package net.torvald.terrarum

import com.badlogic.gdx.Gdx
import com.badlogic.gdx.files.FileHandle
import net.torvald.terrarum.utils.CSVFetcher
import net.torvald.terrarum.itemproperties.GameItem
import net.torvald.terrarum.itemproperties.ItemCodex
import net.torvald.terrarum.blockproperties.BlockCodex
import net.torvald.terrarum.langpack.Lang
import org.apache.commons.csv.CSVFormat
import org.apache.commons.csv.CSVParser
import java.io.File
import java.io.FileInputStream
import java.io.FileNotFoundException
import java.io.FileReader
import java.nio.file.FileSystems
import java.util.*
import javax.script.ScriptEngineManager
import javax.script.Invocable



/**
 * Modules Resource Manager
 *
 *
 * NOTE!!: Usage of Groovy is only temporary; if Kotlin's "JSR 223" is no longer experimental and
 *         is readily available, ditch that Groovy.
 *
 *
 * Created by minjaesong on 2017-04-17.
 */
object ModMgr {

    val groovyEngine = ScriptEngineManager().getEngineByExtension("groovy")!!
    val groovyInvocable = groovyEngine as Invocable


    data class ModuleMetadata(
            val order: Int,
            val isDir: Boolean,
            val properName: String,
            val description: String,
            val author: String,
            val entryPoint: String,
            val releaseDate: String,
            val version: String,
            val libraries: Array<String>
    ) {
        override fun toString() =
                "\tModule #$order -- $properName | $version | $author\n" +
                "\t$description | $releaseDate\n" +
                "\tEntry point: $entryPoint\n" +
                "\tExternal libraries: ${libraries.joinToString(", ")}"
    }
    const val modDir = "./assets/modules"

    val moduleInfo = HashMap<String, ModuleMetadata>()

    init {
        // load modules
        val loadOrderCSVparser = CSVParser.parse(
                FileSystems.getDefault().getPath("$modDir/LoadOrder.csv").toFile(),
                Charsets.UTF_8,
                CSVFormat.DEFAULT.withCommentMarker('#')
        )
        val loadOrder = loadOrderCSVparser.records
        loadOrderCSVparser.close()


        loadOrder.forEachIndexed { index, it ->
            val moduleName = it[0]
            println("[ModMgr] Loading module $moduleName")

            try {
                val modMetadata = Properties()
                modMetadata.load(FileInputStream("$modDir/$moduleName/metadata.properties"))

                val properName = modMetadata.getProperty("propername")
                val description = modMetadata.getProperty("description")
                val author = modMetadata.getProperty("author")
                val entryPoint = modMetadata.getProperty("entrypoint")
                val releaseDate = modMetadata.getProperty("releasedate")
                val version = modMetadata.getProperty("version")
                val libs = modMetadata.getProperty("libraries").split(';').toTypedArray()
                val isDir = FileSystems.getDefault().getPath("$modDir/$moduleName").toFile().isDirectory
                moduleInfo[moduleName] = ModuleMetadata(index, isDir, properName, description, author, entryPoint, releaseDate, version, libs)

                println(moduleInfo[moduleName])


                // run entry script in entry point
                if (entryPoint.isNotBlank()) {
                    val extension = entryPoint.split('.').last()
                    val engine = ScriptEngineManager().getEngineByExtension(extension)!!
                    val invocable = engine as Invocable
                    engine.eval(FileReader(getFile(moduleName, entryPoint)))
                    invocable.invokeFunction("invoke", moduleName)
                }


                println("[ModMgr] $moduleName loaded successfully")
            }
            catch (noSuchModule: FileNotFoundException) {
                System.err.println("[ModMgr] No such module: $moduleName, skipping...")
            }
        }


        // lists available engines
        /*val manager = ScriptEngineManager()
        val factories = manager.engineFactories
        for (f in factories) {
            println("engine name:" + f.engineName)
            println("engine version:" + f.engineVersion)
            println("language name:" + f.languageName)
            println("language version:" + f.languageVersion)
            println("names:" + f.names)
            println("mime:" + f.mimeTypes)
            println("extension:" + f.extensions)
            println("-----------------------------------------------")
        }*/
    }

    private fun checkExistence(module: String) {
        if (!moduleInfo.containsKey(module))
            throw FileNotFoundException("No such module: $module")
    }
    private fun String.sanitisePath() = if (this[0] == '/' || this[0] == '\\')
        this.substring(1..this.lastIndex)
    else this



    fun getPath(module: String, path: String): String {
        checkExistence(module)
        return "$modDir/$module/${path.sanitisePath()}"
    }
    fun getGdxFile(module: String, path: String): FileHandle {
        return Gdx.files.internal(getPath(module, path))
    }
    fun getFile(module: String, path: String): File {
        checkExistence(module)
        return FileSystems.getDefault().getPath(getPath(module, path)).toFile()
    }
    fun getFiles(module: String, path: String): Array<File> {
        checkExistence(module)
        val dir = FileSystems.getDefault().getPath(getPath(module, path)).toFile()
        if (!dir.isDirectory) {
            throw FileNotFoundException("The path is not a directory")
        }
        else {
            return dir.listFiles()
        }
    }



    object GameBlockLoader {
        val blockPath = "blocks/"

        @JvmStatic operator fun invoke(module: String) {
            BlockCodex(module, blockPath + "blocks.csv")
        }
    }

    object GameItemLoader {
        val itemPath = "items/"

        @JvmStatic operator fun invoke(module: String) {
            val csv = CSVFetcher.readFromModule(module, itemPath + "itemid.csv")
            csv.forEach {
                val filename = it["filename"].toString()
                val script = getFile(module, itemPath + filename).readText()
                val itemID = it["id"].toInt()

                groovyEngine.eval(script)
                ItemCodex[itemID] = groovyInvocable.invokeFunction("invoke", itemID) as GameItem
            }
        }
    }

    object GameLanguageLoader {
        val langPath = "locales/"

        @JvmStatic operator fun invoke(module: String) {
            Lang.load(getPath(module, langPath))
        }
    }
}