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 * The Universal Permissive License (UPL), Version 1.0
 *
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
 * one is included with the Software each a "Larger Work" to which the Software
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
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 * This license is subject to the following condition:
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package org.graalvm.wasm.api;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.Truffle;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.interop.ArityException;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.interop.UnknownIdentifierException;
import com.oracle.truffle.api.interop.UnsupportedMessageException;
import com.oracle.truffle.api.interop.UnsupportedTypeException;
import com.oracle.truffle.api.library.ExportLibrary;
import com.oracle.truffle.api.library.ExportMessage;
import com.oracle.truffle.api.nodes.RootNode;
import org.graalvm.wasm.WasmContext;
import org.graalvm.wasm.WasmFunctionInstance;
import org.graalvm.wasm.WasmTable;
import org.graalvm.wasm.exception.Failure;
import org.graalvm.wasm.exception.WasmException;
import org.graalvm.wasm.exception.WasmJsApiException;

@ExportLibrary(InteropLibrary.class)
public class Table extends Dictionary {
    private final TableDescriptor descriptor;
    private final WasmTable table;

    public Table(WasmTable table) {
        this.descriptor = new TableDescriptor(TableKind.anyfunc.name(), table.size(), table.maxSize());
        this.table = table;
        addMembers(new Object[]{
                        "descriptor", this.descriptor,
                        "grow", new Executable(args -> grow((Integer) args[0])),
                        "get", new Executable(args -> get((Integer) args[0])),
                        "set", new Executable(args -> set((Integer) args[0], args[1])),
        });
    }

    public Table(Object descriptor) {
        this(new WasmTable(initial(descriptor), maximum(descriptor)));
    }

    @SuppressWarnings({"unused", "static-method"})
    @ExportMessage
    @Override
    public boolean isMemberReadable(String member) {
        return member.equals("length") || super.isMemberReadable(member);
    }

    @SuppressWarnings({"unused"})
    @ExportMessage
    @Override
    public Object readMember(String member) throws UnknownIdentifierException {
        if (member.equals("length")) {
            return table.size();
        } else {
            return super.readMember(member);
        }
    }

    private static int initial(Object descriptor) {
        try {
            return (Integer) InteropLibrary.getUncached().readMember(descriptor, "initial");
        } catch (UnsupportedMessageException | UnknownIdentifierException e) {
            throw new WasmJsApiException(WasmJsApiException.Kind.TypeError, "Invalid memory descriptor " + descriptor);
        }
    }

    private static int maximum(Object descriptor) {
        try {
            return (Integer) InteropLibrary.getUncached().readMember(descriptor, "maximum");
        } catch (UnsupportedMessageException | UnknownIdentifierException e) {
            throw new WasmJsApiException(WasmJsApiException.Kind.TypeError, "Invalid memory descriptor " + descriptor);
        }
    }

    @TruffleBoundary
    private static WasmException rangeError() {
        return WasmException.create(Failure.UNSPECIFIED_INTERNAL, "Range error.");
    }

    public WasmTable wasmTable() {
        return table;
    }

    public TableDescriptor descriptor() {
        return descriptor;
    }

    public int grow(int delta) {
        final int size = table.size();
        if (!table.grow(delta)) {
            throw rangeError();
        }
        return size;
    }

    public Object get(int index) {
        if (index >= table.size()) {
            throw rangeError();
        }
        final Object function = table.get(index);
        return function;
    }

    public Object set(int index, Object element) {
        if (index >= table.size()) {
            throw rangeError();
        }
        table.set(index, new WasmFunctionInstance(null, Truffle.getRuntime().createCallTarget(new RootNode(WasmContext.getCurrent().language()) {

            @Override
            public Object execute(VirtualFrame frame) {
                if (InteropLibrary.getUncached().isExecutable(element)) {
                    try {
                        return InteropLibrary.getUncached().execute(element, frame.getArguments());
                    } catch (UnsupportedTypeException e) {
                        throw WasmException.format(Failure.UNSPECIFIED_TRAP, "Table element %s has an unsupported type.", element);
                    } catch (ArityException e) {
                        throw WasmException.format(Failure.UNSPECIFIED_TRAP, "Table element %s has unexpected arity.", element);
                    } catch (UnsupportedMessageException e) {
                        throw WasmException.format(Failure.UNSPECIFIED_TRAP, "Table element %s is not executable.", element);
                    }
                } else {
                    throw WasmException.format(Failure.UNSPECIFIED_TRAP, "Table element %s is not executable.", element);
                }
            }
        })));
        return null;
    }

}