/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Other licenses:
 * -----------------------------------------------------------------------------
 * Commercial licenses for this work are available. These replace the above
 * ASL 2.0 and offer limited warranties, support, maintenance, and commercial
 * database integrations.
 *
 * For more information, please visit: http://www.jooq.org/licenses
 *
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 */
package org.jooq.checker;

import static com.sun.source.util.TreePath.getPath;
import static java.util.Arrays.asList;
import static org.checkerframework.javacutil.TreeUtils.elementFromDeclaration;
import static org.checkerframework.javacutil.TreeUtils.elementFromUse;
import static org.checkerframework.javacutil.TreeUtils.enclosingMethod;

import java.io.PrintWriter;
import java.util.EnumSet;

import javax.lang.model.element.Element;
import javax.lang.model.element.ExecutableElement;

import org.jooq.Allow;
import org.jooq.Require;
import org.jooq.SQLDialect;
import org.jooq.Support;

import org.checkerframework.framework.source.SourceVisitor;

import com.sun.source.tree.MethodInvocationTree;

/**
 * A checker to compare {@link SQLDialect} from a use-site {@link Require}
 * annotation with a declaration-site {@link Support} annotation.
 *
 * @author Lukas Eder
 */
public class SQLDialectChecker extends AbstractChecker {

    @Override
    protected SourceVisitor<Void, Void> createSourceVisitor() {
        return new SourceVisitor<Void, Void>(getChecker()) {

            @Override
            public Void visitMethodInvocation(MethodInvocationTree node, Void p) {
                try {
                    ExecutableElement elementFromUse = elementFromUse(node);
                    Support support = elementFromUse.getAnnotation(Support.class);

                    // In the absence of a @Support annotation, or if no SQLDialect is supplied,
                    // all jOOQ API method calls will type check.
                    if (support != null && support.value().length > 0) {
                        Element enclosing = elementFromDeclaration(enclosingMethod(getPath(root, node)));

                        EnumSet<SQLDialect> supported = EnumSet.copyOf(asList(support.value()));
                        EnumSet<SQLDialect> allowed = EnumSet.noneOf(SQLDialect.class);
                        EnumSet<SQLDialect> required = EnumSet.noneOf(SQLDialect.class);

                        boolean evaluateRequire = true;
                        while (enclosing != null) {
                            Allow allow = enclosing.getAnnotation(Allow.class);

                            if (allow != null)
                                allowed.addAll(asList(allow.value()));

                            if (evaluateRequire) {
                                Require require = enclosing.getAnnotation(Require.class);

                                if (require != null) {
                                    evaluateRequire = false;

                                    required.clear();
                                    required.addAll(asList(require.value()));
                                }
                            }

                            enclosing = enclosing.getEnclosingElement();
                        }

                        if (allowed.isEmpty())
                            error(node, "No jOOQ API usage is allowed at current scope. Use @Allow.");

                        if (required.isEmpty())
                            error(node, "No jOOQ API usage is allowed at current scope due to conflicting @Require specification.");

                        boolean allowedFail = true;
                        allowedLoop:
                        for (SQLDialect a : allowed) {
                            for (SQLDialect s : supported) {
                                if (a.supports(s)) {
                                    allowedFail = false;
                                    break allowedLoop;
                                }
                            }
                        }

                        if (allowedFail)
                            error(node, "The allowed dialects in scope " + allowed + " do not include any of the supported dialects: " + supported);

                        boolean requiredFail = false;
                        requiredLoop:
                        for (SQLDialect r : required) {
                            for (SQLDialect s : supported)
                                if (r.supports(s))
                                    continue requiredLoop;

                            requiredFail = true;
                            break requiredLoop;
                        }

                        if (requiredFail)
                            error(node, "Not all of the required dialects " + required + " from the current scope are supported " + supported);
                    }
                }
                catch (final Exception e) {
                    print(new Printer() {
                        @Override
                        public void print(PrintWriter t) {
                            e.printStackTrace(t);
                        }
                    });
                }

                return super.visitMethodInvocation(node, p);
            }
        };
    }
}