ariane/app/src/main/java/oppen/tva/io/GeminiDatasource.kt

package oppen.tva.io

import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.launch
import java.io.*
import java.net.URI
import java.security.SecureRandom
import javax.net.ssl.*

const val GEMINI_SCHEME = "gemini"

class GeminiDatasource: Datasource{

    private var last: URI? = null
    override fun request(uri: URI, onUpdate: (state: TvaState) -> Unit) {

        //Any inputted uri starting with a colon is an app-specific command, eg. :prefs :settings
        if(uri.toString().startsWith(":")){
            onUpdate(TvaState.AppQuery(uri))
            return
        }

        when (uri.scheme) {
            GEMINI_SCHEME -> {

                val cached = RuntimeCache.get(uri)
                if(cached != null){
                    last = uri
                    onUpdate(TvaState.ResponseGemtext(uri, cached.first, cached.second))
                    return
                }else{
                    onUpdate(TvaState.Requesting(uri))

                    GlobalScope.launch {
                        geminiRequest(uri, onUpdate)
                    }
                }
            }
            else -> {
                val address = uri.toString()
                val parsedUri = when {
                    address.startsWith("//") -> {
                        //just missing protocol
                        URI.create("gemini:$address")
                    }
                    address.startsWith("/") -> {
                        //internal navigation
                        val internalNav = "gemini://${last?.host}$address"
                        URI.create(internalNav)
                    }
                    !address.contains("://") -> {
                        //looks like a relative link
                        val lastAddress = last.toString()
                        val relAddress = "${lastAddress.substring(0, lastAddress.lastIndexOf("/") + 1)}$address"
                        URI.create(relAddress)
                    }
                    else -> {
                        onUpdate(TvaState.NotGeminiRequest(uri))
                        return
                    }
                }

                val cached = RuntimeCache.get(parsedUri)
                if(cached != null){
                    last = parsedUri
                    onUpdate(TvaState.ResponseGemtext(parsedUri, cached.first, cached.second))
                }else{
                    request(parsedUri, onUpdate)
                }
            }
        }
    }

    /**
     *
     * This was largely copied from https://framagit.org/waweic/gemini-client/-/blob/master/app/src/main/java/rocks/ism/decentral/geminiclient/GeminiConnection.kt
     *
     */
    private fun geminiRequest(uri: URI, onUpdate: (state: TvaState) -> Unit){
        last = uri
        val port = if(uri.port == -1) 1965 else uri.port

        val sslContext = SSLContext.getInstance("TLSv1.2")
        sslContext.init(null, DummyTrustManager.get(), SecureRandom())

        val factory: SSLSocketFactory = sslContext.socketFactory
        val socket: SSLSocket = factory.createSocket(uri.host, port) as SSLSocket
        socket.enabledProtocols = arrayOf("TLSv1.2")

        socket.startHandshake()

        // OUT >>>>>>>>>>>>>>>>>>>>>>>>>>
        val outputStreamWriter = OutputStreamWriter(socket.outputStream)
        val bufferedWriter = BufferedWriter(outputStreamWriter)
        val outWriter = PrintWriter(bufferedWriter)

        outWriter.print(uri.toString() + "\r\n")
        outWriter.flush()

        if (outWriter.checkError()) {
            onUpdate(TvaState.ResponseError(GeminiResponse.Header(-1, "Print Writer Error")))
            outWriter.close()
            return
        }

        outputStreamWriter.close()
        bufferedWriter.close()
        outWriter.close()

        // IN <<<<<<<<<<<<<<<<<<<<<<<<<<<

        var headerLine = ""
        InputStreamReader(socket.inputStream).use{ streamReader ->
            BufferedReader(streamReader).use{ bufferedReader ->
                headerLine = bufferedReader.readLine()
            }
        }

        println("Tva: header: $headerLine")

        val header = GeminiResponse.parseHeader(headerLine)

        when {
            header.code != GeminiResponse.SUCCESS -> onUpdate(TvaState.ResponseError(header))
            header.meta == "text/gemini" -> getGemtext(socket, uri, header, onUpdate)
            header.meta.startsWith("text/") -> getString(socket, uri, header, onUpdate)
            else -> onUpdate(TvaState.ResponseError(header))
        }
    }

    private fun getGemtext(socket: SSLSocket, uri: URI, header: GeminiResponse.Header, onUpdate: (state: TvaState) -> Unit){

        val lines = mutableListOf<String>()

        socket.inputStream.reader().use { inputStreamReader ->
            BufferedReader(inputStreamReader).use { reader ->
                lines.addAll(reader.readLines())
            }
        }

        socket.close()

        val processed = GemtextHelper.findCodeBlocks(lines)
        RuntimeCache.put(uri, header, processed)
        onUpdate(TvaState.ResponseGemtext(uri, header, processed))
    }

    private fun getString(socket: SSLSocket, uri: URI, header: GeminiResponse.Header, onUpdate: (state: TvaState) -> Unit){
        val content = socket.inputStream.bufferedReader().use { reader -> reader.readText() }

        socket.close()
    }
}