessageParser(context: Application, configuration: SpannableConfiguration): MessageParser {
+        return MessageParser(context, configuration)
+    }
 }
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app/src/main/java/chat/rocket/android/helper/MessageParser.kt

+package chat.rocket.android.helper
+
+import android.app.Application
+import android.content.Context
+import android.graphics.Canvas
+import android.graphics.Color
+import android.graphics.Paint
+import android.graphics.Typeface
+import android.graphics.drawable.Drawable
+import android.text.Layout
+import android.text.Spanned
+import android.text.style.*
+import chat.rocket.android.R
+import chat.rocket.android.chatroom.viewmodel.MessageViewModel
+import chat.rocket.core.model.Url
+import org.commonmark.node.BlockQuote
+import ru.noties.markwon.Markwon
+import ru.noties.markwon.SpannableBuilder
+import ru.noties.markwon.SpannableConfiguration
+import ru.noties.markwon.renderer.SpannableMarkdownVisitor
+import javax.inject.Inject
+
+
+class MessageParser @Inject constructor(val context: Application, private val configuration: SpannableConfiguration) {
+
+    private val parser = Markwon.createParser()
+
+    fun renderMarkdown(text: String, quote: MessageViewModel?, urls: List<Url>): CharSequence {
+        val builder = SpannableBuilder()
+        var content: String = text
+
+        for (url in urls) {
+            content = content.replace(url.url, "[${url.url}](${url.url})")
+        }
+
+        val parentNode = parser.parse(toLenientMarkdown(content))
+        parentNode.accept(SpannableMarkdownVisitor(configuration, builder))
+        quote?.apply {
+            var quoteNode = parser.parse("> $sender $time")
+            parentNode.appendChild(quoteNode)
+            quoteNode.accept(QuoteMessageSenderVisitor(context, configuration, builder, sender.length))
+            quoteNode = parser.parse("> ${toLenientMarkdown(quote.getOriginalMessage())}")
+            quoteNode.accept(QuoteMessageBodyVisitor(context, configuration, builder))
+        }
+
+        return builder.text()
+    }
+
+    /**
+     * Convert to a lenient markdown consistent with Rocket.Chat web markdown instead of the official specs.
+     */
+    private fun toLenientMarkdown(text: String): String {
+        return text.trim().replace("\\*(.+)\\*".toRegex()) { "**${it.groupValues[1].trim()}**" }
+                .replace("\\~(.+)\\~".toRegex()) { "~~${it.groupValues[1].trim()}~~" }
+                .replace("\\_(.+)\\_".toRegex()) { "_${it.groupValues[1].trim()}_" }
+    }
+
+    class QuoteMessageSenderVisitor(private val context: Context,
+                                    configuration: SpannableConfiguration,
+                                    private val builder: SpannableBuilder,
+                                    private val senderNameLength: Int) : SpannableMarkdownVisitor(configuration, builder) {
+
+        override fun visit(blockQuote: BlockQuote) {
+
+            // mark current length
+            val length = builder.length()
+
+            // pass to super to apply markdown
+            super.visit(blockQuote)
+
+            val res = context.resources
+            val timeOffsetStart = length + senderNameLength + 1
+            builder.setSpan(QuoteMarginSpan(context.getDrawable(R.drawable.quote), 10), length, builder.length())
+            builder.setSpan(StyleSpan(Typeface.BOLD), length, length + senderNameLength)
+            builder.setSpan(ForegroundColorSpan(Color.BLACK), length, builder.length())
+            // set time spans
+            builder.setSpan(AbsoluteSizeSpan(res.getDimensionPixelSize(R.dimen.message_time_text_size)),
+                    timeOffsetStart, builder.length())
+            builder.setSpan(ForegroundColorSpan(res.getColor(R.color.darkGray)),
+                    timeOffsetStart, builder.length())
+        }
+    }
+
+    class QuoteMessageBodyVisitor(private val context: Context,
+                                  configuration: SpannableConfiguration,
+                                  private val builder: SpannableBuilder) : SpannableMarkdownVisitor(configuration, builder) {
+
+        override fun visit(blockQuote: BlockQuote) {
+
+            // mark current length
+            val length = builder.length()
+
+            // pass to super to apply markdown
+            super.visit(blockQuote)
+
+            builder.setSpan(QuoteMarginSpan(context.getDrawable(R.drawable.quote), 10), length, builder.length())
+        }
+    }
+
+    class QuoteMarginSpan : LeadingMarginSpan, LineHeightSpan {
+        private var mDrawable: Drawable? = null
+        private var mPad: Int = 0
+
+        constructor(b: Drawable) {
+            mDrawable = b
+        }
+
+        constructor(b: Drawable, pad: Int) {
+            mDrawable = b
+            mPad = pad
+        }
+
+        override fun getLeadingMargin(first: Boolean): Int {
+            return mDrawable!!.intrinsicWidth + mPad
+        }
+
+        override fun drawLeadingMargin(c: Canvas, p: Paint, x: Int, dir: Int,
+                                       top: Int, baseline: Int, bottom: Int,
+                                       text: CharSequence, start: Int, end: Int,
+                                       first: Boolean, layout: Layout) {
+            val st = (text as Spanned).getSpanStart(this)
+            val ix = x
+            val itop = layout.getLineTop(layout.getLineForOffset(st))
+            val dw = mDrawable!!.intrinsicWidth
+            val dh = mDrawable!!.intrinsicHeight
+            // XXX What to do about Paint?
+            mDrawable!!.setBounds(ix, itop, ix + dw, itop + layout.height)
+            mDrawable!!.draw(c)
+        }
+
+        override fun chooseHeight(text: CharSequence, start: Int, end: Int,
+                                  istartv: Int, v: Int,
+                                  fm: Paint.FontMetricsInt) {
+            if (end == (text as Spanned).getSpanEnd(this)) {
+                val ht = mDrawable!!.intrinsicHeight
+                var need = ht - (v + fm.descent - fm.ascent - istartv)
+                if (need > 0)
+                    fm.descent += need
+                need = ht - (v + fm.bottom - fm.top - istartv)
+                if (need > 0)
+                    fm.bottom += need
+            }
+        }
+    }
+}
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