revancedpatches/src/main/kotlin/app/revanced/patches/duolingo/unlocksuper/UnlockDuolingoSuperPatch.kt

package app.revanced.patches.duolingo.unlocksuper

import app.revanced.extensions.exception
import app.revanced.patcher.data.BytecodeContext
import app.revanced.patcher.extensions.InstructionExtensions.getInstructions
import app.revanced.patcher.extensions.InstructionExtensions.replaceInstructions
import app.revanced.patcher.patch.BytecodePatch
import app.revanced.patcher.patch.PatchException
import app.revanced.patcher.patch.annotation.CompatiblePackage
import app.revanced.patcher.patch.annotation.Patch
import app.revanced.patcher.util.proxy.mutableTypes.MutableMethod
import app.revanced.patches.duolingo.unlocksuper.fingerprints.IsUserSuperMethodFingerprint
import app.revanced.patches.duolingo.unlocksuper.fingerprints.UserSerializationMethodFingerprint
import com.android.tools.smali.dexlib2.Opcode
import com.android.tools.smali.dexlib2.builder.instruction.BuilderInstruction22c
import com.android.tools.smali.dexlib2.iface.reference.Reference

@Patch(
    name = "Unlock Duolingo Super",
    compatiblePackages = [CompatiblePackage("com.duolingo")]
)
@Suppress("unused")
object UnlockDuolingoSuperPatch : BytecodePatch(
    setOf(
        UserSerializationMethodFingerprint,
        IsUserSuperMethodFingerprint
    )
) {
    /* First find the reference to the isUserSuper field, then patch the instruction that assigns it to false.
    * This strategy is used because the method that sets the isUserSuper field is difficult to fingerprint reliably.
    */
    override fun execute(context: BytecodeContext) {
        // Find the reference to the isUserSuper field.
        val isUserSuperReference = IsUserSuperMethodFingerprint
            .result
            ?.mutableMethod
            ?.getInstructions()
            ?.filterIsInstance<BuilderInstruction22c>()
            ?.firstOrNull { it.opcode == Opcode.IGET_BOOLEAN }
            ?.reference
            ?: throw IsUserSuperMethodFingerprint.exception

        // Patch the instruction that assigns isUserSuper to true.
        UserSerializationMethodFingerprint
            .result
            ?.mutableMethod
            ?.apply {
                replaceInstructions(
                    indexOfReference(isUserSuperReference) - 1,
                    "const/4 v2, 0x1"
                )
            }
            ?: throw UserSerializationMethodFingerprint.exception
    }

    private fun MutableMethod.indexOfReference(reference: Reference) = getInstructions()
        .filterIsInstance<BuilderInstruction22c>()
        .filter { it.opcode == Opcode.IPUT_BOOLEAN }.indexOfFirst { it.reference == reference }.let {
            if (it == -1) throw PatchException("Could not find index of instruction with supplied reference.")
            else it
        }
}