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package com.oracle.graal.python.runtime.interop;

import com.oracle.graal.python.PythonLanguage;
import com.oracle.graal.python.builtins.objects.dict.PDict;
import com.oracle.graal.python.builtins.objects.function.PArguments;
import com.oracle.graal.python.builtins.objects.object.PythonObject;
import com.oracle.truffle.api.TruffleLanguage;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Cached.Shared;
import com.oracle.truffle.api.frame.Frame;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.interop.TruffleObject;
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.CachedLibrary;
import com.oracle.truffle.api.library.ExportLibrary;
import com.oracle.truffle.api.library.ExportMessage;
import com.oracle.truffle.api.nodes.Node;
import com.oracle.truffle.api.nodes.RootNode;
import com.oracle.truffle.api.profiles.IntValueProfile;
import com.oracle.truffle.api.source.SourceSection;

@ExportLibrary(InteropLibrary.class)
public final class PythonScopes implements TruffleObject {

    static final int LIMIT = 2;

    public final Object[] scopes;
    private final int scopeIndex;

    public PythonScopes(Object[] scopes, int scopeIndex) {
        this.scopes = scopes;
        this.scopeIndex = scopeIndex;
    }

    private static InteropMap scopeFromObject(PythonObject globals) {
        if (globals instanceof PDict) {
            return InteropMap.fromPDict((PDict) globals);
        } else {
            return InteropMap.fromPythonObject(globals);
        }
    }

    public static Object create(Node node, Frame frame) {
        RootNode root = node.getRootNode();
        PythonLocalScope localScope = PythonLocalScope.createLocalScope(root, frame);
        Object[] scopes;
        if (frame != null) {
            PythonObject globals = PArguments.getGlobalsSafe(frame);
            Frame generatorFrame = PArguments.getGeneratorFrameSafe(frame);
            Object globalsScope = null;
            if (globals != null) {
                globalsScope = new PythonMapScope(new Object[]{scopeFromObject(globals)}, new String[]{"globals()"});
            }
            if (globals != null && generatorFrame != null) {
                scopes = new Object[]{localScope, globalsScope, PythonLocalScope.createLocalScope(root, generatorFrame)};
            } else if (globals != null) {
                scopes = new Object[]{localScope, globalsScope};
            } else if (generatorFrame != null) {
                scopes = new Object[]{localScope, PythonLocalScope.createLocalScope(root, generatorFrame)};
            } else {
                return localScope;
            }
        } else {
            return localScope;
        }
        return new PythonScopes(scopes, 0);
    }

    @ExportMessage
    @SuppressWarnings("static-method")
    boolean isScope() {
        return true;
    }

    @ExportMessage
    boolean hasScopeParent() {
        return scopeIndex < (scopes.length - 1);
    }

    @ExportMessage
    Object getScopeParent() throws UnsupportedMessageException {
        if (scopeIndex < (scopes.length - 1)) {
            return new PythonScopes(scopes, scopeIndex + 1);
        } else {
            throw UnsupportedMessageException.create();
        }
    }

    @ExportMessage
    public boolean hasSourceLocation(
                    @CachedLibrary(limit = "1") InteropLibrary lib) {
        return lib.hasSourceLocation(scopes[scopeIndex]);
    }

    @ExportMessage
    public SourceSection getSourceLocation(
                    @CachedLibrary(limit = "1") InteropLibrary lib) throws UnsupportedMessageException {
        return lib.getSourceLocation(scopes[scopeIndex]);
    }

    @ExportMessage
    @SuppressWarnings("static-method")
    boolean hasLanguage() {
        return true;
    }

    @ExportMessage
    @SuppressWarnings("static-method")
    Class<? extends TruffleLanguage<?>> getLanguage() {
        return PythonLanguage.class;
    }

    @ExportMessage
    boolean hasMembers(@Shared("interop") @CachedLibrary(limit = "LIMIT") InteropLibrary interop,
                    @Shared("lenghtProfile") @Cached("createIdentityProfile()") IntValueProfile lengthProfile) {
        int length = lengthProfile.profile(scopes.length);
        for (int i = scopeIndex; i < length; i++) {
            Object vars = this.scopes[i];
            if (interop.hasMembers(vars)) {
                return true;
            }
        }
        return false;
    }

    @ExportMessage
    Object getMembers(@SuppressWarnings("unused") boolean includeInternal,
                    @Shared("interop") @CachedLibrary(limit = "LIMIT") InteropLibrary interop,
                    @Shared("lenghtProfile") @Cached("createIdentityProfile()") IntValueProfile lengthProfile) throws UnsupportedMessageException {
        int length = lengthProfile.profile(scopes.length);
        Object[] keys = new Object[length - scopeIndex];
        for (int i = scopeIndex; i < length; i++) {
            keys[i - scopeIndex] = interop.getMembers(scopes[i]);
        }
        return new MergedPropertyNames(keys);
    }

    @ExportMessage
    boolean isMemberReadable(String member,
                    @Shared("interop") @CachedLibrary(limit = "LIMIT") InteropLibrary interop,
                    @Shared("lenghtProfile") @Cached("createIdentityProfile()") IntValueProfile lengthProfile) {
        int length = lengthProfile.profile(scopes.length);
        for (int i = scopeIndex; i < length; i++) {
            Object scope = this.scopes[i];
            if (interop.isMemberReadable(scope, member)) {
                return true;
            } else if (interop.isMemberExisting(scope, member)) {
                break;
            }
        }
        return false;
    }

    @ExportMessage
    Object readMember(String member,
                    @Shared("interop") @CachedLibrary(limit = "LIMIT") InteropLibrary interop,
                    @Shared("lenghtProfile") @Cached("createIdentityProfile()") IntValueProfile lengthProfile) throws UnknownIdentifierException, UnsupportedMessageException {
        int length = lengthProfile.profile(scopes.length);
        for (int i = scopeIndex; i < length; i++) {
            Object scope = this.scopes[i];
            if (interop.isMemberExisting(scope, member)) {
                return interop.readMember(scope, member);
            }
        }
        throw UnknownIdentifierException.create(member);
    }

    @ExportMessage
    void writeMember(String member, Object value,
                    @Shared("interop") @CachedLibrary(limit = "LIMIT") InteropLibrary interop,
                    @Shared("lenghtProfile") @Cached("createIdentityProfile()") IntValueProfile lengthProfile)
                    throws UnknownIdentifierException, UnsupportedMessageException, UnsupportedTypeException {
        int length = lengthProfile.profile(scopes.length);
        for (int i = scopeIndex; i < length; i++) {
            Object scope = this.scopes[i];
            if (interop.isMemberExisting(scope, member)) {
                interop.writeMember(scope, member, value);
                return;
            }
        }
        throw UnknownIdentifierException.create(member);
    }

    @ExportMessage
    boolean isMemberModifiable(String member,
                    @Shared("interop") @CachedLibrary(limit = "LIMIT") InteropLibrary interop,
                    @Shared("lenghtProfile") @Cached("createIdentityProfile()") IntValueProfile lengthProfile) {
        int length = lengthProfile.profile(scopes.length);
        for (int i = scopeIndex; i < length; i++) {
            Object scope = this.scopes[i];
            if (interop.isMemberModifiable(scope, member)) {
                return true;
            } else if (interop.isMemberExisting(scope, member)) {
                break;
            }
        }
        return false;
    }

    @ExportMessage
    boolean isMemberInsertable(String member,
                    @Shared("interop") @CachedLibrary(limit = "LIMIT") InteropLibrary interop,
                    @Shared("lenghtProfile") @Cached("createIdentityProfile()") IntValueProfile lengthProfile) {
        int length = lengthProfile.profile(scopes.length);
        boolean wasInsertable = false;
        for (int i = scopeIndex; i < length; i++) {
            Object scope = this.scopes[i];
            if (interop.isMemberExisting(scope, member)) {
                return false;
            }
            if (interop.isMemberInsertable(scope, member)) {
                wasInsertable = true;
            }
        }
        return wasInsertable;
    }

    @ExportMessage
    Object toDisplayString(@SuppressWarnings("unused") boolean allowSideEffects,
                    @CachedLibrary(limit = "1") InteropLibrary lib) {
        return lib.toDisplayString(scopes[scopeIndex]);
    }
}
