/* Copyright 2020 Tusky Contributors
 *
 * This file is a part of Tusky.
 *
 * This program 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.
 *
 * Tusky 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 Tusky; if not,
 * see <http://www.gnu.org/licenses>. */

package com.keylesspalace.tusky.json

import android.text.Spanned
import android.text.SpannedString
import androidx.core.text.HtmlCompat
import androidx.core.text.parseAsHtml
import androidx.core.text.toHtml
import com.google.gson.JsonDeserializationContext
import com.google.gson.JsonDeserializer
import com.google.gson.JsonElement
import com.google.gson.JsonParseException
import com.google.gson.JsonPrimitive
import com.google.gson.JsonSerializationContext
import com.google.gson.JsonSerializer
import com.keylesspalace.tusky.util.trimTrailingWhitespace
import org.jsoup.Jsoup
import java.lang.reflect.Type

class SpannedTypeAdapter : JsonDeserializer<Spanned>, JsonSerializer<Spanned?> {
    @Throws(JsonParseException::class)
    override fun deserialize(json: JsonElement, typeOfT: Type, context: JsonDeserializationContext): Spanned {
        return json.asString
            /* Mastodon uses 'white-space: pre-wrap;' so spaces are displayed as returned by the Api.
             * We can't use CSS so we replace spaces with non-breaking-spaces to emulate the behavior.
             */
            ?.replace("<br> ", "<br>&nbsp;")
            ?.replace("<br /> ", "<br />&nbsp;")
            ?.replace("<br/> ", "<br/>&nbsp;")
            ?.replace("  ", "&nbsp;&nbsp;")
            ?.let { html ->
                Jsoup.parse(html)
                    .apply {
                        select(".quote-inline").forEach { it.remove() }
                    }
                    .html()
            }
            ?.parseAsHtml()
            /* Html.fromHtml returns trailing whitespace if the html ends in a </p> tag, which
             * most status contents do, so it should be trimmed. */
            ?.trimTrailingWhitespace()
            ?: SpannedString("")
    }

    override fun serialize(src: Spanned?, typeOfSrc: Type, context: JsonSerializationContext): JsonElement {
        return JsonPrimitive(src!!.toHtml(HtmlCompat.TO_HTML_PARAGRAPH_LINES_INDIVIDUAL))
    }
}