package org.jruby.runtime;

import com.headius.invokebinder.Binder;
import org.jruby.ir.IRScope;
import org.jruby.ir.runtime.IRRuntimeHelpers;
import org.jruby.parser.StaticScope;
import org.jruby.runtime.builtin.IRubyObject;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;

public class CompiledIRBlockBody extends IRBlockBody {
    protected final MethodHandle handle;
    protected final MethodHandle callHandle;
    protected final MethodHandle yieldDirectHandle;
    protected MethodHandle normalYieldHandle;
    protected MethodHandle normalYieldSpecificHandle;
    protected MethodHandle normalYieldUnwrapHandle;

    public CompiledIRBlockBody(MethodHandle handle, IRScope closure, long encodedSignature) {
        super(closure, Signature.decode(encodedSignature));
        // evalType copied (shared) on MixedModeIRBlockBody#completeBuild
        this.handle = handle;
        MethodHandle callHandle = MethodHandles.insertArguments(handle, 2, closure.getStaticScope(), null);
        // This is gross and should be done in IR rather than in the handles.
        this.callHandle = MethodHandles.foldArguments(callHandle, CHECK_ARITY);
        this.yieldDirectHandle = MethodHandles.insertArguments(
                MethodHandles.insertArguments(handle, 2, closure.getStaticScope()),
                4,
                Block.NULL_BLOCK);

        // Done in the interpreter (WrappedIRClosure) but we do it here
        closure.getStaticScope().determineModule();
    }

    private static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();

    private static final MethodHandle VALUE_TO_ARRAY = Binder.from(IRubyObject[].class, IRubyObject.class).invokeStaticQuiet(LOOKUP, IRRuntimeHelpers.class, "singleBlockArgToArray");

    private static final MethodHandle WRAP_VALUE = Binder.from(IRubyObject[].class, IRubyObject.class).invokeStaticQuiet(LOOKUP, CompiledIRBlockBody.class, "wrapValue");

    private static final MethodHandle CHECK_ARITY = Binder
            .from(void.class, ThreadContext.class, Block.class, IRubyObject[].class, Block.class)
            .invokeStaticQuiet(LOOKUP, CompiledIRBlockBody.class, "checkArity");

    private static void checkArity(ThreadContext context, Block selfBlock, IRubyObject[] args, Block block) {
        if (selfBlock.type == Block.Type.LAMBDA) {
            selfBlock.getSignature().checkArity(context.runtime, args);
        }
    }

    private static IRubyObject[] wrapValue(IRubyObject value) { return new IRubyObject[] {value}; }

    @Override
    public ArgumentDescriptor[] getArgumentDescriptors() {
        return closure.getArgumentDescriptors();
    }

    @Override
    public boolean canCallDirect() {
        return true;
    }

    public MethodHandle getCallHandle() {
        return callHandle;
    }

//    protected volatile MethodHandle yieldTwoValuesHandle;
//    protected volatile MethodHandle yieldThreeValuesHandle;
//
    public MethodHandle getNormalYieldSpecificHandle() {
        MethodHandle normalYieldSpecificHandle = this.normalYieldSpecificHandle;
        if (normalYieldSpecificHandle != null) return normalYieldSpecificHandle;

        return this.normalYieldSpecificHandle = Binder.from(IRubyObject.class, ThreadContext.class, Block.class)
                .append(new Class[] {StaticScope.class, IRubyObject.class, IRubyObject[].class, Block.class},
                        getStaticScope(), null, null, Block.NULL_BLOCK)
                .invoke(handle);
    }

    public MethodHandle getNormalYieldHandle() {
        MethodHandle normalYieldHandle = this.normalYieldHandle;
        if (normalYieldHandle != null) return normalYieldHandle;

        return this.normalYieldHandle = Binder.from(IRubyObject.class, ThreadContext.class, Block.class, IRubyObject.class)
                .filter(2, WRAP_VALUE)
                .insert(2, new Class[]{StaticScope.class, IRubyObject.class}, getStaticScope(), null)
                .append(Block.class, Block.NULL_BLOCK)
                .invoke(handle);
    }

    public MethodHandle getNormalYieldUnwrapHandle() {
        MethodHandle normalYieldUnwrapHandle = this.normalYieldUnwrapHandle;
        if (normalYieldUnwrapHandle != null) return normalYieldUnwrapHandle;

        return this.normalYieldUnwrapHandle = Binder.from(IRubyObject.class, ThreadContext.class, Block.class, IRubyObject.class)
                .filter(2, VALUE_TO_ARRAY)
                .insert(2, new Class[] {StaticScope.class, IRubyObject.class}, getStaticScope(), null)
                .append(Block.class, Block.NULL_BLOCK)
                .invoke(handle);
    }
//
//    public MethodHandle getYieldTwoValuesHandle() {
//        MethodHandle yieldTwoValuesHandle = this.yieldTwoValuesHandle;
//        if (yieldTwoValuesHandle != null) return yieldTwoValuesHandle;
//
//        return this.yieldTwoValuesHandle = Binder.from(IRubyObject.class, ThreadContext.class, Block.class, IRubyObject.class, IRubyObject.class)
//                .foldVoid(SET_NORMAL)
//                .fold(FOLD_METHOD1)
//                .fold(FOLD_TYPE1)
//                .collect(5, IRubyObject[].class)
//                .insert(5, new Class[] {StaticScope.class, IRubyObject.class},
//                        getStaticScope(), null)
//                .append(new Class[] {Block.class}, Block.NULL_BLOCK)
//                .permute(2, 3, 4, 5, 6, 7, 1, 0)
//                .invoke(handle);
//    }
//
//    public MethodHandle getYieldThreeValuesHandle() {
//        MethodHandle yieldThreeValuesHandle = this.yieldThreeValuesHandle;
//        if (yieldThreeValuesHandle != null) return yieldThreeValuesHandle;
//
//        return this.yieldThreeValuesHandle = Binder.from(IRubyObject.class, ThreadContext.class, Block.class, IRubyObject.class, IRubyObject.class, IRubyObject.class)
//                .foldVoid(SET_NORMAL)
//                .fold(FOLD_METHOD1)
//                .fold(FOLD_TYPE1)
//                .collect(5, IRubyObject[].class)
//                .insert(5, new Class[] {StaticScope.class, IRubyObject.class},
//                        getStaticScope(), null)
//                .append(new Class[] {Block.class}, Block.NULL_BLOCK)
//                .permute(2, 3, 4, 5, 6, 7, 1, 0)
//                .invoke(handle);
//    }

    @Override
    protected IRubyObject callDirect(ThreadContext context, Block block, IRubyObject[] args, Block blockArg) {
        try {
            return (IRubyObject) callHandle.invokeExact(context, block, args, blockArg);
        } catch (Throwable t) {
            Helpers.throwException(t);
            return null; // not reached
        }
    }

    @Override
    protected IRubyObject yieldDirect(ThreadContext context, Block block, IRubyObject[] args, IRubyObject self) {
        try {
            return (IRubyObject) yieldDirectHandle.invokeExact(context, block, self, args);
        } catch (Throwable t) {
            Helpers.throwException(t);
            return null; // not reached
        }
    }

    @Override
    protected IRubyObject commonYieldPath(ThreadContext context, Block block, Block.Type type, IRubyObject[] args, IRubyObject self, Block blockArg) {
        throw new UnsupportedOperationException("commonYieldPath not implemented");
    }

}
