package dev.openrs2.asm.io

import dev.openrs2.asm.classpath.JsrInliner
import dev.openrs2.asm.classpath.Library
import org.objectweb.asm.ClassReader
import org.objectweb.asm.tree.ClassNode
import java.util.jar.JarEntry
import java.util.jar.JarInputStream

class JarLibraryReader(private val input: JarInputStream) : LibraryReader {

    override fun read(): Library {
        val classes = generateSequence { input.nextJarEntry }
            .filter(::isClass)
            .map { input.readClass() }
            .associateBy(ClassNode::name)

        return Library(classes)
    }

    private fun isClass(entry: JarEntry): Boolean {
        return entry.name.endsWith(CLASS_SUFFIX)
    }

    private fun JarInputStream.readClass(): ClassNode {
        val clazz = ClassNode()
        val reader = ClassReader(this)
        reader.accept(JsrInliner(clazz), ClassReader.SKIP_DEBUG or ClassReader.SKIP_FRAMES)
        return clazz
    }

    private companion object {
        private const val CLASS_SUFFIX = ".class"
    }
}