ariane/app/src/main/java/oppen/ariane/ui/GemtextAdapter.kt

package oppen.ariane.ui

import android.annotation.SuppressLint
import android.net.Uri
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.recyclerview.widget.RecyclerView
import kotlinx.android.synthetic.main.gemtext_code_block.view.*
import kotlinx.android.synthetic.main.gemtext_image_link.view.*
import kotlinx.android.synthetic.main.gemtext_link.view.gemtext_text_link
import kotlinx.android.synthetic.main.gemtext_text.view.gemtext_text_textview
import oppen.ariane.R
import oppen.endsWithImage
import oppen.visible
import java.net.URI

class GemtextAdapter(val onLink: (adapter: GemtextAdapter, link: URI, longTap: Boolean, adapterPosition: Int, view: View?) -> Unit): RecyclerView.Adapter<GemtextAdapter.ViewHolder>() {

    var lines = mutableListOf<String>()
    var inlineImages = HashMap<Int, Uri>()

    private val typeText = 0
    private val typeH1 = 1
    private val typeH2 = 2
    private val typeH3 = 3
    private val typeListItem = 4
    private val typeImageLink = 5
    private val typeLink = 6
    private val typeCodeBlock = 7
    private val typeQuote = 8

    sealed class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView){
        class Text(itemView: View): ViewHolder(itemView)
        class H1(itemView: View): ViewHolder(itemView)
        class H2(itemView: View): ViewHolder(itemView)
        class H3(itemView: View): ViewHolder(itemView)
        class ListItem(itemView: View): ViewHolder(itemView)
        class ImageLink(itemView: View): ViewHolder(itemView)
        class Link(itemView: View): ViewHolder(itemView)
        class Code(itemView: View): ViewHolder(itemView)
        class Quote(itemView: View): ViewHolder(itemView)
    }

    fun render(lines: List<String>){
        this.inlineImages.clear()
        this.lines.clear()
        this.lines.addAll(lines)
        notifyDataSetChanged()
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        return when(viewType){
            typeText -> ViewHolder.Text(LayoutInflater.from(parent.context).inflate(R.layout.gemtext_text, parent, false))
            typeH1 -> ViewHolder.H1(LayoutInflater.from(parent.context).inflate(R.layout.gemtext_h1, parent, false))
            typeH2 -> ViewHolder.H2(LayoutInflater.from(parent.context).inflate(R.layout.gemtext_h2, parent, false))
            typeH3 -> ViewHolder.H3(LayoutInflater.from(parent.context).inflate(R.layout.gemtext_h3, parent, false))
            typeListItem -> ViewHolder.ListItem(LayoutInflater.from(parent.context).inflate(R.layout.gemtext_text, parent, false))
            typeImageLink -> ViewHolder.ImageLink(LayoutInflater.from(parent.context).inflate(R.layout.gemtext_image_link, parent, false))
            typeLink -> ViewHolder.Link(LayoutInflater.from(parent.context).inflate(R.layout.gemtext_link, parent, false))
            typeCodeBlock-> ViewHolder.Code(LayoutInflater.from(parent.context).inflate(R.layout.gemtext_code_block, parent, false))
            typeQuote -> ViewHolder.Quote(LayoutInflater.from(parent.context).inflate(R.layout.gemtext_quote, parent, false))
            else -> ViewHolder.Text(LayoutInflater.from(parent.context).inflate(R.layout.gemtext_text, parent, false))
        }
    }

    override fun getItemViewType(position: Int): Int {
        val line = lines[position]
        return when {
            line.startsWith("```") -> typeCodeBlock
            line.startsWith("###") -> typeH3
            line.startsWith("##") -> typeH2
            line.startsWith("#") -> typeH1
            line.startsWith("*") -> typeListItem
            line.startsWith("=>") && getLink(line).endsWithImage() -> typeImageLink
            line.startsWith("=>") -> typeLink
            line.startsWith(">") -> typeQuote
            else -> typeText
        }
    }

    override fun getItemCount(): Int = lines.size

    @SuppressLint("SetTextI18n")
    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val line = lines[position]

        when(holder){
            is ViewHolder.Text -> holder.itemView.gemtext_text_textview.text = line
            is ViewHolder.Code-> holder.itemView.gemtext_text_monospace_textview.text = line.substring(3)
            is ViewHolder.Quote-> holder.itemView.gemtext_text_monospace_textview.text = line.substring(1).trim()
            is ViewHolder.H1 -> {
                when {
                    line.length > 2 -> holder.itemView.gemtext_text_textview.text = line.substring(2).trim()
                    else -> holder.itemView.gemtext_text_textview.text = ""
                }
            }
            is ViewHolder.H2 -> {
                when {
                    line.length > 3 -> holder.itemView.gemtext_text_textview.text = line.substring(3).trim()
                    else -> holder.itemView.gemtext_text_textview.text = ""
                }
            }
            is ViewHolder.H3 -> {
                when {
                    line.length > 4 -> holder.itemView.gemtext_text_textview.text = line.substring(4).trim()
                    else -> holder.itemView.gemtext_text_textview.text = ""
                }
            }
            is ViewHolder.ListItem -> holder.itemView.gemtext_text_textview.text = "• ${line.substring(1)}".trim()
            is ViewHolder.Link -> {
                val linkParts = line.substring(2).trim().split("\\s+".toRegex(), 2)
                var linkName = linkParts[0]
                if(linkParts.size > 1) {
                    linkName = linkParts[1]
                }
                val displayText = linkName
                holder.itemView.gemtext_text_link.text = displayText
                holder.itemView.gemtext_text_link.paint.isUnderlineText = true
                holder.itemView.gemtext_text_link.setOnClickListener {
                    val uri = getUri(lines[holder.adapterPosition])
                    println("User clicked link: $uri")
                    onLink(this, uri, false, holder.adapterPosition, null)

                }
                holder.itemView.gemtext_text_link.setOnLongClickListener {view ->
                    val uri = getUri(lines[holder.adapterPosition])
                    println("User long-clicked link: $uri")
                    onLink(this, uri, true, holder.adapterPosition, view)
                    true
                }
            }
            is ViewHolder.ImageLink -> {
                //todo - extract, largely duplicate of above
                val linkParts = line.substring(2).trim().split("\\s+".toRegex(), 2)
                var linkName = linkParts[0]
                if(linkParts.size > 1) {
                    linkName = linkParts[1]
                }
                val displayText = linkName
                holder.itemView.gemtext_text_link.text = displayText
                holder.itemView.gemtext_text_link.paint.isUnderlineText = true
                holder.itemView.gemtext_text_link.setOnClickListener {
                    val uri = getUri(lines[holder.adapterPosition])
                    println("User clicked link: $uri")
                    onLink(this, uri, false, holder.adapterPosition, null)

                }
                holder.itemView.gemtext_text_link.setOnLongClickListener {view ->
                    val uri = getUri(lines[holder.adapterPosition])
                    println("User long-clicked link: $uri")
                    onLink(this, uri, true, holder.adapterPosition, view)
                    true
                }

                if(inlineImages.containsKey(position)){
                    holder.itemView.gemtext_inline_image.visible(true)
                    holder.itemView.gemtext_inline_image.setImageURI(inlineImages[position])
                }else{
                    holder.itemView.gemtext_inline_image.visible(false)
                }
            }
        }
    }

    private fun getLink(line: String): String{
        val linkParts = line.substring(2).trim().split("\\s+".toRegex(), 2)
        return linkParts[0]
    }

    private fun getUri(linkLine: String): URI{
        val linkParts = linkLine.substring(2).trim().split("\\s+".toRegex(), 2)
        return URI.create(linkParts.first())
    }

    fun inferTitle(): String? {
        lines.forEach { line ->
            if(line.startsWith("#")) return line.replace("#", "").trim()
        }

        return null
    }

    fun loadImage(position: Int, cacheUri: Uri){
        inlineImages[position] = cacheUri
        notifyItemChanged(position)
    }
}